Modeling the Ligeti Stratos

NO OCR TEXT Left This ground shot shows some aircrafts unusual shapes angles Note dual-strut Fults Tooling nose gear vertical fins tie main canard wings together Also note outrigger wheel canard wing tip Right shot shows sweeping canard canard sweeps back 60 has ilk0 incidence Both wings have Eppler airfoil main wing has 00 incidence 60 dihedral 91-6 Gs 201 best glide ratio weighed mere 172 lb really wanted impress could tell about able fly side ways its ability change altitude withI B-S C B c-c C 0 out changing pitch could also talk about use flaps vertical split-flap rud ders acted air brakes give pi lot wide range angles descent course entire airplane could put LIGETI STRAWS A-A 0-0 0 2 3 trailer dismantling really get across full extent Ligetis genius Id show picture modelor hand transmitter Ligeti family requested pub lish construction plans Stratos design patented time contemplating kitting model threeview photos however obtained Bob Banka Scale Model Research incorporated presentation Since prototype exactly scale made angle error canard shortened span somewhat will list some dimensions end article may some help Properly built canard sweeps back 60 degrees side Let say Mr Ligeti angles what Carl Goldberg curves also want preface remarks say ing success wasnt achieved alone Both additional correspondence Mrs Ligeti friends master mod elers George Sauers Bob Terhune invaluable help Yes believe have two friends master modelers both thought prototype would fly notes Mr Ligeti suggested Ep pler airfoil both canard wing set 0-0 incidence like teachers give just enough formation get started stand back see what come up Since preconception canard has stall first unconvinced recom mendation 000 incidence set ca nard plus 1 cidence now know 00O works course should have listened Fortunately 11/2 also works believe Ligetis theory use same airfoil ca nard wing downdraft created canard will fool wing thinking its flying lower angle attack Pos sibly would occur different ca nard airfoil well really dont know nor wish present myself aerody namicist make Ds algebra dont jump right calculus As recall put total six degrees dihedral wing per three-view After flying full-scale Stratos however Ligeti thought dihedral unneces sary recall reading somewhere 92 Model Aviation inspiration behind model full-scale Ligeti Stratos being admired Oshkosh 1986 unbelievable little airplane de signed built Australia Czech-born Charles Ligeti unfortunately killed experimenting third wing early 1989 plane entered unrecoverable stall just 400 ft over runway Stratos seen 17-ft 7-in wingspan could fly 100 mph 28-hp Konig engine service ceiling 14760 ft 449-mile range climb rate 670 ft per mm stressed Gs 201 best glide ratio weighed mere 172 lb could fly sideways could transported trailer being disassembled four pictures 3-view accompanying article provided Bob Banka Scale Model Research Costa Mesa CA 10 degrees sweep equals degree di hedral sweep canard Ligeti designed would make up zero-degree dihedral wing Remember dihedral changed area rudders will also need changed George Sauers pointed out rud ders could move outboard board since drag created inboard movement would cancel outboard input still have some trouble understanding have learned listen George Bob Terhune suggested eliminating rud ders altogether As turns out both rightrudders uneccessary model suspect effective rudder would enclosed shrouded nose gear per original design would create single rudder building another Stratos would use two servos outboard rudder control else try figure out set up also act air brakes toed-in vertical fin degree sist directional stability have no idea whether actually works know model gives no stability prob lems flight attitude used hackers version Eppler 203 mean increased overall thickness 18% Ligeti recall sug gested thickness between 15 17% also increased overall length fuselage adding 1 area Again Georges suggestion thought Id need nearly much weight up front counterbalance 90 four-stroke engine back al right although didnt need much weight originally anticipated model deviates Ligetis design other ways installed no ailerons canard flaps wing didnt shroud nose gear Designing scratch teaches lot need determination pit bull hang knew early power designing model author friend George Sauer built several small test models work out balance aerodynamics photo left shows cardboard balance model bottom foam Hand-Launched Glider top Figuring out establish CG RC model proved real challenge procedure described text photo right Jim Galstad shows George Sauers test bed joined-wing 049-powered canard millisecond before crashed balancing formula used faulty model tail heavy May 1990 93 Left nearly completed Stratos its original nose gear prop shroud nose gear proved too floppy prop shroud turbu lated airflow around propeller rendering totally ineffective dark line fuselage marks edge canopy Two dowels rear 3-in-long 6-32 screw nose lock place Right Rear view shroud caused much frustration builder 14-in leading edge balsa ring caused turbulation new shroud smooth inside airfoil solved turbulation problems would major problem simply dont like two-stroke power plants never question about installing fourstroke engine Unfortunately four-strokers like large propellers As can see drawings prop diameter design limited because shroud original all-up weight estimate tween 13 15 lb never learn pro totype came out weighing 15 lbwith about 20-oz wing loading Originally planned join two 12 x 6 pusher props would turn about 8000 rpmwhich theoretically enough fly airplane size prop translated shroud diameter 12A 12 ac tual tests Ive getting 8500 rpm two 14 x 6 props cut down 1211* combination gives model adequate pow er although havent tried fly Den ver Bob Routh pointing out originally installed props backwards Stratos might still ground Hey pusher prop people about putting emblem other side props exposed public flipper Youll get advertising wont confuse dummies like original shroud didnt work first three attempts very disappointingthe model would barely move ground thought because needed prop diameter removed shroud stalled 14 x 6 prop worked great Dennis Reichenberger kept telling shroud prop diameter prob lem Convinced own brilliance ig nored Dennis advice first Dennis yet another good friend master modeler cardboard jumbos original approach shroud simply hang circle around prop would look scalelike fall off first shroud built laminating balsa sheets 450 angles other around what looks like cardboard pizza plate covered silkspan keep weight down crafted glued /4 x A-in strips balsa around leading edge help maintain shape accom plished using pieces much way makes built-up wing tip As turned out looked great ever A-in stiffener killing coming airflownot letting get prop could some good Ducted fan people take note Make inverted air foil shrouds Clark Y instance curved part would side shroud Though Stratos flew well shroud fully half character airplane didnt want give up made new laminating thin lay ers white foam sanding small airfoil shape still flat fiber glassing 1-oz cloth isnt pretty well done original per formance went night day Jim Gal stad fuel systems expert Boeing helped design reworked shroud has 13-in open ing forward end tapering 121/2 back results 30 funnel shape about A-in prop clearance shroud weighs seven ounces four ounces lead added nose ever Ive slowly removing extra lead gain experience model outrigger wheels another area concern figured Id have terrible ground handling problems until enough speed gained get wings up level Early dismal results reinforced judgement counteract engine torque seemed keep right wing tip ground added three Dave Brown lightweight wheels main gear total three right side After little prac tice found able remove Im now easily taking off grass just two tandem wheels two outriggers Another problem %2-in nose gear too floppy Id hoping excuse buy dual-strut nose gear Continued page 99 94 Model Aviation _ _ 1 4 ~LTh 71II W110 X4 4-56 8OLT DOW \PfN 4m WIM6TIP 3 /IW0 NL4 ANG4* ~A55I F INS T ANAIW 4 Sq 5MIIC& P P4AT IN WWMII WO uC Ar flP P4N W4UL Left