For some, happiness is a homebuilt. But you need plenty of time, tenacity, and the hobbyist'stemperament. Good homebuilts, say the 'pros,' cost as much as a 'storebuilt'

The BOMEBUILDERS

The No.1 Thorp T-IB, built and flown by BillWarwick, Torrance, Calif. "It sure flies nice,

but it's a little like having a tiger by the tail,"Warwick reportedly said after his first flight in this

plane over nine years ago. The comment is credited withnicknaming the plane the T·IB "Tiger."

All photos by the author, except as noted

by DON DOWNIE/ AOPA 188441

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/ I

Ifyou're a would-be homebuilder, look­ing for the cheapest way to fiy, getthe parts from a wreck or an older, run­out airframe and rebuild it. You'll spendfewer dollars, because most parts arereadily available, and you'll still receivea good education in aircraft construc­tion. Above all, you'll get into the aira great deal sooner than you will bystarting from scratch with your ownhomebuilt." The preceding comment, al-

EDITOR'S NOTE : FAA recently reportedthat FAA-certificated hOlllebuilts in theUnited States now number about 3,600aircraft, or approximately 21/2 % ofgeneral aviation's total fleet of around140,000 aircraft. The agency also esti­mated there are approximately 10,000pilots-a little more than 1% of thetotal pilot population of about 800,000­who are now worhing on homebuilts.The figures indicate, FAA said, thatmany more homebuilt projects arestarted than are ever completed. \VhilePILOT Western Editor Don Downie has

never built his own airplane (exceptfor a hang glider during high school),he has worked closely with many of theveteran builders and IlO1Ilebuilt design­ers on the West Coast. His accompany­ing report is, he says, "one reporter'sopinion of the IlOmebuilders today." Be­cause of space limitations, only a veryfew of the many homebuilt designs arementioned in the report. On the com-

30 THE AOPA PILOT I MAY 1973

most word for word, is from several ofthe nation's leading do-it-yourself de­signers.

Starting with a set of plans and con­structing your very own homebuilt isfun. It's educational. But it can alsobe frustrating and, for many, costly.There's usually a great feeling of per­sonal accomplishment in building yourown aircraft; however, it's not going tosave you any great amount of money, if

parative safety of homebuilts certifi­cated by FAA, agency officials reportedthat National Transportation SafetyBoard statistics on amateur-built air­

craft for 1970 show 13 pilot fatalitiesin a total of 85 accidents in homebuiltplanes. "This is equivalent to one pilotfatality for every 270 aircraft," FAAsaid, "which is comparable to the figuresfor all general aviation (about one pilotfatality for each 230 aircraft)." In re­ferring to the comparative safety be­tween hOlllebuilts and "storebuilts," FAApoints out: "There are some differencesin the handling of amateur-built planes. . . They are generally small planes, thewing loading is high, and thus they donot have the stability of larger planes.Getting used to an inherently unstableaircraft takes practice." Summarizingits appraisal, FAA said, "All in all, thehomebuilt aircraft seems to be just aboutas safe an airplane as its builder is apatient craftsman and careful pilot."

any at all, and you'll invest a great dealof time.

Building your own airplane is a com­plex, long-range project. If it's a familyaffair, the builder needs a sympatheticand understanding wife (or husband)who has long since decided to join 'em,not fight 'em. The family garage maynever see an automobile again. Theliving room or kitchen table may bewhere detailed parts are planned andfabricated.

"If I were to design a plane thatlooked like a Cessna 150 or a PiperCherokee, nobody would buy the plans,"said veteran Lou Stolp (AOPA 11902)of Redland, Calif., who designed the"Starduster" and the "Starlet." "Theman who orders a set of plans for anopen-cockpit, wood, steel,tube and fabricairplane is sort of an adventurer. Heprobably rides a motorcycle, drives asports car, and is a scuba diver."

