THE MAGAZINE OF THEBRITISH ELECTRIC

FLIGHT ASSOCIATION

ELECTRIC FLIGHT U.K.

ISSUE No. 83 WINTER 2005

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E.F.-U.K. 3

Electric Flight - U.K. Issue 83 - Winter 2005

"To Encourage and Further all Aspects of Electric Model Flight inthe British Isles and Elsewhere" - B.E.F.A. Constitution

CONTENTS

NEXT ISSUE. The copy date for the Spring 2006 issue is 28 February 2006, withthe magazine due for publication by 31 March 2006.

Cover Photo: The cover photo is the Editor’s Scorpio threedee. It is powered bya Typhoon 15 brushless motor, a Hacker Master 30-3P brushless controller and3S1P Kokam 15C 2000mAh cells. It is fitted with a Ramoser Technik & DesignVarioPROP 2-blade hub with 9.7" Scale-Optic blades, set at approx. 5" pitch. Thissetup gives a static power to weight ratio of almost 1.5:1 so vertical climbs areeffortless, even after a 10 minutes of aerobatics.

DISCLAIMERB.E.F.A. and Electric Flight U.K. wish to point out that the content, techniques and opinionsexpressed in this magazine are those of the individual authors and do not necessarily represent theviews of either the Editor of this magazine or B.E.F.A. and its committee.© All information in this magazine is copyright of the authors. Any request to use informationfrom this magazine is to be made to the editor (contact details overleaf).All reasonable care is taken in the preparation and compilation of the magazine, but B.E.F.A. andits committee cannot be held liable for any error or omission in the content of this magazine or anysubsequent damage or loss arising howsoever caused.To allow proper appreciation of the photographs used, colour copies of them will be posted on theB.E.F.A. website after publication of this magazine. If you can, check them out at www.befa.org.uk

BEFA Committee 2005/6 ........................... 4Chairman's Chatter .................................. 5Current Lines ........................................... 5BEFA AGM 2006 ...................................... 6Letter to the Editor .................................... 9New-2-U ..................................................25TLC from your TLO ................................. 31Readers’ Models ....................................... 37The Electrifly PolyCharge4 ....................... 42Fixing Günther Propellers ........................44

Wings & Wheels Model Spectacular .......... 47NEAT Fair 2005 ......................................48Perkins ARTF Tiger Moth ........................57A Smarter Dart ....................................... 61Intermodellbau 2005 ................................67Event Calendar ....................................... 72For Sale / Wanted ....................................75New to Electric Flight? Start Here ............77BEFA Sales ............................................. 78Advertisers Index .....................................78

4 E.F.-U.K.

BEFA Committee 2005/6Chairman Robert Mahoney

123 Lane End Road, High Wycombe, Bucks. HP12 4HFEMail: befa@rlmahoney.co.uk

Secretary Peter Turner37 Church Street, Horsley, Derbyshire. DE21 5BQTel: 01332 881 265, Email: peter@alport.fsnet.co.uk

Membership Secretary Bob Smith1 Lynwood Avenue, Tollesby, Middlesborough, Cleveland. TS5 7PDEmail: bob.smith007@ntlworld.com

Treasurer Bob Smith, details as Membership Secretary

EF-UK Editor Jan Bassett111 Plantagenet Chase, Yeovil, Somerset. BA20 2PRTel. 01935 472743, E-mail: editor@befa.org.uk

Events Co-ordinator Terry Stuckey31 Dysart Avenue, Kingston-upon-Thames, Surrey. KT2 5QZEmail: terrystuckey@blueyonder.co.uk

Competition Secretary Bob West51 Haweswater, Huntingdon, Cambs., PE29 6TWTel. 07970 238 704, Email: robertj.west@tesco.net

Midlands Representative Roger Winsor14 Butler Gardens, Market Harborough, Leics. LE16 9LYEmail: Rogerwinsor7@aol.com

Northern Representative Bob Smith, details as Membership Secretary

Southern Representative Dave Chinery251 Station Road, Hayes, Middx. UB3 4JDEmail: DavidDchinery@aol.com

South West Representative Jan Bassett, details as Editor EF-UK

Indoor & Free-Flight Rep. Gordon Tarling87 Cowley Mill Road, Uxbridge, Middx. UB8 2QDEmail: gordon.tarling@ntlworld.com

Technical Liaison Officer Alan Bedingham17 Highcliffe Close, Wickford, Essex. SS11 8JZEmail: bbba18333@blueyonder.co.uk

Public Relations Officer John Thompson19 Park Avenue, Liversedge, West Yorks, WF15 7EQTel. 01924 515 595, Email: johnty99@ntlworld.com

Webmaster Jan Bassett, details as Editor EF-UK - (www.befa.org.uk)

Safety Adviser David Beacor34 Chestnut Close, Brampton, Huntingdon, Cambs., PE28 4TP.

Please enclose an SAE with all correspondence to the committee.

E.F.-U.K. 5

Chairman’s ChatterDear members,Welcome to autumn 2005 issue of your association's quarterly magazine.For once I can give you some good news! Lieutenant Colonel (Retired) R J Thayerhas graciously given his consent for us to hold our annual Middle Wallop eventwith the normal conditions regarding the operations of our model aircraft.So open your diary at the 1st & 2nd of July 2006 and reserve that weekend for theBEFA Middle Wallop Electric weekend.If you or your club is going to hold an electric flight event please let Jan Bassettand myself have the information to put in this magazine and on the websites! Ican see the 2006 being very busy with electric flight events. It will pay to get yourdates in quickly to ensure you are first on any given day.In would like to wish you all seasons greetings and a prosperous New Year

KEEP THE WATTS UP!Robert Mahoney

Current Linesfrom the Editor

Thanks again to all the contributors to this issue, you really make my life easier.I do request that articles are sent electronically if at all possible as it saves meretyping something that has normally been type once before.Unusually I managed to hold a couple of articles over to the next issue, but thatstill leaves most of the magazine to fill. My plea for articles and model informationis therefore just as urgent, please submit something.This is my penultimate issue as Editor. We have a volunteer to take over themagazine who is suitably experienced and keen. However, I may notdisappear completely from the pages of this publication as some fear(or was it cheer!). I will offer my services to the new Editor incommenting on articles if my services are a benefit.I also plan to spend some of my freed time in building a number ofmodels that have been part started, sit in boxes on the top ofcupboards or are just in my mind. I will be submitting articleson these projects, why don’t you do the same.All the best for the festive period and 2006.Regards

Jan

6 E.F.-U.K.

2006 Annual General Meetingto be held at 2.00 pm on

6th March 2006at the

Royal Spa Centre, Royal Leamington Spa, Warks.

with Traders’ Fair from 9:30amAccess will be allowed for the depositing of items for the Bring & Buy stand from9.00 am. It is requested that anyone bringing items to sell on the Bring & Buystand complete the form (or a copy of it) overleaf before arriving. The is alsoavailable from the event page of the BEFA website (www.befa.org.uk). It isessential that all items are listed on the form and that all items are labelled witha minimum of the sellers’ name and the price asked. The Bring & Buy stand willstop trading at 1.00 pm to allow things to be cleared up before the AGM starts.The main doors will open for access to the Bring & Buy and Traders’ Fair at 9.30am. An admission fee of £3 will be charged for access to the Bring & Buy andTraders’ Fair, being payable on the door.Free access will be allowed to members after 1.30 pm so they can attend theAnnual General Meeting, which will commence at 2.00 pm in the Lecture TheatreAGM Agenda

Minutes of the last AGMMatters arising.Annual Reports from the Chairman, Secretary & Membership Secretary.Treasurers statements and review of the Statement of FundsAgree the Annual Subscription for 2005/6Appoint the Financial Auditor for 2005/6Election of Committee Officers -

SecretaryMembership SecretaryEditorEvents Co-ordinatorFree Flight and Indoor Representative

Proposals: The Committee has proposed one resolutions (see facing page).Nominations for the Committee positions due for re-election must be received inwriting by the Secretary (see page 4 for address) at least 15 days before the AGM.

E.F.-U.K. 7

The following change to the BEFA Constitution is proposed by theCommittee for acceptance at the 2006 A.G.M.

Clause 7 – Existing wording

7) Election of the Committee.

The officers of the Committee will be elected at the Annual General Meetingof the Association. Persons nominated for election must confirm in writingthat they are prepared to serve if elected and must be proposed and secondedby paid up members. Nominations must be received by the Secretary atleast fifteen days before the date of the A.G.M. In the event of insufficientnominations being received to fill all positions on the Committee, the electedmembers of the Committee will have the power to co-opt any eligible memberwho is prepared to serve.

The problem with this system is that it is very cumbersome and tends to discouragenominations. This is particularly true in that we cannot accept nominations fromthe floor at our AGM which is the one occasion when we might expect to findvolunteers. Under our present rules we can only co-opt such volunteers for a yearprior to their nomination at the following AGM which also puts their election outof phase with our biannual pattern.

We would like to simplify this procedure such that we can also accept nominationsfrom the floor of the AGM to fill vacancies (supported by a proposer and seconder)and that if successful, such nominees could begin to serve on the committeeimmediately.

The Committee therefore proposes that clause 7) be modified as follows:-

7) Election of the Committee.

The officers of the Committee will be elected at the Annual General Meetingof the Association. The Secretary should normally receive nominations atleast fifteen days before the date of the A.G.M. Persons nominated forelection in this way must confirm in writing that they are prepared to serveif elected and must be proposed and seconded by paid up members.

In the event of insufficient advance nominations being received to fill allpositions on the Committee, the committee may appeal for nominations forthese unfilled positions from the floor. Provided such nominees are proposedand seconded by paid-up members, and are present at the meeting to acceptnomination, then they may also be elected by majority vote of the memberspresent.

Should this procedure still fail to fill the vacancies the elected members ofthe Committee will have the power to co-opt any eligible member who isprepared to serve.

8 E.F.-U.K.

E.F.-U.K. 9

Letters to the EditorFirstly a letter from John Bunting (aj.bunting@btopenworld.com) about ScaleSpeed, following on from my comments to last issues TLC from your TLO article.

I'd like to discuss scale speed, and in particular Bob Boucher's article on theAstroflight website, to which you refer in EF-UK 82. I'm perfectly happy tobe shot down if I'm wrong, but I'm not convinced by the idea that the modelspeed should be derived by multiplying the full-size speed by the square rootof the scale.Let's take a one-ninth scale Spitfire as an example. The full-size span is 36feet, and typical speed 300 mph. The square root of one-ninth is one-third, sothe speed of the 4-foot span model, according to Bob, should be 100 mph. Atthis point I begin to have doubts, which grow stronger when he talks about'Scale Time', and says in the section headed 'Scale Size Loops' that the squareroot factor applies here as well, so the model should do a loop in one third ofthe time taken by the real aircraft.Now, suppose you have a video of a real Spitfire doing aerobatics. You watchit several times, and you have a good idea, possibly assisted by a clock displayin the corner of the screen, of how long it takes for the machine to do variousmanoeuvres. For instance, you may notice that it typically takes about tenseconds to do a loop.Then someone shows you another video, also of a Spitfire. For the first fewseconds the machine is in steady flight, with a clear sky background, and youmight easily think it's a real aircraft. But then it starts doing aerobatics, andthe illusion is shattered, because it does a loop, not in ten seconds, but inabout three seconds, so you know immediately that it must be a model. Somuch for realism.To crown it all, Bob tells us, "These very high power military aircraft are verydifficult to model at scale speed". Well, I'm not surprised, if you think thescale speed for a one-tenth scale P-51 should be 135 mph.My conclusion is that this square-root-of-the-scale idea is misconceived. Forrealism in flight, I think the speed should vary directly as the scale. In otherwords, the real aircraft and the model should each take the same time tocover a distance equal to their own length; in which case our one-ninth scaleSpitfire would fly at about 33 mph, and would do a loop in ten seconds. Notalways easy to achieve in practice perhaps, but that's another matter.

John raises a very interesting point in his letter and I’m sure it has merit. However,I’d like to consider the issue in more detail. I’m not sure about the 300 mph speedthat John gives as typical. For completeness I’m going to compare the figures forstall, manoeuvre and maximum speeds (in mph) for a Spitfire.

10 E.F.-U.K.

Spitfire IX Boucher (1/3) Bunting (1/9)Stall Speed 70 23.3 7.8Manoeuvre Speed 215 71.7 23.9Maximum Speed 408 136.0 45.3The Balsacraft Spitfire Mk IX is 1/9th scale and will be used to test the figuresabove. A typically flying weight for the Balsacraft Spitfire with a Graupner Speed600 Race 8.4v motor and 8 RC-2400 cells is 1.6 kg (3lb. 8oz.). This is a 14 oz.below the Bob Boucher weight of 4 lb. 6 oz.For this weight ElectriCalc estimates a stall speed of 17 mph. The Bob Boucherfigure is reasonably close and will be achieved. The figure using the scheme thatJohn proposes (7.8 mph) is not achievable unless the model weighs only about300g (~11 oz.). Even if this low speed could be achieved, I don’t think that aSpitfire would look credible at only twice walking pace. Certainly when it comesto stall speed, I have to side with Bob Boucher.It must be remembered that Bob Boucher says that the weight and power shouldbe reduced to one half of the calculated values for high power aircraft. This reductionin power will inevitably mean that scale speeds will not be achieved. The 50% lossof power will mean a speed reduction of around 25% at maximum power.Another important factor at the upper speeds is that it is extremely rare for amodel to have a variable pitch propeller. This means we have to compromise onpropeller selection to get acceptable performance for take-off and climb out.Applying the 25% reduction to the maximum speed from Bob Boucher’s systemgives a speed of 102 mph. This speed is still excessive and couldn’t be achievedwith the 266W (at the propeller) available at half scale power. Using this power,it is probably realistic to expect 65 mph allowing for the scale lines.I am fortunate to see the Royal Navy Historic Flight Hawker Sea Fury FB11 flyregularly at RNAS Yeovilton. When you see this superb war bird hammer acrossthe sky at around 450 mph it is an amazing sight (and sound). It is surprisinghow much sky an aircraft covers at these speeds, at a scale distance you could getwhiplash. Because of that I think that John’s maximum speed of 45 mph is justtoo low, the model would appear very slow.I have to agree with John about the times to complete aerobatic manoeuvres, butit is a tricky problem. I think it important that the Manoeuvre Speed is consideredhere as this is typically the limiting speed for such antics. The Manoeuvre Speedusing John’s recommendation is 23.9 mph, which would make it almost impossibleto complete a loop. Again Bob Boucher’s speed is unreasonably high and would notbe achievable.The solution is probably to fly at an intermediate speed and to enlarge the diameterof the loop slightly. You may not get to 10 seconds, but it will look better.

