A well-engineered fascinating machine mini airborne systems U Dave Jones THE AR-25 designed novel entry contest devoted models span less 72 inches wing loading greater seven ounces per square foot formerly designed sev eral all-wing models slope soaring similar wing loading size near two square feet wing area gave good indication much model type would weigh Also built A-l model high aspect ratio wanted emulate set down some design goals cluded geometric aspect ratio 20 weight 12/2 ounces judged tainable left wing area 259 sq model follows general lay out construction methods much larger models also intended add winglets type tip fin bring theoret ical aspect ratio 25hence name AR-25 AR-25a incorporates several minor changes judged improve durability Construction Wing The wing unusually simple structure built complete halves board difficult task cutting ribs because small cut template stack method single slender bolt held stack together shaped ribs An extra rib cut second rib station root tip ribs copied directly tem plates cut stack Ribs through 12th station have notches spar caps 1/16 x 1/8 spruce spruce upper spar cap should re duced thickness zero its end poor practice have sudden change load carrying material cross section /8 sq spruce leading edge shaped near triangular shape after assembly wing leading edge should glue line between lower sheeting spruce upper shape see wing section drawing gives reasonably strong leading edge resists dents spar webs cut 1/16 sheet installed grain vertical run mold line mold line bottom resting building board top trimmed upper sheeting web also closes out semi circle sheeting root giving increased integrity Take care choosing balsa sheet wing covers Use best sheet top wing trailing edge use straight piece triangular stock curved August1978 27 Although pods length less span Cougar Peanut its right preserves niceties modern sailplane designthe airborne system just smaller different can sometimes straightened sanding side help relieve stresses wood wing ribs may capped extra job dont deem necessary model wing under load will act just like full-size fiberglass sailplane bow graceful curve winglets used hard 1/16 sheet balsa leading edge rounded trailing edge square may have airfoil shape also have cam ber supposed reduce tip vor tices some extent curved surface winglet toward center wing though wing bent up Dont change size shape winglets tied dihedral rudder/fin areas Mine have no finish however couple coats dope would good protection Try keep winglets light regardless type use main joiner tube square brass inside hole suitable /s diam eter piano wire spruce sub-spar added root tube parallel trailing edge wing rear tube 1/16-inside-diameter aluminum Epoxy together tubes spar caps fillers glues set cut wing between two ribs station 2 used Dremel gives ab solute match between parts Add ply wood end ribs either 1/32 1/16 thickness part Shape root panel accommodate eight degrees dihedral Slip part wing main rod Epoxy root joint Add 1/16 rear wing rods offset slightly fit tightly tubes Fin Shape fin core skins stabilator bearing stabilator fair ing horn Fit hinge points core Place core horn between skins making sure horn free pivot stabilator pivot stab bilator driver clear move its groove Glue together Keep flat until dry shape Body Cut bottom wing center assembly admit tail boom Add frames 5 6 wing/boom Add upper lower keels Now frames 2 4 added point deck must designed using Can non Tini-Block deck shown good using another system own deck After deck added install frame 3 During installation deck will note inner part wing leading edge must removed Note easier assemble tow hook keel before added frame 5 Shape canted frames between frames 2 4 5 rear canted frame partially removed after planking complete install equipment Thread two Pylon GRC-3 tubes back through boom pod rudder tube exits 28 Model Aviation winglets really improve performance model case answer emphatic yes An excellent report winglets full scale appeared Meusers column August 1977 Installation Cannon Tini Brick bit snug presents no problems Other mini systems may substituted ACE Kraft being likely examples 0 Il iF 0-DIAMETER REQ REQUIRED SQ SQUARE KIN7/BHIBR Ae vERTICAL UAN DECK-PLYWINGII/IGiH-GRAIN----- SPACING TYPSPRUCE4 1-5A6-JLIA6D 3PLS uUPPERU}9I6R -iI5/32R.j6fIAID CANNON TINHBLO K/80/ -l/l /32R5 5I-- 2-GR LOWER-P 1/6STABILATOR TRIBESiWYIA6 IFRAME 4-PLY 6Q-j FRAME 6ALUM 2 REQ WING ROD-SPRING STEEL1-3/4 2 7/8H 2 REQ2PL-A6 GRAN//~WING TUBE RED BRASS 2INSIDEUPPERI362R-4 VeALUM 2REO- WING TUBE- SQT EPOXY TO STRUCTORE 2-3/4EPOXY TO STABILATOR HORN CTURE I/B PLY525/32 2 EA REQt~/I67/B 1/25132RIII S/32R 2PLSSTABILATOR FAIRING 16-IA6D1 3j4I/BFRAME 5-PLYGP/1 L ~ILP r-I/4 -~A6R I/61tV16RLL \ 3/~I4 6__T1-3/4 KEELPLYLOWER UPPE6/32L~TO Iii-lI - --V4jIA STABILATOP BEARINGI/S 7/6R W HOOK-/6 PLY2 REQ NOSE PNESPRING STEEL116GRAIN4 VBFRAME 3-PLYORAN--FULL RADIUS3/32STABILATQR PIVOT LOWER DDER-I/4 SPRINU STEEL 6371 I--*6EPOXY TO HORN 58-17/16 AT5/16I7/B4~2AWZ803/32RI RB BLANK 50 REQRUDDER HORN-PLYI VB2/T 1/4HINGE POINT 2 PLSSTABILATOR SPRING IDRIVERI9 3/B RUDDERSTEELSPAN725o WING8 7/6 UT OUT AFTER ASSY SKID-EPOXY ONCOVER WITH MONOKOTE EP%XY PUSH RODS PYLON GRC-32-7/d PLYI/eR FRAME KEEL 80DM NOSE AND TOW HOOK ASSEMBLY CARVE WING LOWER Cr Co CPLANK WITH I/BI/4 -4 CD FULL-SIZE PLANS AVAILABLE.. SEE PAGE 104 36 __ABOUT TIP SHA perhaps dif ferent tips wings stabilizers models mod eler shapes own artistic talent level back mind concept its pleasing eye its good aero dynamically may influencing choice tips popular idea necessarily true Seldom aerodynamics does simplest least complex de sign produce best results wing tip square sharpedged tip shows best test re sults effective versus geo metrical aspect ratio reaches high 990/0 must trailing edge corner have no less span point tip chord tip easy make strong structurally easy duplicate benefits builder/flier artistic bent tip nearest square performance upswept tip found quite frequently shapes sizes models Perhaps popular because works has pleasing planform shape tip has maximum span high point wing section sharp edge also helpful section through tip form triangle top flat bottom sloped upward outward effec tive versus geometrical aspect ratio moderate 950/0 however whole story Tests show tip vortex core cen ter some 500/0 wing thick ness higher other tested tips same adding tip plate produces 40/o gain effective aspect ratio wing geometrical aspect ratio 30 type tip very good low aspect ratio wings As wing tip fins end plates winglets some simple dos donts will clear air higher geometrical aspect ratio taller winglet must improve effective aspect ratio Tests show addition area form span crease aspect ratio increase beneficial winglets leads us conclusion winglets use span limited aspect ratio lower Dont put wing let both above below wing tip doubles interference drag Tests show winglet extend ing below wing no beneficial extending upward upward winglet has big advantage reduced structural damage possibility An attempt should made keep area wing let low pos sible area destabilizing effects required vertical tail size Horizontal vertical tail tips labor under same aerodynam ics wings same com ments hold true Horizontal tails sometimes have tip fins rud ders improves effective aspect ratio horizontal tail reduces power vertical surface necessitating increase area tee tail has effect increasing effective aspect ratio ver tical 500/a no loss hori zontal tail effectiveness further improvement may orienting aft body vi cinity vertical tail hori zontal direction instead common vertical orienta tion produces effect end plate lower end vertical stabilizer Fluid-Dynamic Lift Dr Ing S F Hoerner H V Borst full helpful information like dig out own data book reference aerodynamic groups may purchased less $30 Hoerner Fluid Dynamics PO Box 342 Brick Town NJ 08723 Dave Jones WING TT -w II II RxII II 1L recent appearance mini systems other CannonsAce Kraft being two examplesthe AR25 one-make-of-radio air plane top side view details shown depict MAs suggestion alternate installation Ace system boom left side ahead stabilator horn Epoxy clevis stabilator cable attach clevis horn Fit fin boom sure everything working free epoxy fin place Now plank pod Add nose block sand plank ing round cross section Shape soft block canopy/hatch Hollow fit equipment skid has fitted bottom pod prone instant removal during crosswind landings mind plastic skid Scuff Guard several layers masking tape provide protection needed adept fiberglass pod can covered made light fiber glass resin will insure ex tremely strong model Control Surface wood stabil ator must light reasonably rigid Very little work done spend time selecting good piece wood flat plate section used simplicity true will stall low angles tack using square trailing