The Launch Rack

Volume 31 Number 4 (Issue 175

MMMMolly olly olly olly RescheduledRescheduledRescheduledRescheduled

Local ContestLocal ContestLocal ContestLocal Contest

Events to be flown:

1/4A Helicopter Duration (1/4A HD)A Parachute Duration (A PD)B Streamer Duration (B SD)Open Spot Landing (OSL)

(Note: OSL must be flown before any other event.)

This meet is open to any National Association of Rocketry member presenting a valid NAR membership card.

See NAR Pink Book for all Rules and Regulation

Entrée Fees as follows: Division C (19 years old and olderDivision B (14 thru 18 years old) & Registered NAR Teams

$7.00 Division A (7 through 13 years old)

FREE

Please Note NEW DATE

Saturday, 31 August, (Launch Window 1000 to 1500)

No flights will be allowed before 1000 or after 1500

North Branch Park, Raritan, New JerseyFor additional information contact GSSS at

gssshq@gmail.com . Contest Director: Jack Sarhage

The Launch RackPublished by the Garden State Spacemodeling Society

National Association of Rocketry Section No. 439

New Jersey’s Oldest Model Rocket Club

Volume 31 Number 4 (Issue 175)

BrownBrownBrownBrownRescheduledRescheduledRescheduledRescheduled: : : : August 31, 2013August 31, 2013August 31, 2013August 31, 2013

Local ContestLocal ContestLocal ContestLocal Contest

1/4A Helicopter Duration (1/4A HD) A Parachute Duration (A PD) B Streamer Duration (B SD) Open Spot Landing (OSL)

be flown before any other event.)

Association of Rocketry NAR membership card.

ulations

ision C (19 years old and older) Registered NAR Teams

Division A (7 through 13 years old)

Please Note NEW DATE

2013 1500)

No flights will be allowed before 1000 or after 1500

North Branch Park, Raritan, New Jersey or additional information contact GSSS at

Jack Sarhage

GSSS ElectionsGSSS ElectionsGSSS ElectionsGSSS Elections

Call for Nominations

for all Club O

Its “that” time again everybody!

That’s right, GSSS Club Officer Elections! The election

process begins with nominations for the

nomination is simply the name of

would like to see in the office. Only Club Members may

make nominations and while you could nominate yourself,

each nomination must be “seconded

Member in good standing (must have

both your nomination(s) and second(s)

at: GSSSHQ@gmail.com Offices to be nominated:

President

Vice President I

Vice President

Secretary/Tre

Deadline: October 30Remember, you must include

nomination and both names must be members in good

standing.

The Launch Rack the Garden State Spacemodeling Society

National Association of Rocketry Section No. 439

New Jersey’s Oldest Model Rocket Club

July-August, 2013

BrownBrownBrownBrown August 31, 2013August 31, 2013August 31, 2013August 31, 2013

Local ContestLocal ContestLocal ContestLocal Contest

GSSS ElectionsGSSS ElectionsGSSS ElectionsGSSS Elections

Call for Nominations

Officers

time again everybody!

s right, GSSS Club Officer Elections! The election

process begins with nominations for the Board offices. A

nomination is simply the name of a Club Member who you

in the office. Only Club Members may

while you could nominate yourself,

seconded” by another Club

must have paid up dues). Send

and second(s) for to Jack Sarhage

Offices to be nominated:

President

Vice President I

Vice President II

/Treasurer

: October 30, 2013

include a “second” to your

both names must be members in good

President’s Message

Arnie Klein

The Zinc-Sulfur Rocket

When the Russians launched the

first satellite Sputnik in 1957 many people

started to make their own rockets using a

variety of propellants. One of the most

popular propellants was 2.5 to 1 zinc

powder. This propellant was easy to obtain

and relatively safe to use. The Army actually

set up an amateur rocket test facility to

facilitate this experimentation at Fort Sill

Oklahoma Missile Center. The specific impulse of zinc

quite low (25 seconds) but was good enough for amateur rocket

experimentation. When the model rocket was invented by Orville

Carlyle the Zinc-Sulfur era ended, because of the increased safety,

and increased impulse of a model rocket engine. Today some people

are back to making their own rocket propellants using a mixture of

Ammonium perchlorate, and sugar and aluminum powder. This

mixture can be heated and poured into mold and put into reloadabl

engines.