"It's going to take a dedicated home­builder at least a year to make one ofmy VW-powered, single-seat PL-4As,"said Ladislao Pazmany, of San Diego."If he's really dedicated, works threehours every nigh t and all day on week­ends, he may be in the air in a year .And that PL-4A is one of the simplestdesigns available." (FAA estimates ittakes the average part-time builc;lerabout 3,000 hours, or as much .••asfour to five years, before he gets FAAapproval to fiy his homebuilt.)

"Once he gets his feet wet, homebuild­ing can become an obsession," explainedJohn Thorp (AOPA 22461), who hasbeen designing homebuilts almost all

his life. "It's a creation where thebuilder is completely involved, and thewhole operation has great therapeuticvalue."

Homebuilts come in all shapes andsizes, various complexities, and uniqueconstruction techniques. Volmer Jensen,Burbank, Calif., built his two-place"Sportsman" amphibian in 1957. Sincethen he has sold more than 700 sets ofplans ($125 per set) and reports thatmore than 70 units are flying. [SeeJan. 1963 PILOT cover.] Jensen has cutbuilder time and cost by designing hisamphibian to use a standard AeroncaChampion or Aeronca Chief wing. Whenhe built his prototype, he was able tobuy a set of used wings for $300, butthis supply has just about vanished.Wings can be purchased new from theBellanca Aircraft Corporation's Cham­pion factory.

Jensen has more than 1,500 hours onhis own "Sportsman" (five times aroundthe world) with nothing more than rou­tine maintenance and two enginechanges. Purchasers of his plans (250square feet of blueprints and 80 photo­graphs) are required to sign an agree­ment (not always followed) that $125for the plans is "for the right to manu­facture one and only one amphibianairplane."

Like almost all other designers, Jen­sen has a single plea. "Please follow theplans!" he says almost automatically ashe picks up the phone. "I get phone callsfrom all over the world asking aboutchanges in construction. I tell everyonewho calls that if he changes anythingin the basic design, he may as well scrapthe project and design a whole newmachine on his own."

Jensen built his first hang glider in1925 and added one new glider eachyear for nine successive years. Last yearhe built a 1OO-pound, 32-foot-span, two­control hang glider with engineeringhelp from Irv Culver (AOP A 117226).Plans are also available for this rela­tively simple machine, which Jensenrecommends as a good "starter kit" forthe newcomer to the home builders'ranks. Jensen recently remained aloftfor 42 minutes, in a 17-mph wind, on

a ridge that was just two feet higherthan the span of the glider. (I've flownit to perhaps 15 feet. It's fun!)

John Thorp, among other projects,designed the "Little Dipper" for Lock­heed. That plane almost became "every­man's infantry airplane" during WorldWar II.

Thorp's FAA-licensed, "Sky Skooter"hit the market just as surplus WorldWar II military aircraft flooded themarket at giveaway prices. Duringthe Korean War, he developed a single­seat, armed lightplane, the FD-25, forFletcher Aviation Corporation. [Theauthor was test and demonstration pilotfor this Army ground-support fighter fornearly two years.-Ed.] Thorp was alsopreliminary engineer for the originalPiper Cherokee, which still bears morethan a passing resemblance to the "SkySkooter ."

But Thorp's most popular design ishis T-18 "Tiger" (the "18" is for his18th basic aircraft design). This two­place, side-by-side sportplane earned itsnickname when the first builder, BillWarwick, of Torrance, Calif., climbedout after his first flight and commented,"It sure flies nice, but it's a little likehaving a tiger by the tail."

Over nine years and 900 hours later,Warwick still flies the same T-18, onlynow he has a multihued, oversized tigerpainted on both sides of the fuselage.

I've flown a number of versions ofthe T-18, including Warwick's, Thorp'sown ship, and one completed by airlinepilot Gene Eckels, who installed a 180­hp Lycoming _and a controllable prop.Eckels is getting more than 200 mphout of his T-18. Several years ago, Ichecked out Rudy Adler (AOP A 425864)in his 125-hp GPU (ground power unit)T-18. Both Adler and I are 6 feet 2inches and not as lean as we once were,yet we can cruise his ship at 160 mph.The "Tiger" is a sensitive, spirited littlebird with just 9 feet 8 inches of wing(20-foot-1O-inch span) hanging outeach side of the fuselage.