edge wake thin allows very small deflections give control response Some Continued page 94 30 Model Aviation GET ORGANIZED s set 4 slardy ties haNs over 4 years yosr tavoste 5 Ii magazrees 4 MAG FILES $495 Seed 5456 ptss SI 00 postage haedtig N DOM INOUSTRES PO BOX 388-K DOVER NH 03820 KITSOPLANSOACCESSORIES BABY ACEP-NUT KITS N BEARINGS BROWN CO-2 ENGINES COMPLETE CATALOG REAL JAPANESE TIISuCPROPj KIT $425 MANY CARD TO FIND ITEMS he*-Pb4tw W BOX 2498LA MESA CALIF 92041 modification give Jet Ranger fliers something just little different Bill Watson vice-president NCHA North Carolina Helicopter Assoc original members NCHA shown group photo first meet Greensboro NC Also NCHA schematic transmitter modification allow mixing throttle collective modification developed Mike Miles Durham NC Mikes modifica tion will work Kraft series 76-78 5channel transmitters will possibly work some other makes although tested modification will eliminate need Y connector between throttle collective servos offers advantage collective trim modify transmitter remove wire center lug retract switch 5th channel wire may attached directly center tap throttle pot collective trim desired Collective trim added addition miniature -watt 5K wirewound pot standard Kraft trim lever part #901 148 mounted convenient location pot electrically connected series fifth channel wire retract switch center tap existing throttle pot 470-ohm resistor placed series throttle channel lead center tap Two connections have made center tap throttle pot 1 5K pot series fifth channel 2 470-ohm resistor series throttle channel set up servos should re-centered using throttle stick pot collective trim pot ie sticks trims readjusted center tightened pot shafts operation circuit will increase servo travel five six degrees either side center Throttle throttle trim will affect both throttle collective col lective trim will affect collective channel final note Somewhere out someone flying hot Red Heli-boy Wolitz-modified EK radio say hot because helicopter radio other modeling articles stolen Walt Schoonards car Perry Georgia few weeks ago find information leading recovery stolen articles Im sure Walt would appreciate David R Chesney Rt 9 Box 621A Greensboro NC 27407 Tiny Sailplane/Jones continued page 30 sharp trailing edge control surfaces can deflected several degrees before im pinge high energy air Cut stabilator soft Vs sheet inset 1/16inside-diameter aluminum tube balsa correct locations Match stabilator horn rudder made three pieces blade driver horn Assemble attach fin used hinge points Finish prototype wing stabilator covered transparent orange top black bottom pod covered black fin good paint finish would easier pod boom canopy white coverings Super Monokote Equipment Installation Care must ex ercised fitting radio model large canopy helps make easy two-channel Cannon Tini-Block fit stock wire plugs switch Yes switch mounted under canopy product review product review product review ~1 40-Size Engine Mount Fourmost con tinuation successful wrap-around de sign 049 Airfla Mount Glas-filled nylon compound provides vibration-free design molded front end reduces aerodynamic drag around engine 2% firewall face 40 mount ideal Quicky-type aircraft Price $525 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review next battery right side antenna routed out pod right side between frames 5 6 through small plastic tube supported top fin plug between switch receiver should above deck ease re-charging placed right side adjacent receiver lead runs switch aft under servo receiver up right side top deck plug placed just front canted frame beside re ceiver lead receiver comes out through deck center forward receiver runs center around right corner re ceiver aft switch lead servo receiver leads pass left re ceiver plugs behind receiver Flying center gravity shown sat isfactory slope flying may want farther aft thermal flying Hand launches 30 feet possible putting fingers behind wing center sec tion High-starts light rubber hand tows easily accomplished familiar characteristics model add winglets im provement flight should evident winglets place prototype glide turn characteristics both im proved Although winglets may look vulnerable arent prone flying/ landing damage However vul nerable during transportation storage Conclusion hope enjoy version much enjoy feel con figuration could scaled twice size gradual increase performance due scale factor Let hear about model Write Dave Jones 5621 Michelle Drive Tor rence CA 90503 CL Scale/Gretz continued page 31 Rd Fallbrook CA 92028 claims pro duce sell aviation aerospace books other publisher world know produce noteworthy books including well known Aero Series profile-type book lets covering famous WW2 military aircraft free catalog shows over 200 books phases aviation space books also available mail-order book dealers Ive already mentioned Sentry Books 10718 White Oak Ave Granada Hills CA 91344 another book publisher can buy directly line aviation books isnt very large yet Ive found book have got ten exceptional quality photos drawings historical accuracy manu facture Most authors interna tionally known experts subjects Sentry also publishes two bi-monthly mag azines called Wings Airpower 94 Model Aviation
Edition: Model Aviation - 1978/08
Page Numbers: 27, 28, 29, 30, 94
A well-engineered fascinating machine mini airborne systems U Dave Jones THE AR-25 designed novel entry contest devoted models span less 72 inches wing loading greater seven ounces per square foot formerly designed sev eral all-wing models slope soaring similar wing loading size near two square feet wing area gave good indication much model type would weigh Also built A-l model high aspect ratio wanted emulate set down some design goals cluded geometric aspect ratio 20 weight 12/2 ounces judged tainable left wing area 259 sq model follows general lay out construction methods much larger models also intended add winglets type tip fin bring theoret ical aspect ratio 25hence name AR-25 AR-25a incorporates several minor changes judged improve durability Construction Wing The wing unusually simple structure built complete halves board difficult task cutting ribs because small cut template stack method single slender bolt held stack together shaped ribs An extra rib cut second rib station root tip ribs copied directly tem plates cut stack Ribs through 12th station have notches spar caps 1/16 x 1/8 spruce spruce upper spar cap should re duced thickness zero its end poor practice have sudden change load carrying material cross section /8 sq spruce leading edge shaped near triangular shape after assembly wing leading edge should glue line between lower sheeting spruce upper shape see wing section drawing gives reasonably strong leading edge resists dents spar webs cut 1/16 sheet installed grain vertical run mold line mold line bottom resting building board top trimmed upper sheeting web also closes out semi circle sheeting root giving increased integrity Take care choosing balsa sheet wing covers Use best sheet top wing trailing edge use straight piece triangular stock curved August1978 27 Although pods length less span Cougar Peanut its right preserves niceties modern sailplane designthe airborne system just smaller different can sometimes straightened sanding side help relieve stresses wood wing ribs may capped extra job dont deem necessary model wing under load will act just like full-size fiberglass sailplane bow graceful curve winglets used hard 1/16 sheet balsa leading edge rounded trailing edge square may have airfoil shape also have cam ber supposed reduce tip vor tices some extent curved surface winglet toward center wing though wing bent up Dont change size shape winglets tied dihedral rudder/fin areas Mine have no finish however couple coats dope would good protection Try keep winglets light regardless type use main joiner tube square brass inside hole suitable /s diam eter piano wire spruce sub-spar added root tube parallel trailing edge wing rear tube 1/16-inside-diameter aluminum Epoxy together tubes spar caps fillers glues set cut wing between two ribs station 2 used Dremel gives ab solute match between parts Add ply wood end ribs either 1/32 1/16 thickness part Shape root panel accommodate eight degrees dihedral Slip part wing main rod Epoxy root joint Add 1/16 rear wing rods offset slightly fit tightly tubes Fin Shape fin core skins stabilator bearing stabilator fair ing horn Fit hinge points core Place core horn between skins making sure horn free pivot stabilator pivot stab bilator driver clear move its groove Glue together Keep flat until dry shape Body Cut bottom wing center assembly admit tail boom Add frames 5 6 wing/boom Add upper lower keels Now frames 2 4 added point deck must designed using Can non Tini-Block deck shown good using another system own deck