Close-up authors latest engine/prop/shroud installation engine OS 90 four-stroke Surpass prop made up two 14 x 6 Zinger pusher props joined cut down 12 x 6 airfoiled shroud 12-in-dia Notice interesting exhaust muf fler arrangement Right look Stratos belly showing details shrouded main landing gear canard-mounted elevators seemed like right time Fults Tool ing model RF 500 gear selected really quite nice unit has worked flaw lessly use old Fox 3A-in aluminumhub wheel nose gear Its stout attractive wheel wish still avail able fully realize 747-type wheel setup pretty Mickey Mouse let has never Mickey-Moused something eat first hole Balsa USA factory Determining balance point presented another major problem designing Stratos experimented Bob Ter hunes Varieze ended up crashing four five times George Sauers per fectly stable box-type canard tried configure like Stratos too crashed tried building 049 ver sion no better luck So far solu tion eluding us time determine just much weight actually resting nose wheel rolled airplane edge table weighed just nose Good griefseven pounds Thats almost half weight airplane Something has wrong ong ong problem aft wheel placed scale center-of-gravity loca tion axle just about lead ing edge wing well aft orig May 1990 99 Left The canopy removed exposing fuel tank installation faces forward located 15 engine 4 below cen terline yet theres no problem drawing fuel airplane has suffered dead-stick landing its maiden flight Right rudder servo installation canard clamped-on plastic spray bottle just visible bottom photo lead ballast Left An earlier main landing gear arrangement employed attempt counteract engine torque caused right wing drop takeoff run setup abandoned ground handling experience gained Right Details right tin/rudder outrigger wheel inally calculated CG youve ever seen tricycle-geared model literally leap Dve APIP II ff ground probably because main gear too far aft CG underWJN Cardboard model used estab lish neutral balance point LEAPl stand Prescott Pusher initially problem quickly solved dilemma though moved main gear too far forwani would nt have enough ground clearance takeoff prop already good three inches overscaled could have gone larger wheels outrigger wheels would have too high good time flying field across town thought crazy wasnt going fly did people assumed 90 engine wouldnt power ful enough point too began wonder Id come up first hangar queen balance point way off youre up tutu alli gators call Croc odile Dundee Af ter Aus tralian design Feel ing however bothered Ligetis enough instead dug out book model aero dynamics Martin Simons research gathered center lift model airplane wings between 24 26% chord further deduced through careful analytical reasoning good average would about 25% draw out wing canard planform piece cardboard chop off rear half both youll end up 50% lifting surface bal ance wing canard would sit fuselage would balancing its respective 25%-of-chord position stead balancing lift balancing weight other words have found what called neutral point done before certain conclusion wrong made new cardboard model wing canard horizontal stabilizer separated some distance attach piece Nyrod similar manmade material made mistake attaching balsa sticks taking account unequal den sity end result balance point two inches forward ideal realized later since wing ca nard overlap other tips could simply glue two lifting halves together would sit fuselage thus elim inating sticks simply balanced edge ruler balance point neutral point moved forward 15% wing chord 15% 12 in case airplane nose-heavy flyable have use Nyrod separate lifting surfaces particular applica tion sure make Nyrod extra long way can position flying sur faces near middle mark balance point measure forward backward measurements must equal arent begin cutting off long half Nyrod until equidistance balance point reached effect what doing negating weight Nyrod After going through exercise realizing two inches too far ward began removing weight About Continued page 192 INLET Left The original shroud showing 1/4-in leading edge used maintain its shape killed incoming air making too turbulent Right Heres shroud presently constructed would probably work better installation designed position prop closer shroud inlet COTL I42S I4Ta ues MOW OJTWAD ONLY MouNI6l IN MIWL0LOCI~0tZEl T ~JZ12 ro IF rL CA0L jr iAT$ 100 Model Aviation dowels holes seen photo mute evidence false starts establishing workable CG prototype model dual rudder linkage setup designed move rud der mostly outboard hardly inboard movement -uEEEEEEEEEmEEE U mum mu mm umm U mum BIG GLOW FUEL MANUFACTURED WITH THE PUREST FINEST QUALITY INGREDIENTS AVAILABLE * *I * * *at * U U U U U U U U S I] Superior Igniters Improve starting idle acceleration Youll notice power bargain fuels Special Detergents Promote clean burning prevent residue buildup Rust Inhibitors Protect engines corrosion After run oil needed engines Film Strength Additives Increase lubricity provide extra lean run protection Anti-Wear Additives Help keep engines running peak performance longer Satisfaction Guaranteed FREE SHIPPING ON ORDERS OVER $1500 SIG CHAMPION 2-STROKE FUEL P4NT 9UART GALLON 0%Nitrontetftne$10 75 5%Nitroithane$65$525$1275 10%Nitro~i$4 15~4Q$1475 15%Nltrom~han$43O$6~$1675 25%Nitrom1I34$21 95 35%Nitromethane$595$925$2695 SIGPREMIUM 4-STROKE FUEL 10% Nitromethane$1425 15% Nitromethane$1625 THE CHOICE OF CHAMPION FLYERS U aver 20 years SIG has blending finest quality model engine fuel available using finest quality ingredients instance Methanol use 995% pure very best grade money can buy also use real 100% pure U Nitromethane get full measure youve paid based honest percentage-of-volume I method percentage weight SIG fuels contam 50-50 blend Bakers purest AA Castor Oil new improved Klotz Techniplate Synthetic Racing Oil U for maximum engine lubrication protection Based experience sincerely believe finest quality fuel can made price dont take word try some judge yourself Pcos sobiod obonge wthoot ,otice See dealer first available order direct Call LZJ 800-247-5008 toll free orders Latest Catalog $300 MANUFACTURING CO Montezuma IA 50171 Dynamic Duo Durability Stand Ready Help Take Encounters Planet Earth scuffle ground isnt some thing should have face own may have gotten own dont think model should stand After two team So join up airplanes thatll stick through thick thin Dumcmft Inc 71007 Qdwd Grove Orwe Royai Oak NI 48067 DuraPlane II 25-size 3-channel basic flight trainer DuraBat 40-size 4-channel aerobatic trainer U U I U U U i I U U U I I U U set rotors collective pitch longitudinal cyclic lateral cyclic main rotor fore/aft shaft tilt angle rpm Figure 11 shows signal processing equipment signal conditioners instrument amplifiers frequency counters computer interface strip chart recorder sig nals monitored include flapping angle lead-lag angle pitch angle four blades flexheams bending twisting strain rotors pitching roll ing moments thrust drag forces flap bending moment blade number rpm plotted continuously strip chart recorder Figure 12 gives some idea nest wires behind instrumentation valuable data collected phenom ena being observed wind tunnel tests bring us nearer goal better safer helicopter 21st century Ligeti Stratos Continued page 100 time George Sauers called tell gained access CADCAM machine plugged models dimensions come up new computer-generated balance point computer agreed calculations within 4 reweighed nose wheel came out weighing 3/2 lb like wheel changes original shroud re moved close attaining flight speed time absolutely knew Stratos would fly next time out after Ed showed off around town club meeting folks still convinced wouldnt fly day flew things just felt right very tense excited weather forecast called 5-15-mph winds out north right down runwaya downhill run north wind summer God side course arrived field wind stronger shifted east-northeast much takeoff room direction grass hadnt mowed So before could attempt fly mow grass devil time getting mower started finally succeeded sec ond pass wind increased temperature dropped fourth pass getting rained jaw muscles set mind