GSSS ElectionsGSSS ElectionsGSSS ElectionsGSSS Elections

Call for Nominations for all Club

Send your nomination(s) for President, Vice Presidents I and II,

and Sec/Tresurer to Jack Sarhage at: GSSSHQ@gmail.com

Deadline: October 30, 2013 – Please include a “second” to your

nomination – both names must be members in good standing.

The Editor’s Pad

Dr. “Oooo - The Trooth Can Hurt” Bob Kreutz

(Hey! I’m only “Acting” as the Editor…

Thanks to the efforts of

(WebMaster) and Jack Sarhage

(Treasurer) we have moved GSSS

into the Digital Age!

overwhelming growth of online

shopping, online banking, cell

phone internet browsers and the

“Cube” for making and accepting payments on your phone, it seemed

only reasonable that GSSS make a similar

move to accommodate the membership. To

that end GSSS can now accept PayPal for

dues, membership renewals and new memberships.

PayPal could actually be expanded in the future, for other types of

transactions. For now, PayPal can be

used for only the actions above. What

accepting this form of payment means

to you is: members can electronically

make their payments from different sources such as:

Sulfur Rocket

When the Russians launched the

first satellite Sputnik in 1957 many people

own rockets using a

of propellants. One of the most

popular propellants was 2.5 to 1 zinc-sulfur

powder. This propellant was easy to obtain

and relatively safe to use. The Army actually

amateur rocket test facility to

facilitate this experimentation at Fort Sill

lahoma Missile Center. The specific impulse of zinc-sulfur was

quite low (25 seconds) but was good enough for amateur rocket

experimentation. When the model rocket was invented by Orville

Sulfur era ended, because of the increased safety,

and increased impulse of a model rocket engine. Today some people

are back to making their own rocket propellants using a mixture of

lorate, and sugar and aluminum powder. This

mixture can be heated and poured into mold and put into reloadable

----ArnieArnieArnieArnie

GSSS ElectionsGSSS ElectionsGSSS ElectionsGSSS Elections

Club Officers

your nomination(s) for President, Vice Presidents I and II,

GSSSHQ@gmail.com

a “second” to your

both names must be members in good standing.

Editor’s Pad

The Trooth Can Hurt” Bob Kreutz “Acting” as the Editor…)

Thanks to the efforts of Rob Nee

) and Jack Sarhage

we have moved GSSS

into the Digital Age! With the

overwhelming growth of online

shopping, online banking, cell

phone internet browsers and the

“Cube” for making and accepting payments on your phone, it seemed

The Club’s use of

PayPal could actually be expanded in the future, for other types of

now, PayPal can be

the actions above. What

this form of payment means

can electronically

different sources such as: their linked

PayPal cash reserve, a linked bank

account (a digital check, as it were)

or even a linked Credit Card!

PayPal transactions can

carry a fee - if you are using it for

business purposes, which in effect,

we are. Any fees associated with

the use of PayPal are paid by the

club. Rest assured, no increase in

dues is planned based on this. Rob Nee, our website

proposed applying for the annual NAR Grant for some other Club

necessities. The small amount we are charged can be recouped

through the Grant.

Countdown 5Countdown 5Countdown 5Countdown 5

You can now subscribe to the GSSS Launch Calendar in iCal

format. This adds the launch calendar to your Outlook, Google

iPhone, iPad, Smartphone Calendar

the launch dates available. Subscribe by clicking the link

paste the URL below into the subscription option of your favorite

calendaring program to always stay informed. If you need more

information try searching for "subscribe calendar" along with the

name of your calendar program (iCal, Google Calendar, Outlook

for help on subscriptions. webcal://robnee.com/gsss/calendar.php

The GSSS Schedule for the remainder of 2013 is posted below.