After deck added install frame 3 During installation deck will note inner part wing leading edge must removed Note easier assemble tow hook keel before added frame 5 Shape canted frames between frames 2 4 5 rear canted frame partially removed after planking complete install equipment Thread two Pylon GRC-3 tubes back through boom pod rudder tube exits 28 Model Aviation winglets really improve performance model case answer emphatic yes An excellent report winglets full scale appeared Meusers column August 1977 Installation Cannon Tini Brick bit snug presents no problems Other mini systems may substituted ACE Kraft being likely examples 0 Il iF 0-DIAMETER REQ REQUIRED SQ SQUARE KIN7/BHIBR Ae vERTICAL UAN DECK-PLYWINGII/IGiH-GRAIN----- SPACING TYPSPRUCE4 1-5A6-JLIA6D 3PLS uUPPERU}9I6R -iI5/32R.j6fIAID CANNON TINHBLO K/80/ -l/l /32R5 5I-- 2-GR LOWER-P 1/6STABILATOR TRIBESiWYIA6 IFRAME 4-PLY 6Q-j FRAME 6ALUM 2 REQ WING ROD-SPRING STEEL1-3/4 2 7/8H 2 REQ2PL-A6 GRAN//~WING TUBE RED BRASS 2INSIDEUPPERI362R-4 VeALUM 2REO- WING TUBE- SQT EPOXY TO STRUCTORE 2-3/4EPOXY TO STABILATOR HORN CTURE I/B PLY525/32 2 EA REQt~/I67/B 1/25132RIII S/32R 2PLSSTABILATOR FAIRING 16-IA6D1 3j4I/BFRAME 5-PLYGP/1 L ~ILP r-I/4 -~A6R I/61tV16RLL \ 3/~I4 6__T1-3/4 KEELPLYLOWER UPPE6/32L~TO Iii-lI - --V4jIA STABILATOP BEARINGI/S 7/6R W HOOK-/6 PLY2 REQ NOSE PNESPRING STEEL116GRAIN4 VBFRAME 3-PLYORAN--FULL RADIUS3/32STABILATQR PIVOT LOWER DDER-I/4 SPRINU STEEL 6371 I--*6EPOXY TO HORN 58-17/16 AT5/16I7/B4~2AWZ803/32RI RB BLANK 50 REQRUDDER HORN-PLYI VB2/T 1/4HINGE POINT 2 PLSSTABILATOR SPRING IDRIVERI9 3/B RUDDERSTEELSPAN725o WING8 7/6 UT OUT AFTER ASSY SKID-EPOXY ONCOVER WITH MONOKOTE EP%XY PUSH RODS PYLON GRC-32-7/d PLYI/eR FRAME KEEL 80DM NOSE AND TOW HOOK ASSEMBLY CARVE WING LOWER Cr Co CPLANK WITH I/BI/4 -4 CD FULL-SIZE PLANS AVAILABLE.. SEE PAGE 104 36 __ABOUT TIP SHA perhaps dif ferent tips wings stabilizers models mod eler shapes own artistic talent level back mind concept its pleasing eye its good aero dynamically may influencing choice tips popular idea necessarily true Seldom aerodynamics does simplest least complex de sign produce best results wing tip square sharpedged tip shows best test re sults effective versus geo metrical aspect ratio reaches high 990/0 must trailing edge corner have no less span point tip chord tip easy make strong structurally easy duplicate benefits builder/flier artistic bent tip nearest square performance upswept tip found quite frequently shapes sizes models Perhaps popular because works has pleasing planform shape tip has maximum span high point wing section sharp edge also helpful section through tip form triangle top flat bottom sloped upward outward effec tive versus geometrical aspect ratio moderate 950/0 however whole story Tests show tip vortex core cen ter some 500/0 wing thick ness higher other tested tips same adding tip plate produces 40/o gain effective aspect ratio wing geometrical aspect ratio 30 type tip very good low aspect ratio wings As wing tip fins end plates winglets some simple dos donts will clear air higher geometrical aspect ratio taller winglet must improve effective aspect ratio Tests show addition area form span crease aspect ratio increase beneficial winglets leads us conclusion winglets use span limited aspect ratio lower Dont put wing let both above below wing tip doubles interference drag Tests show winglet extend ing below wing no beneficial extending upward upward winglet has big advantage reduced structural damage possibility An attempt should made keep area wing let low pos sible area destabilizing effects required vertical tail size Horizontal vertical tail tips labor under same aerodynam ics wings same com ments hold true Horizontal tails sometimes have tip fins rud ders improves effective aspect ratio horizontal tail reduces power vertical surface necessitating increase area tee tail has effect increasing effective aspect ratio ver tical 500/a no loss hori zontal tail effectiveness further improvement may orienting aft body vi cinity vertical tail hori zontal direction instead common vertical orienta tion produces effect end plate lower end vertical stabilizer Fluid-Dynamic Lift Dr Ing S F Hoerner H V Borst full helpful information like dig out own data book reference aerodynamic groups may purchased less $30 Hoerner Fluid Dynamics PO Box 342 Brick Town NJ 08723 Dave Jones WING TT -w II II RxII II 1L recent appearance mini systems other CannonsAce Kraft being two examplesthe AR25 one-make-of-radio air plane top side view details shown depict MAs suggestion alternate installation Ace system boom left side ahead stabilator horn Epoxy clevis stabilator cable attach clevis horn Fit fin boom sure everything working free epoxy fin place Now plank pod Add nose block sand plank ing round cross section Shape soft block canopy/hatch Hollow fit equipment skid has fitted bottom pod prone instant removal during crosswind landings mind plastic skid Scuff Guard several layers masking tape provide protection needed adept fiberglass pod can covered made light fiber glass resin will insure ex tremely strong model Control Surface wood stabil ator must light reasonably rigid Very little work done spend time selecting good piece wood flat plate section used simplicity true will stall low angles tack using square trailing edge wake thin allows very small deflections give control response Some Continued page 94 30 Model Aviation GET ORGANIZED s set 4 slardy ties haNs over 4 years yosr tavoste 5 Ii magazrees 4 MAG FILES $495 Seed 5456 ptss SI 00 postage haedtig N DOM INOUSTRES PO BOX 388-K DOVER NH 03820 KITSOPLANSOACCESSORIES BABY ACEP-NUT KITS N BEARINGS BROWN CO-2 ENGINES COMPLETE CATALOG REAL JAPANESE TIISuCPROPj KIT $425 MANY CARD TO FIND ITEMS he*-Pb4tw W BOX 2498LA MESA CALIF 92041 modification give Jet Ranger fliers something just little different Bill Watson vice-president NCHA North Carolina Helicopter Assoc original members NCHA shown group photo first meet Greensboro NC Also NCHA schematic transmitter modification allow mixing throttle collective modification developed Mike Miles Durham NC Mikes modifica tion will work Kraft series 76-78 5channel transmitters will possibly work some other makes although tested modification will eliminate need Y connector between throttle collective servos offers advantage collective trim modify transmitter remove wire center lug retract switch 5th channel wire may attached directly center tap throttle pot collective trim desired Collective trim added addition miniature -watt 5K wirewound pot standard Kraft trim lever part #901 148 mounted convenient location pot electrically connected series fifth channel wire retract switch center tap existing throttle pot 470-ohm resistor placed series throttle channel lead center tap Two connections have made center tap throttle pot 1 5K pot series fifth channel 2 470-ohm resistor series throttle channel set up servos should re-centered using throttle stick pot collective trim pot ie sticks trims readjusted center tightened pot shafts operation circuit will increase servo travel five six degrees either side center Throttle throttle trim will affect both throttle collective col lective trim will affect collective channel final note Somewhere out someone flying hot Red Heli-boy Wolitz-modified EK radio say hot because helicopter radio other modeling articles stolen Walt Schoonards car Perry Georgia few weeks ago find information leading recovery stolen articles Im sure Walt would appreciate David R Chesney Rt 9 Box 621A Greensboro NC 27407 Tiny Sailplane/Jones continued page 30 sharp trailing edge control surfaces can deflected several degrees before im pinge high energy air Cut stabilator soft Vs sheet inset 1/16inside-diameter aluminum tube balsa correct locations Match stabilator horn rudder made three pieces blade driver horn Assemble attach fin used hinge points Finish prototype wing stabilator covered transparent orange top black bottom pod covered black fin good paint finish would easier pod boom canopy white coverings Super Monokote Equipment Installation Care must ex ercised fitting radio model large canopy helps make easy two-channel Cannon Tini-Block fit stock wire plugs switch Yes switch mounted under canopy product review product review product review ~1 40-Size Engine Mount Fourmost con tinuation successful wrap-around de sign 049 Airfla Mount Glas-filled nylon compound provides vibration-free design molded front end reduces aerodynamic drag around engine 2% firewall face 40 mount ideal Quicky-type aircraft Price $525 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review next battery right side antenna routed out pod right side between frames 5 6 through small plastic tube supported top fin plug between switch receiver should above deck ease re-charging placed right side adjacent receiver lead