clicked lock Reason no longer functioned going fly airplane today moment Bob Terhune showed up saw look face jumped other mower Just quickly rain sub sided George showed up ran model through series taxi tests looked con vincing Other people began showing up hanging around picnic table knew figured airplane went hogwild started attacking everybody theyd just duck under wind dropped dead calm conver sation stopped Stratos started down runway its first takeoff attempt Speed gathered slowly first faster faster Lift-off still get goose bumps just thinking about longawaited moment George Sauers sticks Just after lift off wing dropped dangerously corrected instantly smoothed Out headed out over Continued page 196 192 Model Aviation U U U U U U U U U U i U U U U U U I I U U E ER K EUUEUUUUU Four Great Days Oshkosh WI Wlttman Field Over 30 Manufacturers & Dealers Indoors IHOME OF TIlE EAA T THE EAA MUSEUMI iMemoUoaIWITTMAN FIELD OSI4KOSII WI mIAIOUIS%4% LY OF GIANTS 1 990 Alicaft WIDE JIMAS 10th ANNIVERSARY FIJI4FLY WORLD L.u..ininore~BOx21june28293OJuIV1I99OI Complete Information write Council BluffS IA 51503 IMMA Sanctioned Ligeti Stratos Continued page 192 cornfield George thoroughly wrung plane out Nothing wild like loops rolls after get ting feel declared stable bit nose-heavya pussycat Everything go ing fineuntil engine quit airplane high George started cir cling down last circle seemed too low long way field George said Im going stretch model settled long flat Sailplane-like glide gently touched down edge field Post-flight evalua tions determined ho trim changes re quired just tad up thrust would help Yes 1 heard applause under picnic ta ble Some laughter shout two couple singular superlatives wouldnt hear church wish Mr Ligeti alive thank will remain highlight mod eling career As walked field Dennis Reichenberger said Ive got admit dont mean anything bad just thought wouldnt get off ground George Wells said told Mary Jean last night Mar vin nice guy believed crazy thought thing going fly uess now Ill have go home tell damned thing flew Oh yes did mention also test flew Goldberg Comet Sailplane same night man aged stick tree guess needed dose humility After 30 40 flights can assure Stra tos stable trainer loops rolls will spin once try uncoordinated ham merhead Its truly unbelievable airplane Some final thoughts Install fuel tank balance point prototype requires fuel drawn IS behind engine 4 lower carburator origi nally installed Perry Micro Oscillating pump never needed later removed dead-stick landing Ive experienced Stratos its maiden flight try get people believe strongly urge wings built first us ing wing jig box Since canard sweeps back youll have rather long unusual cutout box suggest first tack glue firmly tape center section canard rear wing can glued together build /32 halsa wing jig box properly set up wing canard Install everything far forward pos sibly can still leaving room good bal last box After its jigged up fins made %2 balsa laminated 4 ply installed simply glue foam box begin sanding Its best use white foam lower part blue upper later can remove blue foam nice fiberglass up per shell Four important points emerged designing building flying Stratos Balance point 2 Airfoil selection 3 canard must stall first 4 thrust line wrecked lot experimental models arriving conclu sions decide build Ligeti Stratos model let know come out Get refer ence material Bob Banka start chop ping latest project original-design sleek 18-ft-span powered Sailplane weighs 17 lb will powered OS 61 four-stroke Surpass engine already know what youre thinking Itll never pull weight Itll never fly etc Well may right Ive already done taxi tests found builds up enough ground speed takeoff using 14 x 6 Master Airscrew Well see may very well fly THE SUPERIOR GLOW PLUGS GO FASTFLYERS ARE BACK! Puts sting engine Unique flat-wound spiral coil element high temperature glass-to-metal seal add up faster ignition Increased RPM 1/2A GloBee plugs designed exclusively 049/051 Cox engines Ask new GB-SRX Speed Plug GB-5R Racing Plug GB-5P Sport Plug local dealer today unavailable locally write call Twinn-K collect pricing delivery information FREE GloBee Catalog MAKE THE GLOBEE INDY CONNECTION Twinn-K Inc 10296 W Washington St Indianapolis IN 46231 Telephone 317-839-6579 FAX 317-839-8928 196 Model Aviation wouldnt first time Ive proved skeptics wrong Specifications Charles Ligetis full-size aircraft has wingspan 17 ft 7 807 sq ft area fuse lage 8 ft 2 long 3 ft 3 high shroud 24/2-in dia balance point 47 ahead main wing leading edge model has 77-in main wingspan chord 12A tapering II degree washout 60 dihedral 00 incidence airfoil both main wing canard modified Eppler 203 15-17% thick canard spans 90 youll have cut longer due some loss creating taper canard has 10-in root 9-in tip de gree washout has no dihedral sweeps back 600 has 1/20 positive incidence fin/rudder 6/2 high chord 11 prop shroud l2-in dia 4/2-in chord ailerons 143A x 2/2 set 2A wing tips elevator 15 x 2% main wheels 3A-in dia out rigger wheels -in dia balance point about 6 ahead leading edge main wing prototype yours may very well different Check described text installed OS 90 Surpass fourstroke engine swinging two Zinger 14 x 6 pusher props mated together cut down 12 Check see reverse cam available particular installation might able use standard props thrust line set about 10 up finished model weighs 15 lb Note You might want consider building larger version Ligeti Stratos using Tartan Twin Its overly heavy will run either direction Aerie/Kanyusik Continued page 106 staged make community aware clubs need new flying siteand spark new interest RC flying made sign informing public need gave us leads followed up Key City Bald Eagles group heav Continued page 198

NO OCR TEXT Left This ground shot shows some aircrafts unusual shapes angles Note dual-strut Fults Tooling nose gear vertical fins tie main canard wings together Also note outrigger wheel canard wing tip Right shot shows sweeping canard canard sweeps back 60 has ilk0 incidence Both wings have Eppler airfoil main wing has 00 incidence 60 dihedral 91-6 Gs 201 best glide ratio weighed mere 172 lb really wanted impress could tell about able fly side ways its ability change altitude withI B-S C B c-c C 0 out changing pitch could also talk about use flaps vertical split-flap rud ders acted air brakes give pi lot wide range angles descent course entire airplane could put LIGETI STRAWS A-A 0-0 0 2 3 trailer dismantling really get across full extent Ligetis genius Id show picture modelor hand transmitter Ligeti family requested pub lish construction plans Stratos design patented time contemplating kitting model threeview photos however obtained Bob Banka Scale Model Research incorporated presentation Since prototype exactly scale made angle error canard shortened span somewhat will list some dimensions end article may some help Properly built canard sweeps back 60 degrees side Let say Mr Ligeti angles what Carl Goldberg curves also want preface remarks say ing success wasnt achieved alone Both additional correspondence Mrs Ligeti friends master mod elers George Sauers Bob Terhune invaluable help Yes believe have two friends master modelers both thought prototype would fly notes Mr Ligeti suggested Ep pler airfoil both canard wing set 0-0 incidence like teachers give just enough formation get started stand back see what come up Since preconception canard has stall first unconvinced recom mendation 000 incidence set ca nard plus 1 cidence now know 00O works course should have listened Fortunately 11/2 also works believe Ligetis theory use same airfoil ca nard wing downdraft created canard will fool wing thinking its flying lower angle attack Pos sibly would occur different ca nard airfoil well really dont know nor wish present myself aerody namicist make Ds algebra dont jump right calculus As recall put total six degrees dihedral wing per three-view After flying full-scale Stratos however Ligeti thought dihedral unneces sary recall reading somewhere 92 Model Aviation inspiration behind model full-scale Ligeti Stratos being admired Oshkosh 1986 unbelievable little