As always, it has a little something for everyone:Jun 29 – Sport Launch

Jul 22-26 - NARAM - Aurora, Ohio (See May/Jun Launch Rack for events)

Jul 27 – Sport Launch (1/2A Boost-Glider Duration)

Aug 31 – Molly Brown GSSS Host - Local Contest

1/4A-Helicopter Duration

A-Parachute Duration

B-Streamer Duration

Open Spot Landing

Sep 29 – Sport Launch (1/2A Cluster-Streamer

Oct 26 – Sport Launch (Open Spot Landing)

Nov 30 – Sport Launch (Leftover Cone

Dec 28 – Sport Launch (FREE Snow Cones)

Please NOTE: The event for the August “Funtest

changed! Instead of A-CAlt, the event will be

Streamer Duration. At the time of this writing, it is uncertain

range setup for optical altitude tracking is available. No

require contestants to purchase electronic altimeters for just 1

If any of the membership has interest in altitude

contact one of the club officers with your desired event!

Arrangements can be made if there is

preference for optical vs electronic altitude determination. [ed.: RTK]

Renewing Members

One & All!! Since the last issue of the newsletter the Family; Greg, Sharon, Tabitha

renewed their membership.

APRIL’S HIDDEN APRIL’S HIDDEN APRIL’S HIDDEN APRIL’S HIDDEN CONTEST WINNER:CONTEST WINNER:CONTEST WINNER:CONTEST WINNER:

No entries received.The $1725.00 Grand Prize will remain in the Club Treasury.

(OK, no more hidden contests…)

bank

as it were)

PayPal transactions can

if you are using it for

, which in effect,

Any fees associated with

the use of PayPal are paid by the

no increase in

dues is planned based on this. Rob Nee, our website Master has

proposed applying for the annual NAR Grant for some other Club

necessities. The small amount we are charged can be recouped

Countdown 5Countdown 5Countdown 5Countdown 5----4444----3333----2222----1...1...1...1...

can now subscribe to the GSSS Launch Calendar in iCal

alendar to your Outlook, Google,

Calendars, etc. Do it once and always have

the launch dates available. Subscribe by clicking the link below or

te the URL below into the subscription option of your favorite

calendaring program to always stay informed. If you need more

information try searching for "subscribe calendar" along with the

name of your calendar program (iCal, Google Calendar, Outlook, etc.)

webcal://robnee.com/gsss/calendar.php

The GSSS Schedule for the remainder of 2013 is posted below.

As always, it has a little something for everyone:

(See May/Jun Launch Rack for events)

Glider Duration)

Local Contest

Helicopter Duration

Parachute Duration

Streamer Duration)

(Open Spot Landing) (Black Pointy Cones ONLY)

Leftover Cone-ucopia)

(FREE Snow Cones)

The event for the August “Funtest” has been

CAlt, the event will be 3x1/2-A Cluster

At the time of this writing, it is uncertain if the

de tracking is available. Nor will the club

ectronic altimeters for just 1 event.

s interest in altitude tracking, please

contact one of the club officers with your desired event!

there is interest. Please state your

electronic altitude determination. [ed.: RTK]

enewing Members – Welcome Back

One & All!! Since the last issue of the newsletter the Greg Ventura

Tabitha, and Gideon of Somerset

CONTEST WINNER:CONTEST WINNER:CONTEST WINNER:CONTEST WINNER:

No entries received. The $1725.00 Grand Prize will remain in the Club Treasury.