runs switch aft under servo receiver up right side top deck plug placed just front canted frame beside re ceiver lead receiver comes out through deck center forward receiver runs center around right corner re ceiver aft switch lead servo receiver leads pass left re ceiver plugs behind receiver Flying center gravity shown sat isfactory slope flying may want farther aft thermal flying Hand launches 30 feet possible putting fingers behind wing center sec tion High-starts light rubber hand tows easily accomplished familiar characteristics model add winglets im provement flight should evident winglets place prototype glide turn characteristics both im proved Although winglets may look vulnerable arent prone flying/ landing damage However vul nerable during transportation storage Conclusion hope enjoy version much enjoy feel con figuration could scaled twice size gradual increase performance due scale factor Let hear about model Write Dave Jones 5621 Michelle Drive Tor rence CA 90503 CL Scale/Gretz continued page 31 Rd Fallbrook CA 92028 claims pro duce sell aviation aerospace books other publisher world know produce noteworthy books including well known Aero Series profile-type book lets covering famous WW2 military aircraft free catalog shows over 200 books phases aviation space books also available mail-order book dealers Ive already mentioned Sentry Books 10718 White Oak Ave Granada Hills CA 91344 another book publisher can buy directly line aviation books isnt very large yet Ive found book have got ten exceptional quality photos drawings historical accuracy manu facture Most authors interna tionally known experts subjects Sentry also publishes two bi-monthly mag azines called Wings Airpower 94 Model Aviation
Edition: Model Aviation - 1978/08
Page Numbers: 27, 28, 29, 30, 94
A well-engineered fascinating machine mini airborne systems U Dave Jones THE AR-25 designed novel entry contest devoted models span less 72 inches wing loading greater seven ounces per square foot formerly designed sev eral all-wing models slope soaring similar wing loading size near two square feet wing area gave good indication much model type would weigh Also built A-l model high aspect ratio wanted emulate set down some design goals cluded geometric aspect ratio 20 weight 12/2 ounces judged tainable left wing area 259 sq model follows general lay out construction methods much larger models also intended add winglets type tip fin bring theoret ical aspect ratio 25hence name AR-25 AR-25a incorporates several minor changes judged improve durability Construction Wing The wing unusually simple structure built complete halves board difficult task cutting ribs because small cut template stack method single slender bolt held stack together shaped ribs An extra rib cut second rib station root tip ribs copied directly tem plates cut stack Ribs through 12th station have notches spar caps 1/16 x 1/8 spruce spruce upper spar cap should re duced thickness zero its end poor practice have sudden change load carrying material cross section /8 sq spruce leading edge shaped near triangular shape after assembly wing leading edge should glue line between lower sheeting spruce upper shape see wing section drawing gives reasonably strong leading edge resists dents spar webs cut 1/16 sheet installed grain vertical run mold line mold line bottom resting building board top trimmed upper sheeting web also closes out semi circle sheeting root giving increased integrity Take care choosing balsa sheet wing covers Use best sheet top wing trailing edge use straight piece triangular stock curved August1978 27 Although pods length less span Cougar Peanut its right preserves niceties modern sailplane designthe airborne system just smaller different can sometimes straightened sanding side help relieve stresses wood wing ribs may capped extra job dont deem necessary model wing under load will act just like full-size fiberglass sailplane bow graceful curve winglets used hard 1/16 sheet balsa leading edge rounded trailing edge square may have airfoil shape also have cam ber supposed reduce tip vor tices some extent curved surface winglet toward center wing though wing bent up Dont change size shape winglets tied dihedral rudder/fin areas Mine have no finish however couple coats dope would good protection Try keep winglets light regardless type use main joiner tube square brass inside hole suitable /s diam eter piano wire spruce sub-spar added root tube parallel trailing edge wing rear tube 1/16-inside-diameter aluminum Epoxy together tubes spar caps fillers glues set cut wing between two ribs station 2 used Dremel gives ab solute match between parts Add ply wood end ribs either 1/32 1/16 thickness part Shape root panel accommodate eight degrees dihedral Slip part wing main rod Epoxy root joint Add 1/16 rear wing rods offset slightly fit tightly tubes Fin Shape fin core skins stabilator bearing stabilator fair ing horn Fit hinge points core Place core horn between skins making sure horn free pivot stabilator pivot stab bilator driver clear move its groove Glue together Keep flat until dry shape Body Cut bottom wing center assembly admit tail boom Add frames 5 6 wing/boom Add upper lower keels Now frames 2 4 added point deck must designed using Can non Tini-Block deck shown good using another system own deck After deck added install frame 3 During installation deck will note inner part wing leading edge must removed Note easier assemble tow hook keel before added frame 5 Shape canted frames between frames 2 4 5 rear canted frame partially removed after planking complete install equipment Thread two Pylon GRC-3 tubes back through boom pod rudder tube exits 28 Model Aviation winglets really improve performance model case answer emphatic yes An excellent report winglets full scale appeared Meusers column August 1977 Installation Cannon Tini Brick bit snug presents no problems Other mini systems may substituted ACE Kraft being likely examples 0 Il iF 0-DIAMETER REQ REQUIRED SQ SQUARE KIN7/BHIBR Ae vERTICAL UAN DECK-PLYWINGII/IGiH-GRAIN----- SPACING TYPSPRUCE4 1-5A6-JLIA6D 3PLS uUPPERU}9I6R -iI5/32R.j6fIAID CANNON TINHBLO K/80/ -l/l /32R5 5I-- 2-GR LOWER-P 1/6STABILATOR TRIBESiWYIA6 IFRAME 4-PLY 6Q-j FRAME 6ALUM 2 REQ WING ROD-SPRING STEEL1-3/4 2 7/8H 2 REQ2PL-A6 GRAN//~WING TUBE RED BRASS 2INSIDEUPPERI362R-4 VeALUM 2REO- WING TUBE- SQT EPOXY TO STRUCTORE 2-3/4EPOXY TO STABILATOR HORN CTURE I/B PLY525/32 2 EA REQt~/I67/B 1/25132RIII S/32R 2PLSSTABILATOR FAIRING 16-IA6D1 3j4I/BFRAME 5-PLYGP/1 L ~ILP r-I/4 -~A6R I/61tV16RLL \ 3/~I4 6__T1-3/4 KEELPLYLOWER UPPE6/32L~TO Iii-lI - --V4jIA STABILATOP BEARINGI/S 7/6R W HOOK-/6 PLY2 REQ NOSE PNESPRING STEEL116GRAIN4 VBFRAME 3-PLYORAN--FULL RADIUS3/32STABILATQR PIVOT LOWER DDER-I/4 SPRINU STEEL 6371 I--*6EPOXY TO HORN 58-17/16 AT5/16I7/B4~2AWZ803/32RI RB BLANK 50 REQRUDDER HORN-PLYI VB2/T 1/4HINGE POINT 2 PLSSTABILATOR SPRING IDRIVERI9 3/B RUDDERSTEELSPAN725o WING8 7/6 UT OUT AFTER ASSY SKID-EPOXY ONCOVER WITH MONOKOTE EP%XY PUSH RODS PYLON GRC-32-7/d PLYI/eR FRAME KEEL 80DM NOSE AND TOW HOOK ASSEMBLY CARVE WING LOWER Cr Co CPLANK WITH I/BI/4 -4 CD FULL-SIZE PLANS AVAILABLE.. SEE PAGE 104 36 __ABOUT TIP SHA perhaps dif ferent tips wings stabilizers models mod eler shapes own artistic talent level back mind concept its pleasing eye its good aero dynamically may influencing choice tips popular idea necessarily true Seldom aerodynamics does simplest least complex de sign produce best results wing tip square sharpedged tip shows best test re sults effective versus geo metrical aspect ratio reaches high 990/0 must trailing edge corner have no less span point tip chord tip easy make strong structurally easy duplicate benefits builder/flier artistic bent tip nearest square performance upswept tip found quite frequently shapes sizes models Perhaps popular because works has pleasing planform shape tip has maximum span high point wing section sharp edge also helpful section through tip form triangle top flat bottom sloped upward outward effec tive versus geometrical aspect ratio moderate 950/0 however whole story Tests show tip vortex core cen ter some 500/0 wing thick ness higher other tested tips same adding tip plate produces 40/o gain effective aspect ratio wing geometrical aspect ratio 30 type tip very good low aspect ratio wings As wing tip fins end plates winglets some simple dos donts will clear air higher geometrical aspect ratio taller winglet must improve effective aspect ratio Tests show addition area form span crease aspect ratio increase beneficial winglets leads us conclusion winglets use span limited aspect ratio lower Dont put wing let both above below wing tip doubles interference drag Tests show winglet extend ing below wing no beneficial extending upward upward winglet has big advantage reduced structural damage possibility An attempt