Rutan_Quickie - Type Aircraft Design Origins

7/29/2019 Rutan_Quickie - Type Aircraft Design Origins

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AIRCRAFTDESIGN ORIGINS

B v Burt Rutan (EAA 26033)Rutan Aircraft FactoryBox 656Mojave. CA 93501

(Photo Courtety Rutan Aircraft)Burt with N7EZ and N4EZ.

-L H E R E I S C U R R E N T L Y a lot of c o n f u s i o n a b o u tthe design origins of the recent crop o f n e w t a n d e mw i n g a i r c r a f t d e ve lo pe d o ve r the last several years.T he co n fu s io n is the result of my s i lence on the sub-ject and the v a r i o u s c l a i m s and c on f r on t a t i on s of someof the other participants. In order to clear the air onthe subject I am publishing the f o l l o w i n g facts. Myhope is to invite the other developers to w o r k togetherin a n e n v i r o n m e n t o f constructive co o pe ra t i o n to a s -sure th e d e ve lo pme nt o f s a f e , e f f i c i e n t t a n d e m w i n gai rcraf t and to c o n t i n u e their deserved reputation o fexce l lent f ly ing qualities an d no-c om p r om i se safety.

Quickie OriginIn the spring of 1977 Gene Sheehan. who had beenevaluating several sm a l l powerplants. and Tom Jewett,

then a Roc k we l l employee , proposed to m e that I de-sign a sca led-down s ingle-p lace Var iEze that would havestructure l i g h t enough a n d a e r o d y n a m i c s e f f i c i e n tenough to a l low adequate p er f o r m a nc e wi t h th e O n a ne n g i n e (16 to 20 hp an d 80 Ibs .) . The or ig inal sketchI made of that conf igura t ion is reproduced in Figure 1( "Model 49") sketch, complete with the results of myi n i t i a l p e r f o r m a n c e c a l c u l a t i o n s . W h i l e the Model 4 9appeared feas ib le , i t had potential shortcomings: verylo w Reynolds number on the f in s and canard w i n g andexcessive C G travel wi t h pi lo t w ei gh t v a r i a t i o n .Over the n e x t several weeks I sketched an d then ra np r e l i m i n a r y a e r o d y n a m i c c a l c u l a t i o n s o n several con-f i g u r a t i o n s w h i c h c o u l d use the Onan engine. One ofthem, the Model 54, solved the problems of the Model49, offered potential fo r stall resistance, and had s imi -

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lar performance. The original sketch of the Model 54,which was refined to the Quickie, is reproduced in Figure2 ("M odel 54")sketch. It was first called the "X-Fighter"after seeing the then-new fi lm Star Wars (note re-semblance with front view). It was later called Quickie,the name I had previously reserved for my RAF M odel44, a quick-to-build minimum-manhour-construction air-plane designed in 1975.While I was proud of the potential of the Quickiedesign, the summer of '77 found me very busy with theexpanding V ariE ze homebuil t program and the initialdevelopment of the Defiant twin. Thus, I did not wantto expand into a large kit business to market Quickie.Gene and Tom did,however, so we worked out an agree-ment where I would fund, develop and test the Quickieat RAF.Then, after testing was completed (designfreeze), I would turn the entire program over to Geneand Tom,they paying me for the development out offuture sales of Quickie and future Quickie relateddesigns.Gene worked with me full time and did all the fire-wall-forward (engine installation) design and develop-ment. After the aircraft was flying, Tom joined us fulltime and converted the shop drawings to the formatfor printing the Quickie plans.

The Quickie prototype, N77Q, flew reasonably wellon its initial test flights in November 1977. I t did,however, have several deficiencies that required aero-dynamic rework, including a new canard configurationas well as airfoil and span changes on the aft wing.

By early spring of 1978, we were all satisfied withthe flying qualities and had the entire test envelopecompleted. The Quickie effort then left the RAF fa-cility and has since been run as a complete-kit conceptby Gene and Tom without any active participation onmy part. I have not had any authority or associationwith the Quickie Aircraft Corporation regarding theirmarketing, builder support or any other aspect of theirbusiness.

HistoryThe tractor tandem-canard/vertical-fin-on-fuselageconfiguration is not one I "invented" for the Quickie,as it has been used on experimental aircraft since thetwenties and in larger numbers during the fifties inFrance. I'm not a good aviation historian, but when adesign is introduced i t generally prompts many oldtimers to send me their old photos and drawings, prov-ing that there are really very few truly "new"designs.For example, Jack Cox found adesign from a 1912avia-tion journal that had been wind tunnel tested and wasreputed to be stall proof. This Drzewiecki-designed air-plane was the same general configuration as the originalV ariEze, down to the one-way rudders and loaded can-ard with elevons (seeFigure 3). One wonders in whatdirection aviation development might have veered hadthis airplane been built and flown. This 1912 designappears to have performance and flying qualities muchbetter and safer than the conventional and canard air-

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(Photo by J ack Cox)The P.A.T.-1. or Pugmobile as many like to call it. The Q2. (Photo by Tad Koton)