Nine hundred sets of T-18 plans havebeen sold, and there are just over 100of these planes in the air. Thorp is re­luctantly going into the parts business,

since FAA regulations permit prefab­rication of complex parts beyond "theequipment and skills ... normally pos­sessed by the amateur." He's buildingcomplete T-18 cowlings that sell for$495; however, he says, "It's almostall handwork, and it's going to take along time to get the tooling investmentback. We're considering using templatesto scribe sheet aluminum for all the flatmetal parts, then rolling them up andsending them out to the builder for cut­ting and drilling. That way we wouldn'tdo anything but mark the metal.

"The trend toward supplying hard-to­build parts will produce a higher com­pletion ratio of plans to flying aircraft,"continued Thorp. "One of the manyadvantages of homebuilding is purelyeconomic. The builder doesn't have toput out a large amount of money, atleast not all at once. He can purchaseplans and a 'starter kit,' then add com­ponents as time and money permit."(FAA estimates the average home­builder buys anywhere from $2,000 to$3,000 worth of supplies and equip­ment. )

One of the most colorful homebuiltdesigners is 76-year-young P. H. Spencer(AOPA 129012), "father" of the Re­public "Seabee." Spencer has been activein aviation since 1913 when he soloeda hydro glider. A year later he completeda partially built, 50-hp Curtiss-type fly­ing boat and soloed that. "I flew fivemiles down the river with the Curtissshoulder yoke controL" He designed the"Seabee" and sold it to Republic shortlybefore the beginning of World War II.With the project shelved "for the dura­tion," "Spence" became a faCtory testpilot on P-43s and P-47s. He remainedwith Republic after World War II untilthe "Seabee" project was safely on itsway (1,250 were built), and then he

Ultralight IOB·pound "Whing Ding,"developed by Lockheed engineer

Robert Hovey, Newhall, Calif. Theaircraft is powered by a 13·to-15-hp

McCulloch chain saw. Wingspan is 17feet. The designer, says author,

"suggested this not be flown at analtitude higher than you wish to

fall." Photo courtesy of designer

~h prr'EBUILDERS

Veteran designer John Thorp (AOPA 22461). who has designed 18 different aircraft. explainsmodifications he has made on a standard Lycoming engine.

Pazmany PL·4A. with Pete Girard at the controls. A canopy was subsequently added tothis homebuilt. The design has created much interest within the homebuilders' ranks.The aircraft is powered by a Volkswagen engine. Photo courtesy of designer

•

rate of climb continued to register at120 fpm at this altitude, but the VWengine finally quit because it had nomixture control. It restarted easily,though, in a lower, denser atmosphere.

The PL-4A was designed at the re­quest of Experimental Aircraft Associa­tion (EAA) President Paul Poberezny(AOPA 117957), who wanted "a fliv­ver ship that could cost between$1,000 and $2,000 .... One desirablefeature would be to have wings thatcould be removed or fold easily, so thatit could be kept at home .... I wouldsuggest a single seat for a start andVolkswagen-powered. It should haveenough wingspan to give a reasonableglide ratio, so that in the event of pow~failure its handling would be within thecapabilities of the average pilot."

After reading The History of BritishLight Aviation, which covers the long­distance rallies between World War Iand World War II, Pazmany is now

majority of the landings were on saltwater, and there was no evidence ofcorrosion," Spencer said.

Ladislao Pazmany, an Argentineannow living in San Diego, sold 133 setsof plans for his VW-powered PL-4Asingle-seater during the first fourmonths after it was announced theplans were available. Forty drawings,on 21-inch by 60-inch lithograph sheets,cost $60. None of the plans were solduntil after the aircraft had been test­flown and all the major "bugs" hadbeen removed. Test flights without acanopy were made by former Ryan testpilot Pete Girard. Addition of a largecanopy upped the rate of climb to 650fpm and increased the cruise to 95 mph.Five "V" belts cut the 4,000 engine rpmto 1,745 propeller rpm.