E.F.-U.K. 11

Next is a series of letters / emails from Peter Vivian following on from his article“Some LiPo Experiments” in the last issue. I’m sure there are a lot of readers thatare unsure about LiPo cells and balancers, so it is worth printing the whole history.

I was interested to see that you published my LiPo experiments - as you say,you are short of offers!Seriously, one of the most important aspects of your efforts and contributionsto the BEFA is that you make comments upon articles you publish, commentsbased upon knowledge and, more importantly, experience. This is importantbecause it encourages articles which might seem pretty basic to some but canhave serious input to even the "experts" when your comments are added. SoI am afraid your plan to retire is not welcome.To get to my article, firstly I may have given a slightly incorrect impression- I am not totally new to electrics, just electric flight. In fact I am (or was) anelectro-chemist and at one time I actually designed and made batteries! Sea-water activated, ever heard of them? Think of the problems of series-connectedopen cells in a common electrolyte, the sea! So Ohms Law etc are not exactlyegghead science to me.But to your comments in that article. Firstly, no I did not actually charge at1C. I gave the charger, a Mercury EX as I said, all the details it requested -type of cell, capacity, charge rate (1C) etc and the charger decided what toactually do when I switched it in. It started quite quickly to charge at 1C butthen the current dropped off pretty rapidly towards about half that figureand carried on down. So recharging was in fact a long process. Now eitherI could assume the charger knows best or override the charger or buy a newcharger. You imply the latter, I prefer the former because then I do not blowbatteries up but others do! But if you know of a safe charger which will give afairly level charge rate to a LiPo cell, much as my EX does to a NiMH orNiCd, please tell me.As for balancing leads, firstly my LiPo do not have them, I had to do that.But then, connection to a connector is space & weight when you think of thecurrent-carrying capacity needed by wires and connector. And I am suspiciousof "balancing chargers". How many people actually bother to do what I did -after some use and final charge disconnect all cells and check the after-chargevoltage of each individual cell. I think most people believe what they are told.If they checked they may be a bit disenchanted - or wreck the battery!Finally, you compare 5S2P Kokam with 18S GP3700. Surely more exactlythis should be 6S2P Kokam? (6 x 4.1 = 24.6, 18 x 1.35 = 24.3 OR 6 x 3.7 =22.2, 18 x 1.2 = 21.6) But anyway, is there a charger which can charge at thatvoltage? You also say that LiPo will charge in 90 minutes. Well, that was amajor point of my article, I found that they will not equally charge in thattime (or any other time) if connected up in series. The same amount of

12 E.F.-U.K.

current passes through each (Kirchoffs Law) but because the voltage drop isdifferent across each cell the wattage per cell is different. Yes, in parallelprobably but my results show that 5S (or 6S) charging is not acceptable aftera time, the cells go too far out of balance. And they do so for exactly thereason you say, different internal resistances which are exacerbated by repeatedcharging. So, LiPo or NiMH? High cost, low weight, long charge time (inreality) versus lower cost, higher weight, shorter charge time. I have theimpression that you favour LiPo - or have I got that wrong?Anyway, please keep up the good work. And incidentally, another of yourcontributors to the same issue, Nick Fitton, rang me and we met up at asuitable hostelry. We had a very interesting couple of hours during which hestrongly advocated Motocalc when trying to convert an IC to electric. I havedownloaded it but I am not too sure yet - but of course not sufficientlyexperienced with it probably. Any comments?

Do I have any comments, it would be surprising if I didn’tI thought your article was extremely useful as it allowed the explanation of anumber of issues.I appreciate what you say about the worth of my comments, but I've spentthousands of hours doing the magazine over the last 5 years and now I want todo some more hands-on modelling. I've a number of projects I want to do butcan't find the time whilst editing the magazine and working full time. I amnot adverse to helping out the new editor and may still be making commentsonce the new editor has taken up post.I know a little about immersion batteries, salt and fresh water - they are usedin a number of military projects that I am, and have been, involved in. It isalways difficult to know at what level to pitch information, but there is alwayssomeone out there without the basic knowledge.From what you say it seems that the Mercury charger is extremely cautiousin charging LiPo cells. My Schulze chamelëon isl6-330d & isl6-430d chargerswill both complete a 1C charge in around 90 minutes, whilst still following thecharge guidelines.My isl6-430d charger alsohas a RS-232 output,which allows connectionto a PC to monitor or plotthe (dis)charge. I'veattached the graph froma charge conducted todayon my Kokam 2000mAh15C 3S pack, which isstarting to loose capacity.

E.F.-U.K. 13

Both these Schulze chargers can charge up to 11 LiPo cells and at currents upto 5A where the pack allows. I am rapidly starting to think that a balancer orbalancing charger is advisable for every charge. These limit the voltage acrosseach cell to a maximum of 4.2V. The excess power is dumped by the balancercircuit so that the cell itself isn't passing the full charging current. Therebyeach cell can charge to full capacity unaffected by the other cells. With externalbalancers connected I would have no qualms about charging an 11S pack withthe Schulze chargers.I am looking around at different balancers and balancing chargers and maywell put an article in the next issue on them. To use a balancing charger nodisconnection of cells is required provide the pack was wired for balancing inthe 1st place. All recent packs seem to have balancing leads, which means thecells must be paralleled and then connected in series. Unfortunately there isno standard balancing connector, which means that adapter lead need to beused for most packs.You are quite correct, I must have hit a 5 instead of a 6 and the spell checkerwont spot that.I tend to prefer ElectriCalc to MotoCalc as the results are immediate. Bychanging the equipment or settings you can see the effects immediately. I doalso use MotoCalc, but it takes a little more getting used to and I find it moretime consuming.

Peter Vivian the responded with a follow-up message:Thank you, that charging graph is interesting and I shall draw up acomparison with my Mercury charger. Long hand of course, no PC connection!And most interesting is your input on chargers generally, I shall have to lookinto it and see what I can afford.I would look forward to an article on balancing please - I still have doubtsand I am sure that some people are being fooled. You say all recent packshave balancing leads. Really? From what little have seen I fail to understandthe logic, some people seem to think that because you can see cellinterconnection leads and the battery has a connector on the end of 2 wiresthis is a balancing system. You will know this is rubbish, but much morebasic technical data is needed - right down to basics.Personally I fail to see, at the moment, how any series connection can bebalanced without breaking/making connections. Kirchoff's Law, "the currentthrough components in series is equal in all parts of the circuit" means thatirrespective of the state of charge all series cells will have the same currentpassing through them. Parallel cells will of course have different currentspassing through depending upon their internal resistance - and state of charge- and so will eventually balance.

14 E.F.-U.K.

So a "basics" article would be most welcome, to very many people I think andnot just to me - but perhaps less so to battery dealers!Best regards and many thanks. You will be missed but when work gets in theway of other interests it is always a problem - one I no longer have!

Before I had chance to respond, Peter sent anther email:I attach a graphic representation which is designed to show my concernsabout charger "balancing" and your comments would be appreciated.

Assume that I have 6 LiPo cells each of 2500 mAh, part discharged.Now, I have named these cells cell 1, cell 2 etc and connected them up inparallel pairs to make 3 off 1S2P batteries, labelled Battery 1, 2 and 3. The"ohmic impedance" of each cell has been measured, commonly referred to asinternal resistance but that is not really the correct term.Internal resistance is more exactly a fixed manufacturing condition whereasthe total impedance depends not only on that but the stage of charge, thetemperature, electrolyte and electrode conditions, contact resistance etc. etc.However, the effect is much the same at the start of charging.Then I show these batteries connected up in series and you will see from thediagram that if charging commences at 5 amps (1C) then 13 volts is theapplied voltage. Using maths you can see the effective resistance of each 2-cell battery and hence the voltage applied over that battery, the current passingthrough the total 3S2P battery and the current passing through each cell.Same current through each battery, different through each cell of course.

E.F.-U.K. 15

Now, the parallel pairs will eventually balance. Take Cell 1 and Cell 2, aftera time the different current passing through will charge the lower one tocatch up with the higher - they essentially have to reach the same voltagebecause the higher-voltage cell is "charging" the lower one until voltages areequal. Until that happens the cell at the higher voltage will be constantlytrying to input into the lower, so voltage balance is unavoidable.However, since equalisation of impedance would depend simply on luck thereis little chance of the cells having equal capacities. Provide they are used inparallel that is of little problem because, as with charging, they will "correct"each other as they discharge. Well, they should but I have so far failed toconfirm that.However, if we look at the other pairs of cells, the other batteries numbers 2and 3, they can never achieve the same voltage. Each of the series-connected2-cell batteries will receive the same amount of current for the whole of thetime they are on charge (unlike those connected in parallel) and because ofthe different impedances, to say nothing of capacities, they will have differentfinal voltages. If charging ends when, say, the total voltage of the 3S2Pbattery is 12.3 volts then each 2-cell battery may differ substantially - couldeasily be (as I know) 1 at 3.9 volts, 1 at 4.1 volts and 1 at 4.3 volts, a differenceof 9% between highest and lowest. Not the way for a long life. The only waythey can match is for each 2-cell battery to be charged up separately to thesame final voltage. But it is claimed that a "balancing" charger can compensatein some way, can "bleed off" the overcharge being offered to the better batteryand concentrate on boosting the lesser charged ones.OK if that is true why can no-one explain to me what the connections are,how it works. I have been told that it works by "rewiring" the cells andconnecting them all up in both parallel and series/parallel. Oh yeah? Itwould be possible to have a connector panel (high current capacity PC board?Difficult) such that cells are connected to one set of terminals in series/paralleland another set in parallel only. Then applying charger leads to the parallelset only would charge all cells up to equal voltage. Then connecting to theseries/parallel set for discharge would give you the required output voltage.True, but in this simple little case 6 cells of 2500 mAh would need to chargeat 15 amps for 1C charging. Now imagine a 6S2P battery, 12 cells each of say2500 mAh. All magically connected in parallel, charge at 30amps and hope tofinish in 90 minutes. 400+ watts and a sick car battery! Or 5 amps for 9hours. Or 10 minutes flying time and go home. Or take out a second mortgagefor a bag of power packs.Or am I badly wrong somewhere?I have not put in all this information in the belief that I am teaching youanything or telling you anything you do not already know, but simply toshow exactly where I am coming from so that you can teach me - and others!

16 E.F.-U.K.

Not wanting to write an article on this (I have far too much to do and too little timealready), I decided to respond to Peter directly and include the text in the ‘Lettersto the Editor’ feature.

I appreciate your concerns, but they are unfounded when using a balancingcharger or external balancer. There is no need to perform any soldering orchange pack connections to achieve balanced charging. Hopefully the followingwill explain it properly.Firstly, the limiting voltage for a 3S pack should be 12.6V (4.2V/cell) andtherefore 13V should never be seen. If a LiPo charger is at 13V when set for 3Sthere is a serious safety fault with it and it should not be used.I have modified your spreadsheet to show the action of the balancer circuits.

Each balancer is a variable resistance provided by a FET, which dissipates theunwanted current as heat. Typically they start to operate at 4.21V and limitindividual cell groups to 4.25V. This is so that they don't interfere with thefunction of the charger. As the pack nears fully charged, the pack voltagerises to 12.6V and the charger will limit it to that.If one group on a 3S pack is extremely low it could be at 4.1V, with the othersat 4.25V. As the voltage on this group increases above 4.1V, the voltagesacross the other packs will drop, maintaining the 12.6V overall.You will notice on your diagram that cells 4 and 5 are exceeding the 1C chargecurrent of 2.5A. I produced another chart at 4.5A (0.9C), but cell 5 still exceedsthe 1C cell rate at a pack rate of 0.8C. Reducing the current further to 4A(0.8C) drops the current to an acceptable level. For this last diagram I had to

Charging at 5A with balancers connected

E.F.-U.K. 17

increase the resistance of each cell otherwise the voltages were all below 4.2Vand the balancer would have been doing nothing.This is one of the reasons why we recommend a maximum rate of 0.75C whencharging packs connected in parallel. This reduces current means that thecells should stay in the safe zone even when considerable imbalance is present.In most case the negative of cells 1 & 2 and positive terminals of cells 3 & 4share a single pin on the balancing connector. Thus a 4-pin balancing connectoris all that is required for a 3S pack. Most LiPo balancers have an LED that

Charging at 4.5A with balancers connected

Charging at 4A with balancers connected

18 E.F.-U.K.

shows when 4.2V is reached on each paralleled group (e.g. R1 + R2).The critical point is that each of the paralleled groups must be connected to abalancer otherwise the voltage on those cells is completely uncontrolled andcould rise to dangerous levels.Hopefully this and the spreadsheet all make sense, if not please ask forclarification.