The Quickie. (Photo by J ack Cox) The Viking Dragonfly. (Photo by J ac k Cox)

of that day. It would be an interesting historicalse to dig up the drawings, get a group of EAAusiasts together and to bu i ld and fly the 1912design. It would be well suited to the pres-ultralight engines.Dragonfly

Bob Walters, a 36 year old aeronautical engineerd Navy fighter pilot from San Diego, was a charterber of the "composite revolution", joining othersho began building VariEzes in 1976.The EZ he builtis one of the nicest ones around. He and lawyerA l Nelson were interested in low-power, highaerodynamics and thus were attracted toe Quickie. When suggestions made to Quickie Air-to scale the Quickie up to a 2-place VW poweredwere met with objections, they decidedo it themselves. With Bob's aeronautical engineer-g background. Al's experience in shaping custom surf-ds and a set of Quickie plans, they went to work.Their result, first flown in J une 1980.was a beauti-built prototype. N5WN. It was flown to the 1980Convention and won the Outstanding NewA ward. It is a relatively low wing loading con-with nearly 100 square feet of wing area, aapproach to handle the inevitable weightthat occur with homebuilts. It uses either the1600cc VW engine or the mid-displacement 1700

or 1834cc, apparently producing satisfactory perfor-mance (approximately 130 knots) on 47 to 62 horse-power, with a gross weight of 1075Ibs. I was not in-volved in the design or test effort of the Dragonfly.I have not yet flown the Dragonfly. Thus, I cannotcomment on the state of its development, the adequacyof its f lying qualities, difficulty of piloting or perfor-mance. It initially had a trim authority/speed stabilityproblem due to a large difference between its trim ele-vator position and float elevator position. This waspresumably solved by adding the external-boom trimtabs wedeveloped for the V ariV iggen.The Dragonfly is marketed similarly to our Long-EZin that Bob sells plans and builders obtain materialsfrom either manufacturers or distributors.

02Unknown to Bob Walters (andvice versa). CarryLeGare. a Canadian pilot businessman and homebuiltparts supplier, also wanted to scale the Quickie up totwo-placeand VW power. Carry had a business relation-ship with Quickie A ircraft Corporation as the dealerfor the Quickie kits in Canada. Upon asking, Carryfound that Gene and Tom were indeed interested in atwo-place and had already done some prel iminarysketches. They arrived at an agreement where Carrywould develop and build the prototype in Canada andthey would all be involved in its testing. Quickie would

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then market the kit and reimburse Carry from sales.A rmed with the Quickie design and some additionaldesign information from Gene and Tom, Carry set outin late 1979todesign and build the prototype Q2. Carryflew the first flight in July 1980 It was originally regis-tered in Canada and later registered as N8490P afterit was brought to M ojave for testing in the fall of 1980I was not involved in the design or test effort of the Q2in any way. Quickie Corporation redesigned the fuse-lage to a molded-shell configuration and built their ownQ2 (N81QA) in early 1981. The Q2 prototype was d am -aged in an accident caused by propeller failure andCarry salvaged the aft wing to build a new Q2. I t usedthe new fuselage design. Both these aircraft appearedat the 1981 Oshkosh Convention.I have not yet flown the Q2. Thus, I cannot c om -ment on the state of its development, the adequacy ofi ts flying qualities or difficulty of piloting. I wouldlike very much to fly a Dragonfly or a Q2 and offer aL ong-EZ checkout to anyone who completes their air-planeand would liketotrade rides!Comparisons

Despite their similar appearance, the Q2 is in a d i f -ferent class than the Dragonfly. Its engine is larger andits wing area is only about 2/3 that of the Dragonfly.Thus, it was aimed more at high speed cruise.Few people remember my original concept for theV ariE ze since it has now been over six years since theM ay '75 first flight date of N7EZ, a small, light, V W-powered prototype. Only one of these aircraft was everbuilt. N7EZ now resides in the EAA Air M useum afterlogging 480 hours divided between three different VW-conversions and a Franklin two-cylinder. N7EZ wasflown by over 30 different pilots and set a world's dis-tance record.

The adjacent table shows that N7EZ and Q2 werein the same class, with nearly identical power loadingand wing loading.It was a very difficult decision that I made in 1975to not market plans for the N7EZ type airplane. I wasobviously proud of the performance and efficiency. H o w -ever, I was concerned that it was too small, i.e.,too"hot" and sensitive for the average pilot on initial check-outs. I was also concerned about the safety of using anon-aircraft engine with the approach speeds as highas they were. Thus, I scaled the airplane up in size toaccept the Continental 0-200 aircraft engine. Thisraised the empty weight by 160 Ibs. and made a larger,more solid flying airplane. The change required me tobuild and test a new prototype (N4EZ) and delayed in-troduction of the V ariE ze plans until mid-1976. Eventhough scaling the airplane up reduced the fuel ef-ficiency, the net result was lower cost, since the air-craft engine has been trouble-free for its entire 520hours and has cost considerably less than the four en-gines did in N7EZ. During 1979/1980 the VariEze wasfurther scaled up, adding 46 more wing area and in-creasing empty weight another 160 Ibs. This aircraft( the Long-EZ) was designed for the excellent Lycoming0235 engine. The L ong-EZ (prototype is N79RA) hasgreatly increased utility and improved flying qualities.It has nowvirtually replaced the V ariEze.