should made keep area wing let low pos sible area destabilizing effects required vertical tail size Horizontal vertical tail tips labor under same aerodynam ics wings same com ments hold true Horizontal tails sometimes have tip fins rud ders improves effective aspect ratio horizontal tail reduces power vertical surface necessitating increase area tee tail has effect increasing effective aspect ratio ver tical 500/a no loss hori zontal tail effectiveness further improvement may orienting aft body vi cinity vertical tail hori zontal direction instead common vertical orienta tion produces effect end plate lower end vertical stabilizer Fluid-Dynamic Lift Dr Ing S F Hoerner H V Borst full helpful information like dig out own data book reference aerodynamic groups may purchased less $30 Hoerner Fluid Dynamics PO Box 342 Brick Town NJ 08723 Dave Jones WING TT -w II II RxII II 1L recent appearance mini systems other CannonsAce Kraft being two examplesthe AR25 one-make-of-radio air plane top side view details shown depict MAs suggestion alternate installation Ace system boom left side ahead stabilator horn Epoxy clevis stabilator cable attach clevis horn Fit fin boom sure everything working free epoxy fin place Now plank pod Add nose block sand plank ing round cross section Shape soft block canopy/hatch Hollow fit equipment skid has fitted bottom pod prone instant removal during crosswind landings mind plastic skid Scuff Guard several layers masking tape provide protection needed adept fiberglass pod can covered made light fiber glass resin will insure ex tremely strong model Control Surface wood stabil ator must light reasonably rigid Very little work done spend time selecting good piece wood flat plate section used simplicity true will stall low angles tack using square trailing edge wake thin allows very small deflections give control response Some Continued page 94 30 Model Aviation GET ORGANIZED s set 4 slardy ties haNs over 4 years yosr tavoste 5 Ii magazrees 4 MAG FILES $495 Seed 5456 ptss SI 00 postage haedtig N DOM INOUSTRES PO BOX 388-K DOVER NH 03820 KITSOPLANSOACCESSORIES BABY ACEP-NUT KITS N BEARINGS BROWN CO-2 ENGINES COMPLETE CATALOG REAL JAPANESE TIISuCPROPj KIT $425 MANY CARD TO FIND ITEMS he*-Pb4tw W BOX 2498LA MESA CALIF 92041 modification give Jet Ranger fliers something just little different Bill Watson vice-president NCHA North Carolina Helicopter Assoc original members NCHA shown group photo first meet Greensboro NC Also NCHA schematic transmitter modification allow mixing throttle collective modification developed Mike Miles Durham NC Mikes modifica tion will work Kraft series 76-78 5channel transmitters will possibly work some other makes although tested modification will eliminate need Y connector between throttle collective servos offers advantage collective trim modify transmitter remove wire center lug retract switch 5th channel wire may attached directly center tap throttle pot collective trim desired Collective trim added addition miniature -watt 5K wirewound pot standard Kraft trim lever part #901 148 mounted convenient location pot electrically connected series fifth channel wire retract switch center tap existing throttle pot 470-ohm resistor placed series throttle channel lead center tap Two connections have made center tap throttle pot 1 5K pot series fifth channel 2 470-ohm resistor series throttle channel set up servos should re-centered using throttle stick pot collective trim pot ie sticks trims readjusted center tightened pot shafts operation circuit will increase servo travel five six degrees either side center Throttle throttle trim will affect both throttle collective col lective trim will affect collective channel final note Somewhere out someone flying hot Red Heli-boy Wolitz-modified EK radio say hot because helicopter radio other modeling articles stolen Walt Schoonards car Perry Georgia few weeks ago find information leading recovery stolen articles Im sure Walt would appreciate David R Chesney Rt 9 Box 621A Greensboro NC 27407 Tiny Sailplane/Jones continued page 30 sharp trailing edge control surfaces can deflected several degrees before im pinge high energy air Cut stabilator soft Vs sheet inset 1/16inside-diameter aluminum tube balsa correct locations Match stabilator horn rudder made three pieces blade driver horn Assemble attach fin used hinge points Finish prototype wing stabilator covered transparent orange top black bottom pod covered black fin good paint finish would easier pod boom canopy white coverings Super Monokote Equipment Installation Care must ex ercised fitting radio model large canopy helps make easy two-channel Cannon Tini-Block fit stock wire plugs switch Yes switch mounted under canopy product review product review product review ~1 40-Size Engine Mount Fourmost con tinuation successful wrap-around de sign 049 Airfla Mount Glas-filled nylon compound provides vibration-free design molded front end reduces aerodynamic drag around engine 2% firewall face 40 mount ideal Quicky-type aircraft Price $525 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review next battery right side antenna routed out pod right side between frames 5 6 through small plastic tube supported top fin plug between switch receiver should above deck ease re-charging placed right side adjacent receiver lead runs switch aft under servo receiver up right side top deck plug placed just front canted frame beside re ceiver lead receiver comes out through deck center forward receiver runs center around right corner re ceiver aft switch lead servo receiver leads pass left re ceiver plugs behind receiver Flying center gravity shown sat isfactory slope flying may want farther aft thermal flying Hand launches 30 feet possible putting fingers behind wing center sec tion High-starts light rubber hand tows easily accomplished familiar characteristics model add winglets im provement flight should evident winglets place prototype glide turn characteristics both im proved Although winglets may look vulnerable arent prone flying/ landing damage However vul nerable during transportation storage Conclusion hope enjoy version much enjoy feel con figuration could scaled twice size gradual increase performance due scale factor Let hear about model Write Dave Jones 5621 Michelle Drive Tor rence CA 90503 CL Scale/Gretz continued page 31 Rd Fallbrook CA 92028 claims pro duce sell aviation aerospace books other publisher world know produce noteworthy books including well known Aero Series profile-type book lets covering famous WW2 military aircraft free catalog shows over 200 books phases aviation space books also available mail-order book dealers Ive already mentioned Sentry Books 10718 White Oak Ave Granada Hills CA 91344 another book publisher can buy directly line aviation books isnt very large yet Ive found book have got ten exceptional quality photos drawings historical accuracy manu facture Most authors interna tionally known experts subjects Sentry also publishes two bi-monthly mag azines called Wings Airpower 94 Model Aviation
Edition: Model Aviation - 1978/08
Page Numbers: 27, 28, 29, 30, 94
A well-engineered fascinating machine mini airborne systems U Dave Jones THE AR-25 designed novel entry contest devoted models span less 72 inches wing loading greater seven ounces per square foot formerly designed sev eral all-wing models slope soaring similar wing loading size near two square feet wing area gave good indication much model type would weigh Also built A-l model high aspect ratio wanted emulate set down some design goals cluded geometric aspect ratio 20 weight 12/2 ounces judged tainable left wing area 259 sq model follows general lay out construction methods much larger models also intended add winglets type tip fin bring theoret ical aspect ratio 25hence name AR-25 AR-25a incorporates several minor changes judged improve durability Construction Wing The wing unusually simple structure built complete halves board difficult task cutting ribs because small cut template stack method single slender bolt held stack together shaped ribs An extra rib cut second rib station root tip ribs copied directly tem plates cut stack Ribs through 12th station have notches spar caps 1/16 x 1/8 spruce spruce upper spar cap should re duced thickness zero its end poor practice have sudden change load carrying material cross section /8 sq spruce leading edge shaped near triangular shape after assembly wing leading edge should glue line between lower sheeting spruce upper shape see wing section drawing gives reasonably strong leading edge resists dents spar webs cut 1/16 sheet installed grain vertical run mold line mold line bottom resting building board top trimmed upper sheeting web also closes out semi circle sheeting root giving increased integrity Take care choosing balsa sheet wing covers Use best sheet top