Peter responded with a long letter:Thank you for your e-mail of the 10th Nov. Now all is clear, I had neverconsidered the use of a FET for “switching off” the charger, in fact I just didnot realise how cheap they are today and such a means would never havecrossed my mind. That said, I still have a problem. This may be because Iam “out of date” with FETs or may be because you are simplifying things forgeneral consumption.Firstly, a FET has 3 terminations in my world, Source, Drain and Gate, butin your diagram you show only two so I am not clear on your connections.Next, so far as I know, and I am an Electro-Chemist not a Physicist orElectronics man, a FET works by conducting a signal down a “channel” fromSource to Drain unless a positive charge is applied to the Gate. Such acharge, as it increases, reduces the Drain effect (reduces the current flow) byincreasing the resistance of the channel. This resistance increase carries onas the Gate charge voltage rises until the channel is totally “blocked”, nomore current can pass.The voltage at which this total blockage occurs depends upon the design ofthe FET, for use on LiPo balancing a FET would be selected which “switches”at 4.2 volts. And it should be noted that at this point current flow ceases, itis not dissipated as heat. Such an action is not possible, current flows from ahigher Potential Difference to a lower but it cannot be dissipated (Kirchoff’sLaw). The effect of that, again so far as I understand, is illustrated in myattached Method 1 schematic and explanation. When a cell is fully chargedthen the charged Gate stops an current flow, throughout a total circuit ofseries connections.However, you appear to show the FETs connected in parallel with the cellsand if this is correct it demonstrates a technology and FET property of whichI have no knowledge - it would need in effect FET to be normal resistive in theSource to Drain channel, not conductive, until a charge is applied to theGate. By this means, as the cell charges up so the Gate charge would increaseand the channel would open, and at 4.2v (for a LiPo) the channel would betotally conductive.All the current would cease to flow through the cell, it would bypass the celland go down the channel to the next cell. This would have the advantage ofmaintaining current flow through the 3S system even when one cell was

E.F.-U.K. 19

Method 1Three FET devices are connected in series with 3 LiPo cells as shown below.Note the 3 FET leads, SOURCE, DRAIN and GATE. The Charger is connectednegative to Lead 1, positive to Lead 4 and set up to charge 3 LiPo cells at 1C.The Red part of the FET is totally resistive at all times so does not conductbut the Black “conductor channel” conducts, so current (the same current)passes right through the FETs and charges up the cells. However, as a cellcharges up its +ve voltage becomes greater of course and something called a“field effect” puts a +ve charge on the Gate.Now this increase in the “positiveness” of the Gate effectively “squeezes up” the“conductor channel” and when the +ve reaches its “switching” limit (4.2 voltsfor LiPo cells) the conductor channel actually becomes effectively “blocked”and hence a total resistor and so it stops any more current flowing-hencethere is no more charging of anything.So when the first cell to reach full charge “blocks” the conductor it blocks allcurrent flow so all charging ceases. No cell can become over-charged, but ofcourse two cells will remain under-charged. Probably not by much, but notacceptable. The charger should indicate which cell is fully charged, and let ussay it is Cell 2. So now we have to “top up” Cells 1 &3.So we firstly put the charger negative to Lead 1 and positive to Lead 2 and setthe charger to charge 1 LiPo cell at 1C. Again, when the +ve of Cell 1 reaches4.2v the field effect from the positive of Cell 1 puts 4.2v on Gate 1 and FET 1stops conducting. So Cell 1 is now fully charged but Cell 3 still needs a bitmore so we repeat as before, put the charger –ve to Lead 3 and positive toLead 4 and set the charger for 1 cell 1C. These “topping up” operations shouldonly take a few minutes but if it takes much longer it means that cell was veryout of balance and it is just as well you discovered it!

charged, and it would continue for the remaining 2 cells and then finally theremaining 1 cell. There would be no need to “top-up” any cells separately aswould be needed with my Method 1. I show all this graphically in my Method2 schematic, but I must emphasise that although I am conversant with FETsof Method 1 I have no actual knowledge of Method 2 and all that I havewritten is pure speculation. Be good if it was correct!

20 E.F.-U.K.

However, what this means is that for Method 1 the cell manufacturers wouldneed to supply flying leads. For a 2S there would be 1 positive and 2 negatives(one to each cell) or for a 3S 1 plus 3 and so on. I can find no evidence ofKokam or any manufacturer doing this except PolyCell - ignoring simple 2Ssystems with centre pole connection. But I am sure you know better so pleaselet me know, I am sick of soldering and unsoldering LiPo cells, I have wrecked2 so far and I am supposed to know what I am doing! As to packs withbalancing FETs fitted, sounds good but for me only if connections are visibleand can be reached with meter or clip contacts. I would prefer to be able to

Method 2Three FET devices are connected in parallel with 3 LiPo cells as below. Notethe 3 FET leads, SOURCE, DRAIN and GATE.The Charger positive is connected to Lead 1, negative to Lead 2 and set up tocharge 3 LiPo cells at 1C.The Red part of the FET is totally resistive at all times and at the start so isthe Black “conductor channel” which can conduct under certain conditions -see later - but which is a total resistor at the start.So current (the same current) passes right through the cells and charges themup. However, as a cell charges up its -ve voltage becomes greater of course andsomething called a “field effect” puts a -ve charge on the Gate.Now this Increases the “negativeness” of the Gate which effectively “opens up”the “conductor channel” and when the –ve reaches its “switching” limit (4.2voltsfor LiPo cells) the conductor channel actually becomes effectively “open” andhence a total conductor of no resistance. So the current by-passes the fullycharged cell and so the cell does not overcharge.Because there is now less resistance in circuit the charge current drops butthe remaining two cells continue to charge up.The next highest charged cell will then “shutdown” as it fully charges, followedby the third one.

E.F.-U.K. 21

buy a PC board with assembled FETs, say for a 2S or a 3S or a 4S (orwhatever the limiting series charging is today) and plug/unplug this to/from the factory-installed battery flying leads. Or, how do I specify andwhere do I buy such FETs, to make my own balancer?Finally, how can any model shop claim to sell a “balancing charger” to pluginto a battery? I cannot visualise any such thing. In spite of you saying thereis no need for a soldering iron I remain certain that connection to each cell isessential and if not factory supplied we must do it ourselves. Yes, if my Method2 works you would be able just to connect up a FET-fitted battery to a suitablecharger - but such a charger would simply have a limiting capability not anybalancing capability and should not be so described.But again, if I’ve got it wrong I would be delighted to be told.

OK, a lot to cover, so here goes.In my last response I did simplify things in an attempt to make it easier tounderstand the principle. I also erred slightly, what I should have said is thateach balancer circuit contains a FET. Peter is correct that FETs have 3 leadsas identified. However, FETs are available in a number of different varietieswith very different characteristics. The majority of FETs available do notconduct when the Gate voltage = Drain voltage, which means they are “off”when power is initially applied.Over the past few years the “on” resistance has reduced markedly, with surfacemount FETs available as low as 6mÙ for a single FET. This ultra low resistancemeans very low loses and that these small packages can handle higher currentsthan their predecessors. This is one of the main reasons for the reduction incost and size of speed controllers as less FETs are required. For brushlesscontrollers this is a major advantage when 6 banks of FETs are required.Peter’s Method 1 could be used, but if that was to chosen method it would bebetter incorporated in the charger. Provided the voltage across each cell canbe maintained it would work. I consider that this method is unnecessarilycomplicated and would not be cost effective.Method 2 is along the lines used by commercial balancers, although you cando it as simply as this. I’ll describe how a typical LiPo balancer circuit worksin the following paragraphs and hopefully everything will become clear.A LiPo balancer typically contains a precision voltage reference, a voltagecomparator, a number of discharge resistors, a pulse-width modulator (PWM),and a FET. The voltage reference is used by the comparator to produce anerror signal. This error signal controls the PWM, which turns the FET onand off. As the voltage rises above 4.21v, the PWM starts with short pulses,which increase in width until, the FET is always on at 4.25v.Typically they also have a LED on the board, which indicates what the balancer

22 E.F.-U.K.

is doing. If the LED is off the battery voltage is below 4.21v. The LED lightsonce the PWM circuit starts to operate and effectively indicates the pulse lengthbeing produce (although at a much slower, visible, rate). If an LED is constantlylit, the balancer is at maximum load and the voltage could be above 4.25v. Toensure that no damage is done the charging current needs to be immediatelyreduced to a level that all the LEDs are flashing or off. As the charging cyclesnears completion the LEDs will extinguish as all the cells are below 4.21v.Some balancers are designed to be permanently connect across the cells, whilstothers are connected only when charging. Those permanently connected havesome advantages as they can’t be forgotten, however, you will need a balancerfor every series cell in your packs. To explain, a 3S1P pack would require 3balancers, a 3S2P pack requires 3 balancers and a 5S4P packs requires 5balancers. As you can imagine this will be expensive if you have a lot of packs.Balancers that plugged in to external connections offer a method of balancingall your cells, whilst keeping the costs down. I said it before, but I’ll repeat itagain here - it is essential that every series cell in a pack on charge isconnected to a balancer.Balancers have a limit to the current that they can sink. Cells can be chargedat currents considerably above the balancer rating provided they are sufficientlywell matched. In the example I gave in one of the earlier responses, the balancerwas required to sink 514mA to limit the voltage at a 5A charge current. If thebalancer could only sink 250mA it would not be able to control the voltage,which would rise to approx. 4.50v - extremely unsafe.Please bear in mind that the above is typical, but wont be the case for allbalancer designs. Please read, understand and follow the instructions suppliedwith the balancer you are using.I’ve hunted around to find balancing chargers and balancers to provide thebest list I can of those currently available. The list is not exhaustive and I’d beinterested in details of any others that are known.Balancing ChargersMake + Model Cells LiIo LiPo Max I Comments Schulze LiPoCard 1-4 Y Y 3.85A PC Interface, Auto setup

The Schulze LiPoCard in use on a 3S1P Kokam 2000 pack

E.F.-U.K. 23

Cell BalancersMake + Model Cells LiIo LiPo Max I Comments Astroflight Blinky 1-6 N Y 200mACSM LiPo Balancer 1 N Y 335mA Designed for permanent fitDualSky Balancer 3 N Y unknownFlightPower Duralite 3 N Y unknownFlightPower Duralite 2-6 N Y unknownGraupner Micro Bal 1-5 N Y 100mAHyperion EOS LBA6 2-5 N Y 6A charge Charge & discharge controlMGM Compro BLCR-4 2-4 N Y unknownOrbit LiPo-Checker 1 N Y 550mA Supplied as a block of 5 unitsPro LiPo Balancer 1-6 N Y 350mASchulze LiPoBal08 1-8 Y Y 1.0A PC Interface, Auto setupSchulze LiPoBal14 1-14 Y Y 1.0A PC Interface, Auto setupSky-Holic H021 2.4 N Y 300mAThunder Power 2-5 N Y 420mA Linkable to some TP chargers

The only unit I have experience of is the Orbit LiPo Checker, which is availablewith (•58.60) or without (•44.60) BEC type leads from http://orbitronic.de. Theseunits are used by Jean-Paul Schlosser (JéPé) and I found these units very goodand wont charge 2S+ packs without them connected.

5 Orbit LiPo Checkers

Sky-Holic H021 BalancerAstro Blinky

Schulze LiPoBal 14

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If your packs do not have balancing leads fitted it is relatively simple to fit them toyour packs. To fit a lead all that is needed is a suitable connector, some heatshrinktubing, a soldering iron and a little solder.The connector can be of any type to suit the balancer you intend to use but 0.1”pitch Molex connectors are a good choice. If using the Orbit LiPo Checker withthe supplied BEC leads, use these connectors for the balancing leads.Firstly carefully remove the heatshrink sleeve from the pack and expose the solderedconnections to the cells. You may find that hot glue has been used to stop the thinelectrodes from moving about, this will need to be removed from the solderingarea.It is easiest to solder to theelectrodes where they arealready covered in solder fromthe original connections.Carefully solder the leads tothe terminals, as shown in thephotograph and diagramsbelow, minimising the heatapplied to the electrodes.Reapply hot glue or epoxy toprotect the electrodes fromflexing and re-cover the packwith heatshrink.

A 3S pack of 15C Kokam 2000 mAh cells withbalancer lead retrofitted.

E.F.-U.K. 25

New-2-UA Brief Round-up of New Items of Interest.

If you are a manufacturer or retailer that has something new they want toshare with the readers, please send details to the Editor (addresses on page 4).

Whilst this first item has been released for a while, it has not been seen in otherpress or at any of the fly-ins I’ve attended. The Rödelmodell Kobra “Revival” is a90cm (35½”) span, 79cm (31”) long sleek, moulded, twin boom, ARTF sports model.The original Kobra was a1980s model designed for2cc glow motors, but thislatest version is solely forelectric power.The flying weight isintended to be around950g (33½ oz.). Power isan AXi 2820/10 on a 3Spack of 15C 2000mAhLiPo cells or similar,giving unlimited verticalperformance and 10 to 12minute flights.

The low weight and reasonable wing area alsogive excellent slow speed handling.As can be seen left, the wing and fuselage aresupplied as a single piece with tail boommounts, giving excellent strength for highspeed manoeuvring. The transparent or carbonfibre canopy gives good access to the battery.The Kobra is supplied with hardware anddecals (I’m not sure about the P-38 markings).

A power set containing the AXi motor, speed controller, battery pack, foldingpropeller and hardware is also available.It is available from the Rödelmodell onlineshop at www.roedelmodell.de or contactthem on +49 82 68 713, by email atinfo@roedelmodell.de or by mail toRödelmodell GbR, Bernd & Petra Dörfler,Lausangerweg 4, 86874 Mattsies,Germany

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Hyperion have recently released a newrange of outrunner motors, the Z-40series. They have a 45mm diameterstator, and is available in 3 differentlengths 25mm, 35mm and 45mm.The magnets are specially made forthese motors and are curved on bothbell and stator sides. This maximisesheat transfer and improves themagnetic flux.

They also feature shielded stainlessbearings. The motors also feature a largering bearing at the at the front of themotor to prevent deformation of the bellat high rpm. The motors can be backmounted directly to a bulkhead or via themounting kit. They can also be mountedusing the rigid front mount, which canbe adjusted over a wide range of lengths.

Model Max Eff. I Max. I IO KV Ri Weight Power(A) (A) (A) (rpm/v) (mÙ) (g) (W)

Z4025-10 40-60 80 2.96 560 16.2 356 600-1100Z4025-12 35-50 65 2.38 486 21.8 356 600-1100Z4025-16 30-40 50 1.85 368 37.2 356 600-1100Z4035-10 40-60 78 2.38 405 18.7 446 800-1400Z4035-12 36-53 65 1.98 343 26.1 446 800-1400Z4035-14 33-44 57 1.80 299 34.5 446 800-1400Z4045-10 40-60 77 2.05 320 22.1 553 900-1800Z4045-12 35-50 63 1.63 275 31.3 553 900-1800Z4045-14 31-40 48 1.50 236 40.9 553 900-1800A typical application is a 1/4 scale Ryan STA, 82” span, Hyperion Z4045-10 withHyperion Titan-90HV and 8S Hyperion 3700mAh 20C LiPo and APC 16” x 8” thinelectric propeller. This gives a flying weight of 12 lb. 4 oz. and draws 56A staticcurrent at 27.9v, giving 1560W and 5790 rpm. After flight the calculated averagecurrent was under 35A, motor was 51°C, the battery 36°C and controller 38°C.The Hyperion Z-40 motors and back mounts are available online from Robotbirdsat http://robotbirds.com or contact them on 0208 841 7873.

