NO OCR TEXT NO OCR TEXT range airfoils LID values range 18 thick highly-cambered airfoils 24 lowcambered ones Table 1 describes correc tions finite aspect ratios wing thick ness given chord airspeed airfoil increas ing aspect ratio will bring about increase LID Anyone has stretched span model changing airfoil chord weight least much will know relation ship true Also note other things being equal thicker airfoils tend have lower LIDs What happens design around areabased rules like FAI rather span given area increase aspect ratio brings about reduction average chord wing therefore lower Reynolds Number given airspeed Reynolds Number can considered measure scale effect range airspeed also measure relative efficiency Indeed data paper S J Miley demonstrates increase LID Reynolds Numbers upto about 1000000 Using values LID vs Reynolds Number Miley paper correction factor Table 1 maximum value possible LID can cal culated values shown Table 2 various configurations Again keep mind maximum possible LID values will reality less due wing tip losses fuselage drag surface imperfections ever definite trend becomes apparent sufficient increase wing chord can definitely outweigh advantages high aspect ratio Minimum sinking speed also depends wing loading camber aspect ratio Table 3 would seem favor higher aspect ratios However same wing area would very difficult build high aspect ratio aircraft same wing loadings low aspect ratio though feel existing planform near optimum refinements wing tip shape fillets airfoils can still made Merlyn large enough carry instrumentation capable measuring effect design refinements Budder horn made fr, ince Merlyn operating higher Reynolds stock Note blending fuse fin lots Numbers lower lift coefficients suspect sanding means less nose weight needed significant improvements could come inermaionijieriseplybrackets p plate behind Snirner tor cam-bc canopy hold-down 0-cells for4 amps . ing times 16 hours possible Forward end thefuselagesldesshowthetoughbutlightconstmctionIn rear 1/4-in square balsa braces added prevent splitting spruce longeron 1/4-in ply top brace triangle stockThey beveled fit top bottom triangle pieces Wing root area top bulkheads place Note theThis view shows wing root area after top block place box wing tod tube located underthe plytop brace thespoiler servo wiring goes first glass tube second spruce longeron butts up agalns itspare large tube wing rods 22 Model Aviation BALSA TEANDLE OFFiN 3/s SQ STABLIZER1/8 SHEET BALSA 3/BADRILLROOFROM KEN BATESROOT RIB FRAMESSIDES OFFiN BASE3/B SOBALSARUOCER FACES ON HINGE POSiS 1/J/13/8X 3/32 BALSA RIBS 125 DIAMJSIC WIRE7 BALLAST TUBE OPT1ONAL3/BSHEEr FIN FAIRING CLAMP ROD C/S ONLY/2 BALSA BLOCKS VBI D BRASSBALSA BLOCK FAIRINGS VI6PLYVJCCO5/32COLLAR ALLOWS ELIMOL 5/B BALSA BLOCK WITH PLYSKID CLBLER ASBEAI SNIFFER TUBE HOOKS AND BANDSI/B UTE-PLY SICES AFT OF SPliCEL 2 THEWAAL SNIFFER INSTAL CANOPY IS BALSA ROCKI/B BIRO-I PLYWOOD SIDES FWD OF SICE -3/32SHEET BALSA TEl P/ROTFOMELEVATOR PUSHROD TAB-U WING ARTCOMPRESSED TOGETITALL IN-HC --S I/4BARIB 3/32 X 1/4 BALSA CAPSTRPS TOPAND YflOM ALL RIBS PLASTiC 1 I-KDK -- BALSA --TEFILLERS DOWELS 10 LOCATE CANOPY.- BRAS5 TIJBE TOP2BALSA~R Bi I/BPIYWOOD%EN ---- WOODBALSA TOPSAME FOR 82-3AND BOTTOMWEBS END HERE LOW NOSENOSE BLOCK BLOCK 3/32 SHEEV BALSAVBX 1/4 SPRUCE V4 PLYWOOD FORMS AT JOINTLE SKIN FULL SPANSPAR TCP ONLY TO END OF SPOILER3/850 BALSA OF FUSELAGE AND CANOPYLEFULL N 1/4K 1/2 SPRUCE 1/4K 1/2 SPRUCE1/2 BALSA TRIAN3LESPARS TOPAND BOTTOM PiT RAILBOlTOM CORNERS FULLLENGTUREINFORCING FROM3/B BALSA SPOILER ADE WITH -ROOT TO BELLCRANKPUSH ROD-TOBELLCRANKANDSBWOL16 PLYWOOD JOINS WING SPARS I/B WEBS FROM SPOILER OUTWARD 3BRIRPW EBOP 0 3 WIWIT BBSWROk RLL RIBS 10 W B MLSA RIIcRPT RIB O tRY BA BR 83 NEAR TRIMRWART PInUP ORB TT -4WLRff1R-- BALSA RLRSRROT NBYBRIRUTB RI I--4i-VRRTRBRRRERTCRBB RSECTION 0-B SPEAR CROCIIII -ml CR10 BROSSILBOtB IL YUBA SBPR PLUSIIIXIA SOBER DU1RR3WRRS ORIj-BR BAlSAIBXRI1BI II CrOP B ROT COPUSTIBB W4Y IBPBv~PAIPAp IIIIII Ii II I Ii I II LII RWROT WUOB 00 ICC 8150 OBhIRT PBJURB BAlSa WIll RIRASS TORITRPRROC BR SQ BALSABAlSA FILSOR lEERPRL WOO BRORT B 1pBRAISS R00C1 ASSRRBAVP45AlERt ROALWOIS BAl BALSA %SIIRAT BALSA BLURBAR IRABROC SBCTORR OB A 54 BALSA BlOCK BALLRRWR/SPRIER PARER 51501 RTOR P0044000k RLLRAP&W4L~z1 PR TO BRASS IA RANSULAR WA R75450IIPREPI -BRA o RPQDy PS WA ARISE WARBALSA SECTION A-AcRUSIIINA TULYUR0RAL FORMER U PLY[1 airfoils normally considered Design game compromise have designed Merlyn according preferences handling indications higher possible efficiency Obviously constrained PAl size limits could better using higher aspect ratio wing same chord However World Record attempts Great Race rules cross-country events require compliance FAI rules also prefer structural integrity inherent such configuration Merlyn very rugged aircraft very encouraging paying wood Construction Merlyn builders beginners difficult cheap no glue Part Part B instructions need dont build general style construction follows Airtronics Aquila structure well-proven well engineered will glad correspond ModelAviation have problem forewarned love talk about airplanes especially Remember airplane size Reynolds Number much larger normal Thus 8-lb Merlyn floater 10-lb Merlyn flies authority Built plans Merlyn should weight 10 lb Modifications described later allow build Merlyn all-up weight about 8 lb Please note since tip panel 36 long trailing edge sheet 37 long Use 4ft wood extra goes roof area Rocket City towhook reliable size Sailplane wrap link wire solder towhook shown plans 24 Model Aviation Airfoil Thickness % chordAspect RatioL/D Maximum Correction Factor2 10%litol17to185% 10%16to1l8tol90% 10%2Otoll9tol95% 13%l6toll7tol85% 13%20to 1175 1875% Table 2 effect Reynolds Number maximum possible L/D various designs 15mph airspeed1 AreaAspect%AverageRN atMax L/D sq inRatioThickness DesignChord15mphPossible2 21001110Merlyn138 in17300038 2100161011Sin 14400035 210020101025 in12800034 2100161311Sin 14400033 210020131025in 12800031 137016613Astro Jeff90 in11300028 Note data Table 1 paper S J Miley titled Design Air foils Low Reynolds Numbers published Massachusetts Institute Technolo gy Proceedings Second International Symposium Technology Science Low-speed Motoriess Flight Note 2 table results data indicating maximum L/D infinite aspect ratios various airfoils functioning Reynolds Number applying correc tion factor Table 1 various