airplane de signed built Australia Czech-born Charles Ligeti unfortunately killed experimenting third wing early 1989 plane entered unrecoverable stall just 400 ft over runway Stratos seen 17-ft 7-in wingspan could fly 100 mph 28-hp Konig engine service ceiling 14760 ft 449-mile range climb rate 670 ft per mm stressed Gs 201 best glide ratio weighed mere 172 lb could fly sideways could transported trailer being disassembled four pictures 3-view accompanying article provided Bob Banka Scale Model Research Costa Mesa CA 10 degrees sweep equals degree di hedral sweep canard Ligeti designed would make up zero-degree dihedral wing Remember dihedral changed area rudders will also need changed George Sauers pointed out rud ders could move outboard board since drag created inboard movement would cancel outboard input still have some trouble understanding have learned listen George Bob Terhune suggested eliminating rud ders altogether As turns out both rightrudders uneccessary model suspect effective rudder would enclosed shrouded nose gear per original design would create single rudder building another Stratos would use two servos outboard rudder control else try figure out set up also act air brakes toed-in vertical fin degree sist directional stability have no idea whether actually works know model gives no stability prob lems flight attitude used hackers version Eppler 203 mean increased overall thickness 18% Ligeti recall sug gested thickness between 15 17% also increased overall length fuselage adding 1 area Again Georges suggestion thought Id need nearly much weight up front counterbalance 90 four-stroke engine back al right although didnt need much weight originally anticipated model deviates Ligetis design other ways installed no ailerons canard flaps wing didnt shroud nose gear Designing scratch teaches lot need determination pit bull hang knew early power designing model author friend George Sauer built several small test models work out balance aerodynamics photo left shows cardboard balance model bottom foam Hand-Launched Glider top Figuring out establish CG RC model proved real challenge procedure described text photo right Jim Galstad shows George Sauers test bed joined-wing 049-powered canard millisecond before crashed balancing formula used faulty model tail heavy May 1990 93 Left nearly completed Stratos its original nose gear prop shroud nose gear proved too floppy prop shroud turbu lated airflow around propeller rendering totally ineffective dark line fuselage marks edge canopy Two dowels rear 3-in-long 6-32 screw nose lock place Right Rear view shroud caused much frustration builder 14-in leading edge balsa ring caused turbulation new shroud smooth inside airfoil solved turbulation problems would major problem simply dont like two-stroke power plants never question about installing fourstroke engine Unfortunately four-strokers like large propellers As can see drawings prop diameter design limited because shroud original all-up weight estimate tween 13 15 lb never learn pro totype came out weighing 15 lbwith about 20-oz wing loading Originally planned join two 12 x 6 pusher props would turn about 8000 rpmwhich theoretically enough fly airplane size prop translated shroud diameter 12A 12 ac tual tests Ive getting 8500 rpm two 14 x 6 props cut down 1211* combination gives model adequate pow er although havent tried fly Den ver Bob Routh pointing out originally installed props backwards Stratos might still ground Hey pusher prop people about putting emblem other side props exposed public flipper Youll get advertising wont confuse dummies like original shroud didnt work first three attempts very disappointingthe model would barely move ground thought because needed prop diameter removed shroud stalled 14 x 6 prop worked great Dennis Reichenberger kept telling shroud prop diameter prob lem Convinced own brilliance ig nored Dennis advice first Dennis yet another good friend master modeler cardboard jumbos original approach shroud simply hang circle around prop would look scalelike fall off first shroud built laminating balsa sheets 450 angles other around what looks like cardboard pizza plate covered silkspan keep weight down crafted glued /4 x A-in strips balsa around leading edge help maintain shape accom plished using pieces much way makes built-up wing tip As turned out looked great ever A-in stiffener killing coming airflownot letting get prop could some good Ducted fan people take note Make inverted air foil shrouds Clark Y instance curved part would side shroud Though Stratos flew well shroud fully half character airplane didnt want give up made new laminating thin lay ers white foam sanding small airfoil shape still flat fiber glassing 1-oz cloth isnt pretty well done original per formance went night day Jim Gal stad fuel systems expert Boeing helped design reworked shroud has 13-in open ing forward end tapering 121/2 back results 30 funnel shape about A-in prop clearance shroud weighs seven ounces four ounces lead added nose ever Ive slowly removing extra lead gain experience model outrigger wheels another area concern figured Id have terrible ground handling problems until enough speed gained get wings up level Early dismal results reinforced judgement counteract engine torque seemed keep right wing tip ground added three Dave Brown lightweight wheels main gear total three right side After little prac tice found able remove Im now easily taking off grass just two tandem wheels two outriggers Another problem %2-in nose gear too floppy Id hoping excuse buy dual-strut nose gear Continued page 99 94 Model Aviation _ _ 1 4 ~LTh 71II W110 X4 4-56 8OLT DOW \PfN 4m WIM6TIP 3 /IW0 NL4 ANG4* ~A55I F INS T ANAIW 4 Sq 5MIIC& P P4AT IN WWMII WO uC Ar flP P4N W4UL Left Close-up authors latest engine/prop/shroud installation engine OS 90 four-stroke Surpass prop made up two 14 x 6 Zinger pusher props joined cut down 12 x 6 airfoiled shroud 12-in-dia Notice interesting exhaust muf fler arrangement Right look Stratos belly showing details shrouded main landing gear canard-mounted elevators seemed like right time Fults Tool ing model RF 500 gear selected really quite nice unit has worked flaw lessly use old Fox 3A-in aluminumhub wheel nose gear Its stout attractive wheel wish still avail able fully realize 747-type wheel setup pretty Mickey Mouse let has never Mickey-Moused something eat first hole Balsa USA factory Determining balance point presented another major problem designing Stratos experimented Bob Ter hunes Varieze ended up crashing four five times George Sauers per fectly stable box-type canard tried configure like Stratos too crashed tried building 049 ver sion no better luck So far solu tion eluding us time determine just much weight actually resting nose wheel rolled airplane edge table weighed just nose Good griefseven pounds Thats almost half weight airplane Something has wrong ong ong problem aft wheel placed scale center-of-gravity loca tion axle just about lead ing edge wing well aft orig May 1990 99 Left The canopy removed exposing fuel tank installation faces forward located 15 engine 4 below cen terline yet theres no problem drawing fuel airplane has suffered dead-stick landing its maiden flight Right rudder servo installation canard clamped-on plastic spray bottle just visible bottom photo lead ballast Left An earlier main landing gear arrangement employed attempt counteract engine torque caused right wing drop takeoff run setup abandoned ground handling experience gained Right Details right tin/rudder outrigger wheel inally calculated CG youve ever seen tricycle-geared model literally leap Dve APIP II ff ground probably because main gear too far aft CG underWJN Cardboard model used estab lish neutral balance point LEAPl stand Prescott Pusher initially problem quickly solved dilemma though moved main gear too far forwani would nt have enough ground clearance takeoff prop already good three inches overscaled could have gone larger wheels outrigger wheels would have too high good time flying field across town thought crazy wasnt going fly did people assumed 90 engine wouldnt power ful enough point too began wonder Id come up first