E.F.-U.K. 27

Another recently introduced item byRobotbirds is the nifty PJS 550R DoubleContra rotating brushless outrunner.Stock is limited and they may have goneby the time this is published, however,contact them as they may get more.The PJS 550R is designed for scalemodels that need contra-rotating props,in other words one propeller rotating left& the other to the right. It has adiameter of 32mm and an overall lengthof 117mm and the weight is 139g.The motors have a Kv value of 1300 rpm/v and are 100mÙ each. The suggestedpropeller is 8” x 6” and you need one normal propeller and one with reverse pitch(commonly called Left hand). The battery is 2 to 3 cell Lithium and the maximumcurrent is given as 21.7A per motor.The price is a very good £69.95 +P&P. Contact details for Robotbirds on page 26.

Robotbirds have also justintroduced the Smart Charger2020 (left), a 1 - 3 cell LithiumPolymer charger with outputcurrents of 110mA, 250mA,500mA, 750mA and 1200mA. Itis reverse polarity & short circuitprotected and measures only90mm x 48mm x 11mm.

The input voltage range is 10.5v to 15v. It features power on LED, error LED,charge complete LED and an LED for each cell connected. The settings are allmanual using jumpers on the right hand side. Price only £17.95 +P&P.

The final items included fromRobotbirds are 3 new carbonundercarriage legs. They don’t statethe weight of the legs, but the followinginformation is available (alldimensions in mm)

W H L Model Price190 100 25 700g £ 8245 120 28 1000g £ 9290 145 35 1300g £ 13

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Here we have a new EDF jet model fromSchübeler Jets called the Vector II. Themost striking thing about this jet is theleading edge slats allowing the profilegeometry to be adjusted during flight.Due to the leading edge flaps the stallspeed is reduced and it enables a highthrust-weight ratio (up to 1.2:1 withLiPo cells) jet-like acrobatics.At the EDF-Meeting in Gronaumeasurements showed the very goodslow flying characteristics of Vector II.

They also recorded a top speed of 183 mph (295 km/h)when using the DS-51-DIA (3 ph) moulded carbon fanand a brushless motor running on 20 Sanyo RC-2400NiCds. When using LiPo a much higher thrust toweight can be achieved.The fuselage and wing roots are hand moulded as asingle piece

from CRP, GRP & ARP, with balsacovered foam outer panels. The wingletsare CNC milled and are screwed ontothe wing to allow removal.The model is supplied with seamlessducts for the DS-51-DIA (3 ph) fan, whichare almost “plug & fly”.The wing span is 1158mm (45½”), thelength 1103mm (43½”). The flyingweight is given as 2.75kg (6 lb.) (20 RC-2400 cells) or 2.25kg (5 lb.) (LiPo).

Schübeler Jets products are importedinto the UK by Al’s Hobbies, but as yetdo not appear in their website(www.alshobbies.com). For moredetails email info@alshobbies.com orcall 0208 500 8884. The kit price is £350plus £180 for a DS-51-DIA (3 ph) fan.More info and other worldwide dealerscan be found on the Schübeler Jetswebsite at www.schuebeler-jets.de

E.F.-U.K. 29

Two models from Graupner on this page.Firstly an unusual model that is boat andplane - the HYDROPLANE 3D.The model resembles a typical fast racinghydroplane design, but has 2 sets ofelevons at the tail (stern?) that areinterconnected. It also features twin airrudders. Manoeuvrability on water isunlikely to be brilliant, but this is a verydifferent model..

The Hydroplane 3D is 79cm(31”) long, 55cm (21½”) wideand 22cm (8½”) high. Theflying weight is around 235g(8¼ oz.) giving a wing loadingof only 11.9g/dm2 (3.9 oz./sq.ft.)

It is quick and easy to assemble from vacuum-moulded and laser-cut Depron®

components. The reinforcing struts are lightweight, high-strength CRP profiledstrips, ensuring a low all-up weight. To complete the model you’ll want a 280class brushless motor, a suitable 10A controller, propeller, a 3s LiPo pack between350mA and 650mA and 3 mini-servos.The Hydroplane 3D should be available through your local model shop or any ofthe internet model shops. The cost of the kit should be around £60.

The second model is the GraupnerSPEED CAT. The Speed Cat is a pylonracer of all-GRP construction. All themodel´s components, i.e. fuselage, one-piece wing, tailplane & wheel fairings,are supplied ready-made moulded items,high-gloss , painted in the mould.The key features of the Speed Cat areits beautifully, harmonious, lines and distinctive “apple cheeks”, which give themodel an interesting semi-scale appearance. The model is capable of very highairspeeds, especially electric powered. The aerodynamic layout of the Speed Catgives the model pleasantly stable flying characteristics, and any RC pilot withaverage flying skills will not find it difficult to control.It features aileron, elevator and throttle control, has a span of 101cm (39¾”) and awing area of 18.8 dm2 (290 sq.in.). The target flying weight is 1.2kg (2 lb. 10 oz.)using a 500 size brushless motor and 3s LiPo with 40A ESC. Also included are thepre-formed aluminium undercarriage, 2 foam wheels, plastic spinner, small items,decal sheet & linkage pack. Price around £150 from local model shops/internet.

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Want a small andinexpensive brushlessmotor and controller,then maybe the newbudget items from AllElectric RC are for you.The motor is equivalent to a Speed 400 motor andcosts only £9.99. The controller is £15.99, rated at

10A, weighs only 10g (0.35 oz.), is a simple plug & play design and has a jumper toselect between 2s and 3s LiPo. Even better, buy the two together for only £19.99.Check out the All Electric RC website at www.allelectricrc.co.uk for the completerange of products. Call them on 01782 788 778 to order or for more details.

Another recent product that you might havemissed are the Saphion Lithium Phosphate cellsavailable from Overlander. Lithium Phosphate(LiPh) cells are much safer than Lithium Polymer(LiPo) & Lithium Ion (LiIo). They are onlydangerous when short circuited or put in a fire,much the same as with NiCd or NiMH.The only capacity available at present are 1200mAhcells, which are rated at 15C, which is an 18Adischarge rate. According to the data, they canwithstand burst at 25C (30A). They also have thebenefit of being chargeable at 2C (2.4A) so recharging in the field is more practical.LiPh cells have a lower terminal voltage at 3.2v/cell. Despite this difference,Overlander stated that they can be charged using a LiIo or LiPo charger (3.6v or3.7v per cell). They can be discharged down to 2v/cell without harming the cell.Each cell weighs 42g, broadly the same as similar capacity and discharge rated

LiPo cells, however, the Watt-Hours are lowerdue to the lower voltage.Packs are available as 2S1P (6.4v) £16.99, 3S1P(9.6v) £24.99, 4S1P (12.8v) £32.99 or 5S1P (16.0v)£41.99. Packs can be parallelled (as LiIo andLiPo) to increase capacity or discharge rating.Saphion cells should be available from your localmodel shop, or direct from Overlander. Checkout their website at www.overlander.co.uk orcontact them by phone on 0870 750 6411 or emailat john@overlander.co.uk

E.F.-U.K. 31

TLC from your TLOBy Alan Bedingham

It all started when I bought a glider fuselage for my 2.5m electric Silent Dream. Afew twangs off the bungee later, I was surprised how easy it was to get away inlight lift with the glider versus the electric version. I don’t know about you, but tome, an electric glider is for just plain enjoying the day rather than competitions.No hassle with laying out bungees or trying to find the blasted parachute when itdrops in the long grass. The sheer pleasure of working a little bit of lift low downand a long way off that you wouldn’t dream of trying for if you didn’t have theelectric thermal to fall back on. Competing against myself I suppose.One guilty pleasure is deliberately circling in sink with the power on waiting forother gliders to join me and watching them drop like stones. Tee hee! So why isthe glider version better in light lift than the electric version? Well, the obviousanswer is that it is quite a bit lighter, over 19 oz. lighter in fact. The wing loadingof the glider is 10.6 oz/sq.ft., the electric is 14.9 oz/sq.ft., some 40% higher – blimey!The next question was - how can I get the weight down?The setup I’m using is an Irvine 05/07 Cobalt with a 3:1 gearbox driving a 14” x10” folder on 8 RC-2400 cells. I had an 8 cell pack of CP-1600s that was 4oz.lighter than the RC-2400s, let’s try them. Much to my surprise, the climb (alwayspretty brisk) resembled a homesick angel and I needed a bit more down trimmixed in.Hmm – let’s try a smaller propeller. I had a 12.5” x 10” folder in stock, so I gaveit a try. The climb was pretty good but it was obvious that saving 4oz wasn’t going

32 E.F.-U.K.

to be enough to get the glide performance I was looking for.Changing to the smaller propeller had dropped the current from 31A to 20A, maybeI should be looking at LiPo batteries? I’ve been using a 3S pack of 1500mAhbatteries in a Speed 400 powered Hawk for a while, but they wouldn’t give 20A,more like 12A. Then the penny dropped – buy another 3S 1500mAh pack and runthe two in parallel.I made up a balsa crate to fit them in the space where the NiCds used to go andmade up a couple of Y leads. Luckily, the NiCds were on the CG, so the LiPo pack

had no effect on the overall CG of the ‘plane. Weight saved so far – 10 oz, droppingthe wing loading to 12.7 oz./sq.ft., still some 20% more than the glider version.Flying it was a revelation, the climb is back to homesick angel levels and light liftscratching is much easier than before. Not only that but I had more batterycapacity (3Ah instead of 2.4Ah) and nearly double the power on time because of thelower current draw! Roll on the next All Up Last Down competition!My best flight in one of those was nearly an hour and three quarters with the oldsetup, what’s possible with the new one?It’s difficult to see where I could lose that last 9oz., maybe an outrunner wouldsave me about 4 of them (at a cost) and if I could find one that will swing a big

E.F.-U.K. 33

propeller on 3S LiPo and only pull 20A or so. I think I’ll leave things as they arefor now and enjoy flying a ‘plane that’s much lighter than it was.

Lessons LearnedI was surprised at the difference relatively small reductions in all up weight canmake to climb performance.Changing an existing ‘plane to LiPo saves so much weight that you can thinkabout cutting the current by using smaller propellers and still have the sameperformance.Cutting the current means that you can use lower capacity LiPo packs or get

more power on time.

Next StepsI was at the Southern Model Air Show and spotted on the RCM Direct stand a 3s10C capable pack of 3600mAh LiPos for a very reasonable £48. Wonder if they’llgo into my Vermont Belle? This is fitted with an AXi 2820/10 (when willmanufacturers stop using these gibberish names?) running a 12” x 6” propeller onan 8 cell pack of RC-2400 at around 38A.Performance is good with enough vertical for big loops and even vertical eights.It’s only problem is that I have to limit myself to six minutes to make sure I haveenough grunt left for a go around if I need one. Still haven’t quite got the hang ofthis landing lark after all these years!

34 E.F.-U.K.

The LiPo is wider than the NiCd pack so a bit of hacking and carving was need toget it to fit. Weight saved is just over 8oz., some 15% lighter overall. I trieddifferent propellers with an eagle eye on the Whattmeter and settled on a 10” x 7”that pulled 36A. Note the big change in propeller size, don’t forget a LiPo is wortharound 3 NiCds so I was effectively fitting a 9 cell pack and I also wanted to cut thecurrent a bit. It flew very well, the vertical is better than before and the durationis working up to 10 minutes.Perhaps I should explain that remark. I don’t have a single LiPo capable speedcontroller, so what I do is start at a conservative flight time, like six minutes,recharge the battery after each flight and gradually increase the flight time untilI’m putting back about 70% of the capacity.My transmitter has separate count down timer settings for each memory whichmakes this easy to do. The only problem is hearing the beeps over the noisy oilyfans! It’s a conservative approach that leaves a bit of leeway for windy days (youalways use more power on windy days, have you noticed?) and that keeps me on arelatively level part of the discharge curve and well away from the LiPo 3V limit.My aim with this electric lark has always been to equal or better the oily fan‘planes. I’m there in terms of performance, in fact, when I took over a learner’sglow model to show him how to do a proper circuit for his ‘A’ test, I was surprisedhow under powered it felt compared to my electric models. Duration has alwaysbeen the bugbear, until now.

E.F.-U.K. 35

I was flying the Vermont Belle, trying out aerobatics, when I heard a glow modelstart up behind me. Both of us shared the pattern until he called ‘landing’ andbrought his ‘plane in. I was still in the air! First time that has happened to me.Flushed with success, I started looking at some other models that hadn’t beenflown for a while. My gaze lighted upon the venerable Fiasco. This had beendesigned to fit in the trunk of the Fiesta I owned at the time (always known to usFordies as the Fiasco – just black humour - you don’t want to know what we calledthe Focus) lengthways with the rear seats folded, so it is 50” wide and 50” long.Designed as a knockabout fun model, with a symmetrical wing section, it flies justas well inverted as the right way up. My trademark of rolling inverted just as thewheels left the ground once attracted a ‘had a glitch did you?’ comment from one ofour members. Isn’t it nice to know your engine isn’t going to misfire or stop?It was fitted with an Astro 25 geared swinging a 12” x 8” on 14 cells and weighed70oz. all up. It has served me well, doing plenty of flying and surviving a fewcrashes over the years. Have you noticed how long electric planes live for if youmanage to keep them away from terra firma? I reckon it’s the lack of vibration

36 E.F.-U.K.

and oil that does it. The oil because it makes them easy to repair!It had been put on the backburner because you don’t get many charges of a 14 cellpack from a car battery in a day and it had a distressing tendency to bend theundercarriage if a landing wasn’t absolutely perfect. I tend to average one out often landings perfect, six out of ten acceptable and the rest I don’t want to mention.There followed a feverish session on ElectriCalc assessing the possibilities. I endedup with the 3s 3600mAh LiPo pack and an Astro 05 geared swinging an 11” x 7”,the Astro simply because I had one in stock. This doesn’t seem possible until youlook at one of the useful numbers ElectriCalc works out – W/lb.The 14 cell version is 89 W/lb., the LiPo version is 103 W/lb. The drop from 410Wto 310W is more than made up for by the massive weight saving. Have a look atthe pictures, the 14 cell powertrain weighs 44½oz. including a receiver battery,the LiPo 18½oz. (no receiver battery required), a reduction of 26oz.The whole ‘plane is 35% lighter! Looking at the ‘plane pictures you can see howeerily empty it appears with the LiPo setup.Off to the flying field to give it a go. This can’t work, can it? It can! Just as livelyand aerobatic as before and with a lighter feel, more like the Vermont Belle. Thelandings were like a butterfly on thistledown.Well, you know what I mean, it’s always easier to make a landing look good witha light ‘plane than a heavy one. So it flies just as well for longer and I can get moreflights in a day since charging the LiPo hardly dents the capacity of the car battery.As the Americans say, ‘a win-win situation’.