(OK, no more hidden contests…)

The current NAR US Record for 1/2A Cluster Altitude stands

at 224 meters, set on 12/15/01 by Bruce Markielewski. Bruce just

eeked out the 1% he needed to retire my previous 1/2A-CAlt record

of 222 meters. I would argue that 2 meters is just short of the 2.22

meters he needed, but 224 is higher than 222, so I congratulate

Bruce! Oh Brother, that one really hurt folks…

Cluster Altitude is comprised of 6 events open to single

staged model rockets which are required to ignite all motor

simultaneously. Motor clusters increase in the number of motors for

each impulse class starting with 2 for 1/8A, up to 6 for C-CAlt. This

year at NARAM, the A (x4) CAlt event will be held. Presented here, is

a record setting 1/2A cluster model which you may derive a few ideas

for your own model from. So, instead of the linear alignment of the

1/2A’s, you may elect to use a triangle or diamond arrangement for

the A class event. There are some basic consistancies across all

cluster altitude events you should be aware of. As long as you adhere

to them, your results should be superior.

You will note in the photo of the actual Cluster Buster below,

the model was made from fiberglass tubing. This material is as

strong, but lighter in weight than

classic paper tubing. In altitude

events, every fraction of a gram

counts! All surface projections or

irregularities will increase drag,

so no launch lugs and tower

launch these models in custom fit

towers. In addition, I piston

launched the model on a single

piston fitted to the central

motor. All joints between tubes

and fins should be filleted and

smoothed to reduce drag. The

tube surfaces should be polished

smooth. Nose-Tube joints must

be tangent and practically

undetectable, with no gaps at the

shoulder. Note that there are

plywood spacers between the

outboards and main body. This is

so you will have room to tape

wrap 360° around your motors

for retention. Use silver mylar

tape because it is extra adhesive.

The four Blo-Holes in the

outboard pods create a lot of

drag. Be sure to use a paper tape

“disc” over each hole to seal them before launch. The ejection will

simply blow them off. You will also note the extended length of the

main body. This is absolutely necessary for the model’s stability with

the extra spent engines during the coast phase of the flight. If you

can follow some of these basic rules, you can be successful flying

Cluster Altitude. With good luck – you might retire Bruce’s Record!

“Cluster BUSTER”“Cluster BUSTER”“Cluster BUSTER”“Cluster BUSTER”

1/2a Calt RECORD1/2a Calt RECORD1/2a Calt RECORD1/2a Calt RECORD

Setting MODELSetting MODELSetting MODELSetting MODEL

RELIABLE CLUSTER

MOTOR IGNITION

A true Adventure, Clustering is the act of using two or more

motors in a group (or cluster), and having them all ignite

simultaneously; as opposed to staging, which ignites motors in

succession (one after the other). Clustering rocket motors

presents a challenge and level of difficulty all it’s own. All the

motors in a cluster must ignite simultaneously. If all the clustered

motors have not ignited by the time the rocket leaves the pad, the

rocket may veer off course; as the center of thrust under the

rocket is no longer in line with the center axis of the airframe.

Thrust under a rocket that is not in line with the center axis will

cause it to continually push to one side, which in most cases will

cause the rocket to arc under thrust. When this happens, the

rocket may not be at the minimum required altitude for proper

recovery deployment. Can you say: “Lawn Dart?”

Once you have more than two motors in the cluster, things

get a little tricky trying to keep common igniter wires from

touching each other (or shorting out). Again, make sure that none

of the wires, alligator clips, or the solder tab are touching each

other or any metal part of the launch pad. Various short-

preventing methods have been used, including: clip whips,

covering leads with tape and small plastic straws to cover exposed

wire. They are all somewhat busy, time consuming and/or messy.

There are many differences between igniter pyrogen and bridge

wire resistance. The Quest Q2G2 igniters are probably the best

selection for igniting a black powder motor cluster. They fire

consistently with minimal current and have insulated leads of

various length, to accommodate a wide range of applications.