hangar queen balance point way off youre up tutu alli gators call Croc odile Dundee Af ter Aus tralian design Feel ing however bothered Ligetis enough instead dug out book model aero dynamics Martin Simons research gathered center lift model airplane wings between 24 26% chord further deduced through careful analytical reasoning good average would about 25% draw out wing canard planform piece cardboard chop off rear half both youll end up 50% lifting surface bal ance wing canard would sit fuselage would balancing its respective 25%-of-chord position stead balancing lift balancing weight other words have found what called neutral point done before certain conclusion wrong made new cardboard model wing canard horizontal stabilizer separated some distance attach piece Nyrod similar manmade material made mistake attaching balsa sticks taking account unequal den sity end result balance point two inches forward ideal realized later since wing ca nard overlap other tips could simply glue two lifting halves together would sit fuselage thus elim inating sticks simply balanced edge ruler balance point neutral point moved forward 15% wing chord 15% 12 in case airplane nose-heavy flyable have use Nyrod separate lifting surfaces particular applica tion sure make Nyrod extra long way can position flying sur faces near middle mark balance point measure forward backward measurements must equal arent begin cutting off long half Nyrod until equidistance balance point reached effect what doing negating weight Nyrod After going through exercise realizing two inches too far ward began removing weight About Continued page 192 INLET Left The original shroud showing 1/4-in leading edge used maintain its shape killed incoming air making too turbulent Right Heres shroud presently constructed would probably work better installation designed position prop closer shroud inlet COTL I42S I4Ta ues MOW OJTWAD ONLY MouNI6l IN MIWL0LOCI~0tZEl T ~JZ12 ro IF rL CA0L jr iAT$ 100 Model Aviation dowels holes seen photo mute evidence false starts establishing workable CG prototype model dual rudder linkage setup designed move rud der mostly outboard hardly inboard movement -uEEEEEEEEEmEEE U mum mu mm umm U mum BIG GLOW FUEL MANUFACTURED WITH THE PUREST FINEST QUALITY INGREDIENTS AVAILABLE * *I * * *at * U U U U U U U U S I] Superior Igniters Improve starting idle acceleration Youll notice power bargain fuels Special Detergents Promote clean burning prevent residue buildup Rust Inhibitors Protect engines corrosion After run oil needed engines Film Strength Additives Increase lubricity provide extra lean run protection Anti-Wear Additives Help keep engines running peak performance longer Satisfaction Guaranteed FREE SHIPPING ON ORDERS OVER $1500 SIG CHAMPION 2-STROKE FUEL P4NT 9UART GALLON 0%Nitrontetftne$10 75 5%Nitroithane$65$525$1275 10%Nitro~i$4 15~4Q$1475 15%Nltrom~han$43O$6~$1675 25%Nitrom1I34$21 95 35%Nitromethane$595$925$2695 SIGPREMIUM 4-STROKE FUEL 10% Nitromethane$1425 15% Nitromethane$1625 THE CHOICE OF CHAMPION FLYERS U aver 20 years SIG has blending finest quality model engine fuel available using finest quality ingredients instance Methanol use 995% pure very best grade money can buy also use real 100% pure U Nitromethane get full measure youve paid based honest percentage-of-volume I method percentage weight SIG fuels contam 50-50 blend Bakers purest AA Castor Oil new improved Klotz Techniplate Synthetic Racing Oil U for maximum engine lubrication protection Based experience sincerely believe finest quality fuel can made price dont take word try some judge yourself Pcos sobiod obonge wthoot ,otice See dealer first available order direct Call LZJ 800-247-5008 toll free orders Latest Catalog $300 MANUFACTURING CO Montezuma IA 50171 Dynamic Duo Durability Stand Ready Help Take Encounters Planet Earth scuffle ground isnt some thing should have face own may have gotten own dont think model should stand After two team So join up airplanes thatll stick through thick thin Dumcmft Inc 71007 Qdwd Grove Orwe Royai Oak NI 48067 DuraPlane II 25-size 3-channel basic flight trainer DuraBat 40-size 4-channel aerobatic trainer U U I U U U i I U U U I I U U set rotors collective pitch longitudinal cyclic lateral cyclic main rotor fore/aft shaft tilt angle rpm Figure 11 shows signal processing equipment signal conditioners instrument amplifiers frequency counters computer interface strip chart recorder sig nals monitored include flapping angle lead-lag angle pitch angle four blades flexheams bending twisting strain rotors pitching roll ing moments thrust drag forces flap bending moment blade number rpm plotted continuously strip chart recorder Figure 12 gives some idea nest wires behind instrumentation valuable data collected phenom ena being observed wind tunnel tests bring us nearer goal better safer helicopter 21st century Ligeti Stratos Continued page 100 time George Sauers called tell gained access CADCAM machine plugged models dimensions come up new computer-generated balance point computer agreed calculations within 4 reweighed nose wheel came out weighing 3/2 lb like wheel changes original shroud re moved close attaining flight speed time absolutely knew Stratos would fly next time out after Ed showed off around town club meeting folks still convinced wouldnt fly day flew things just felt right very tense excited weather forecast called 5-15-mph winds out north right down runwaya downhill run north wind summer God side course arrived field wind stronger shifted east-northeast much takeoff room direction grass hadnt mowed So before could attempt fly mow grass devil time getting mower started finally succeeded sec ond pass wind increased temperature dropped fourth pass getting rained jaw muscles set mind clicked lock Reason no longer functioned going fly airplane today moment Bob Terhune showed up saw look face jumped other mower Just quickly rain sub sided George showed up ran model through series taxi tests looked con vincing Other people began showing up hanging around picnic table knew figured airplane went hogwild started attacking everybody theyd just duck under wind dropped dead calm conver sation stopped Stratos started down runway its first takeoff attempt Speed gathered slowly first faster faster Lift-off still get goose bumps just thinking about longawaited moment George Sauers sticks Just after lift off wing dropped dangerously corrected instantly smoothed Out headed out over Continued page 196 192 Model Aviation U U U U U U U U U U i U U U U U U I I U U E ER K EUUEUUUUU Four Great Days Oshkosh WI Wlttman Field Over 30 Manufacturers & Dealers Indoors IHOME OF TIlE EAA T THE EAA MUSEUMI iMemoUoaIWITTMAN FIELD OSI4KOSII WI mIAIOUIS%4% LY OF GIANTS 1 990 Alicaft WIDE JIMAS 10th ANNIVERSARY FIJI4FLY WORLD L.u..ininore~BOx21june28293OJuIV1I99OI Complete Information write Council BluffS IA 51503 IMMA Sanctioned Ligeti Stratos Continued page 192 cornfield George thoroughly wrung plane out Nothing wild like loops rolls after get ting feel declared stable bit nose-heavya pussycat Everything go ing fineuntil engine quit airplane high George started cir cling down last circle seemed too low long way field George said Im going stretch model settled long flat Sailplane-like glide gently touched down edge field Post-flight evalua tions determined ho trim changes re quired just tad up thrust would help Yes 1 heard applause under picnic ta ble Some laughter shout two couple singular superlatives wouldnt hear church wish Mr Ligeti alive thank will remain highlight mod eling career As walked field Dennis Reichenberger said Ive got admit dont mean anything bad just thought wouldnt get off ground George Wells said told Mary Jean last night Mar vin nice guy believed crazy thought thing going fly uess now Ill have go home tell damned thing flew Oh yes did mention also test flew Goldberg Comet Sailplane same night man aged stick tree guess needed dose humility After 30 40 flights can assure Stra tos stable trainer loops rolls will spin once try uncoordinated ham merhead Its truly unbelievable airplane Some final thoughts Install fuel tank balance point prototype requires fuel drawn IS behind engine 