Lessons Learned 2

LiPo conversions aren’t necessarily just a simple substitution of one battery foranother, you really need to think about the whole power train before and after.You may be surprised at how much weight you can save.

Anyone want to buy a pile of NiCds? Velly cheap!

E.F.-U.K. 37

Readers’ ModelsYour chance to show the members your model(s).

Above is the “Donald 4” flying boat of Rich Flichbaugh, South Dennis, MA. It hasa Mega ACn 22/10/6 motor, Castle Creations Phoenix 35 controller and a 10-cellSanyo 1300mAh battery pack. This gives ample power for up to 10 minute flights.Below is Rich Flichbaugh with his Great Planes Piper J3 Cub float plane taken atScargo Lake, Florida. It features scale early design Edo “flat top” floats. A MegaACn 600/20/5 motor with the same equipment as above give 8 - 10 minutes. Theweight is 51 oz. (1.45kg), giving a wing loading of 15.6 oz./sq.ft. (47.6g/dm2).

38 E.F.-U.K.

These pages feature the 'Interceptor' of Mike Pirie, built from Gordon Whitehead'splan. It certainly does! What's more it then gives a 20 minute aerobatic flight.

The original 'FROG' Interceptor was produced in the 1930s and was probably oneof the world's first ARTFs. With a span of 11” it came in a small cardboard boxand comprised a fuselage, two plug-in wings, removable undercarriage and agearbox/propeller unit with a rubber motor. After assembly, it was wound up byplacing the fuselage in its cradle in the bottom half of the box so that the propellerengaged with a ratchet mechanism at the front of the box, then a small handlewas inserted into the box from the outside and turned the required number oftimes. With sufficient winds the model would then rise off a smooth surface to flyfor a short time - probably only for a few seconds.

The original Frog ‘Interceptor’ with Mike Pirie’s model

Mike’s model in flight

E.F.-U.K. 39

Gordon's stylish model is a four times scaled up version of the original, and spans118cm (46½”). Things have moved on a bit since the time of Gordon's plan (atleast a decade ago) and by the elimination of gearbox, receiver battery and heavyradio gear, I succeeded in reducing the a.u.w. by a respectable 100g to 1230g(43 oz), giving a wing loading of 54 g/dm² (18 oz/ft²).On my model, a Fanfare Powermax 40T up front, turns a 10” x 5” APC propellerdirect drive, the energy coming from a 3s2p pack of Kokam 2000s. The motordraws 25A (static) so I guess the power loading must be in the region of 250 W/kgor 90 W/lb - this could explain the stunning performance!The colour scheme is as per the original FROG model, the silver fuselage beingreplicated by the use of chrome Fibafilm. The 'FROG' logo was found on theinternet and transferred on to transparent inkjet vinyl (from Overlander).The plane is a shear delight to fly, and performs aerobatics (limited in my case)with ease. It is difficult to avoid a bounce on the landing however, anddisappointingly it is not very willing to taxi in a straight line (it needs a steerabletail wheel).The only deviation from theplan was for the batteryaccess which is now byremoval of the wings (one boltto unscrew) rather thanhaving an unsightly hatch onthe lower fuselage.I also added a fibre-glassbandage at the wing joint asI didn't like the idea of a buttjoin. And oh yes . . . I addeda pilot!

On Finals, very graceful

40 E.F.-U.K.

I thought that you might like to see the following photos of my fellow GuildfordModel Flying Group members’, Dave Dyer (above) and Tony Skilton (top right),Lancasters, and maybe include them in a future edition of Electric Flight U.K.Both models were built from the Priory Models kit using standard 6v Speed 400motors, and 8 x 3300mAh cells - either GP 3300’s or Puffin Hi-Flow 3300’s. Tony’sLancaster weighs 5lbs 4ozs, Dave’s weighs a little more as he has fitted workingrudders to his model. The wing span is 6ft. Both get between 8 - 10 minutes flyingtime on the 8 cell packs. Unfortunately, the only time we managed to get both ofthese Lancasters in the air together, we had no camera around !!

E.F.-U.K. 41

42 E.F.-U.K.

The Electrifly PolyCharge4by John Stennard

Every now and then modelling items appear that answer a particular need andthis charger is certainly one of them. I saw this charger advertised in Americanmodel magazine and quickly found that not only did Tower Hobbies have them instock but they were at a ‘special deal’ rate. Following a phone call to a helpful ladyat Tower one of these chargers was on its way to me.Why was I particularly excited about this charger? In common with virtually allthe flyers at our indoor sessions I never charge in the sports hall as I now haveenough cell packs to keep me flying all evening. Of course the problems startwhen I get home and have about ten packs to charge.There is no question of leaving LiPo packs connected and charging overnight so itis a long process the next day charging all the cells. The Polycharge4 is unique asit is actually four chargers combined in one unit. Each charger can charge 1 – 4cells at rates from 300mAh to 3000mAh. A built in fan keeps the charger cool andthe unit is fused. The unit is packed with ‘features’ and mine works perfectly.The charger requires a 12- 15v power source and of course if running all theoutputs at the maximum current at least a 12A required. A mains regulated unitis obviously preferred rather than a Leisure battery to supply the charger.

E.F.-U.K. 43

Two A4 sheets of instructions cover the handling and use of the charger. Basicallyit is extremely simple and as usual the only likely cause of an error would be if youset an incorrect charge rate. After connecting the pack and setting the correctcharge rate, normally 1C, the black button is pressed. The system uses a tri-colour LED to indicate certain conditions starting with the automatic cell count.Initially a solid green LED indicates that the cell count is being checked. Whenthis has been done, the LED flashes according to the number of cells that thecharger has read as being present. This is a first indicator that the pack is in goodcondition. Obviously an incorrect count means that a cell is malfunctioning.When the pack is fully charged the LED flashes red and an audible tone sounds.Again the red LED flashes according to the cell count so this is a further check onthe state of the pack. If for any reason the pack does not charge within a three-hour period the charger switches off automatically and the LED flashes orange.Included in the instructions are ‘Important Precautions’ that deal with the correcthandling of LiPo cells. These instructions are very clear and explicit and areworth reading even if you are experienced in handling LiPo cells.I hope this charger will soon be available in the UK from the GreatPlanes distributoras it has certainly been one of my ‘best buys’.

44 E.F.-U.K.

Fixing Günther Propellersby Nick Fitton

My first encounter with 2.3mm shafts was via the TwinJet. I was sceptical aboutthe recommended method of propeller attachment (push it on) so I phoned a highlyexperienced EF guru, who shall remain nameless. He told me that a bit of spit onthe shaft and a good push was all that was needed. Indeed, he told me that he hadnever had a Günther propeller come off, saying that he must have spit like epoxy!Thus assured I flew my TwinJet with delight until one day a propeller came off atexactly the wrong moment, i.e. the instant it left my hand at launch. I couldn'thold the resultant asymmetric thrust and the clutching hand which is gravitytook over. Not much damage but a lot of annoyance.I wanted to be convinced that pushing propellers on was sound practice, but myfathers oft repeated dictum "A man convinced against his will remainethunconvinced still" was never far from my mind. I tried bonding the propeller onusing thin cyano, being careful to remove all traces of oil from the shaft and not tobond the shaft to the motors front bearing. But still propellers flew off occasionally,fortunately at non-critical times.My next cunning plan was to drill a pin hole right through the black plastic insertand allow a blob of gap filling cyano to flow into the insert before pushing it on tothe shaft - you have to do this quickly otherwise the cyano starts curing before thepropeller is fully home. I was convinced this would solve the problem, but therewas no improvement.I tried the same with epoxy, poking it into the insert with a match, but whilst thisseemed better than cyano, it was only better in the sense that the propeller stayedon longer before letting go.As a last resort I tried high shear strength adhesive, one of those specificallydesigned for fixing pinions to shafts in geared applications - and I have never hada failure in this application. Again I was unsuccessful. Presumably these adhesivesare not designed for metal/plastic bonding, which comes as no surprise.I persevered, but I knew in my heart that gluing propellers on was not the rightpath - as Taoists would put it, it was a "path without a heart", thus one to beabandoned. It takes a lot of pressure to force a Günther propeller on to the shaft.I was sure that what was happening was that the black plastic sleeve was relaxingover time, weakening its grip on the shaft.In addition, propeller acceleration/deceleration forces would constantly test theintegrity of the bond line, as would the occasional ground contact. Cyclic thermalstresses may play a malign part too.Thus I was forced to conclude that all glued methods must eventually fail, and Imoved to mechanical type adapters. Here are my findings:

E.F.-U.K. 45

The Collet typeThese exert an enormous clamping force on the motor shaft, and are self centring.The ones I bought had, however, a number of disadvantages. Firstly, the relativelylarge back plate fouled the back of the Günther propeller, and I don't like hackingaway at any propeller, especially one turning at 14000 rpm, even if it is very light.Secondly, the collet was relatively massive, with a centre of gyration some distancefrom the shaft axis. Any inherent vibration in the system will be amplified bythese factors, as will mounting the collet near the end of the shaft. The Speed 400shaft is long, thin and 'whippy'.A big advantage was that one could achieve a very small gap between nose and theback of the spinner, which is aesthetically pleasing, but fitting the spun blue foamspinners I use proved impossible. Sometimes collets can be difficult to remove,such is their massive hold on the shaft.The Grub Screw typeTo all intents and purposes these too have a virtually unbreakable hold on themotor shaft, and certainly so in the case of Speed 400 motors. Those with twogrub screws (Graupner do a lovely one) are to be preferred, if only for theirengineering excellence, more on these later.A major disadvantage is that it is difficult to produce an aesthetically pleasingfuselage / spinner gap. The way round this is to glue a balsa ring to the nose to fillthis gap: one might also mount the motor some distance back from the bulkheadbut this would introduce problems of lack of rigidity and high localised forces onthe mounting plate.The Graupner propeller adapter is beautifully produced (see below), is light andthus has low rotational inertia. It also has a bullet type nut, this feature giving ussomething to which a spinner can be attached.The spinner is spun blue foam. I make a 1/16” ply disc of the required diameterand using double sided tape, fix a block of blue foam to it. Spin it (in a power drillin a vice) to the desired shape and length and separate it from the ply former. Thisis not needed any more, but is retained for future use.

46 E.F.-U.K.

As accurately as possible, carve the foam to receive the Günther propeller so thatthe back of the propeller is flush with the back of the spinner. Using the coneshaped rotary stone attachment for the Dremel, lightly bore into the foam, keepingeverything as central as possible.Now the clever bit. Cover the Graupner spinner with double sided tape and simplypress the foam spinner on, using the model's nose former as a square, flat guide.You'll probably have to experiment a bit to get it right.A small degree of eccentricity is not noticed in practice. There is no flight load onit, the only force being the airstream pushing it on, which is to our advantage, andthe rotating mass is so low that there is no vibration, even at 13000 rpm.One of the features of using the Günther propeller is that spinners tend look toolarge in relation to the propeller, blocking out a seemingly high percentage of theswept area. The small Günther propeller has a diameter of 125mm. Even if aspinner were half that at 62.5mm, which is unlikely, it would blank out only 25%of the swept area. Actual spinners required are typically less than 40mm, blockingout less than 10% of the disc area.More important is the effect a large nose diameter has on the airflow leaving theback of the propeller, so it makes sense to reduce the nose diameter to the minimumpracticable. This can be achieved by utilising the full length of the Speed 400shaft. About 30mm diameter spinners can then be fitted. These have a mere 6%blanking effect. It is always good practice on an aeroplane, full size or model, toreduce everything to the minimum that will do the job.My Speed 400 Tucano incorporating all the above best practices, built light andwith an 8 cell KAN pack has a flying weight of just over 18 ozs. It goes like stink,has good duration and amazes the IC mob. What price now brushless / LiPo !So far going the 'grub screw adapter' route has proved completely satisfactory. Ikeep two spare complete propeller/spinner assemblies in my flight box just in case.Propellers can be quickly and easily changed in the field should one experience aless-than-ideal landing, not that this has ever happened to me (honest).

E.F.-U.K. 47

Wing & Wheels Model Spectacular is delighted to be able to remind Modellers that24th and 25th June 2006 represents the 20th Anniversary of the show.

First held at North Weald Airfield in1986, the show has evolved into one ofthe most respected and popular modelshows in the UK and has featured someof the very best models and pilots fromthe UK and Europe. With its fabulousrunway facilities, excellent crowdproximity capability and massive tradesupport, Wings & Wheels has alwaysbeen able to put on a show thatspectators return to year after year.

A large part of our success has been dueto the support and participation of theShow Pilots, helpers and their models,the loyalty of our Traders, as well asthe many other supporting attractionssuch as Modellers’ Bring & Buy, IndoorFlying Displays, Large Model Boat Pool,Model Car Displays and huge SaturdayMarket adjacent to the Show.

Whether you are a participant of one of the above attractions or a visitor wewould be delighted if you would come to next year’s show to celebrate 20 years of

Wings & WheelsSee more about us at: www.wingsnwheelsspectacular.com

or contact the Show OrganiserDesignaction Limited, PO Box 284, Huntingdon, Cambs PE28 9WT, UK.

Tel/fax: 01480 462 265. Mobile: 07836 297 168email: wingsnwheels@dial.pipex.com

48 E.F.-U.K.

NEAT Fair16-18 September 2005

by John AndersonDownsville, NY, is now firmly established as the place to be for electric flyers inNorth East America on the third weekend in September. A few make long journeysto be there, a thousand miles or so!At this point I have to confess that some of my notes cannot be found now that Iam back at home. Accordingly not all the photos have full captions and some haveonly what I can remember or given to me on a piece of paper by the modeller.