P.A.T.-1The Piper A dvanced Technology P.A.T.-l, knownaffectionately as the "Pugmobile", was designed byGeorge M ead in late summer 1980 The late Howard( P u g ) Piper, son of the founder of Piper Aircraft, hadcontracted with George to develop a four-place proto-type aircraft of all-composite construction, that mightlead toa production aircraft.

F i g . 3 Canard/Tandem Design from 1912 .The Drzewiecki Monoplane.

(Photo Courtesy R A F )This aircraft is currently keeping folks busy around the RutanAircraft Factory in Mojave. It's a 62% scale version of theFairchild Republic entry in the competition to replace ormodernize the T - 3 7 military trainer. Burt Rutan was commis-sioned to design a scaled-down, all composite version thatcould be used to obtain flight test data quickly and moreeconomically than conventional wind tunnel/prototype pro-grams. The airframe was built by the A mes Industrial Corpora-tion, which also provided the two TRS-18-046 turbo jet en-gines. Rutan Aircraft got the flight test contract and DickRutan made the initial flight on September 10. Dick, Burt,Mike Melvill and Fairchild Republic pilot, Wendy Shawler,are doing the flying. This program is similar to the one Burtdid for NASA involving the swing-wing A D - 1 . Industry andNASA have apparently found Burt can provide more info fortheir buck than traditional methods . . . and in a fraction ofthe time.

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George has been associated with EAA aircraft sincewhen he was a BD-4 co-builder. In October 1975George to assist me in building the second Vari-(N4EZ) and to help draw the plans for printing.also assisted me in drafting the drawings forAD-1, the composite skew-wing jet I designed forGeorge left RAF in June 1977,about the timeformulating the design of the Defiant twin. Into his composite experience at RAF, Georgea conventional single place aircraft called theure, using VariEze construction techniques andterials.For Mr. Piper's project, George selected a tractortandem-wing canard configuration. Materialshowever, I was not involved nor consulted dur-the design and development of the P.A .T .-l. A ftercompleted and before the flight tests, Georgeme to study the design to verify his calculations.configuration through my computer programsdict neutral point, stall speeds, stall characteris-CG range, airload distribution and basic stabilityd control characteristics. That was the extent of myinvolvement with P.A .T.-l. I have not yet flownairplane, but hope to soon.

Design Flexibility, Not GuaranteeUse of the canard configuration does not assureperformance, stability or stall characteristics.ting two lifting wing systems fore-aft merelythe designer more flexibility in being able tothe stability of the configuration and the inducedWedesign the stability to be very non-linear, withlarge aft-shift in the neutral point as angle-of-attacks above a max.useable value. This is not some-

thing that happens automatically for example, theCurtiss Ascender had the opposite effect, with the re-sult being dangerous departures in pitch attitude atthe stall.The canard tandem wing aircraft, particularly thosel ike the Quickie with approximately equal load car-ried on each wing system, are very sensitive to minorairfoil changes. The boundary-layer transition andseparation patterns that are altered by minor variancesin contour, incidence and even flying in rain, can havemajor effects on pitch stability, trim and speed sta-bility. The aeroelastic effects (airframe twisting andbending with speed and angle-of-attack) which are nor-mally negligible in a conventional aircraft can changea stableairframe to dangerous instability at high speeds.Conversely, aeroelastic effects can aid high speed sta-bility with proper structural and aerodynamic design.I have used the Quickie configuration concept in thedesign of nine aircraft since 1977.These have rangedfrom ultralights and sailplanes to agricultural planesand 32-passenger commuter airliners (for N A SA ). M yM odel 68, the A msoil racing biplane, uses a very smallhorizontal tail, geared to optimize canard camber auto-matically for both the straightaways and 5-G turns.The designers' data base for these types of designsis extremely limited, and the importance of understand-ing their aerodynamics is great. A strong possibilityexists for the introduction of inferior designs that donot meet all the requirements for satisfactory flyingqualities and safety and thus give the configurationa bad reputation. I am proud of the potential promisedby this configuration to improve aviation safety andefficiency. Thus, I encourage other developers to notaccept less than perfection in their aircraft that areoffered to the public. I am willing to assist in solvingaerodynamic or aeroelastic problems during your flighttest programs if you are willing to incorporate the in-dicated fixes. Let's work together for better aircraft,rather than separately in a relative vacuum.Comparison

VariEze Prototype (1975) and Q2

Rutan Model 78-1

Empty WeightUseful LoadGross WeightSpanWing AreaWing L oadingPower LoadingFuelTake-OffL andingS/L Rateof ClimbimCruiseRangeat 75r/fN/M Gal. at lb c/

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Rutan_Quickie - Type Aircraft Design Origins