4 lower carburator origi nally installed Perry Micro Oscillating pump never needed later removed dead-stick landing Ive experienced Stratos its maiden flight try get people believe strongly urge wings built first us ing wing jig box Since canard sweeps back youll have rather long unusual cutout box suggest first tack glue firmly tape center section canard rear wing can glued together build /32 halsa wing jig box properly set up wing canard Install everything far forward pos sibly can still leaving room good bal last box After its jigged up fins made %2 balsa laminated 4 ply installed simply glue foam box begin sanding Its best use white foam lower part blue upper later can remove blue foam nice fiberglass up per shell Four important points emerged designing building flying Stratos Balance point 2 Airfoil selection 3 canard must stall first 4 thrust line wrecked lot experimental models arriving conclu sions decide build Ligeti Stratos model let know come out Get refer ence material Bob Banka start chop ping latest project original-design sleek 18-ft-span powered Sailplane weighs 17 lb will powered OS 61 four-stroke Surpass engine already know what youre thinking Itll never pull weight Itll never fly etc Well may right Ive already done taxi tests found builds up enough ground speed takeoff using 14 x 6 Master Airscrew Well see may very well fly THE SUPERIOR GLOW PLUGS GO FASTFLYERS ARE BACK! Puts sting engine Unique flat-wound spiral coil element high temperature glass-to-metal seal add up faster ignition Increased RPM 1/2A GloBee plugs designed exclusively 049/051 Cox engines Ask new GB-SRX Speed Plug GB-5R Racing Plug GB-5P Sport Plug local dealer today unavailable locally write call Twinn-K collect pricing delivery information FREE GloBee Catalog MAKE THE GLOBEE INDY CONNECTION Twinn-K Inc 10296 W Washington St Indianapolis IN 46231 Telephone 317-839-6579 FAX 317-839-8928 196 Model Aviation wouldnt first time Ive proved skeptics wrong Specifications Charles Ligetis full-size aircraft has wingspan 17 ft 7 807 sq ft area fuse lage 8 ft 2 long 3 ft 3 high shroud 24/2-in dia balance point 47 ahead main wing leading edge model has 77-in main wingspan chord 12A tapering II degree washout 60 dihedral 00 incidence airfoil both main wing canard modified Eppler 203 15-17% thick canard spans 90 youll have cut longer due some loss creating taper canard has 10-in root 9-in tip de gree washout has no dihedral sweeps back 600 has 1/20 positive incidence fin/rudder 6/2 high chord 11 prop shroud l2-in dia 4/2-in chord ailerons 143A x 2/2 set 2A wing tips elevator 15 x 2% main wheels 3A-in dia out rigger wheels -in dia balance point about 6 ahead leading edge main wing prototype yours may very well different Check described text installed OS 90 Surpass fourstroke engine swinging two Zinger 14 x 6 pusher props mated together cut down 12 Check see reverse cam available particular installation might able use standard props thrust line set about 10 up finished model weighs 15 lb Note You might want consider building larger version Ligeti Stratos using Tartan Twin Its overly heavy will run either direction Aerie/Kanyusik Continued page 106 staged make community aware clubs need new flying siteand spark new interest RC flying made sign informing public need gave us leads followed up Key City Bald Eagles group heav Continued page 198

NO OCR TEXT Left This ground shot shows some aircrafts unusual shapes angles Note dual-strut Fults Tooling nose gear vertical fins tie main canard wings together Also note outrigger wheel canard wing tip Right shot shows sweeping canard canard sweeps back 60 has ilk0 incidence Both wings have Eppler airfoil main wing has 00 incidence 60 dihedral 91-6 Gs 201 best glide ratio weighed mere 172 lb really wanted impress could tell about able fly side ways its ability change altitude withI B-S C B c-c C 0 out changing pitch could also talk about use flaps vertical split-flap rud ders acted air brakes give pi lot wide range angles descent course entire airplane could put LIGETI STRAWS A-A 0-0 0 2 3 trailer dismantling really get across full extent Ligetis genius Id show picture modelor hand transmitter Ligeti family requested pub lish construction plans Stratos design patented time contemplating kitting model threeview photos however obtained Bob Banka Scale Model Research incorporated presentation Since prototype exactly scale made angle error canard shortened span somewhat will list some dimensions end article may some help Properly built canard sweeps back 60 degrees side Let say Mr Ligeti angles what Carl Goldberg curves also want preface remarks say ing success wasnt achieved alone Both additional correspondence Mrs Ligeti friends master mod elers George Sauers Bob Terhune invaluable help Yes believe have two friends master modelers both thought prototype would fly notes Mr Ligeti suggested Ep pler airfoil both canard wing set 0-0 incidence like teachers give just enough formation get started stand back see what come up Since preconception canard has stall first unconvinced recom mendation 000 incidence set ca nard plus 1 cidence now know 00O works course should have listened Fortunately 11/2 also works believe Ligetis theory use same airfoil ca nard wing downdraft created canard will fool wing thinking its flying lower angle attack Pos sibly would occur different ca nard airfoil well really dont know nor wish present myself aerody namicist make Ds algebra dont jump right calculus As recall put total six degrees dihedral wing per three-view After flying full-scale Stratos however Ligeti thought dihedral unneces sary recall reading somewhere 92 Model Aviation inspiration behind model full-scale Ligeti Stratos being admired Oshkosh 1986 unbelievable little airplane de signed built Australia Czech-born Charles Ligeti unfortunately killed experimenting third wing early 1989 plane entered unrecoverable stall just 400 ft over runway Stratos seen 17-ft 7-in wingspan could fly 100 mph 28-hp Konig engine service ceiling 14760 ft 449-mile range climb rate 670 ft per mm stressed Gs 201 best glide ratio weighed mere 172 lb could fly sideways could transported trailer being disassembled four pictures 3-view accompanying article provided Bob Banka Scale Model Research Costa Mesa CA 10 degrees sweep equals degree di hedral sweep canard Ligeti designed would make up zero-degree dihedral wing Remember dihedral changed area rudders will also need changed George Sauers pointed out rud ders could move outboard board since drag created inboard movement would cancel outboard input still have some trouble understanding have learned listen George Bob Terhune suggested eliminating rud ders altogether As turns out both rightrudders uneccessary model suspect effective rudder would enclosed shrouded nose gear per original design would create single rudder building another Stratos would use two servos outboard rudder control else try figure out set up also act air brakes toed-in vertical fin degree sist directional stability have no idea whether actually works know model gives no stability prob lems flight attitude used hackers version Eppler 203 mean increased overall thickness 18% Ligeti recall sug gested thickness between 15 17% also increased overall length fuselage adding 1 area Again Georges suggestion thought Id need nearly much weight up front counterbalance 90 four-stroke engine back al right although didnt need much weight originally anticipated model deviates Ligetis design other ways installed no ailerons canard flaps wing didnt shroud nose gear Designing scratch teaches lot need determination pit bull hang knew early power designing model author friend George Sauer built several small test models work out balance aerodynamics photo left shows cardboard balance model bottom foam Hand-Launched Glider top Figuring out establish CG RC model proved real challenge procedure described text photo right Jim Galstad shows George Sauers test bed joined-wing 049-powered canard millisecond before crashed balancing formula used faulty model tail heavy May 1990 93 Left nearly completed Stratos its original nose gear prop shroud nose gear proved too floppy prop shroud