Own design sailplane by Joseph Dellutris named Rita. 4m span powered by AXI 2826-10with 14” x 7” propeller and 2S2P 2000 mAh

E.F.-U.K. 49

Last year the meeting was washed out by 14 inches of rain in 24 hours. This yearthe weather was much kinder. Most of the time it was sunshine and varyingamounts of cloud. The site opens on the Thursday for traders but also manymodellers arrive to claim a good position to pitch their canopies including myfriends from Syracuse who provide cover and seats for me.As the weekend wore on the sun increased and by Saturday lunchtime the crowdwas four or five deep to watch the lunch time demo flights. Generally the windwas light but being in a valley occasionally a gust would funnel through.Each year I try to take out a model that is produced in U K. My selection islimited to a model that can be transported easily. This year I had been playingwith a P-51D from Electro Flight.This is basically a Depron model with a printed paper overlay. I selected theSpitfire from the range and undertook the pasting of the printed paper to theDepron at home. This enabled me to transport it in my checked suitcase sandwichedbetween my unmentionablesAssembling the model and installing the motor, ESC, servos and links wasundertaken at my daughter’s home in upstate New York. Range checks and testflights took place nearby and attracted most of the children (and some dads) fromthe nearby houses. With the test flights completed it was off to the Fair.

A Spruce Goose from Laddie Mikulasko, span 86” and powered by 8x Speed 400 motorseach powered from 8 cells in a combination of series and parallel. Weight around 9lbs.

50 E.F.-U.K.

So what was new. Nothing I saw couldbe described as revolutionary. Thecharging of LiPos is where safety is beinggiven priority. “Astro” Bob Boucher hasdeveloped the ‘Blinky’ cell balancer (seepage 23) and Kokam are charging eachcell in a series pack individually.

These two are tackling the problem from different angles although both requireeach cell to have a tap to a terminal. Astro Flight Balancer is used with a chargerconnected in the usual way and the balancer connected to a tap from each cell.The circuitry looks continually at the voltage of each cell to three decimal pointsand discharges the higher voltage cell(s) to reach equilibrium. Only a small numberhave been made for test purposes but they should be available later this year.With Kokam it is simply each cell being individually charged by a special charger.The Kokam Balance Charger comes for 2 series and 3 series cells and detectswhen each cell is full and shuts down the charge to an individual cell as it peaks.A different charger is needed for 2S packs and 3S packs which makes the set uprather expensive as they may not be suitable for other brands of LiPos. PersonallyI am drawn towards the Astro gismo but before I can consider this I need to get my3S LiPos tapped. Is this a job for a modeller or should it only be trusted to aspecialist? I look for guidance. (Editor: see my notes on page 24)

Beautifully built Antoinette about 6ft span.Only a few seconds in the air before stalling

E.F.-U.K. 51

Some new models were on show, the most noteworthy from a commercial concernbeing the B-25 Mitchell from Hobby Lobby. A kit should be available towards theend of the year with pricing in the region of $500.An exceptional model of an Antoinette was on a stand by the truck of Don Bosquetalthough I am not sure that he had built it although it was in his style. DaveBarron, the regular B-17 pilot, was recruited to test fly the model. But as you willsee from the photos the angle of climb shortly after take off was too steep and asecond or so after the photo it stalled. Repairable in the workshop where no doubtthe C of G will be examined.The Hobby Lobby stand was decked out with about 20 models from their range,although they had taken the decision not to sell direct. Every one who has visitedthe USA will know that the price on the ticket will have sales tax added at the till.This varies from state to state but is not applicable to sales made and shipped toresidents of other states or exports.Hobby Lobby had taken the view that by selling at the NEAT Fair they maybecome caught by the New York tax system and this would mean all sales to NYresidents would be taxed, instead of tax free coming from their home state ofTennessee. They have been supporters of the Fair since inception and this yearprovided raffle prizes for the draws on each of the three days. The star was theGee Bee complete outfit which had been flown regularly in the hours leading up tothe raffle. A very generous gesture as its value must be at least $1000.There is a down side to this well attended meeting, over 250 pilots registered thisyear. It is the lack of accommodation in the area. Most motels within 20 miles are

Hobby Lobby B-25 Mitchell. 19lbs 2x AXI 4130 driving 15” x 8” propellers on 6S3P

52 E.F.-U.K.

Also from Laddie this Blohm und Voss, span 50”, weight 4¼lbs, 2x S400 with 2:1 boxes

Spectator line for the Saturday demo hour.

small, not more than 15 or so rooms, and are often booked up months before.Camping is popular and there is plenty of room on the site for mobile homes andtents. Caterers provide a good selection of food from early morning to evening.The campers using tents can rely on sustenance without having to leave the site.I shall go again next year, God willing, as I get 3 days away from my grandchildren!

E.F.-U.K. 53

Balsacraft fan Edward Brimo brought three models to the Fair. Sea Fury powered byAXI 2820-10 with 10.5” x 6” propeller and Kokam 3S1P 2100 mAh. Spitfire powered by

Phasor 30/3 and 10” x 7” propeller and Thunder Power 3S7P 3200 mAh. Bearcatpowered by AXI 2820-12 with 10” x 7” propeller and Thunder Power 4S2P 4200 mAh

This autogyro is built by Dave Ramsey based on a design of Mickey Knowles. Uses ahelicopter linkage to the rotor (kit bashed 2 sets to make up head) and set the head in

GWS gearbox. Flew nicely in the calm conditions

54 E.F.-U.K.

Here is Dave Barron with the Joe Bashir B-17 making final preparation for yet anotherflight with this impressive model.

Ric Vaughn drove from Atlanta with his workshop trailer housing this enormous model.Don’t have details but it has a floodlight system making night flying a piece of cake

E.F.-U.K. 55

Apologies to David ? This 10 year old flew a superb slot in the lunch time demo. Sorryno details of this pattern ship but I remember that 800W was available at full throttle.

Flown by Hobby Lobby was this Funtana. Power was Hacker C50XL with 6:1 gearbox.10S3P Tanic cells gave urge to this 9lb model

56 E.F.-U.K.

The writer’s Electro Flight Spitfire. Tweety Torque motor with Jeti 8-3P controller andKokam 3S1P 640mAh pack turning GWS 7” x 4.3” propeller

E.F.-U.K. 57

Perkins ARTF Tiger Mothby John Thompson

This kit is by Green R/C Model Airplane Co Ltd made for J. Perkins, spans 50”(128cm), and is designed for a .30 cu. in. (5cc) 4-stroke glow motor. Mine wasbought part assembled from my local model shop, where it had been in this statefor some months. The assembly appears straight forward as all the main partsare supplied covered, even the decals fixed in place.The tail unit is attached with two bolts from below, and here was one of the changesI made. The kit includes a tail wheel, and I have never seen a Tiggy with one ofthose, so a steerable skid was made, much better for our grass runways.The rudder servo is coupled to an idler that protrudes through the fuselage sides totake the closed loop wires in scale fashion. This idler is supplied made from CNCcut plywood that did not seem very good to me, so a replacement was made out offibreglass circuit board (see below).

Beside the rudder servo is the elevator one and this also has closed loop connections.I was concerned that these actually twist through 90° so a simple addition to thetray turned the servo to be in the same plane as the elevator hinges. Both thesecontrols now worked in a smooth fashion and gave accurate neutrals.The ailerons use separate servos with short rods, so were no problems here. Perkinshad included some of their own items in the contents of the kit, with an addendumto the instructions.

58 E.F.-U.K.

These included metal quick-links with springs to secure them. I found these linksrather tight on the threaded connectors, and had one strip. The landing andflying wires also use these links which fit into alloy angle brackets, and thesewent together quite well. One thing would improve it, a moulded corrugated coverfor the centre section tank.The electric conversion was not difficult as the deep cowling gave space under themotor for a battery pack. This cowling is a superb light, fibreglass moulding butthere was no indication as to exactly where or how it should fit. I installed it as farback as possible using a hardwood block below and an alloy bracket above to takeself-tapping screws. My first choice of motor was an AXi 2820/10 that I had spare,and it was installed in a simple plywood mount with speed controller behind.Under it a ply box was fitted tailored to fit a 3s2p 2600 LiPo battery. Access to thisis a removable panel between the undercarriage ()shown below) and the firewallthat has two Balsa rails to stop the cells from moving backwards. Scale air intakesare used and the floor of the front cockpit was removed to allow the cooling air toexit. With this layout the CG was too far back, so against my usual principleslead was added to the battery box.The motor was pulling 20A on an 11” x 7” propeller so it should fly. However thefirst flight showed that more lead was needed. The model showed promise, althoughfull throttle was required most of the time. In true Tiggy fashion a dive precededany attempt at manoeuvres, and flights of six minutes were easily accomplished.

E.F.-U.K. 59

Later one of the new 18/15 outrunners from Plettenberg was tried, and this was alittle better, but pulled more amps. A new pack of 2200 LiPo from FlightPowerproved to be much lighter so needed even more weight. In the meantime I had hadthe lucky escape with my Diablotin (see the last magazine) so was even morecareful with LiPo.Looking through the specifications a new AXi was chosen to give more power andreduce the deadweight a bit. The 2826/12 happily swings a 12” x 7” propeller andimproves the flight performance noticeably. It is now possible to throttle back andhave power to spare, and thecontrols are well synchronised.Then my local shop had some ofthe new Saphion cells in fromOverlander. These are LithiumPhospate (LiPh) cells whichpromise improved safety (againharking back to the Diablotin).Two 4-cell 1200mAh packs werebought. Saphion cells are only3.2v/cell, lower than LiPo, but the4s pack gives extra volts which

60 E.F.-U.K.

should also help. The 2p configuration and 15C continuous rating, gives 36Amaximum. Interestingly they also quote a 2C charge rate, which makes fieldcharging the cells more practical than LiPo.These packs are almost twice the weight but better that than lead. A small batterybox mod and they fitted snugly. So that I could use the individual packs in smallermodels 2mm gold connectors were fitted, and 4mm parallelling adaptors made.The CG came out dead on without the lead, and the Tiggy will now leap into theair and do consecutive loops with ease. This means scale speed is now half throttle,and ten minute flights with power left to taxi back. I could still experiment withdifferent propellers but it all works fine so what’s the point if the model flies well?It is now a pussy cat to fly and has the presence of the full size as long as you do notopen the taps.My model weighs 3lb. 10oz. (1.64kg) without batteries, about the same as the ICversion without fuel. Batteries-R/C Smart LiPo 2600 3s1p 6.2 oz. (174g)FlightPower LiPo 2200 3s1p 5.0 oz. (141g)Saphion LiPh 1200 4s2p 12.3 oz. (348g)So Saphions are heavier than LiPo, but safer, lighter than NiMH - time will tell.

E.F.-U.K. 61

A Smarter Dartby John Stennard

I’m going to begin with some background information before launching the SmarterDart. I am a committed electric flier with a particular interest in indoor flyingand as a result also organise the indoor flying sessions for our club. As part of myindoor interest I write monthly features for two model magazines and this combinedwith my club involvement, has resulted in a constant search for a model that canbe flown as an indoor trainer but also be enjoyed by flyers with more experience.I regularly fly in different sized venues that vary from a one basketball court gymto a five badminton court sports hall. At last believe I have found a model that canbe flown comfortably in the smallest to the largest hall and put a smile on anyflier’s face. Before going into details I think it is worth spending a short timelooking at the requirements of an ‘indoor’ trainer.Firstly it needs to be easy to fly and relatively impact proof. Outdoors the ‘impactproof’ requirement does not rate the same importance as indoors where floor/wall/ceiling impacts (plus the occasional mid-air!) are a constant hazard. A light wingloading is essential to enable the model to be flown slowly plus enough power to getout of trouble. A suitable model combined with a good power system should benefitfrom a high power/weight ratio. A ratio of 2:1 is easy to achieve using the correctmotor/battery combination and will provide a high degree of agility.Agility is extremely important when flying in smaller spaces and can frequentlysave models from collision damage. A reasonable duration is need never a problemand anywhere between 5-10 minutes is easily obtained and perfectly adequate. Infact in crowded venues you might be unpopular if you stayed aloft for much longer.Most electric enthusiasts now accept that while many models perform perfectlywell, or are even particularly suited to brushed motors and NiCd/NiMH cells,indoor models are at their best when combined with brushless motors and Lithiumcells. The model I am writing about in this feature is powered by a low cost,brushless motor and flies extremely well using a 2s1p LiPo pack. The GWS IPSsystem is suggested as an alternative but I’m personally only interested in fittingthe optimum power system.Now let’s take a look at the model. Paul Cook produces a number of excellentplans for electric enthusiasts. These are all small high performance electric poweredmodels, and the plans are extremely well drawn and printed. Paul’s plans areavailable direct from him at flightline@hotmail.co.ukOne of Paul’s plans is for an enlarged RC version of the rubber powered BMFASmart Dart and is called the Smart Dart ‘XS’. His model has a 560mm (22”)wingspan and weighs around 125g (4.4oz.). Paul’s first version of this model hasa 3mm (1/8”) balsa fuselage and built up wings, tailplane and fin using differentwidths of 3mm strip balsa. The flying surfaces are covered in lightweight film

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and the model uses rudder and elevatorcontrol. I was quite surprised when Paultold me that his model hovers well but thiswas confirmed by a photo of him and hismodel and I’ve since proved it veryconvincingly for myself.

The arrival of our indoor season coincidedwith a gap in my ‘model reviewing’ scheduleso I decided to build a Smart Dart ‘XS’myself. Anticipating that I would buildthis model I had already purchased one ofPaul’s ‘Aircraft-World’ type CD-ROMconversion motors (right).Paul’s motors are ready to run and at the time of writing cost just £16. Searchingin my building material storage boxes soon revealed a deficit of 3mm balsa but asurplus of 3mm Depron foam.I was about to abandon the project until I had a chance to restock with balsa whenI realized that I could substitute Depron for balsa on the flying surfaces. Withoutthe natural rigidity of the balsa framework I would have to use some CF strip forstrengthening but otherwise there seemed to be no problems. Using foam allowedme to build the model in a couple of hours.The fuselage was built exactly as per the plan complete with undercarriage andmotor and 3mm Depron used for the wings, fin, rudder, tailplane and elevator.The only modification I made was to use a straight trailing edge on the elevator tokeep this parallel with the front edge and give some additional strength.The wing leading edges required stiffening and I used a very convenient 3mm halfround section strip of CF rod obtained from Woolmer Forest Composites. Flat3mm CF strip or even 3mm square balsa or spruce could be used. The half roundCF on the leading edges did affect the C of G but I’ll come back to this later.Apart from the wing leading edges the only other strengthening was a length of3mm CF strip on the rear edge of the fin and on the front edge of the elevator. 3M

Blenderm™ tape (left)hinged the control surfaces,coming from OnlyRC. Thisfirm sells this excellent tapeat a price much lower thanyou will pay in the chemistsand in three differentwidths. The wings werejoined with epoxy and nodihedral braces were used.