With the Q2G2, insulation minimizes shorting the igniter,

therefore, no need to keep igniter wires separate, no clip whips,

taping or straws. All that need be done is to twist the igniter tails

into 2 pairs of windings and attach your launch clips there. One

interesting ability of the Quest Q2G2 is that they will supposedly

work if connected in series. While I do NOT recommend this

method of cluster ignition, ever, Tim VanMilligan of Apogee has a

video on how he got it to work at:

https://www.youtube.com/watch?feature=player_embedded&v=

4ZqpFCTS4P8

Series vs Parallel

To fully understand the concept and associated concerns

with clustering, one must understand two basic electronic terms:

Series and Parallel Circuits. As an example, we’ll use Christmas

lights – Some strings are in series: when one light goes out they all

go out. On better, parallel strands, if one goes out, all the others

stay on. Which strand do you prefer? As soon as the first bulb

blows, the whole strand goes out because the others are

dependent on current running through that bad bulb. It doesn’t

matter where in the strand the bulb is, one burnt filament is all

you have to have to shut down the whole string. Same with series

cluster ignition. Once the first igniter fires, power is lost to the

rest. Now, with the strand of lights that stay on when one bulb

burns out (parallel), electricity is still applied to all the other bulbs

and the lights keep working. The preferred arrangement for

Christmas lights on the roof line and so is it, with clustered

igniters.

However, what happens when there are more lights on

the parallel string that are out, than on? (ie: have already lit their

respective motors) If this were our rocket, all those lights that are

out would have ignited their motors and they would be thrusting

– wouldn’t they? The model would be moving with a motor or

two that were unlit – still with a “good bulb” (unfired igniter) in

the nozzle. Chances are that the launch clips would pull those

remaining igniter(s) out of the nozzle before the motor(s) had a

chance to ignite. It’s a matter of chance. You can minimize this

happening by having a well charged, high current battery,

pretesting your igniters with an Ohm Meter to make sure they are

good and lastly, using some sort of igniter retention: either an

(Estes) igniter plug, a plastic straw (Quest) or a round bio-

degradable toothpick (Apogee) to hold the igniter in the nozzle

and against the propellant. Minimize the events that can cause

your cluster to fail and you will have a great deal of success in

your cluster flight adventures.

When launching your cluster rocket, remember to keep

the launch button depressed until the rocket has cleared the

launch rod. The single most common failure of cluster ignition is

releasing the launch button after one motor ignites (as soon as

you see smoke), but before all the motors have ignited! No

matter how well manufactured, some igniters may take a fraction

of a second longer to ignite the motor than others. The safest rule

is to depress the launch button and keep it depressed until the

rocket has cleared the launch rod. Here are some notable tips to make your cluster

“adventure” a memorable one:

1) Your entry will be more reliable if the motor arrangement (cluster) is

symmetrical. Examples of clusters for Cluster Altitude Competition:

http://ojames3.tripod.com/tccnarcontesttips/23CA_patterns.html

2) Your motor mount tubes must be carefully aligned so that all of the

motors in the cluster are thrusting in the same direction or vector.

3) You have to seal your motor mount assembly so that ejection gasses

cannot escape except by deploying the recovery system.

4) You are using more motors than usual. This moves the rocket’s

center of gravity toward the rear. You’ll need larger/more fins and/or

nose weight or a longer rocket.

Based on: http://www.tmrk.rocketshoppe.com/info/TR-01.pdf TRUE MODELER’S ROCKET KITS www.TrueModeler.com

Competition Boost-Gliders

What it Takes to Win Trip Barber

NAR 4322

•Reliability •Good Boost •Clean Transition to Glide

•Good Glide •Returned Model

Glider Reliability

•Proper structural strength for boost

–Balsa thickness & grain, gluing technique

•Good release from launcher

–Restrain ignition clips from catching the tail, provide

wind bracing so glider stays on pod

•Clean pod separation

–Proper friction fit, small chute for recovery

•Practice makes perfect!

Good Boost

•Provide enough launch rod travel length

–Use “power tower”, extended rod lengths

•Get the force balance and stability right

–Thrust vs aerodynamic balance, CG vs CP

•Align wings correctly on pad

–Wing span parallel to wind direction

•Use a smaller glider unless it’s windy

–High altitude = long duration

Clean Transition

•Put some (~2%) incidence on stabilizer

–Pulls out of “death dives”

–Too much incidence causes boost loops & glide issues

•Trim for wide-diameter right turn

–Check with hand launches straight up

•Choose proper delay time

–Eject pod on the way up, not down

Good Glide

•Minimize glider drag and weight

–Smooth wing surface, without paint

•Select and shape an appropriate airfoil

–High point at 30% chord, taper wing thickness

•Minimize wing loading (weight / wing area)