More than 20 pilots flew Pazmany'sPL-4A shortly after the "bugs" had beenworked out. I was No. 7 on the list. Onepilot took the plane to 13,000 feet. The

(Continued from preceding page)"retired" to Florida in 1947, But hedidn't stay retired for long,

He flew a Fairchild 91 for over a year,serving as personal pilot for JuanTrippe of Pan American Airways, (Onlynine of these 12-passenger amphibianswere built.) More than 25% ofSpencer's 5,000-hours-plus has been inwater birds, and this penchant for thepontoons and amphibs drew him intothe homebuilt ranks.

Aided by Co!. Dale L. Anderson, aSepulveda (Calif.) Junior High Schoolmath teacher, Spencer built the proto­type "Amphibian Air Car" in 181/2months in a two-car garage. His bro­chure on the aircraft reports use of"only the usual hobby-shop machinetools, with the exception of certain partsof the landing gear. Cost of constructionwas $4,700, less engine, propeller, in­struments, and radios. Completed costwas $8,700, which included a low-time,180-hp 0-360 Lycoming."

In the past 21/2 years, Spencer hassold 75 sets of plans ($185 each) forthe Air Car. Molded fiber-glass parts,complex metal assemblies for the gear,and steel-lube car frame are availablelo builders on a "prefab" basis. Engines,including the new Teledyne ContinentalTiara, are available to Air Car builders,at substantial discounts, as are Hartzellpropellers, Spencer said. He recentlyordered five 300-hp Tiaras for his mostactive builders, plus one for himself.

"Homebuilding has made tremendousprogress, despite some early objectionsfrom the FAA," Spencer stated. "NowI feel that it's a real business proposi­tion. It's amazing to me to see the typeof people who are building that Air Carof mine. They're first class, all the way.With that Tiara engine and any nav/com equipment at all, you have at least$12,000 in an amphibian that will carryfour people 'and stuff.' At least 28 of the75 people who have my plans are'pro' amateur builders, and have at leastone previous homebuilt under their belts.We'll soon have a number of Air Carsin the air and on the water."

The business of selling plans and par­tial kits for homebuilts is on the in­crease. New designs-some complete,some still skin-and-bones (more bonesthan skin)-show up at fly-ins all overthe country. For example, Spencer andColonel Anderson took 21 days, latelast summer, to cover 5,000 miles. Theylogged 571/2 hours, including a visit tothe EAA "spectacular" at Oshkosh, Wis.,and the Abbotsford, B.C., Canadian AirShow. Demonstrations were made atSouth Lake Tahoe, Calif., where thedensity altitude was 8,400 feet.. Withthe Air Car at 2,700 pounds grossweight and heading into a 5-mph wind,takeoffs took 21 seconds. At the conclu­sion of last year's sales and demonstra­tion tour, Spencer's prototype Air Carhad logged 352 hours in the air and hadmade two round trips across the UnitedStates. A total of 637 landings (326 onwater) were made during the trip. "A

32 THE AOPA PILOT I MAY 1973

Prototype Spencer "Air Car,"a four-place amphibian, takesoff at Cable Airport (Cable-Claremont),Upland, Calif.

Folding·wing design of the PL-4A isdemonstrated On the prototype

during its construction.

proposing a homebuilt rally, perhapswith Alaska as a destination, for a start.He also said he would eventually liketo see an efficiency contest flown fromthe United States to his homeland,Argentina.

"We have been kicking around somenew names for the amateur-built pro­gram," explained EAA's Poberezny. "Wefeel that 'experimental' and 'amateur'are not very popular with general avia­tion, with the press, or even with con­gressmen .... On those aircraft thathave met their 50 or 75 hours' flyingrequirement, along with some othersimple standards, we feel they shouldbe moved from the 'experimental' cate­gory into a new category called 'sport'or 'custom' .... [This] could make adifference in personal life insurancepolicies. Many policies carry the state­ment ... that the individual is notcovered while flying an 'experimental'aircraft ... The FAA is looking veryfavorably on this matter."