E.F.-U.K. 63

With the model assembled I soon found that I would have to move the servos fromthe position shown on the plan to achieve the correct C of G. The foam wing withthe CF on the leading edges had made the model nose heavy. However it was quiteeasy to move the 4.4g Titch servos from Perkins rearward to enable the correctCofG to be achieved. A bonus here was that the control rods would be very short.

The length of the lead from the controller, a Phoenix 10 from Castle Creations,and the length of the servo leads establishedthe position of the RX, this was then held inplace with Velcro. The battery location,again using Velcro was established near theCofG as this allows different weights of packto be used with having to move the batterypack too much in either direction.

I was delighted to find that the Smart Dartweighed just 100g (3.5 oz.) without a batterypack. I had three sizes of 2s1p LiPo packsavailable to try and these were a 310 mAhpack from WES-Technik, a 350 mAh Kokampack from Robotbirds and a 450 mAh E-Tecpack from Puffin Models. These weighed19g (0.67 oz.), 22g (0.78 oz.) and 25g (0.89 oz.)respectively.

64 E.F.-U.K.

So with my lightest pack my depronDart had an AUW of 119g (4.25 oz.)and with the heaviest 125g (4.5 oz.).Initial flights were made using aGWS 7” x 5” propeller but I laterchanged to the APC 8” x 3.8”propeller recommended by Paul forthis particular motor.I very quickly found that the SmartDart ‘XS’ is a delightful model to flyand our one basketball court gymprovided plenty of space. It can beflown safely in different ways, slowor fast level flight, slower flight withmedium alpha attitude or very slow

extremely high alpha ‘hovering’ flight. The design of the model with its ampledihedral makes it very stable and with Paul’s motor and a 2s1p pack it will hovereasily and perform loops from level flight.In fact it is one of the easiest models I have flown in hovering flight. It will roll,somewhat reluctantly, but rolls off the top of a loop more easily. Considering its‘specs’ I think that the Smart Dart ‘XS’ has an absolutely amazing performance.

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With some expo and reduced movements on the control surfaces I think this modelwould make an ideal trainer. However well past that stage you might be it’s stillgreat fun to fly and ideal for multi plane flying where you might not want to riskyour best 3D model.My opinion was shared by the other regular club indoor flyers especially those onthe same mode who had a go on the sticks. The enthusiasm shown was such thatthis model is likely to become the recommended model for anyone who wants to flyin our rather restrictive one basketball court flying space. A ‘standard’ model likethis would be perfect for fun events like Limbo and I know the Smart Dart ‘XS’population in our club is about to increase rapidly.I found that while the 310 mAh battery pack was perfectly adequate for generalflying and offered the lowest weight. The 350 mAh or 450 mAh packs are preferableif you want to spend a lot of time looping and hovering. The 450 mAh pack givesa 20 minute plus duration.Personally I like to decorate even functional models, particularly if they are madefrom white foam, so I applied some simple but eye-catching colour to my SmartDart ‘XS’. I used felt pens for the layout and acrylic paint for filling in.

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Delighted with my foamversion I got in touch withPaul to praise his designand found out from himthat a plan for a foamversion was nowavailable.After seeing how well myfoam Smart Dart ‘XS’ fliesI am going to now buildthe balsa version. Ifcovered with translucentfilm I think it will lookparticularly attractive inthe air when the openframework will be visible.If you are looking for acheap, multi-role, indoormodel with a sparklingperformance look nofurther than Paul Cook’sSmart Dart ‘XS’.

ContactsPaul Cookflightline@hotmail.co.ukFlight Line Plans, BourneCourt, Ragged Appleshaw,Andover, Hants, SP11 9HX

Puffin Modelswww.puffinmodels.comTel 01454 228 254

Robotbirdswww.robotbirds.comTel 0208 841 7873

OnlyRCwww.onlyrc.comTel 01702 477 626

Woolmer Forest Compositeswww.woolmer.co.ukTel 01428 712 126

E.F.-U.K. 67

Intermodellbau 2005by Dave Chinery

As models shows go, the Americans have the quaint impression that their Toledomodel exhibition is the biggest. In fact the annual Intermodellbau show atDortmund in Germany is much bigger, with just the aeroplane hall, by itself,outsizing the Yanks!This year’s show was open from the 13th – 18th April, and was attended by a largenumber of British modellers. Although the state of the German economy and theEuro means the knock-down prices of a few years ago are no more, the show’s wellworth attending for the huge variety of models and accessories, either new, ornever seen in the UK.The show is even easier to get to now! We used to drive over – it’s about 400 milesfrom West London via the Tunnel, and the BMFA have organised coach/hotelpackages for those who won’t drive. However, from this year EasyJet have atwice-daily service from Luton direct to Dortmund Airport, just a bus ride fromyour hotel, and this year’s fare was only £31 return, booked well in advance!

Marble halls!The huge exhibition complex is right next to the stadium of the famous BorussiaDortmund football club, and hotels are within easy walking distance of the doors.As usual, this year’s show occupied eight halls, the largest of which, Hall 4, isdedicated to flying models of all types. The smallest hall, 2N, is still big enoughfor the indoor flying demonstrations, with Shock Fliers doing rolling loops throughthe roof girders!Of the rest of the site, Hall 1, the original Westfalenhalle, is full of model boats,Hall 2 is mainly model cars and fire engines, and Hall 3 contains a big indoor R/Ccar race-track and spectators bleachers.This year, a new Hall 3N contained a separate Computer and Games exhibition,with free entry from the Modellbau. Halls 5 and 6 are mainly devoted to R/C cars

68 E.F.-U.K.

and trucks, with a big arena full of 6ft-long artics and scale model contractor’splant, the latter shifting piles of dirt from A to B then back to A again – whateverturns them on! The Germans are into this in a big way, with many modelsfeaturing miniaturised real hydraulic systems.Hall 5 also contains the Conrads stand – a magnet for modellers and electronicsbuffs of all types. Conrads is the German equivalent to Maplins, except that itcarries an extensive range of model products as well. The stand is set up like asupermarket, through which a densely-packed line of customers shuffle. The binsof goods contain a vast range of items, from solder to epoxy to assorted modelwheels, and usually cheap servos. This year, I bought good quality standardservos with accessories, for a mere • 4 each!Halls 7 and 8 are for railway fans, and the latter is filled with enormous layoutsfrom societies all over Europe. They even lay on little “play” layouts for the youngervisitors to have a go! Another branch of the hobby, which I saw for the first timethis year, was a stand selling a construction system for design-your-own miniatureroller-coasters. Loops, spirals and “stall turns” can all be included in your owntable-top “white knuckle” ride! Helps to cover the ups and down of the Germaneconomy, I suppose!

Plane speaking!Hall 4 is the one I spent most time in, looking at the myriad models and accessorieson sale from all over Europe. As usual, most of the models, kits, ARTFs andaccessories on offer are seldom seen in the UK. With the German economy indecline, the “good old days” of super-cheap prices have gone, along with traderslike Langnickel, and many smaller vendors like WeMoTec can no long afford tohave stands at the show, but their wares are available from some of the retailersstill at the show. All the major manufacturers like Graupner, Robbe, Simprop,Aeronaut and Jamara had display stands at the show, but there were no real eye-catchers in the way of revolutionary new models, except for the latter (see below).Simprop were showing their “TurnLeft” pylon-racers, which suit the new F5Drules, together with their existing trainer pair of Pilatus PC-9 and Harvard 1.

Dortmund 2005 Hall 4

E.F.-U.K. 69

They also showed a badge-engineeredversion of the SuperNova charger with,according to them, more advancedfeatures including Lithium programs.Graupner showed a range of new models,smallest but not least was a tiny Junkers52 trimotor park-flyer. It looks thepicture for those able to combine a calmday with short grass, although the littlemodel could obviously be hand-launched.

The colourful Hollein stand had its usualselection of kit-build models, and thisyear showed an all-moulded Speed-400-size pylon racer, the Voodoo.Among the smaller manufacturers,PAF Modell has its usual range of ARTFmodels, ranging from big gliders toelectric scale types. These included anice Grumman Albatross and two sizesof PBY Catalina seaplanes. FrankenModellbau have been previouslyassociated with sport and scale typemodels. My big P-47 Thunderbolt camefrom the range, but this year their standwas almost monopolised by electric andconventional soarers.FVK Modell occupied their customaryplace in a corner of the hall, and, inaddition to their well-known range ofhigh-tech soarers like the “Simply theBest”, “Organic”, etc, offered a new

electric sportster, the ROCCO-M. Witha sleek moulded fuselage and plug-onwings, it really looked the part of a lightyet manoeuvrable Sunday flyer. Thismodel was right up my street, but Iresisted as I already have too manyairframes (wanna buy a Brabazon?).However, clubmate Tom Lambertsuccumbed (see photo left) and his wascompleted in record time and flies atreat! Another model I did like was a

70 E.F.-U.K.

large (about 70” or 1.7metres) ZlinAcrobat, reminiscent of my own-design“Czech-mate” but bigger. This was seenon the Jamara stand, but this was a non-retail display and I couldn’t find oneamong the retail sites.Elsewhere in the hall, the legendaryBatt-Mann was doing his usual roaringtrade, with customers scrumming fivedeep to get to his counters (photo takenmoments after the doors opened).

I found some of the excellent newGP1100 cells, which will be essentialthis year for me to remain competitivein the E-400 competition. The same sizeas the old Sanyo 500ARs, these new cellspack over twice the capacity whilehaving a much lower internal resistancethan the KAN1050s I bought last year.(Since using these new cells, the climbrate of my model has been transformed– but I don’t know how long the “hot”4.8V Speed 400 Race motor will last!)

I have been used to seeing the RamoserVarioPROP stand (right) at successiveDortmund shows, but have neverpreviously been tempted to buy one.However, this time, I bought a 3-bladedunit with the “Harvard 2” in mind. It’sdifficult to match motor load and modelperformance when changing from a 2-bladed propeller to a 3- or 4-bladed, sothe adjustable pitch feature of theseingenious propellers would give me aconsiderable “fudge factor” to play with.

Ramoser produce propellers in varioussize ranges and with from two to fiveblades! They even produce forked metalroots to take standard 8mm foldingpropeller blades, allowing a very widerange of sizes to be assembled. Adaptersare also available for standard spinners.

E.F.-U.K. 71

As usual, about 30% of the hall wastaken up with models on display, rangingfrom huge model airliners and raremilitary types, to daringly-decorated“Funky Chicken” models. In contrastwith the up-to-date stuff, there was anextensive display of vintage & veteranmodels with gliders, rubber models,compressed-air, and i.c. types. Theusual selection of “wacky” models with7 wings and 3 undercarts were there too.

Making an exhibition!This year’s Dortmund show wastechnically very interesting even if theprices were no great shakes. It was easyto see that the German economy is nolonger buoyant, which was reflected inthe smaller number of stands (Editor:and the comments of the traders).

Notable absentees were OliverWennmacher’s WeMoTec and Airworld,however, product from both thesesources were available elsewhere in thehall. Unfortunately the exhibition is notimproving with time, we’ll have to seehow things fair.However, using the EasyJet route makesit much more accessible than hitherto.

This saved a day travelling and alsosaved a night in the hotel. (Editor: Davedidn’t mention that the cost was lessthan the fuel and fery or tunnel costs.The only restriction is you are limitedin what you can bring back and youcan’t stop at Aucan or the WineMerchant’s before the return crossing.)I’m definitely going again next year!(Editor: Me too!)

72 E.F.-U.K.

Electric Flight CalendarIf you would like details of your event to appear in these pages please send fulldetails to the Editor EF-UK, contact details on page 4. Please bear in mind thatthis magazine is quarterly so ensure that the details are sent in good time.For last minute information on events please check out the events list on theBEFA website (www.befa.org.uk). Dates, times and, even, locations of eventscan change at the last minute. You are strongly advised to check on events withthe given contacts before setting out on your journey to any event.All BEFA flying events require proof of BMFA (or equivalent) insuranceand an ‘A’ Certificate to fly. For fixed wing models, any of the fixed wing ‘A’certificates are acceptable. For helicopters, a helicopter ‘A’ certificate is required.

All flying models must have been satisfactorily flown at least twicesince build or repair before flying at a BEFA event.NO TEST FLIGHTS ON THE DAY

January 20061st The Brighouse Vintage MAC have been using the small airfield at

Tockwith, near Wetherby, Yorkshire for several years, but haverecently had noise problems. The field is now all electric and anyBMFA Member is invited to fly there on the First Sunday in eachmonth from 10 to 5pm for a small fee. Do not be put off by the 'Vintage'part they fly anything! There is a concrete runway available anddetails of the site can be had from Derek Haviour on 01422 204 472.

14th BMFA Northern Area Indoor RC Flying at the Garforth Squash& Leisure Centre, Ninelands Lane, Leeds, LS25 - off the A63, Leeds-Selby Road. Flying from 2pm to 5 pm. Separate slots for Slowfly,Aerobatic, Scale and Helicopters. Sub 350 and equivalent brushlessmotors only. Any legal frequency. Proof of BMFA membershipessential. No free flight or IC. Spectators £1 on balcony, Pilots £5.00(Juniors £2.00). Contact John Thompson on 01924 515 595, or emailhim at johnty99@ntlworld.com

14th North London MFC Indoor R/C Meeting. Fixed Wing 225g max,Heli 400g max. 6pm to 10pm. Furzefield Sports Centre, Potters Bar.(J24, M25). Contact Peter Elliott on 01707 336 982.

14th Waltham Chase Aeromodellers Indoor RC Meeting. 7 to 10pm.Havant Leisure Centre, Havant, Hants. Call Alan Wallington on01489 573 141 or Chris Carr on 0238 043 7805 or check outwww.wcaero.fsnet.co.uk

E.F.-U.K. 73

22nd Black Lion Indoor Fun Fly. 10am to 5pm. Black Lion LeisureCentre, Gillingham, Kent. Contact Brian Millgate on 01634 570809or Neville Legg on 01795 877 918 or at nevlegg@aol.com or seewww.medwaymfc.co.uk

February 20065th The Brighouse Vintage MAC - see 1st January for details.

11th North London MFC Indoor R/C Meeting. See 14th January.