aspect ratios thicknesses Table 1 Maximum possible LID various thicknesses flat-bottom air foils Reynolds Number about 500001 Note data article Heinz G Struck Optimum Aspect Ratios RC Sailplanes RCModeier February 1976 Note 2 Percentage compared L/D 20 Reynolds Number 0 infinite aspect ratio FULLSIZEPLANSAVAILABLE E PAGE 140 A- 501 C0-4~ A 0551 GROIN FBI ISBN 31 0B0~Nt 55 BALSA SOOtY TO 55 BALSA NOFRO GOON 151 0Y 80050 ALBCC 005 S00IrA 000~ Frv SSNWA40005NY 0000BL 0 PLY BBLSB BLOCK SBCLLA LBLA%ONA 800505505K BALSAAS SGOBBA ALLOt PLYSYAaAtt RIOGROBBOB-NOLSA BLJ 050030000 --- S NOLBALL BOOLA SOLO PLY OBLY IS 30 SPOOL 300 0004 SPROCA50580 00 OuSAL0G$ AT AUTO PLY OBTOLO AOLJLSYABW OR 005030 BALAKSO YPOS 4000 MAY 80 05W MEN LYN OKORINEBO PRAWN BY SON BOlES -NOW BY Nat Design No 1 Merlyn 10% thickDesign No 22 13% thick airfoil 11 1 ARairfoil 20 1 AR Wing LoadingSinking SpeedWing LoadingSinking Speed ozIsq ft ec ozIsq ft ec 5 111 6119 71287102 81378108 91449115 10121 11127 12133 made aluminum T extrusion purchased local hardware store rearward location preferred 12-volt winch launches weaker winch hi-start i-in rubber would use forward location Please use heavy duty servos 10-lb cross-country Merlyn KPS-15s would good plane can get up 90 mph return downwind putting Quarter Scale power category radio compartment sized four D-size ni-cd cells 4 amp/hour balance bird give about 16 hours operation canopy balsa block have almost never entirely successful gluing blasted plastic canopies straight always get glue wrong place Besides like carve wood comments hear about Merlyn carving Carving fun have right tools project pieces wood large try sharp block plane use Stanley 9 Razor planes have uses big cuts Disston Company makes neat tool called Abrader works like rasp better Abraders really chew wood dont load up leave much better surface final sanding using two tools band saw blank out canopy block entire shaping takes 45 minutes less original Merlyn used blade-type wing joiner Sailplane Factory PO Box 341 Red Lion PA 17356 has heavy duty 14mm blade blade holder brass sleeve can used also have suitable stab bellcrank sake keeping home shop project now use h-in drill rod rod has heat-treated follows austenitize oil quench temper Rockwell C Scale 4245 can get done local heattreatment shop finished wing rod can obtained $500 Ken Bates 738 N Harris St Saline MI 48176 specifications very important Too hard will brittle source doesnt understand dont take chance Make sure rod tempered hardness Rockwell C Scale 42 45 Several variations structure have successfully used have built three Merlyns have used ribs 1/16th tips have also substituted arbon fiber spar Flite-spar Wing sheeting 1/16 balsa tried proved too prone hangar rash Another substitution tct use narrower stock tail surface trailing edges * x i light thermal machine rather rugged cross-country bird desire substitute Lite Ply nose sides bottom a tail boom sides bottom spoiler system shown construction photos new attempt has proven have favorite method use December1981 25 Table 3 effect wing loadings calculated sinking speeds two designs operating Reynolds Numbers around 500001 Note 1 same source table 1 some interpolation necessary Note 2 Hypothetical design optimized lowest minimum sinking speed General Note Reynolds Number calculations done using shortened formula Model Glider Design Frank Zaic RN 0 x chord feet x mph Miller Mod-type bottom leading edge sheet option used prototype feel modification made better handling high speeds prefer flat-bottom airfoil Pre cision Duration work thing worse crooked airplane great big expensive crooked airplane make stab bellcrank first can used space stab wire tubes correctly build fin can use stab align bellcrank pivot bushings First glue Lite Ply stab plate make alignment other plate place glued everything correct glue place wings can used align wing rod tubes fuselage Use stab bellcrank mounting wires line up tubes before add top spar root sheeting After clamping lightly final stab sheet place align stab mounting wires carefully use instant glue permanently attach sheeting view wing root shows spoiler servo mount ballast tube front spar tube forthe Thermal Snifflers antenna Note Graupner-type wing hold-down others workable 26 Model Aviation riula piy oreaim Draces competition good results Merlyn can flown too slow wont entirely obvious except stopwatch Keep speed groovy~ area best performanceto produce normal slide Spot landings require planning 8-lbyour normal landing pattern can fooled airplane much wing will difficult toThe Merlyn will farther away moving plant firmly Ground effect mass conspirefaster think might want substitute own favorite spoiler drive mechanics shown lust make sure its strong positive spoiler servo should slide out easily hatch cover holds tThough Merlyns size much ditterent Sagitta author notes place Flange around hole 1/16 plysimilarity proportionseach designed independently other December 1981 27 spoiler servo sits between wing rod tube main spar opumiur rnvu i cessible bottom Note tube tne servo wires cut away avoid rough edges chafe wire servo pushrod shown place surethatthe pushrod doesnt bind against spar bellcrank moves
Edition: Model Aviation - 1981/12
Page Numbers: 20, 21, 22, 23, 24, 25, 26, 27
NO OCR TEXT NO OCR TEXT range airfoils LID values range 18 thick highly-cambered airfoils 24 lowcambered ones Table 1 describes correc tions finite aspect ratios wing thick ness given chord airspeed airfoil increas ing aspect ratio will bring about increase LID Anyone has stretched span model changing airfoil chord weight least much will know relation ship true Also note other things being equal thicker airfoils tend have lower LIDs What happens design around areabased rules like FAI rather span given area increase aspect ratio brings about reduction average chord wing therefore lower Reynolds Number given airspeed Reynolds Number can considered measure scale effect range airspeed also measure relative efficiency Indeed data paper S J Miley demonstrates increase LID Reynolds Numbers upto about 1000000 Using values LID vs Reynolds Number Miley paper correction factor Table 1 maximum value possible LID can cal culated values shown Table 2 various configurations Again keep mind maximum possible LID values will reality less due wing tip losses fuselage drag surface imperfections ever definite trend becomes apparent sufficient increase wing chord can definitely