Last year, about 30 of the country'sleading designers who sell plans andmaterial for homebuilts formed theNational Association of Sport AircraftDesigners (N ASAD). Purpose of the

new organization is to seek compliancewith self-imposed minimum require­ments of excellence in the design andconstruction of their aircraft. Dr. IgorB. Bensen (AOPA 151081) was electedpresident of NASAD. He told The PILOTthat "the establishment of NASADstandards is only the first step towardimproving the image of non-type-certifi­cated aircraft, both with the public andthe FAA."

NASAD standards require that a

minimum of 150 hours be logged by thedesigner's prototype before Class AA(designed for the average amateur with­out previous experience in aircraft)plans and kits are sold to the public byany NASAD member. Another standardspecifies that no drawings or informa­tional data packages may be advertisedfor sale until after the prototype haslogged at least five hours of prescribedflight time.

NASAD's charter members reportedlyhave an average of 26.4 years of experi­ence with aircraft, and their averageage is 481/2. Regarding their homebuiltdesigns, 81 % test-flew their own pro­totypes, and 11% sold plans for theircreations before their prototypes hadeven flown. Of the remaining members,56% sold plans within a year after thefirst flight of their aircraft, and 33%waited for more than a year. At thetime NASAD was formed, 64% of thedesigners-nearly two-thirds-indicatedthey were continuing to refine theirdesigns, while the remaining 36% had"frozen" further development. Costs ofplans sold by NASAD members rangefrom $15 to $150 and involve from five

The venerable "Sportsman" amphibian,whose design dates back to 1957.Seventy reportedly are now flying, andabout 700 sets of plans($125 per set) have been sold tohomebuilders. Photo courtesy of designer

MAY 1973 I THE AOPA PILOT 33

Hornebuills Recerlilicaled AI Fly-InS

FAA inspectors ErnestHeald (left) and AlanButterworth inspect

"Biggy Rat," designedand built by John,Mark, and Hobie

Sorrell, of Tenino, Wash.Photo by Don Downie

The HOMEBUILDERS

(Continued from preceding page)to 350 sheets of drawings. About 92%of the designers said they felt that anamateur hobbyist without previous air­craft-construction experience could buildtheir creations, but more than halfstated that some previous shop experi­ence would be required.

The nearest FAA General AviationDistrict Office (GADO) or FAA Engi­neering and Manufacturing DistrictOffice should be notified whenever aperson starts a homebuilt project. AnFAA maintenance inspector must checkeach homebuilder's work before any sec­tions are "closed up," and after taxi teststhe FAA official must again inspect theaircraft before it attempts its maidenflight. After the first flight, the newhomebuilt is restricted to a radius of25 miles from its home airport, whichusually must be in a sparsely populatedarea. This restriction applies for thefirst 50 hours, if a standard aircraftengine is used, and for 75 hours if anon certificated powerplant is installed.After all that, the owner is free to flyhis homebuilt-but not for hire-exceptsubject to certain limitations (F AR91.42).

Most home builders caution new­comers to "look before you leap." Theyrecommend that newcomers attend afly-in of homebuilt aircraft and talkwith those who have already built theiraircraft, and with the homebuilt de­signers in attendance. Kick a few tires,they say, and ask for the opportunity tosit in some of the single-place jobs. Per­haps talk yourself into a ride in a two­placer of your choice. Most homebuildersare justifiably proud of their creationsand many are willing to demonstratetheir particular aircraft to anyone whois seriously thinking of building a sim­ilar model.

Regarding this latter point, though,Lou Stolp commented: "Many finehomebuilders spend much more of theirtime and energy in building than inflying. Thus, some of the immaculatehomebuilts are somewhat beyond thepiloting capabilities of the builder ....The builder of an open biplanesometimes thinks he's automatically anaerobatic pilot, and usually he isn't."