wing trailing edge use straight piece triangular stock curved August1978 27 Although pods length less span Cougar Peanut its right preserves niceties modern sailplane designthe airborne system just smaller different can sometimes straightened sanding side help relieve stresses wood wing ribs may capped extra job dont deem necessary model wing under load will act just like full-size fiberglass sailplane bow graceful curve winglets used hard 1/16 sheet balsa leading edge rounded trailing edge square may have airfoil shape also have cam ber supposed reduce tip vor tices some extent curved surface winglet toward center wing though wing bent up Dont change size shape winglets tied dihedral rudder/fin areas Mine have no finish however couple coats dope would good protection Try keep winglets light regardless type use main joiner tube square brass inside hole suitable /s diam eter piano wire spruce sub-spar added root tube parallel trailing edge wing rear tube 1/16-inside-diameter aluminum Epoxy together tubes spar caps fillers glues set cut wing between two ribs station 2 used Dremel gives ab solute match between parts Add ply wood end ribs either 1/32 1/16 thickness part Shape root panel accommodate eight degrees dihedral Slip part wing main rod Epoxy root joint Add 1/16 rear wing rods offset slightly fit tightly tubes Fin Shape fin core skins stabilator bearing stabilator fair ing horn Fit hinge points core Place core horn between skins making sure horn free pivot stabilator pivot stab bilator driver clear move its groove Glue together Keep flat until dry shape Body Cut bottom wing center assembly admit tail boom Add frames 5 6 wing/boom Add upper lower keels Now frames 2 4 added point deck must designed using Can non Tini-Block deck shown good using another system own deck After deck added install frame 3 During installation deck will note inner part wing leading edge must removed Note easier assemble tow hook keel before added frame 5 Shape canted frames between frames 2 4 5 rear canted frame partially removed after planking complete install equipment Thread two Pylon GRC-3 tubes back through boom pod rudder tube exits 28 Model Aviation winglets really improve performance model case answer emphatic yes An excellent report winglets full scale appeared Meusers column August 1977 Installation Cannon Tini Brick bit snug presents no problems Other mini systems may substituted ACE Kraft being likely examples 0 Il iF 0-DIAMETER REQ REQUIRED SQ SQUARE KIN7/BHIBR Ae vERTICAL UAN DECK-PLYWINGII/IGiH-GRAIN----- SPACING TYPSPRUCE4 1-5A6-JLIA6D 3PLS uUPPERU}9I6R -iI5/32R.j6fIAID CANNON TINHBLO K/80/ -l/l /32R5 5I-- 2-GR LOWER-P 1/6STABILATOR TRIBESiWYIA6 IFRAME 4-PLY 6Q-j FRAME 6ALUM 2 REQ WING ROD-SPRING STEEL1-3/4 2 7/8H 2 REQ2PL-A6 GRAN//~WING TUBE RED BRASS 2INSIDEUPPERI362R-4 VeALUM 2REO- WING TUBE- SQT EPOXY TO STRUCTORE 2-3/4EPOXY TO STABILATOR HORN CTURE I/B PLY525/32 2 EA REQt~/I67/B 1/25132RIII S/32R 2PLSSTABILATOR FAIRING 16-IA6D1 3j4I/BFRAME 5-PLYGP/1 L ~ILP r-I/4 -~A6R I/61tV16RLL \ 3/~I4 6__T1-3/4 KEELPLYLOWER UPPE6/32L~TO Iii-lI - --V4jIA STABILATOP BEARINGI/S 7/6R W HOOK-/6 PLY2 REQ NOSE PNESPRING STEEL116GRAIN4 VBFRAME 3-PLYORAN--FULL RADIUS3/32STABILATQR PIVOT LOWER DDER-I/4 SPRINU STEEL 6371 I--*6EPOXY TO HORN 58-17/16 AT5/16I7/B4~2AWZ803/32RI RB BLANK 50 REQRUDDER HORN-PLYI VB2/T 1/4HINGE POINT 2 PLSSTABILATOR SPRING IDRIVERI9 3/B RUDDERSTEELSPAN725o WING8 7/6 UT OUT AFTER ASSY SKID-EPOXY ONCOVER WITH MONOKOTE EP%XY PUSH RODS PYLON GRC-32-7/d PLYI/eR FRAME KEEL 80DM NOSE AND TOW HOOK ASSEMBLY CARVE WING LOWER Cr Co CPLANK WITH I/BI/4 -4 CD FULL-SIZE PLANS AVAILABLE.. SEE PAGE 104 36 __ABOUT TIP SHA perhaps dif ferent tips wings stabilizers models mod eler shapes own artistic talent level back mind concept its pleasing eye its good aero dynamically may influencing choice tips popular idea necessarily true Seldom aerodynamics does simplest least complex de sign produce best results wing tip square sharpedged tip shows best test re sults effective versus geo metrical aspect ratio reaches high 990/0 must trailing edge corner have no less span point tip chord tip easy make strong structurally easy duplicate benefits builder/flier artistic bent tip nearest square performance upswept tip found quite frequently shapes sizes models Perhaps popular because works has pleasing planform shape tip has maximum span high point wing section sharp edge also helpful section through tip form triangle top flat bottom sloped upward outward effec tive versus geometrical aspect ratio moderate 950/0 however whole story Tests show tip vortex core cen ter some 500/0 wing thick ness higher other tested tips same adding tip plate produces 40/o gain effective aspect ratio wing geometrical aspect ratio 30 type tip very good low aspect ratio wings As wing tip fins end plates winglets some simple dos donts will clear air higher geometrical aspect ratio taller winglet must improve effective aspect ratio Tests show addition area form span crease aspect ratio increase beneficial winglets leads us conclusion winglets use span limited aspect ratio lower Dont put wing let both above below wing tip doubles interference drag Tests show winglet extend ing below wing no beneficial extending upward upward winglet has big advantage reduced structural damage possibility An attempt should made keep area wing let low pos sible area destabilizing effects required vertical tail size Horizontal vertical tail tips labor under same aerodynam ics wings same com ments hold true Horizontal tails sometimes have tip fins rud ders improves effective aspect ratio horizontal tail reduces power vertical surface necessitating increase area tee tail has effect increasing effective aspect ratio ver tical 500/a no loss hori zontal tail effectiveness further improvement may orienting aft body vi cinity vertical tail hori zontal direction instead common vertical orienta tion produces effect end plate lower end vertical stabilizer Fluid-Dynamic Lift Dr Ing S F Hoerner H V Borst full helpful information like dig out own data book reference aerodynamic groups may purchased less $30 Hoerner Fluid Dynamics PO Box 342 Brick Town NJ 08723 Dave Jones WING TT -w II II RxII II 1L recent appearance mini systems other CannonsAce Kraft being two examplesthe AR25 one-make-of-radio air plane top side view details shown depict MAs suggestion alternate installation Ace system boom left side ahead stabilator horn Epoxy clevis stabilator cable attach clevis horn Fit fin boom sure everything working free epoxy fin place Now plank pod Add nose block sand plank ing round cross section Shape soft block canopy/hatch Hollow fit equipment skid has fitted bottom pod prone instant removal during crosswind landings mind plastic skid Scuff Guard several layers masking tape provide protection needed adept fiberglass pod can covered made light fiber glass resin will insure ex tremely strong model Control Surface wood stabil ator must light reasonably rigid Very little work done spend time selecting good piece wood flat plate section used simplicity true will stall low angles tack using square trailing edge wake thin allows very small deflections give control response Some Continued page 94 30 Model Aviation GET ORGANIZED s set 4 slardy ties haNs over 4 years yosr tavoste 5 Ii magazrees 4 MAG FILES $495 Seed 5456 ptss SI 00 postage haedtig N DOM INOUSTRES PO BOX 388-K DOVER NH 03820 KITSOPLANSOACCESSORIES BABY ACEP-NUT KITS N BEARINGS BROWN CO-2 ENGINES COMPLETE CATALOG REAL JAPANESE TIISuCPROPj KIT $425 MANY CARD TO FIND ITEMS he*-Pb4tw W BOX 2498LA MESA CALIF 92041 modification give Jet Ranger fliers something just little different Bill Watson vice-president NCHA North Carolina Helicopter Assoc original members NCHA shown group photo first meet Greensboro NC Also NCHA schematic transmitter modification allow mixing throttle collective modification developed Mike Miles Durham NC Mikes modifica tion will work Kraft series 76-78 5channel transmitters will possibly work some other makes although tested modification will eliminate need Y connector between throttle collective servos offers advantage collective trim modify transmitter remove wire center lug retract switch 5th channel wire may attached directly center tap throttle pot collective trim desired Collective trim added addition miniature -watt 5K wirewound pot standard Kraft trim lever part #901 148 mounted convenient location pot electrically connected series fifth channel wire retract switch center tap existing throttle pot 470-ohm resistor placed series throttle channel lead center tap Two connections have made center tap throttle pot 1 5K pot series fifth channel 2 470-ohm resistor series throttle channel set up servos should re-centered using throttle stick pot collective trim pot ie sticks trims readjusted center tightened pot shafts operation