outweigh advantages high aspect ratio Minimum sinking speed also depends wing loading camber aspect ratio Table 3 would seem favor higher aspect ratios However same wing area would very difficult build high aspect ratio aircraft same wing loadings low aspect ratio though feel existing planform near optimum refinements wing tip shape fillets airfoils can still made Merlyn large enough carry instrumentation capable measuring effect design refinements Budder horn made fr, ince Merlyn operating higher Reynolds stock Note blending fuse fin lots Numbers lower lift coefficients suspect sanding means less nose weight needed significant improvements could come inermaionijieriseplybrackets p plate behind Snirner tor cam-bc canopy hold-down 0-cells for4 amps . ing times 16 hours possible Forward end thefuselagesldesshowthetoughbutlightconstmctionIn rear 1/4-in square balsa braces added prevent splitting spruce longeron 1/4-in ply top brace triangle stockThey beveled fit top bottom triangle pieces Wing root area top bulkheads place Note theThis view shows wing root area after top block place box wing tod tube located underthe plytop brace thespoiler servo wiring goes first glass tube second spruce longeron butts up agalns itspare large tube wing rods 22 Model Aviation BALSA TEANDLE OFFiN 3/s SQ STABLIZER1/8 SHEET BALSA 3/BADRILLROOFROM KEN BATESROOT RIB FRAMESSIDES OFFiN BASE3/B SOBALSARUOCER FACES ON HINGE POSiS 1/J/13/8X 3/32 BALSA RIBS 125 DIAMJSIC WIRE7 BALLAST TUBE OPT1ONAL3/BSHEEr FIN FAIRING CLAMP ROD C/S ONLY/2 BALSA BLOCKS VBI D BRASSBALSA BLOCK FAIRINGS VI6PLYVJCCO5/32COLLAR ALLOWS ELIMOL 5/B BALSA BLOCK WITH PLYSKID CLBLER ASBEAI SNIFFER TUBE HOOKS AND BANDSI/B UTE-PLY SICES AFT OF SPliCEL 2 THEWAAL SNIFFER INSTAL CANOPY IS BALSA ROCKI/B BIRO-I PLYWOOD SIDES FWD OF SICE -3/32SHEET BALSA TEl P/ROTFOMELEVATOR PUSHROD TAB-U WING ARTCOMPRESSED TOGETITALL IN-HC --S I/4BARIB 3/32 X 1/4 BALSA CAPSTRPS TOPAND YflOM ALL RIBS PLASTiC 1 I-KDK -- BALSA --TEFILLERS DOWELS 10 LOCATE CANOPY.- BRAS5 TIJBE TOP2BALSA~R Bi I/BPIYWOOD%EN ---- WOODBALSA TOPSAME FOR 82-3AND BOTTOMWEBS END HERE LOW NOSENOSE BLOCK BLOCK 3/32 SHEEV BALSAVBX 1/4 SPRUCE V4 PLYWOOD FORMS AT JOINTLE SKIN FULL SPANSPAR TCP ONLY TO END OF SPOILER3/850 BALSA OF FUSELAGE AND CANOPYLEFULL N 1/4K 1/2 SPRUCE 1/4K 1/2 SPRUCE1/2 BALSA TRIAN3LESPARS TOPAND BOTTOM PiT RAILBOlTOM CORNERS FULLLENGTUREINFORCING FROM3/B BALSA SPOILER ADE WITH -ROOT TO BELLCRANKPUSH ROD-TOBELLCRANKANDSBWOL16 PLYWOOD JOINS WING SPARS I/B WEBS FROM SPOILER OUTWARD 3BRIRPW EBOP 0 3 WIWIT BBSWROk RLL RIBS 10 W B MLSA RIIcRPT RIB O tRY BA BR 83 NEAR TRIMRWART PInUP ORB TT -4WLRff1R-- BALSA RLRSRROT NBYBRIRUTB RI I--4i-VRRTRBRRRERTCRBB RSECTION 0-B SPEAR CROCIIII -ml CR10 BROSSILBOtB IL YUBA SBPR PLUSIIIXIA SOBER DU1RR3WRRS ORIj-BR BAlSAIBXRI1BI II CrOP B ROT COPUSTIBB W4Y IBPBv~PAIPAp IIIIII Ii II I Ii I II LII RWROT WUOB 00 ICC 8150 OBhIRT PBJURB BAlSa WIll RIRASS TORITRPRROC BR SQ BALSABAlSA FILSOR lEERPRL WOO BRORT B 1pBRAISS R00C1 ASSRRBAVP45AlERt ROALWOIS BAl BALSA %SIIRAT BALSA BLURBAR IRABROC SBCTORR OB A 54 BALSA BlOCK BALLRRWR/SPRIER PARER 51501 RTOR P0044000k RLLRAP&W4L~z1 PR TO BRASS IA RANSULAR WA R75450IIPREPI -BRA o RPQDy PS WA ARISE WARBALSA SECTION A-AcRUSIIINA TULYUR0RAL FORMER U PLY[1 airfoils normally considered Design game compromise have designed Merlyn according preferences handling indications higher possible efficiency Obviously constrained PAl size limits could better using higher aspect ratio wing same chord However World Record attempts Great Race rules cross-country events require compliance FAI rules also prefer structural integrity inherent such configuration Merlyn very rugged aircraft very encouraging paying wood Construction Merlyn builders beginners difficult cheap no glue Part Part B instructions need dont build general style construction follows Airtronics Aquila structure well-proven well engineered will glad correspond ModelAviation have problem forewarned love talk about airplanes especially Remember airplane size Reynolds Number much larger normal Thus 8-lb Merlyn floater 10-lb Merlyn flies authority Built plans Merlyn should weight 10 lb Modifications described later allow build Merlyn all-up weight about 8 lb Please note since tip panel 36 long trailing edge sheet 37 long Use 4ft wood extra goes roof area Rocket City towhook reliable size Sailplane wrap link wire solder towhook shown plans 24 Model Aviation Airfoil Thickness % chordAspect RatioL/D Maximum Correction Factor2 10%litol17to185% 10%16to1l8tol90% 10%2Otoll9tol95% 13%l6toll7tol85% 13%20to 1175 1875% Table 2 effect Reynolds Number maximum possible L/D various designs 15mph airspeed1 AreaAspect%AverageRN atMax L/D sq inRatioThickness DesignChord15mphPossible2 21001110Merlyn138 in17300038 2100161011Sin 14400035 210020101025 in12800034 2100161311Sin 14400033 210020131025in 12800031 137016613Astro Jeff90 in11300028 Note data Table 1 paper S J Miley titled Design Air foils Low Reynolds Numbers published Massachusetts Institute Technolo gy Proceedings Second International Symposium Technology Science Low-speed Motoriess Flight Note 2 table results data indicating maximum L/D infinite aspect ratios various airfoils functioning Reynolds Number applying correc tion factor Table 1 various aspect ratios thicknesses Table 1 Maximum possible LID various thicknesses flat-bottom air foils Reynolds Number about 500001 Note data article Heinz G Struck Optimum Aspect Ratios RC Sailplanes RCModeier February 1976 Note 2 Percentage compared L/D 20 Reynolds Number 0 infinite aspect ratio FULLSIZEPLANSAVAILABLE E PAGE 140 A- 501 C0-4~ A 0551 GROIN FBI ISBN 31 0B0~Nt 55 BALSA SOOtY TO 55 BALSA NOFRO GOON 151 0Y 80050 ALBCC 005 S00IrA 000~ Frv SSNWA40005NY 0000BL 0 PLY BBLSB BLOCK SBCLLA LBLA%ONA 800505505K BALSAAS SGOBBA ALLOt PLYSYAaAtt RIOGROBBOB-NOLSA BLJ 050030000 --- S NOLBALL BOOLA SOLO PLY OBLY IS 30 SPOOL 300 0004 SPROCA50580 00 OuSAL0G$ AT AUTO PLY OBTOLO AOLJLSYABW OR 005030 BALAKSO YPOS 4000 MAY 80 05W MEN LYN OKORINEBO PRAWN BY SON BOlES -NOW BY Nat Design No 1 Merlyn 10% thickDesign No 22 13% thick airfoil 11 1 ARairfoil 20 1 AR Wing LoadingSinking SpeedWing LoadingSinking Speed ozIsq ft ec ozIsq ft ec 5 111 6119 71287102 81378108 91449115 10121 11127 12133 made aluminum T extrusion purchased local hardware store rearward location preferred 12-volt winch launches weaker winch hi-start i-in rubber would use forward location Please use heavy