According to FAA, "Building an air­craft from scratch is probably one ofthe most demanding tasks any humanbeing can set out upon."

There's little question but what youhave to have plenty of both spare timeand sustained enthusiasm. "And don'tforget," cautions John Thorp, "that thecost of a good homebuilt is about thesame as a 'storebuilt' with the same typeof engine."

All these factors should be car~fullystudied, weighed, and faced before youembark upon a homebuilt project. Butif you have the available time, the tem­perament, the tenacity, and the treasurynotes, there's a good chance that you toomight someday stand next to a wingedsteed bearing the proud label "Flownand built by.... " 0

34 THE AOPA PILOT I MAY 1973

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•• Each year, homebuilt aircraft musthave a visual inspection by an FAAGADO (General Aviation District Of­fice) maintenance inspector for recerti­fication. "Storebought" aircraft can beinspected and certificated by a non­FAA designee.

Inspecting homebuilts one at a timefor recertification is a time-consumingprocess. Last year, 140 of the 200homebuilts in western WashingtonState were inspected at five scheduledfly-ins.

''I'd estimate that we saved at least60 man-days, or roughly $3,800, overthe previous system where an inspec­tor has to drive or fly to an outlyingfield just to inspect one aircraft," ex­plained Ernest J. Heald (AOPA 164323),principal maintenance inspector forFAA's Northwest Region. "In an effortto streamline amateur-built experimen­tal recertification, we set up a scheduleof summer weekend fly-ins, each witha rain date. Amateur builders were en­couraged to fly their homebuilts to thesefly-ins, which I would attend with atleast one other member of our three­man maintenance staff. We'd inspectthe aircraft, fill in the paperwork, andsend the pilots on their merry way withnew airworthiness certificates allow­ing them to fly their homebuilts foranother year."

Four recertification fly-ins have beenscheduled for Washington State in1973. Two have already taken place; theothers are to be held this month­one at Chehalis on May 12, and oneat Bellingham on May 26.

On recertification day, the FAA in­spectors arrive at the airport at 9 a.m.and remain until all certification activi­ties are over.

"By having these inspections in vari­ous areas, on weekends when most pri­vate pilots are active, these recertifica­tion dates also serve as an impromptugathering that helps promote theamateur-built movement and aviationin general," said Heald. "The program

is geared for weekend meetings so thatowners won't have to take a day awayfrom their regular jobs to be availablefor annual recertification."

FAA Northwest Regional DirectorC. B. Walk, Jr., is keeping a watchfuleye on the success of the time-saving"fly-in" recertification program. It ispossible that such a program may ex­pand to a national basis as the numberof man-hours required for inspectionsgoes down.

Historically, this type of maintenanceinspection program was begun by theCAA (now FAA) in the 1930s, wheninspectors traveled to various airportsin their assigned areas to revalidatelicenses of both production aircraft andthe small number of homebuilts flyingat that time. Since then, the designatedaircraft maintenance inspector hasgone into operation, and the presentsystem, permitting certification of pro­duction aircraft by authorized inspec­tors, has evolved. FAA inspection is stillrequired, however, for annual recertifi­cation of homebuilts.

"When a man builds his own air­plane, he knows much more about itthan the owner of a production air­craft," said Heald. "He usually spendsmore time in maintenance, polishing,and general 'TLC' [tender, loving care]on his homebuilt than does the produc­tion owner. In 90 percent of our in­spections, we find absolutely no prob­lems and merely update the paperwork.

"vVe had no amateur-built accidentsin Washington attributed to main­tenance-or the lack of it-in 1972,"explained Heald. "So the system seemsto be working."

Northwest Region homebuilders con­tinue to have the fun of a fly-in andthe convenience of picking up thejrannual recertification paperwork at thesame time. Other FAA regions mighttake a close look at the program'ssuccess, with an eye toward improvingservice and convenience to their "cus­tomers." -D.D.