•Trim to glide at a small angle of attack

–Maximize CL1.5/ CD for max duration

•Get the CG vs neutral point balance right

–Glide CG at ¾-chord point is ideal

Glider Sizes

Engine Wing Area Wing & Boom Stab/Rudder

Power (Sq. inches) Thickness Thickness

½ A 15 –25 3/32 1/32

A 20 –35 1/8 1/16

B 30 –45 1/8 –3/16 1/16

C 40 –60 3/16 3/32

Wings & stabilizers from 6 lb/ft3density C-grain balsa

Fuselage booms from 12-16 lb density

Returning Models

•Enhance glider visibility

–Dark magic marker on underside of wings, aluminized mylar on

tops of wingtips

–Use larger gliders in windy weather

•Use a dethermalizer

–Wing flap, “beer can”, or drop weight

•Use radio control –at least for “C” and larger

From: http://nar.org/competition/plans/boostglide.html [Edited by Dr. Bob Kreutz, 2013]

Parting Shots from April’s Launch ff

To describe the April Sport Launch in one word….”WINDY.” Even

Arnie Klein’s wind meter could not measure some gusts (it only measures up to

10mph). And a couple of times the little ball got stuck momentarily at the top of it.

Though we are used to having breezy conditions at North Branch Park

they arrived earlier than usual. Like before we set up the launch equipment!

It was decided then that the Fun Test would not be flown. We will see if

we can’t reschedule this later in the year. Rockets that were flown where the

flying saucer type of Arnie’s or those using streamers. Your writer, Jack Sarhage

did not fly the rocket brought. It was to be flown in the FunTest and left in the car.

Mickey Spain got off one or two flights. And Jim Zindle flew a new

rocket that had not gotten the final finish applied by launch day. On its second

flight it was lost to all on the field. The ejection charge was visible and well as

hearing it “pop” but not one saw it after that. A search of the field all the way to

Milltown Road resulted in the rocket not being found.

After about two hours without any improvement in conditions it was

decided to close down the launch pad.

Jim’s rocket was found thanks to my wife Imelda needing to use a CR. I

knew the one by the baseball fields would probably be open and we drove there.

Wanting to use Route 206 for a stop at the Christmas Tree Shop (the reason she

came with me) as we went by the Ranger’s House I spotted the rocket’s Mylar

streamer in a depression in the yard. I pulled to the side of the road went across

the road and returned said errant rocket to its owner.

Jose Andrade-Cora from Heavenly Hobbies was

there. And I own an apology for not getting or

remembering several others that attended. Maybe we

should have a sign in sheet.

The Launch Rack

Volume 31, Number 4

Issue 175

July-August, 2013 (A Bit Ahead of Schedule…)

The Launch Rack is the official publication

of the Garden State Spacemodeling Society and is

published for the enlightenment and entertainment of

the membership. It is published bi-monthly.

You are invited to send your articles, photos,

letters and hard earned cash to the editor for his

enlightenment and entertainment, ect., and for

publication. This publication is by and for the

membership.

Articles appearing in the newsletter may be

used by other publications provided proper credit is

given to the author and this newsletter.

Jack Sarhage, Chief Editor

24 Canterbury Court

Piscataway, NJ 08854

E-mail: gssshq@gmail.com

Dr. Bob Kreutz, Lackey to the Chief Editor

506 Hunters Road

Brick, NJ 08724-4614

The Launch Rack

c/o Jack Sarhage

24 Canterbury Court

Piscataway, NJ 08854-6206

July-August, 2013

Volume 31, No.4 (Issue 175) Issue 176 Submission Deadline: 08-15-13

1 2 3

1 - Jim Zindle preps and makes 2 - Jim sends his offering skyward! 3 - Mickey Spain's Solar Warrior

an offering to the Rocket Gods. A Star-Trek-Nexus like model.