duty servos 10-lb cross-country Merlyn KPS-15s would good plane can get up 90 mph return downwind putting Quarter Scale power category radio compartment sized four D-size ni-cd cells 4 amp/hour balance bird give about 16 hours operation canopy balsa block have almost never entirely successful gluing blasted plastic canopies straight always get glue wrong place Besides like carve wood comments hear about Merlyn carving Carving fun have right tools project pieces wood large try sharp block plane use Stanley 9 Razor planes have uses big cuts Disston Company makes neat tool called Abrader works like rasp better Abraders really chew wood dont load up leave much better surface final sanding using two tools band saw blank out canopy block entire shaping takes 45 minutes less original Merlyn used blade-type wing joiner Sailplane Factory PO Box 341 Red Lion PA 17356 has heavy duty 14mm blade blade holder brass sleeve can used also have suitable stab bellcrank sake keeping home shop project now use h-in drill rod rod has heat-treated follows austenitize oil quench temper Rockwell C Scale 4245 can get done local heattreatment shop finished wing rod can obtained $500 Ken Bates 738 N Harris St Saline MI 48176 specifications very important Too hard will brittle source doesnt understand dont take chance Make sure rod tempered hardness Rockwell C Scale 42 45 Several variations structure have successfully used have built three Merlyns have used ribs 1/16th tips have also substituted arbon fiber spar Flite-spar Wing sheeting 1/16 balsa tried proved too prone hangar rash Another substitution tct use narrower stock tail surface trailing edges * x i light thermal machine rather rugged cross-country bird desire substitute Lite Ply nose sides bottom a tail boom sides bottom spoiler system shown construction photos new attempt has proven have favorite method use December1981 25 Table 3 effect wing loadings calculated sinking speeds two designs operating Reynolds Numbers around 500001 Note 1 same source table 1 some interpolation necessary Note 2 Hypothetical design optimized lowest minimum sinking speed General Note Reynolds Number calculations done using shortened formula Model Glider Design Frank Zaic RN 0 x chord feet x mph Miller Mod-type bottom leading edge sheet option used prototype feel modification made better handling high speeds prefer flat-bottom airfoil Pre cision Duration work thing worse crooked airplane great big expensive crooked airplane make stab bellcrank first can used space stab wire tubes correctly build fin can use stab align bellcrank pivot bushings First glue Lite Ply stab plate make alignment other plate place glued everything correct glue place wings can used align wing rod tubes fuselage Use stab bellcrank mounting wires line up tubes before add top spar root sheeting After clamping lightly final stab sheet place align stab mounting wires carefully use instant glue permanently attach sheeting view wing root shows spoiler servo mount ballast tube front spar tube forthe Thermal Snifflers antenna Note Graupner-type wing hold-down others workable 26 Model Aviation riula piy oreaim Draces competition good results Merlyn can flown too slow wont entirely obvious except stopwatch Keep speed groovy~ area best performanceto produce normal slide Spot landings require planning 8-lbyour normal landing pattern can fooled airplane much wing will difficult toThe Merlyn will farther away moving plant firmly Ground effect mass conspirefaster think might want substitute own favorite spoiler drive mechanics shown lust make sure its strong positive spoiler servo should slide out easily hatch cover holds tThough Merlyns size much ditterent Sagitta author notes place Flange around hole 1/16 plysimilarity proportionseach designed independently other December 1981 27 spoiler servo sits between wing rod tube main spar opumiur rnvu i cessible bottom Note tube tne servo wires cut away avoid rough edges chafe wire servo pushrod shown place surethatthe pushrod doesnt bind against spar bellcrank moves
Edition: Model Aviation - 1981/12
Page Numbers: 20, 21, 22, 23, 24, 25, 26, 27
NO OCR TEXT NO OCR TEXT range airfoils LID values range 18 thick highly-cambered airfoils 24 lowcambered ones Table 1 describes correc tions finite aspect ratios wing thick ness given chord airspeed airfoil increas ing aspect ratio will bring about increase LID Anyone has stretched span model changing airfoil chord weight least much will know relation ship true Also note other things being equal thicker airfoils tend have lower LIDs What happens design around areabased rules like FAI rather span given area increase aspect ratio brings about reduction average chord wing therefore lower Reynolds Number given airspeed Reynolds Number can considered measure scale effect range airspeed also measure relative efficiency Indeed data paper S J Miley demonstrates increase LID Reynolds Numbers upto about 1000000 Using values LID vs Reynolds Number Miley paper correction factor Table 1 maximum value possible LID can cal culated values shown Table 2 various configurations Again keep mind maximum possible LID values will reality less due wing tip losses fuselage drag surface imperfections ever definite trend becomes apparent sufficient increase wing chord can definitely outweigh advantages high aspect ratio Minimum sinking speed also depends wing loading camber aspect ratio Table 3 would seem favor higher aspect ratios However same wing area would very difficult build high aspect ratio aircraft same wing loadings low aspect ratio though feel existing planform near optimum refinements wing tip shape fillets airfoils can still made Merlyn large enough carry instrumentation capable measuring effect design refinements Budder horn made fr, ince Merlyn operating higher Reynolds stock Note blending fuse fin lots Numbers lower lift coefficients suspect sanding means less nose weight needed significant improvements could come inermaionijieriseplybrackets p plate behind Snirner tor cam-bc canopy hold-down 0-cells for4 amps . ing times 16 hours possible Forward end thefuselagesldesshowthetoughbutlightconstmctionIn rear 1/4-in square balsa braces added prevent splitting spruce longeron 1/4-in ply top brace triangle stockThey beveled fit top bottom triangle pieces Wing root area top bulkheads place Note theThis view shows wing root area after top block place box wing tod tube located underthe plytop brace thespoiler servo wiring goes first glass tube second spruce longeron butts up agalns itspare large tube wing rods 22 Model Aviation BALSA TEANDLE OFFiN 3/s SQ STABLIZER1/8 SHEET BALSA 3/BADRILLROOFROM KEN BATESROOT RIB FRAMESSIDES OFFiN BASE3/B SOBALSARUOCER FACES ON HINGE POSiS 1/J/13/8X 3/32 BALSA RIBS 125 DIAMJSIC WIRE7 BALLAST TUBE OPT1ONAL3/BSHEEr FIN FAIRING CLAMP ROD C/S ONLY/2 BALSA BLOCKS VBI D BRASSBALSA BLOCK FAIRINGS VI6PLYVJCCO5/32COLLAR ALLOWS ELIMOL 5/B BALSA BLOCK WITH PLYSKID CLBLER ASBEAI SNIFFER TUBE HOOKS AND BANDSI/B UTE-PLY SICES AFT OF SPliCEL 2 THEWAAL SNIFFER INSTAL CANOPY IS BALSA ROCKI/B BIRO-I PLYWOOD SIDES FWD OF SICE -3/32SHEET BALSA TEl P/ROTFOMELEVATOR PUSHROD TAB-U WING ARTCOMPRESSED TOGETITALL IN-HC --S I/4BARIB 3/32 X 1/4 BALSA CAPSTRPS TOPAND YflOM ALL RIBS PLASTiC 1 I-KDK -- BALSA --TEFILLERS DOWELS 10 LOCATE CANOPY.