circuit will increase servo travel five six degrees either side center Throttle throttle trim will affect both throttle collective col lective trim will affect collective channel final note Somewhere out someone flying hot Red Heli-boy Wolitz-modified EK radio say hot because helicopter radio other modeling articles stolen Walt Schoonards car Perry Georgia few weeks ago find information leading recovery stolen articles Im sure Walt would appreciate David R Chesney Rt 9 Box 621A Greensboro NC 27407 Tiny Sailplane/Jones continued page 30 sharp trailing edge control surfaces can deflected several degrees before im pinge high energy air Cut stabilator soft Vs sheet inset 1/16inside-diameter aluminum tube balsa correct locations Match stabilator horn rudder made three pieces blade driver horn Assemble attach fin used hinge points Finish prototype wing stabilator covered transparent orange top black bottom pod covered black fin good paint finish would easier pod boom canopy white coverings Super Monokote Equipment Installation Care must ex ercised fitting radio model large canopy helps make easy two-channel Cannon Tini-Block fit stock wire plugs switch Yes switch mounted under canopy product review product review product review ~1 40-Size Engine Mount Fourmost con tinuation successful wrap-around de sign 049 Airfla Mount Glas-filled nylon compound provides vibration-free design molded front end reduces aerodynamic drag around engine 2% firewall face 40 mount ideal Quicky-type aircraft Price $525 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review next battery right side antenna routed out pod right side between frames 5 6 through small plastic tube supported top fin plug between switch receiver should above deck ease re-charging placed right side adjacent receiver lead runs switch aft under servo receiver up right side top deck plug placed just front canted frame beside re ceiver lead receiver comes out through deck center forward receiver runs center around right corner re ceiver aft switch lead servo receiver leads pass left re ceiver plugs behind receiver Flying center gravity shown sat isfactory slope flying may want farther aft thermal flying Hand launches 30 feet possible putting fingers behind wing center sec tion High-starts light rubber hand tows easily accomplished familiar characteristics model add winglets im provement flight should evident winglets place prototype glide turn characteristics both im proved Although winglets may look vulnerable arent prone flying/ landing damage However vul nerable during transportation storage Conclusion hope enjoy version much enjoy feel con figuration could scaled twice size gradual increase performance due scale factor Let hear about model Write Dave Jones 5621 Michelle Drive Tor rence CA 90503 CL Scale/Gretz continued page 31 Rd Fallbrook CA 92028 claims pro duce sell aviation aerospace books other publisher world know produce noteworthy books including well known Aero Series profile-type book lets covering famous WW2 military aircraft free catalog shows over 200 books phases aviation space books also available mail-order book dealers Ive already mentioned Sentry Books 10718 White Oak Ave Granada Hills CA 91344 another book publisher can buy directly line aviation books isnt very large yet Ive found book have got ten exceptional quality photos drawings historical accuracy manu facture Most authors interna tionally known experts subjects Sentry also publishes two bi-monthly mag azines called Wings Airpower 94 Model Aviation
Edition: Model Aviation - 1978/08
Page Numbers: 27, 28, 29, 30, 94
A well-engineered fascinating machine mini airborne systems U Dave Jones THE AR-25 designed novel entry contest devoted models span less 72 inches wing loading greater seven ounces per square foot formerly designed sev eral all-wing models slope soaring similar wing loading size near two square feet wing area gave good indication much model type would weigh Also built A-l model high aspect ratio wanted emulate set down some design goals cluded geometric aspect ratio 20 weight 12/2 ounces judged tainable left wing area 259 sq model follows general lay out construction methods much larger models also intended add winglets type tip fin bring theoret ical aspect ratio 25hence name AR-25 AR-25a incorporates several minor changes judged improve durability Construction Wing The wing unusually simple structure built complete halves board difficult task cutting ribs because small cut template stack method single slender bolt held stack together shaped ribs An extra rib cut second rib station root tip ribs copied directly tem plates cut stack Ribs through 12th station have notches spar caps 1/16 x 1/8 spruce spruce upper spar cap should re duced thickness zero its end poor practice have sudden change load carrying material cross section /8 sq spruce leading edge shaped near triangular shape after assembly wing leading edge should glue line between lower sheeting spruce upper shape see wing section drawing gives reasonably strong leading edge resists dents spar webs cut 1/16 sheet installed grain vertical run mold line mold line bottom resting building board top trimmed upper sheeting web also closes out semi circle sheeting root giving increased integrity Take care choosing balsa sheet wing covers Use best sheet top wing trailing edge use straight piece triangular stock curved August1978 27 Although pods length less span Cougar Peanut its right preserves niceties modern sailplane designthe airborne system just smaller different can sometimes straightened sanding side help relieve stresses wood wing ribs may capped extra job dont deem necessary model wing under load will act just like full-size fiberglass sailplane bow graceful curve winglets used hard 1/16 sheet balsa leading edge rounded trailing edge square may have airfoil shape also have cam ber supposed reduce tip vor tices some extent curved surface winglet toward center wing though wing bent up Dont change size shape winglets tied dihedral rudder/fin areas Mine have no finish however couple coats dope would good protection Try keep winglets light regardless type use main joiner tube square brass inside hole suitable /s diam eter piano wire spruce sub-spar added root tube parallel trailing edge wing rear tube 1/16-inside-diameter aluminum Epoxy together tubes spar caps fillers glues set cut wing between two ribs station 2 used Dremel gives ab solute match between parts Add ply wood end ribs either 1/32 1/16 thickness part Shape root panel accommodate eight degrees dihedral Slip part wing main rod Epoxy root joint Add 1/16 rear wing rods offset slightly fit tightly tubes Fin Shape fin core skins stabilator bearing stabilator fair ing horn Fit hinge points core Place core horn between skins making sure horn free pivot stabilator pivot stab bilator driver clear move its groove Glue together Keep flat until dry shape Body Cut bottom wing center assembly admit tail boom Add frames 5 6 wing/boom Add upper lower keels Now frames 2 4 added point deck must designed using Can non Tini-Block deck shown good using another system own deck After deck added install frame 3 During installation deck will note inner part wing leading edge must removed Note easier assemble tow hook keel before added frame 5 Shape canted frames between frames 2 4 5 rear canted frame partially removed after planking complete install equipment Thread two Pylon GRC-3 tubes back through boom pod rudder tube exits 28 Model Aviation winglets really improve performance model case answer emphatic yes An excellent report winglets full scale appeared Meusers column August 1977 Installation Cannon Tini Brick bit snug presents no problems Other mini systems may substituted ACE Kraft being likely examples 0 Il iF 0-DIAMETER REQ REQUIRED SQ SQUARE KIN7/BHIBR Ae vERTICAL UAN DECK-PLYWINGII/IGiH-GRAIN----- SPACING TYPSPRUCE4 1-5A6-JLIA6D 3PLS uUPPERU}9I6R -iI5/32R.j6fIAID CANNON TINHBLO K/80/ -l/l /32R5 5I-- 2-GR LOWER-P 1/6STABILATOR TRIBESiWYIA6 IFRAME 4-PLY 6Q-j FRAME 6ALUM 2 REQ WING ROD-SPRING STEEL1-3/4 2 7/8H 2 REQ2PL-A6 GRAN//~WING TUBE RED BRASS 2INSIDEUPPERI362R-4 VeALUM 2REO- WING TUBE- SQT EPOXY TO STRUCTORE 2-3/4EPOXY TO STABILATOR HORN CTURE I/B PLY525/32 2 EA REQt~/I67/B 1/25132RIII S/32R 2PLSSTABILATOR FAIRING 16-IA6D1 3j4I/BFRAME 5-PLYGP/1 L ~ILP r-I/4 -~A6R I/61tV16RLL \ 3/~I4 6__T1-3/4 KEELPLYLOWER UPPE6/32L~TO Iii-lI - --V4jIA STABILATOP BEARINGI/S 7/6R W HOOK-/6 PLY2 REQ NOSE PNESPRING STEEL116GRAIN4 VBFRAME 3-PLYORAN--FULL RADIUS3/32STABILATQR PIVOT LOWER DDER-I/4 SPRINU STEEL 6371 I--*6EPOXY TO HORN 58-17/16 AT5/16I7/B4~2AWZ803/32RI RB BLANK 50 REQRUDDER HORN-PLYI VB2/T 1/4HINGE POINT 2 PLSSTABILATOR SPRING IDRIVERI9 3/B RUDDERSTEELSPAN725o WING8 7/6 UT OUT AFTER ASSY SKID-EPOXY ONCOVER WITH MONOKOTE EP%XY PUSH RODS PYLON GRC-32-7/d PLYI/eR FRAME KEEL 80DM