turbu lated airflow around propeller rendering totally ineffective dark line fuselage marks edge canopy Two dowels rear 3-in-long 6-32 screw nose lock place Right Rear view shroud caused much frustration builder 14-in leading edge balsa ring caused turbulation new shroud smooth inside airfoil solved turbulation problems would major problem simply dont like two-stroke power plants never question about installing fourstroke engine Unfortunately four-strokers like large propellers As can see drawings prop diameter design limited because shroud original all-up weight estimate tween 13 15 lb never learn pro totype came out weighing 15 lbwith about 20-oz wing loading Originally planned join two 12 x 6 pusher props would turn about 8000 rpmwhich theoretically enough fly airplane size prop translated shroud diameter 12A 12 ac tual tests Ive getting 8500 rpm two 14 x 6 props cut down 1211* combination gives model adequate pow er although havent tried fly Den ver Bob Routh pointing out originally installed props backwards Stratos might still ground Hey pusher prop people about putting emblem other side props exposed public flipper Youll get advertising wont confuse dummies like original shroud didnt work first three attempts very disappointingthe model would barely move ground thought because needed prop diameter removed shroud stalled 14 x 6 prop worked great Dennis Reichenberger kept telling shroud prop diameter prob lem Convinced own brilliance ig nored Dennis advice first Dennis yet another good friend master modeler cardboard jumbos original approach shroud simply hang circle around prop would look scalelike fall off first shroud built laminating balsa sheets 450 angles other around what looks like cardboard pizza plate covered silkspan keep weight down crafted glued /4 x A-in strips balsa around leading edge help maintain shape accom plished using pieces much way makes built-up wing tip As turned out looked great ever A-in stiffener killing coming airflownot letting get prop could some good Ducted fan people take note Make inverted air foil shrouds Clark Y instance curved part would side shroud Though Stratos flew well shroud fully half character airplane didnt want give up made new laminating thin lay ers white foam sanding small airfoil shape still flat fiber glassing 1-oz cloth isnt pretty well done original per formance went night day Jim Gal stad fuel systems expert Boeing helped design reworked shroud has 13-in open ing forward end tapering 121/2 back results 30 funnel shape about A-in prop clearance shroud weighs seven ounces four ounces lead added nose ever Ive slowly removing extra lead gain experience model outrigger wheels another area concern figured Id have terrible ground handling problems until enough speed gained get wings up level Early dismal results reinforced judgement counteract engine torque seemed keep right wing tip ground added three Dave Brown lightweight wheels main gear total three right side After little prac tice found able remove Im now easily taking off grass just two tandem wheels two outriggers Another problem %2-in nose gear too floppy Id hoping excuse buy dual-strut nose gear Continued page 99 94 Model Aviation _ _ 1 4 ~LTh 71II W110 X4 4-56 8OLT DOW \PfN 4m WIM6TIP 3 /IW0 NL4 ANG4* ~A55I F INS T ANAIW 4 Sq 5MIIC& P P4AT IN WWMII WO uC Ar flP P4N W4UL Left Close-up authors latest engine/prop/shroud installation engine OS 90 four-stroke Surpass prop made up two 14 x 6 Zinger pusher props joined cut down 12 x 6 airfoiled shroud 12-in-dia Notice interesting exhaust muf fler arrangement Right look Stratos belly showing details shrouded main landing gear canard-mounted elevators seemed like right time Fults Tool ing model RF 500 gear selected really quite nice unit has worked flaw lessly use old Fox 3A-in aluminumhub wheel nose gear Its stout attractive wheel wish still avail able fully realize 747-type wheel setup pretty Mickey Mouse let has never Mickey-Moused something eat first hole Balsa USA factory Determining balance point presented another major problem designing Stratos experimented Bob Ter hunes Varieze ended up crashing four five times George Sauers per fectly stable box-type canard tried configure like Stratos too crashed tried building 049 ver sion no better luck So far solu tion eluding us time determine just much weight actually resting nose wheel rolled airplane edge table weighed just nose Good griefseven pounds Thats almost half weight airplane Something has wrong ong ong problem aft wheel placed scale center-of-gravity loca tion axle just about lead ing edge wing well aft orig May 1990 99 Left The canopy removed exposing fuel tank installation faces forward located 15 engine 4 below cen terline yet theres no problem drawing fuel airplane has suffered dead-stick landing its maiden flight Right rudder servo installation canard clamped-on plastic spray bottle just visible bottom photo lead ballast Left An earlier main landing gear arrangement employed attempt counteract engine torque caused right wing drop takeoff run setup abandoned ground handling experience gained Right Details right tin/rudder outrigger wheel inally calculated CG youve ever seen tricycle-geared model literally leap Dve APIP II ff ground probably because main gear too far aft CG underWJN Cardboard model used estab lish neutral balance point LEAPl stand Prescott Pusher initially problem quickly solved dilemma though moved main gear too far forwani would nt have enough ground clearance takeoff prop already good three inches overscaled could have gone larger wheels outrigger wheels would have too high good time flying field across town thought crazy wasnt going fly did people assumed 90 engine wouldnt power ful enough point too began wonder Id come up first hangar queen balance point way off youre up tutu alli gators call Croc odile Dundee Af ter Aus tralian design Feel ing however bothered Ligetis enough instead dug out book model aero dynamics Martin Simons research gathered center lift model airplane wings between 24 26% chord further deduced through careful analytical reasoning good average would about 25% draw out wing canard planform piece cardboard chop off rear half both youll end up 50% lifting surface bal ance wing canard would sit fuselage would balancing its respective 25%-of-chord position stead balancing lift balancing weight other words have found what called neutral point done before certain conclusion wrong made new cardboard model wing canard horizontal stabilizer separated some distance attach piece Nyrod similar manmade material made mistake attaching balsa sticks taking account unequal den sity end result balance point two inches forward ideal realized later since wing ca nard overlap other tips could simply glue two lifting halves together would sit fuselage thus elim inating sticks simply balanced edge ruler balance point neutral point moved forward 15% wing chord 15% 12 in case airplane nose-heavy flyable have use Nyrod separate lifting surfaces particular applica tion sure make Nyrod extra long way can position flying sur faces near middle mark balance point measure forward backward measurements must equal arent begin cutting off long half Nyrod until equidistance balance point reached effect what doing negating weight Nyrod After going through exercise realizing two inches too far ward began removing weight About Continued page 192 INLET Left The original shroud showing 1/4-in leading edge used maintain its shape killed incoming air making too turbulent Right Heres shroud presently constructed would probably work better installation designed position prop closer shroud inlet COTL I42S I4Ta ues MOW OJTWAD ONLY MouNI6l IN MIWL0LOCI~0tZEl T ~JZ12 ro IF rL CA0L jr iAT$ 100 Model Aviation dowels holes seen photo mute evidence false starts establishing workable CG prototype model dual rudder linkage setup designed move rud der mostly outboard hardly inboard movement -uEEEEEEEEEmEEE U mum mu mm umm U mum BIG GLOW FUEL MANUFACTURED WITH THE PUREST FINEST QUALITY INGREDIENTS AVAILABLE * *I * * *at * U U U U U U U U S I] Superior Igniters Improve starting 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50-50 blend