- BRAS5 TIJBE TOP2BALSA~R Bi I/BPIYWOOD%EN ---- WOODBALSA TOPSAME FOR 82-3AND BOTTOMWEBS END HERE LOW NOSENOSE BLOCK BLOCK 3/32 SHEEV BALSAVBX 1/4 SPRUCE V4 PLYWOOD FORMS AT JOINTLE SKIN FULL SPANSPAR TCP ONLY TO END OF SPOILER3/850 BALSA OF FUSELAGE AND CANOPYLEFULL N 1/4K 1/2 SPRUCE 1/4K 1/2 SPRUCE1/2 BALSA TRIAN3LESPARS TOPAND BOTTOM PiT RAILBOlTOM CORNERS FULLLENGTUREINFORCING FROM3/B BALSA SPOILER ADE WITH -ROOT TO BELLCRANKPUSH ROD-TOBELLCRANKANDSBWOL16 PLYWOOD JOINS WING SPARS I/B WEBS FROM SPOILER OUTWARD 3BRIRPW EBOP 0 3 WIWIT BBSWROk RLL RIBS 10 W B MLSA RIIcRPT RIB O tRY BA BR 83 NEAR TRIMRWART PInUP ORB TT -4WLRff1R-- BALSA RLRSRROT NBYBRIRUTB RI I--4i-VRRTRBRRRERTCRBB RSECTION 0-B SPEAR CROCIIII -ml CR10 BROSSILBOtB IL YUBA SBPR PLUSIIIXIA SOBER DU1RR3WRRS ORIj-BR BAlSAIBXRI1BI II CrOP B ROT COPUSTIBB W4Y IBPBv~PAIPAp IIIIII Ii II I Ii I II LII RWROT WUOB 00 ICC 8150 OBhIRT PBJURB BAlSa WIll RIRASS TORITRPRROC BR SQ BALSABAlSA FILSOR lEERPRL WOO BRORT B 1pBRAISS R00C1 ASSRRBAVP45AlERt ROALWOIS BAl BALSA %SIIRAT BALSA BLURBAR IRABROC SBCTORR OB A 54 BALSA BlOCK BALLRRWR/SPRIER PARER 51501 RTOR P0044000k RLLRAP&W4L~z1 PR TO BRASS IA RANSULAR WA R75450IIPREPI -BRA o RPQDy PS WA ARISE WARBALSA SECTION A-AcRUSIIINA TULYUR0RAL FORMER U PLY[1 airfoils normally considered Design game compromise have designed Merlyn according preferences handling indications higher possible efficiency Obviously constrained PAl size limits could better using higher aspect ratio wing same chord However World Record attempts Great Race rules cross-country events require compliance FAI rules also prefer structural integrity inherent such configuration Merlyn very rugged aircraft very encouraging paying wood Construction Merlyn builders beginners difficult cheap no glue Part Part B instructions need dont build general style construction follows Airtronics Aquila structure well-proven well engineered will glad correspond ModelAviation have problem forewarned love talk about airplanes especially Remember airplane size Reynolds Number much larger normal Thus 8-lb Merlyn floater 10-lb Merlyn flies authority Built plans Merlyn should weight 10 lb Modifications described later allow build Merlyn all-up weight about 8 lb Please note since tip panel 36 long trailing edge sheet 37 long Use 4ft wood extra goes roof area Rocket City towhook reliable size Sailplane wrap link wire solder towhook shown plans 24 Model Aviation Airfoil Thickness % chordAspect RatioL/D Maximum Correction Factor2 10%litol17to185% 10%16to1l8tol90% 10%2Otoll9tol95% 13%l6toll7tol85% 13%20to 1175 1875% Table 2 effect Reynolds Number maximum possible L/D various designs 15mph airspeed1 AreaAspect%AverageRN atMax L/D sq inRatioThickness DesignChord15mphPossible2 21001110Merlyn138 in17300038 2100161011Sin 14400035 210020101025 in12800034 2100161311Sin 14400033 210020131025in 12800031 137016613Astro Jeff90 in11300028 Note data Table 1 paper S J Miley titled Design Air foils Low Reynolds Numbers published Massachusetts Institute Technolo gy Proceedings Second International Symposium Technology Science Low-speed Motoriess Flight Note 2 table results data indicating maximum L/D infinite aspect ratios various airfoils functioning Reynolds Number applying correc tion factor Table 1 various aspect ratios thicknesses Table 1 Maximum possible LID various thicknesses flat-bottom air foils Reynolds Number about 500001 Note data article Heinz G Struck Optimum Aspect Ratios RC Sailplanes RCModeier February 1976 Note 2 Percentage compared L/D 20 Reynolds Number 0 infinite aspect ratio FULLSIZEPLANSAVAILABLE E PAGE 140 A- 501 C0-4~ A 0551 GROIN FBI ISBN 31 0B0~Nt 55 BALSA SOOtY TO 55 BALSA NOFRO GOON 151 0Y 80050 ALBCC 005 S00IrA 000~ Frv SSNWA40005NY 0000BL 0 PLY BBLSB BLOCK SBCLLA LBLA%ONA 800505505K BALSAAS SGOBBA ALLOt PLYSYAaAtt RIOGROBBOB-NOLSA BLJ 050030000 --- S NOLBALL BOOLA SOLO PLY OBLY IS 30 SPOOL 300 0004 SPROCA50580 00 OuSAL0G$ AT AUTO PLY OBTOLO AOLJLSYABW OR 005030 BALAKSO YPOS 4000 MAY 80 05W MEN LYN OKORINEBO PRAWN BY SON BOlES -NOW BY Nat Design No 1 Merlyn 10% thickDesign No 22 13% thick airfoil 11 1 ARairfoil 20 1 AR Wing LoadingSinking SpeedWing LoadingSinking Speed ozIsq ft ec ozIsq ft ec 5 111 6119 71287102 81378108 91449115 10121 11127 12133 made aluminum T extrusion purchased local hardware store rearward location preferred 12-volt winch launches weaker winch hi-start i-in rubber would use forward location Please use heavy duty servos 10-lb cross-country Merlyn KPS-15s would good plane can get up 90 mph return downwind putting Quarter Scale power category radio compartment sized four D-size ni-cd cells 4 amp/hour balance bird give about 16 hours operation canopy balsa block have almost never entirely successful gluing blasted plastic canopies straight always get glue wrong place Besides like carve wood comments hear about Merlyn carving Carving fun have right tools project pieces wood large try sharp block plane use Stanley 9 Razor planes have uses big cuts Disston Company makes neat tool called Abrader works like rasp better Abraders really chew wood dont load up leave much better surface final sanding using two tools band saw blank out canopy block entire shaping takes 45 minutes less original Merlyn used blade-type wing joiner Sailplane Factory PO Box 341 Red Lion PA 17356 has heavy duty 14mm blade blade holder brass sleeve can used also have suitable stab bellcrank sake keeping home shop project now use h-in drill rod rod has heat-treated follows austenitize oil quench temper Rockwell C Scale 4245 can get done local heattreatment shop finished wing rod can obtained $500 Ken Bates 738 N Harris St Saline MI 48176 specifications very important Too hard will brittle source doesnt understand dont take chance Make sure rod tempered hardness Rockwell C Scale 42 45 Several variations structure have successfully used have built three Merlyns have used ribs 1/16th tips have also substituted arbon fiber spar Flite-spar Wing sheeting 1/16 balsa tried proved too prone hangar rash Another substitution tct use narrower stock tail surface trailing edges * x i light thermal machine rather rugged cross-country bird desire substitute Lite Ply nose sides bottom a tail boom sides bottom spoiler system shown construction photos new attempt has proven have favorite method use December1981 25 Table 3 effect wing loadings calculated sinking speeds two designs operating Reynolds Numbers around 500001 Note 1 same source table 1 some interpolation necessary Note 2 Hypothetical design optimized lowest minimum sinking speed General Note Reynolds Number calculations done using shortened formula Model Glider Design Frank Zaic RN 0 x chord feet x mph Miller Mod-type bottom leading edge sheet option used prototype feel modification made better handling high speeds prefer flat-bottom airfoil Pre cision Duration work thing worse crooked airplane great big expensive crooked airplane make stab bellcrank first can used space stab wire tubes correctly build fin can use stab align bellcrank pivot bushings First glue Lite Ply stab plate make alignment other plate place glued everything correct glue place wings can used align wing rod tubes fuselage Use stab bellcrank mounting wires line up tubes before add top spar root sheeting After clamping lightly final stab sheet place align stab mounting wires carefully use instant glue permanently attach sheeting view wing root shows spoiler servo mount ballast tube front spar tube forthe Thermal Snifflers antenna Note Graupner-type wing hold-down others workable 26 Model Aviation riula piy oreaim Draces competition good results Merlyn can flown too slow wont entirely obvious except stopwatch Keep speed groovy~ area best performanceto produce normal slide Spot landings require planning 8-lbyour normal landing pattern can fooled airplane much wing will difficult toThe Merlyn will farther away moving plant firmly Ground effect mass conspirefaster think might want substitute own favorite spoiler drive mechanics shown lust make sure its strong positive spoiler servo should slide out easily hatch cover holds tThough Merlyns size much ditterent Sagitta author notes place Flange around hole 1/16 plysimilarity proportionseach designed independently other December 1981 27 spoiler servo sits between wing rod tube main spar opumiur rnvu i cessible bottom Note tube tne servo wires cut away avoid rough edges chafe wire servo pushrod shown place surethatthe pushrod doesnt bind against spar bellcrank moves
Edition: Model Aviation - 1981/12
Page Numbers: 20, 21, 22, 23, 24, 25, 26, 27
NO OCR TEXT NO OCR TEXT range airfoils LID values range 18 thick highly-cambered airfoils 24 lowcambered ones Table 1 describes correc tions finite aspect ratios wing thick ness given chord airspeed airfoil increas ing aspect ratio will bring about increase LID Anyone has stretched span model changing airfoil chord weight least much will know relation ship true Also note other things being equal thicker airfoils tend have lower LIDs What happens design around areabased rules like FAI rather span given area increase aspect ratio brings about reduction average chord wing therefore lower Reynolds Number given airspeed Reynolds Number can considered measure scale effect range airspeed also measure relative efficiency Indeed data paper S J Miley demonstrates increase LID Reynolds Numbers upto about 1000000 Using values LID vs Reynolds Number Miley paper correction factor Table 1 maximum value possible LID can cal culated values shown Table 2 various configurations Again keep mind maximum possible LID values will reality less due wing tip losses fuselage drag surface imperfections ever definite trend becomes apparent sufficient increase wing chord can definitely outweigh advantages high aspect ratio Minimum sinking speed also depends wing loading camber aspect ratio Table 3 would seem favor higher aspect ratios However same wing area would very difficult build high aspect ratio aircraft same wing loadings low aspect ratio though feel existing planform near optimum refinements wing tip shape fillets airfoils can still made Merlyn large enough carry instrumentation capable measuring effect design refinements Budder horn made fr, ince Merlyn operating higher Reynolds stock Note blending fuse fin lots Numbers lower lift coefficients suspect sanding means less nose weight needed significant improvements could come inermaionijieriseplybrackets p plate behind Snirner tor cam-bc canopy hold-down 0-cells for4 amps . ing times 16 hours possible Forward end thefuselagesldesshowthetoughbutlightconstmctionIn rear 1/4-in square balsa braces added prevent splitting spruce longeron 1/4-in ply top brace triangle stockThey beveled fit top bottom triangle pieces Wing root area top bulkheads place Note theThis view shows wing root area after top block place box wing tod tube located underthe plytop brace thespoiler servo wiring goes first glass tube second spruce longeron butts up agalns itspare large tube wing rods 22 Model Aviation BALSA TEANDLE OFFiN 3/s SQ STABLIZER1/8 SHEET BALSA 3/BADRILLROOFROM KEN BATESROOT RIB FRAMESSIDES OFFiN BASE3/B SOBALSARUOCER FACES ON HINGE POSiS 1/J/13/8X 3/32 BALSA RIBS 125 DIAMJSIC WIRE7 BALLAST TUBE OPT1ONAL3/BSHEEr FIN FAIRING CLAMP ROD C/S ONLY/2 BALSA BLOCKS VBI D BRASSBALSA BLOCK FAIRINGS VI6PLYVJCCO5/32COLLAR ALLOWS ELIMOL 5/B BALSA BLOCK WITH PLYSKID CLBLER ASBEAI SNIFFER TUBE HOOKS AND BANDSI/B UTE-PLY SICES AFT OF SPliCEL 2 THEWAAL SNIFFER INSTAL CANOPY IS BALSA ROCKI/B BIRO-I PLYWOOD SIDES FWD OF SICE -3/32SHEET BALSA TEl P/ROTFOMELEVATOR PUSHROD TAB-U WING ARTCOMPRESSED TOGETITALL IN-HC --S I/4BARIB 3/32 X 1/4 BALSA CAPSTRPS TOPAND YflOM ALL RIBS PLASTiC 1 I-KDK -- BALSA --TEFILLERS DOWELS 10 LOCATE CANOPY.