18th BMFA Northern Area Indoor RC Flying at the Garforth Squash& Leisure Centre. See 14th January

18th Waltham Chase Aeromodellers Indoor RC Meeting, see eventon 14th January for details.

22nd Black Lion Indoor Fun Fly. See 22nd January for information.

March 20065th BEFA 2006 Annual General Meeting & Traders’ Fair at the Royal

Spa Centre, Leamington Spa. See page 6 for more information.

5th The Brighouse Vintage MAC - see 1st January for details

11th North London MFC Indoor R/C Meeting. See 14th January.

18th BMFA Northern Area Indoor RC Flying at the Garforth Squash& Leisure Centre. See 14th January

18th Waltham Chase Aeromodellers Indoor RC Meeting, see eventon 14th January for details.

19th Impington Village College Indoor Meeting. 9am to 5pm – FlyAll Day. Including Bostonian Comp and Separate RTP Hall. Impington,Nr Cambridge. Contact Chris Strachan on 01223 860 498 or atchris.strachan@btinternet.com

April 20062nd The Brighouse Vintage MAC - see 1st January for details8th North London MFC Indoor R/C Meeting. See 14th January.

May 20067th The Brighouse Vintage MAC - see 1st January for details

June 20064th Hayes & DMAC West London Fly-in at Cranford Park, Hayes.

More details to follow.

74 E.F.-U.K.

4th The Brighouse Vintage MAC - see 1st January for details

24th - 25th Wings & Wheels at North Weald Airfield, Nr Epping, Essex, CM166AA. Email wingsnwheels@dial.pipex.com

July 20061st - 2nd BEFA Middle Wallop Fly-In. Possibly the largest electric event in

the UK. The Saturday is shared with the League event. Only even35MHz frequencies can be guaranteed as available, but it is plannedthat the odd frequencies not in use by the league event will be alsoavailable. On the Sunday all 35MHz frequencies will be available.More details to follow.

2nd Ebor Silent Flight meeting on the York Racecourse.

2nd The Brighouse Vintage MAC - see 1st January for details

9th Chester "Roodee" Electric Fly-In.

August 20066th The Brighouse Vintage MAC - see 1st January for details

18th - 26th 2006 FAI World Electric Flight Aeromodelling Championshipsfor classes F5B and F5D in Pitesti, Romania. For more details contactMihail Zanciu at mzanciu@modelism.mcit.ro or Marius Conumconu@modelism.mcit.ro

September 20063rd The Brighouse Vintage MAC - see the event details on the listing

on 1st January.

October 20061st The Brighouse Vintage MAC - see 1st January for details

November 20065th BEFA 2006 Technical Workshop & Traders’ Fair (provisional

date) at the Royal Spa Centre, Leamington Spa, Warks. All theusual fun of the fair.

5th The Brighouse Vintage MAC - full details of this regular event onthe 1st January listing.

December 20063rd The Brighouse Vintage MAC - see 1st January for details

E.F.-U.K. 75

Member's Sales & WantsFOR SALE / WANTED

The items below are for sale by Trevor Wain, contact at trevorwain@tiscali.co.ukor on 01332 792 508.

• Puffin Models Elegant, 2.6m glider / electric glider. Flown twice, butother interests took over - no equipment fitted. Offers around £100.

• Kontronik Smile 40-6-18 opto, brushless, speed controller, 40A 6-24V with Kontronik 4mm silver connectors on the output and Schulze 3.5mmconnectors on the input and has been used twice. He would like to exchangefor the same or very similar with BEC or sell for £65.

Neil Stainton is selling the following items. All are plus postage or can be pickedup from Leamington Spa. Contact Neil Stainton on 01926 314 011 or email him atNeil@ITpartnership.com

• Schulze 6-636+ 8A charger for 1-36 NiCd / NiMH cells & 1-11 LiPo cells.V8 software: £179

• New Blade Runner indoor helicopter, including 27Mhz R/C, LiPobattery & charger: £49

• Hornet Helicopter FP VGC, with carbon blades: £35• GWS PG03 gyro: £19• Blue Arrow 4.3g servos, new, boxed £8.95 each• Blue Bird 3.4g quality micro servos with coreless motor £11.95 each

Jim Horne has a WeMoTec Midi-fan with Aveox 36/24/2 sensorless brushlessmotor for sale - £70. Email Jim at HORNEGb@aol.com or phone 01388 819 638

For Sale by Martin Collins. Contact Martin by email or telephone on 01908 583545 (Milton Keynes). Can be picked up from me in Milton Keynes

• KYOSHO T-33 in Thunderbirds aerobatic colours. Comes with the motor& fan unit installed (I was told it was a WeMoTec fan but I cannot confirmthat). Good condition apart from a couple of the decals missing. Price is £60(no offers).

• RIPMAX ARTF SPITFIRE fitted with AXi 28/20/10 and model motorsbrushless controller. The Spitfire has 2 mini servos in it (aileron/elevator) andcomes with an 8 cell 2400 Sanyo pack and 11" x 7" propeller. Just fit yourreceiver to make it a flyer, selling due to house move and other projects it hasonly 6 flights from new on it, price is £200

76 E.F.-U.K.

Neil Stainton wants a Highlight Electric Fuselage, any condition. Contact Neilat Neil@ITpartnership.com or on 01926 314 011

Peter Vivian would like to contact any others in his approximate area (Camberley,Surrey) who are also new to Electric Flying, with a view to mutual assistance andsupport. Peter returned to model aircraft fairly recently after a 55-year break,with an interest mainly in building and experimenting (definitely NOT ARTF!).He would like to meet up with others having similar interests. Contact Peter byemail at PGLV@aol.com or on 01276 21 304

Wanted by the Editor, any of the following (see page 4 for contact details):

• General / Technical Articles.

• Hints & Tips.

• Product Reviews.

• New Product notifications.

• Electric Flight Event Reports.

• Photographs of your models.

• Other items of interest.

Please send colour Digital photos or photographic (6” x 4” or bigger) prints tothe editor. Please do not send inkjet prints as too much quality is lost duringthe printing and scanning process. If you have no way to write the files to aCD, contact the Editor for other options.

Photographic prints supplied will be returned, unless specified otherwise (aslong as you give a return address).

Digital photos should be sent at the highest resolution possible, in colour, andpreferably uncompressed. Where compression is unavoidable the camera shouldbe set to the lowest compression possible. Photographs can be emailed to theEditor at editor@befa.org.uk

Readers want to know what equipment is fitted to models so they know whatcombinations work well. Therefore please include as many details of the modelsin the photographs as possible, but ideallt at least span, power train, batteryused & flight performance.

Where articles are produced on a wordprocessor package, please include anelectronic copy - it make the Editors job much easier and quicker. Ideal formatsare Microsoft Word (any version), Works wordprocessor, WordPad or Notepad.Other formats can be accommodated, but please contact the Editor first.

E.F.-U.K. 77

New to ELECTRIC FLIGHT?START HERE . . . . .

You may be taking up Electric Flight for the first time or you may be convertingfrom another discipline. Whatever your situation, help and advice is available.BEFA has prepared an information sheet which details further sources ofinformation which you may find useful when just joining the hobby. To receive acopy, please send a Stamped Addressed Envelope (S.A.E.) to Robert Mahoney,address on page 4.

BEGINNER'S GUIDEA Beginner’s Guide to Electric Flight is available, which explains many of the‘Mysteries' of Electrics’ and will, hopefully, set you off on the right foot. Pleasesend £3.00 per copy required to The Editor of EF-UK at the address on page 4.Please add £1.00 extra for overseas postage and remit in Sterling. Cheques shouldbe made payable to BEFA.

TECHNICAL HELP SERVICETechnical help is now available again for the use of all members. We regret thatno telephone service is available, but all questions in writing (or email) will beanswered by our Technical Liaison Officer (TLO). Please refer your queries to ourTLO, to the postal or email address on page 4. If sent by post, please ensure thatyou include an S.A.E. for a reply.

CONNECTIONS SERVICERequests are frequently received from members who wish to be put in contactwith other members living in the same area. The easiest method of doing this isto place a free 'wanted' advert in the classified section of this magazine.Alternatively, a request may be made IN WRITING to the Membership Secretarywho is allowed to divulge such information to members ONLY. Please supply asmuch information about your location as possible and please remember to includean S.A.E. for your reply.

B.E.F.A. MEMBERSHIPMembership of the Association is open to all. Those who are not members ofBMFA (our national controlling body) will have a subscription to EF-UK membershipwith none of the other benefits. Overseas members are very welcome and will beclassed as full members if they belong to their own national controlling body.

CONTACTFor full details, please send an S.A.E. to the Membership Secretary (address onpage 4) requesting a membership application form. Those with Internet accessmay visit the B.E.F.A. website at www.befa.org.uk where you will find all themembership information you should require and a application form.

78 E.F.-U.K.

B.E.F.A. SalesBEFA Round, Coloured Rub-down Decals - Ultra-thin & light - 50p each

EF-UK Back Issues - Issues 71 to 73 and 75 to 81 are available to BEFA membersat £3.00 each, or £5.00 each to non-members. These prices include UK P&P,overseas rates on application. Reprints of earlier issues may be available to specialorder at slightly higher cost, contact the Editor for details (see page 4).

EF-UK Index. A comprehensive index of EF-UK, from issue 28 to date, is availableby sending a £1 coin to cover copying and postage cost.

Binders:- are available to hold 8 to 12 issues of Electric Flight U.K. Produced indark blue with gold lettering on the spine, these cost £4.50 each including U.K.postage. Please add £1 for European postage and £2 for Worldwide postage.

Please send all orders to The Editor of EF-UK at the address on page 4.

Sweat Shirts & Tee-Shirts: Stock of these is now almost all gone - pleasecontact Robert Mahoney regarding remaining stock, sizes and prices.

PLEASE REMIT IN STERLING ONLY,WITH ALL CHEQUES MADE PAYABLE TO B.E.F.A.

Advertisers IndexBEFA Sales................................................................. 78

Fanfare.............................................. Inside Back Cover

For Sale / Wanted ....................................................... 75

New-2-U ............................................................. 25 to 30

RC Groups / E-Zone ......................... Inside Front Cover

Traplet ............................................Outside Back Cover

Wings & Wheels Model Spectacular .......................... 47

EF-UK advertising rates are £25 per inside or outside cover page,£20 per full page, £10 per half page, all per issue.

Contact the EF-UK Editor for more details (see page 4).

– MAIL ORDER –SPORTS ELECTRIC FLIGHT

FANS AND GEARBOXESwww.fanfare.f9.co.uk

FANSMorley ‘Jet Elec’ Fan .............................. £15.00WeMoTec Micro-Fan (280/300/330) ..... £14.00WeMoTec Mini-Fan (400/480) ............... £28.00WeMoTec Midi-Fan (540/ 600/930) ....... £38.00

GEARBOXESMaster Airscrew - 2.5, 3, 3.5:1 ............................. £18.00MP Jet Planetary - 3.33 & 3.8:1 - 400 / Pro 480 ...... £28.00MP Jet Planetary - 3.33 & 3.8:1 - Speed 480 ........ £28.00MP Jet Planetary - 3.33 & 3.8:1 - 540 / 600 ............ £28.00MP Jet Plastic BB - 4 & 5:1 - 280 / 300 ...................... £8.00MP Jet Plastic BB - 3, 3.5 & 4:1 - 400 / Pro 480 ......... £8.00MP Jet Plastic BB - 2.33, 3.5 & 4:1 - Speed 480 ..... £10.00MP Jet Plastic BB - 1.75, 2.33 & 2.8:1 - 540 / 600 .. £15.00Mini Olympus ............................................ £8.00Olympus ................................................. £12.00

MOTORSMPJet Brushless motors; 9 motors; outrunners,inrunners & geared; 280 to 700 .... £37.00 to £58.00 WEP Turbo 10 ....................................... £55.00Fanfare Silver 16T & 20T ...................... £34.00Fanfare Powermax 40T ........................ £38.00Speed 600 8.4v BB SP .......................... £17.00Speed 600 8.4v Race ............................ £22.00RE 380 / Rocket 400 ................................ £5.00Speed 480 BB ........................................ £21.00Pro 400 .................................................... £5.00Pro 480 HS ............................................... £6.00Pro 480 HS BB ......................................... £8.00

MAXCIM BRUSHLESSMax Neo 13Y 1430 rpm/v ................... £160.00Max Neo 13D 2470 rpm/v .................... £160.00Maxu 35D, 21 Cell Controller ............... £140.00Maxu 35C, 25 Cell Controller ............... £180.00Superbox 1.6 to 4.28:1 ......................... £50.00Monsterbox 4 to 6.8:1 .......................... £60.00Motor Mount ........................................... £12.00

MOTORS / GEARBOXESSpeed 400 FG3 ..................................... £17.00SpeedGear 400 4:1 Inline ...................... £38.00SpeedGear 480 3.45:1 .......................... £55.00SpeedGear 600 2.8:1 ............................ £52.00SpeedGear 700 2.7:1 9.6v .................... £70.00SpeedGear 700 Neo .............................. £92.00Mini-Olympus & RE380 .......................... £12.00Olympus & 540 ...................................... £19.00Jamara 600 2.9:1 ................................... £24.00Jamara 650 2.9:1 ................................... £26.00

PROPSM.A. Folding 12x8 ................ £14.00

15x12 .............. £15.25M.A. Wood Electric 10x6/10x8 ......... £4.00

11x7/11x9 ......... £4.2512x8/12x10 ....... £4.5013x8/13x10 ....... £5.00

Carbon Folders 7x4 .................... £6.00(Perkins) 8x4 .................... £6.00

11x8 .................. £9.00Slimprops 8x4, 8x6, 9x6 .... £3.50APC Electric 5½” - 12” dia . £3 to £4(full range available) 13 ” - 20” dia.£5 to £15

Selection of Graupner & Aeronautfolding & fixed props.

CHARGERSSpeed 1 Pulse / Pk

Det 4-8 cells ........................................... £27.00Speed Ex Digital

as above with discharge ...................... £55.00Simprop 25 cell .................................... £100.00

Wheels, Wire, Servos, Fuses, Caps,Powerpole, 4mm & 2mm gold conns.

FANFARE • 18 HILLSIDE ROAD • TANKERTON • WHITSTABLE • KENT • CT5 3EX‘Sports Electric’ Helpline - Phone / Fax: (01227) 771331 - E-mail: john.swain1@virgin.net

Now online at - www.fanfare.f9.co.uk