NOSE AND TOW HOOK ASSEMBLY CARVE WING LOWER Cr Co CPLANK WITH I/BI/4 -4 CD FULL-SIZE PLANS AVAILABLE.. SEE PAGE 104 36 __ABOUT TIP SHA perhaps dif ferent tips wings stabilizers models mod eler shapes own artistic talent level back mind concept its pleasing eye its good aero dynamically may influencing choice tips popular idea necessarily true Seldom aerodynamics does simplest least complex de sign produce best results wing tip square sharpedged tip shows best test re sults effective versus geo metrical aspect ratio reaches high 990/0 must trailing edge corner have no less span point tip chord tip easy make strong structurally easy duplicate benefits builder/flier artistic bent tip nearest square performance upswept tip found quite frequently shapes sizes models Perhaps popular because works has pleasing planform shape tip has maximum span high point wing section sharp edge also helpful section through tip form triangle top flat bottom sloped upward outward effec tive versus geometrical aspect ratio moderate 950/0 however whole story Tests show tip vortex core cen ter some 500/0 wing thick ness higher other tested tips same adding tip plate produces 40/o gain effective aspect ratio wing geometrical aspect ratio 30 type tip very good low aspect ratio wings As wing tip fins end plates winglets some simple dos donts will clear air higher geometrical aspect ratio taller winglet must improve effective aspect ratio Tests show addition area form span crease aspect ratio increase beneficial winglets leads us conclusion winglets use span limited aspect ratio lower Dont put wing let both above below wing tip doubles interference drag Tests show winglet extend ing below wing no beneficial extending upward upward winglet has big advantage reduced structural damage possibility An attempt should made keep area wing let low pos sible area destabilizing effects required vertical tail size Horizontal vertical tail tips labor under same aerodynam ics wings same com ments hold true Horizontal tails sometimes have tip fins rud ders improves effective aspect ratio horizontal tail reduces power vertical surface necessitating increase area tee tail has effect increasing effective aspect ratio ver tical 500/a no loss hori zontal tail effectiveness further improvement may orienting aft body vi cinity vertical tail hori zontal direction instead common vertical orienta tion produces effect end plate lower end vertical stabilizer Fluid-Dynamic Lift Dr Ing S F Hoerner H V Borst full helpful information like dig out own data book reference aerodynamic groups may purchased less $30 Hoerner Fluid Dynamics PO Box 342 Brick Town NJ 08723 Dave Jones WING TT -w II II RxII II 1L recent appearance mini systems other CannonsAce Kraft being two examplesthe AR25 one-make-of-radio air plane top side view details shown depict MAs suggestion alternate installation Ace system boom left side ahead stabilator horn Epoxy clevis stabilator cable attach clevis horn Fit fin boom sure everything working free epoxy fin place Now plank pod Add nose block sand plank ing round cross section Shape soft block canopy/hatch Hollow fit equipment skid has fitted bottom pod prone instant removal during crosswind landings mind plastic skid Scuff Guard several layers masking tape provide protection needed adept fiberglass pod can covered made light fiber glass resin will insure ex tremely strong model Control Surface wood stabil ator must light reasonably rigid Very little work done spend time selecting good piece wood flat plate section used simplicity true will stall low angles tack using square trailing edge wake thin allows very small deflections give control response Some Continued page 94 30 Model Aviation GET ORGANIZED s set 4 slardy ties haNs over 4 years yosr tavoste 5 Ii magazrees 4 MAG FILES $495 Seed 5456 ptss SI 00 postage haedtig N DOM INOUSTRES PO BOX 388-K DOVER NH 03820 KITSOPLANSOACCESSORIES BABY ACEP-NUT KITS N BEARINGS BROWN CO-2 ENGINES COMPLETE CATALOG REAL JAPANESE TIISuCPROPj KIT $425 MANY CARD TO FIND ITEMS he*-Pb4tw W BOX 2498LA MESA CALIF 92041 modification give Jet Ranger fliers something just little different Bill Watson vice-president NCHA North Carolina Helicopter Assoc original members NCHA shown group photo first meet Greensboro NC Also NCHA schematic transmitter modification allow mixing throttle collective modification developed Mike Miles Durham NC Mikes modifica tion will work Kraft series 76-78 5channel transmitters will possibly work some other makes although tested modification will eliminate need Y connector between throttle collective servos offers advantage collective trim modify transmitter remove wire center lug retract switch 5th channel wire may attached directly center tap throttle pot collective trim desired Collective trim added addition miniature -watt 5K wirewound pot standard Kraft trim lever part #901 148 mounted convenient location pot electrically connected series fifth channel wire retract switch center tap existing throttle pot 470-ohm resistor placed series throttle channel lead center tap Two connections have made center tap throttle pot 1 5K pot series fifth channel 2 470-ohm resistor series throttle channel set up servos should re-centered using throttle stick pot collective trim pot ie sticks trims readjusted center tightened pot shafts operation circuit will increase servo travel five six degrees either side center Throttle throttle trim will affect both throttle collective col lective trim will affect collective channel final note Somewhere out someone flying hot Red Heli-boy Wolitz-modified EK radio say hot because helicopter radio other modeling articles stolen Walt Schoonards car Perry Georgia few weeks ago find information leading recovery stolen articles Im sure Walt would appreciate David R Chesney Rt 9 Box 621A Greensboro NC 27407 Tiny Sailplane/Jones continued page 30 sharp trailing edge control surfaces can deflected several degrees before im pinge high energy air Cut stabilator soft Vs sheet inset 1/16inside-diameter aluminum tube balsa correct locations Match stabilator horn rudder made three pieces blade driver horn Assemble attach fin used hinge points Finish prototype wing stabilator covered transparent orange top black bottom pod covered black fin good paint finish would easier pod boom canopy white coverings Super Monokote Equipment Installation Care must ex ercised fitting radio model large canopy helps make easy two-channel Cannon Tini-Block fit stock wire plugs switch Yes switch mounted under canopy product review product review product review ~1 40-Size Engine Mount Fourmost con tinuation successful wrap-around de sign 049 Airfla Mount Glas-filled nylon compound provides vibration-free design molded front end reduces aerodynamic drag around engine 2% firewall face 40 mount ideal Quicky-type aircraft Price $525 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review next battery right side antenna routed out pod right side between frames 5 6 through small plastic tube supported top fin plug between switch receiver should above deck ease re-charging placed right side adjacent receiver lead runs switch aft under servo receiver up right side top deck plug placed just front canted frame beside re ceiver lead receiver comes out through deck center forward receiver runs center around right corner re ceiver aft switch lead servo receiver leads pass left re ceiver plugs behind receiver Flying center gravity shown sat isfactory slope flying may want farther aft thermal flying Hand launches 30 feet possible putting fingers behind wing center sec tion High-starts light rubber hand tows easily accomplished familiar characteristics model add winglets im provement flight should evident winglets place prototype glide turn characteristics both im proved Although winglets may look vulnerable arent prone flying/ landing damage However vul nerable during transportation storage Conclusion hope enjoy version much enjoy feel con figuration could scaled twice size gradual increase performance due scale factor Let hear about model Write Dave Jones 5621 Michelle Drive Tor rence CA 90503 CL Scale/Gretz continued page 31 Rd Fallbrook CA 92028 claims pro duce sell aviation aerospace books other publisher world know produce noteworthy books including well known Aero Series profile-type book lets covering famous WW2 military aircraft free catalog shows over 200 books phases aviation space books also available mail-order book dealers Ive already mentioned Sentry Books 10718 White Oak Ave Granada Hills CA 91344 another book publisher can buy directly line aviation books isnt very large yet Ive found book have got ten exceptional quality photos drawings historical accuracy manu facture Most authors interna tionally known experts subjects Sentry also publishes two bi-monthly mag azines called Wings Airpower 94 Model Aviation