- BRAS5 TIJBE TOP2BALSA~R Bi I/BPIYWOOD%EN ---- WOODBALSA TOPSAME FOR 82-3AND BOTTOMWEBS END HERE LOW NOSENOSE BLOCK BLOCK 3/32 SHEEV BALSAVBX 1/4 SPRUCE V4 PLYWOOD FORMS AT JOINTLE SKIN FULL SPANSPAR TCP ONLY TO END OF SPOILER3/850 BALSA OF FUSELAGE AND CANOPYLEFULL N 1/4K 1/2 SPRUCE 1/4K 1/2 SPRUCE1/2 BALSA TRIAN3LESPARS TOPAND BOTTOM PiT RAILBOlTOM CORNERS FULLLENGTUREINFORCING FROM3/B BALSA SPOILER ADE WITH -ROOT TO BELLCRANKPUSH ROD-TOBELLCRANKANDSBWOL16 PLYWOOD JOINS WING SPARS I/B WEBS FROM SPOILER OUTWARD 3BRIRPW EBOP 0 3 WIWIT BBSWROk RLL RIBS 10 W B MLSA RIIcRPT RIB O tRY BA BR 83 NEAR TRIMRWART PInUP ORB TT -4WLRff1R-- BALSA RLRSRROT NBYBRIRUTB RI I--4i-VRRTRBRRRERTCRBB RSECTION 0-B SPEAR CROCIIII -ml CR10 BROSSILBOtB IL YUBA SBPR PLUSIIIXIA SOBER DU1RR3WRRS ORIj-BR BAlSAIBXRI1BI II CrOP B ROT COPUSTIBB W4Y IBPBv~PAIPAp IIIIII Ii II I Ii I II LII RWROT WUOB 00 ICC 8150 OBhIRT PBJURB BAlSa WIll RIRASS TORITRPRROC BR SQ BALSABAlSA FILSOR lEERPRL WOO BRORT B 1pBRAISS R00C1 ASSRRBAVP45AlERt ROALWOIS BAl BALSA %SIIRAT BALSA BLURBAR IRABROC SBCTORR OB A 54 BALSA BlOCK BALLRRWR/SPRIER PARER 51501 RTOR P0044000k RLLRAP&W4L~z1 PR TO BRASS IA RANSULAR WA R75450IIPREPI -BRA o RPQDy PS WA ARISE WARBALSA SECTION A-AcRUSIIINA TULYUR0RAL FORMER U PLY[1 airfoils normally considered Design game compromise have designed Merlyn according preferences handling indications higher possible efficiency Obviously constrained PAl size limits could better using higher aspect ratio wing same chord However World Record attempts Great Race rules cross-country events require compliance FAI rules also prefer structural integrity inherent such configuration Merlyn very rugged aircraft very encouraging paying wood Construction Merlyn builders beginners difficult cheap no glue Part Part B instructions need dont build general style construction follows Airtronics Aquila structure well-proven well engineered will glad correspond ModelAviation have problem forewarned love talk about airplanes especially Remember airplane size Reynolds Number much larger normal Thus 8-lb Merlyn floater 10-lb Merlyn flies authority Built plans Merlyn should weight 10 lb Modifications described later allow build Merlyn all-up weight about 8 lb Please note since tip panel 36 long trailing edge sheet 37 long Use 4ft wood extra goes roof area Rocket City towhook reliable size Sailplane wrap link wire solder towhook shown plans 24 Model Aviation Airfoil Thickness % chordAspect RatioL/D Maximum Correction Factor2 10%litol17to185% 10%16to1l8tol90% 10%2Otoll9tol95% 13%l6toll7tol85% 13%20to 1175 1875% Table 2 effect Reynolds Number maximum possible L/D various designs 15mph airspeed1 AreaAspect%AverageRN atMax L/D sq inRatioThickness DesignChord15mphPossible2 21001110Merlyn138 in17300038 2100161011Sin 14400035 210020101025 in12800034 2100161311Sin 14400033 210020131025in 12800031 137016613Astro Jeff90 in11300028 Note data Table 1 paper S J Miley titled Design Air foils Low Reynolds Numbers published Massachusetts Institute Technolo gy Proceedings Second International Symposium Technology Science Low-speed Motoriess Flight Note 2 table results data indicating maximum L/D infinite aspect ratios various airfoils functioning Reynolds Number applying correc tion factor Table 1 various aspect ratios thicknesses Table 1 Maximum possible LID various thicknesses flat-bottom air foils Reynolds Number about 500001 Note data article Heinz G Struck Optimum Aspect Ratios RC Sailplanes RCModeier February 1976 Note 2 Percentage compared L/D 20 Reynolds Number 0 infinite aspect ratio FULLSIZEPLANSAVAILABLE E PAGE 140 A- 501 C0-4~ A 0551 GROIN FBI ISBN 31 0B0~Nt 55 BALSA SOOtY TO 55 BALSA NOFRO GOON 151 0Y 80050 ALBCC 005 S00IrA 000~ Frv SSNWA40005NY 0000BL 0 PLY BBLSB BLOCK SBCLLA LBLA%ONA 800505505K BALSAAS SGOBBA ALLOt PLYSYAaAtt RIOGROBBOB-NOLSA BLJ 050030000 --- S NOLBALL BOOLA SOLO PLY OBLY IS 30 SPOOL 300 0004 SPROCA50580 00 OuSAL0G$ AT AUTO PLY OBTOLO AOLJLSYABW OR 005030 BALAKSO YPOS 4000 MAY 80 05W MEN LYN OKORINEBO PRAWN BY SON BOlES -NOW BY Nat Design No 1 Merlyn 10% thickDesign No 22 13% thick airfoil 11 1 ARairfoil 20 1 AR Wing LoadingSinking SpeedWing LoadingSinking Speed ozIsq ft ec ozIsq ft ec 5 111 6119 71287102 81378108 91449115 10121 11127 12133 made aluminum T extrusion purchased local hardware store rearward location preferred 12-volt winch launches weaker winch hi-start i-in rubber would use forward location Please use heavy duty servos 10-lb cross-country Merlyn KPS-15s would good plane can get up 90 mph return downwind putting Quarter Scale power category radio compartment sized four D-size ni-cd cells 4 amp/hour balance bird give about 16 hours operation canopy balsa block have almost never entirely successful gluing blasted plastic canopies straight always get glue wrong place Besides like carve wood comments hear about Merlyn carving Carving fun have right tools project pieces wood large try sharp block plane use Stanley 9 Razor planes have uses big cuts Disston Company makes neat tool called Abrader works like rasp better Abraders really chew wood dont load up leave much better surface final sanding using two tools band saw blank out canopy block entire shaping takes 45 minutes less original Merlyn used blade-type wing joiner Sailplane Factory PO Box 341 Red Lion PA 17356 has heavy duty 14mm blade blade holder brass sleeve can used also have suitable stab bellcrank sake keeping home shop project now use h-in drill rod rod has heat-treated follows austenitize oil quench temper Rockwell C Scale 4245 can get done local heattreatment shop finished wing rod can obtained $500 Ken Bates 738 N Harris St Saline MI 48176 specifications very important Too hard will brittle source doesnt understand dont take chance Make sure rod tempered hardness Rockwell C Scale 42 45 Several variations structure have successfully used have built three Merlyns have used ribs 1/16th tips have also substituted arbon fiber spar Flite-spar Wing sheeting 1/16 balsa tried proved too prone hangar rash Another substitution tct use narrower stock tail surface trailing edges * x i light thermal machine rather rugged cross-country bird desire substitute Lite Ply nose sides bottom a tail boom sides bottom spoiler system shown construction photos new attempt has proven have favorite method use December1981 25 Table 3 effect wing loadings calculated sinking speeds two designs operating Reynolds Numbers around 500001 Note 1 same source table 1 some interpolation necessary Note 2 Hypothetical design optimized lowest minimum sinking speed General Note Reynolds Number calculations done using shortened formula Model Glider Design Frank Zaic RN 0 x chord feet x mph Miller Mod-type bottom leading edge sheet option used prototype feel modification made better