Bakers purest AA Castor Oil new improved Klotz Techniplate Synthetic Racing Oil U for maximum engine lubrication protection Based experience sincerely believe finest quality fuel can made price dont take word try some judge yourself Pcos sobiod obonge wthoot ,otice See dealer first available order direct Call LZJ 800-247-5008 toll free orders Latest Catalog $300 MANUFACTURING CO Montezuma IA 50171 Dynamic Duo Durability Stand Ready Help Take Encounters Planet Earth scuffle ground isnt some thing should have face own may have gotten own dont think model should stand After two team So join up airplanes thatll stick through thick thin Dumcmft Inc 71007 Qdwd Grove Orwe Royai Oak NI 48067 DuraPlane II 25-size 3-channel basic flight trainer DuraBat 40-size 4-channel aerobatic trainer U U I U U U i I U U U I I U U set rotors collective pitch longitudinal cyclic lateral cyclic main rotor fore/aft shaft tilt angle rpm Figure 11 shows signal processing equipment signal conditioners instrument amplifiers frequency counters computer interface strip chart recorder sig nals monitored include flapping angle lead-lag angle pitch angle four blades flexheams bending twisting strain rotors pitching roll ing moments thrust drag forces flap bending moment blade number rpm plotted continuously strip chart recorder Figure 12 gives some idea nest wires behind instrumentation valuable data collected phenom ena being observed wind tunnel tests bring us nearer goal better safer helicopter 21st century Ligeti Stratos Continued page 100 time George Sauers called tell gained access CADCAM machine plugged models dimensions come up new computer-generated balance point computer agreed calculations within 4 reweighed nose wheel came out weighing 3/2 lb like wheel changes original shroud re moved close attaining flight speed time absolutely knew Stratos would fly next time out after Ed showed off around town club meeting folks still convinced wouldnt fly day flew things just felt right very tense excited weather forecast called 5-15-mph winds out north right down runwaya downhill run north wind summer God side course arrived field wind stronger shifted east-northeast much takeoff room direction grass hadnt mowed So before could attempt fly mow grass devil time getting mower started finally succeeded sec ond pass wind increased temperature dropped fourth pass getting rained jaw muscles set mind clicked lock Reason no longer functioned going fly airplane today moment Bob Terhune showed up saw look face jumped other mower Just quickly rain sub sided George showed up ran model through series taxi tests looked con vincing Other people began showing up hanging around picnic table knew figured airplane went hogwild started attacking everybody theyd just duck under wind dropped dead calm conver sation stopped Stratos started down runway its first takeoff attempt Speed gathered slowly first faster faster Lift-off still get goose bumps just thinking about longawaited moment George Sauers sticks Just after lift off wing dropped dangerously corrected instantly smoothed Out headed out over Continued page 196 192 Model Aviation U U U U U U U U U U i U U U U U U I I U U E ER K EUUEUUUUU Four Great Days Oshkosh WI Wlttman Field Over 30 Manufacturers & Dealers Indoors IHOME OF TIlE EAA T THE EAA MUSEUMI iMemoUoaIWITTMAN FIELD OSI4KOSII WI mIAIOUIS%4% LY OF GIANTS 1 990 Alicaft WIDE JIMAS 10th ANNIVERSARY FIJI4FLY WORLD L.u..ininore~BOx21june28293OJuIV1I99OI Complete Information write Council BluffS IA 51503 IMMA Sanctioned Ligeti Stratos Continued page 192 cornfield George thoroughly wrung plane out Nothing wild like loops rolls after get ting feel declared stable bit nose-heavya pussycat Everything go ing fineuntil engine quit airplane high George started cir cling down last circle seemed too low long way field George said Im going stretch model settled long flat Sailplane-like glide gently touched down edge field Post-flight evalua tions determined ho trim changes re quired just tad up thrust would help Yes 1 heard applause under picnic ta ble Some laughter shout two couple singular superlatives wouldnt hear church wish Mr Ligeti alive thank will remain highlight mod eling career As walked field Dennis Reichenberger said Ive got admit dont mean anything bad just thought wouldnt get off ground George Wells said told Mary Jean last night Mar vin nice guy believed crazy thought thing going fly uess now Ill have go home tell damned thing flew Oh yes did mention also test flew Goldberg Comet Sailplane same night man aged stick tree guess needed dose humility After 30 40 flights can assure Stra tos stable trainer loops rolls will spin once try uncoordinated ham merhead Its truly unbelievable airplane Some final thoughts Install fuel tank balance point prototype requires fuel drawn IS behind engine 4 lower carburator origi nally installed Perry Micro Oscillating pump never needed later removed dead-stick landing Ive experienced Stratos its maiden flight try get people believe strongly urge wings built first us ing wing jig box Since canard sweeps back youll have rather long unusual cutout box suggest first tack glue firmly tape center section canard rear wing can glued together build /32 halsa wing jig box properly set up wing canard Install everything far forward pos sibly can still leaving room good bal last box After its jigged up fins made %2 balsa laminated 4 ply installed simply glue foam box begin sanding Its best use white foam lower part blue upper later can remove blue foam nice fiberglass up per shell Four important points emerged designing building flying Stratos Balance point 2 Airfoil selection 3 canard must stall first 4 thrust line wrecked lot experimental models arriving conclu sions decide build Ligeti Stratos model let know come out Get refer ence material Bob Banka start chop ping latest project original-design sleek 18-ft-span powered Sailplane weighs 17 lb will powered OS 61 four-stroke Surpass engine already know what youre thinking Itll never pull weight Itll never fly etc Well may right Ive already done taxi tests found builds up enough ground speed takeoff using 14 x 6 Master Airscrew Well see may very well fly THE SUPERIOR GLOW PLUGS GO FASTFLYERS ARE BACK! Puts sting engine Unique flat-wound spiral coil element high temperature glass-to-metal seal add up faster ignition Increased RPM 1/2A GloBee plugs designed exclusively 049/051 Cox engines Ask new GB-SRX Speed Plug GB-5R Racing Plug GB-5P Sport Plug local dealer today unavailable locally write call Twinn-K collect pricing delivery information FREE GloBee Catalog MAKE THE GLOBEE INDY CONNECTION Twinn-K Inc 10296 W Washington St Indianapolis IN 46231 Telephone 317-839-6579 FAX 317-839-8928 196 Model Aviation wouldnt first time Ive proved skeptics wrong Specifications Charles Ligetis full-size aircraft has wingspan 17 ft 7 807 sq ft area fuse lage 8 ft 2 long 3 ft 3 high shroud 24/2-in dia balance point 47 ahead main wing leading edge model has 77-in main wingspan chord 12A tapering II degree washout 60 dihedral 00 incidence airfoil both main wing canard modified Eppler 203 15-17% thick canard spans 90 youll have cut longer due some loss creating taper canard has 10-in root 9-in tip de gree washout has no dihedral sweeps back 600 has 1/20 positive incidence fin/rudder 6/2 high chord 11 prop shroud l2-in dia 4/2-in chord ailerons 143A x 2/2 set 2A wing tips elevator 15 x 2% main wheels 3A-in dia out rigger wheels -in dia balance point about 6 ahead leading edge main wing prototype yours may very well different Check described text installed OS 90 Surpass fourstroke engine swinging two Zinger 14 x 6 pusher props mated together cut down 12 Check see reverse cam available particular installation might able use standard props thrust line set about 10 up finished model weighs 15 lb Note You might want consider building larger version Ligeti Stratos using Tartan Twin Its overly heavy will run either direction Aerie/Kanyusik Continued page 106 staged make community aware clubs need new flying siteand spark new interest RC flying made sign informing public need gave us leads followed up Key City Bald Eagles group heav Continued page 198