handling high speeds prefer flat-bottom airfoil Pre cision Duration work thing worse crooked airplane great big expensive crooked airplane make stab bellcrank first can used space stab wire tubes correctly build fin can use stab align bellcrank pivot bushings First glue Lite Ply stab plate make alignment other plate place glued everything correct glue place wings can used align wing rod tubes fuselage Use stab bellcrank mounting wires line up tubes before add top spar root sheeting After clamping lightly final stab sheet place align stab mounting wires carefully use instant glue permanently attach sheeting view wing root shows spoiler servo mount ballast tube front spar tube forthe Thermal Snifflers antenna Note Graupner-type wing hold-down others workable 26 Model Aviation riula piy oreaim Draces competition good results Merlyn can flown too slow wont entirely obvious except stopwatch Keep speed groovy~ area best performanceto produce normal slide Spot landings require planning 8-lbyour normal landing pattern can fooled airplane much wing will difficult toThe Merlyn will farther away moving plant firmly Ground effect mass conspirefaster think might want substitute own favorite spoiler drive mechanics shown lust make sure its strong positive spoiler servo should slide out easily hatch cover holds tThough Merlyns size much ditterent Sagitta author notes place Flange around hole 1/16 plysimilarity proportionseach designed independently other December 1981 27 spoiler servo sits between wing rod tube main spar opumiur rnvu i cessible bottom Note tube tne servo wires cut away avoid rough edges chafe wire servo pushrod shown place surethatthe pushrod doesnt bind against spar bellcrank moves
Edition: Model Aviation - 1981/12
Page Numbers: 20, 21, 22, 23, 24, 25, 26, 27
NO OCR TEXT NO OCR TEXT range airfoils LID values range 18 thick highly-cambered airfoils 24 lowcambered ones Table 1 describes correc tions finite aspect ratios wing thick ness given chord airspeed airfoil increas ing aspect ratio will bring about increase LID Anyone has stretched span model changing airfoil chord weight least much will know relation ship true Also note other things being equal thicker airfoils tend have lower LIDs What happens design around areabased rules like FAI rather span given area increase aspect ratio brings about reduction average chord wing therefore lower Reynolds Number given airspeed Reynolds Number can considered measure scale effect range airspeed also measure relative efficiency Indeed data paper S J Miley demonstrates increase LID Reynolds Numbers upto about 1000000 Using values LID vs Reynolds Number Miley paper correction factor Table 1 maximum value possible LID can cal culated values shown Table 2 various configurations Again keep mind maximum possible LID values will reality less due wing tip losses fuselage drag surface imperfections ever definite trend becomes apparent sufficient increase wing chord can definitely outweigh advantages high aspect ratio Minimum sinking speed also depends wing loading camber aspect ratio Table 3 would seem favor higher aspect ratios However same wing area would very difficult build high aspect ratio aircraft same wing loadings low aspect ratio though feel existing planform near optimum refinements wing tip shape fillets airfoils can still made Merlyn large enough carry instrumentation capable measuring effect design refinements Budder horn made fr, ince Merlyn operating higher Reynolds stock Note blending fuse fin lots Numbers lower lift coefficients suspect sanding means less nose weight needed significant improvements could come inermaionijieriseplybrackets p plate behind Snirner tor cam-bc canopy hold-down 0-cells for4 amps . ing times 16 hours possible Forward end thefuselagesldesshowthetoughbutlightconstmctionIn rear 1/4-in square balsa braces added prevent splitting spruce longeron 1/4-in ply top brace triangle stockThey beveled fit top bottom triangle pieces Wing root area top bulkheads place Note theThis view shows wing root area after top block place box wing tod tube located underthe plytop brace thespoiler servo wiring goes first glass tube second spruce longeron butts up agalns itspare large tube wing rods 22 Model Aviation BALSA TEANDLE OFFiN 3/s SQ STABLIZER1/8 SHEET BALSA 3/BADRILLROOFROM KEN BATESROOT RIB FRAMESSIDES OFFiN BASE3/B SOBALSARUOCER FACES ON HINGE POSiS 1/J/13/8X 3/32 BALSA RIBS 125 DIAMJSIC WIRE7 BALLAST TUBE OPT1ONAL3/BSHEEr FIN FAIRING CLAMP ROD C/S ONLY/2 BALSA BLOCKS VBI D BRASSBALSA BLOCK FAIRINGS VI6PLYVJCCO5/32COLLAR ALLOWS ELIMOL 5/B BALSA BLOCK WITH PLYSKID CLBLER ASBEAI SNIFFER TUBE HOOKS AND BANDSI/B UTE-PLY SICES AFT OF SPliCEL 2 THEWAAL SNIFFER INSTAL CANOPY IS BALSA ROCKI/B BIRO-I PLYWOOD SIDES FWD OF SICE -3/32SHEET BALSA TEl P/ROTFOMELEVATOR PUSHROD TAB-U WING ARTCOMPRESSED TOGETITALL IN-HC --S I/4BARIB 3/32 X 1/4 BALSA CAPSTRPS TOPAND YflOM ALL RIBS PLASTiC 1 I-KDK -- BALSA --TEFILLERS DOWELS 10 LOCATE CANOPY.- BRAS5 TIJBE TOP2BALSA~R Bi I/BPIYWOOD%EN ---- WOODBALSA TOPSAME FOR 82-3AND BOTTOMWEBS END HERE LOW NOSENOSE BLOCK BLOCK 3/32 SHEEV BALSAVBX 1/4 SPRUCE V4 PLYWOOD FORMS AT JOINTLE SKIN FULL SPANSPAR TCP ONLY TO END OF SPOILER3/850 BALSA OF FUSELAGE AND CANOPYLEFULL N 1/4K 1/2 SPRUCE 1/4K 1/2 SPRUCE1/2 BALSA TRIAN3LESPARS TOPAND BOTTOM PiT RAILBOlTOM CORNERS FULLLENGTUREINFORCING FROM3/B BALSA SPOILER ADE WITH -ROOT TO BELLCRANKPUSH ROD-TOBELLCRANKANDSBWOL16 PLYWOOD JOINS WING SPARS I/B WEBS FROM SPOILER OUTWARD 3BRIRPW EBOP 0 3 WIWIT BBSWROk RLL RIBS 10 W B MLSA RIIcRPT RIB O tRY BA BR 83 NEAR TRIMRWART PInUP ORB TT -4WLRff1R-- BALSA RLRSRROT NBYBRIRUTB RI I--4i-VRRTRBRRRERTCRBB RSECTION 0-B SPEAR CROCIIII -ml CR10 BROSSILBOtB IL YUBA SBPR PLUSIIIXIA SOBER DU1RR3WRRS ORIj-BR BAlSAIBXRI1BI II CrOP B ROT COPUSTIBB W4Y IBPBv~PAIPAp IIIIII Ii II I Ii I II LII RWROT WUOB 00 ICC 8150 OBhIRT PBJURB BAlSa WIll RIRASS TORITRPRROC BR SQ BALSABAlSA FILSOR lEERPRL WOO BRORT B 1pBRAISS R00C1 ASSRRBAVP45AlERt ROALWOIS BAl BALSA %SIIRAT BALSA BLURBAR IRABROC SBCTORR OB A 54 BALSA BlOCK BALLRRWR/SPRIER PARER 51501 RTOR P0044000k RLLRAP&W4L~z1 PR TO BRASS IA RANSULAR WA R75450IIPREPI -BRA o RPQDy PS WA ARISE WARBALSA SECTION A-AcRUSIIINA TULYUR0RAL FORMER U PLY[1 airfoils normally considered Design game compromise have designed Merlyn according preferences handling indications higher possible efficiency Obviously constrained PAl size limits could better using higher aspect ratio wing same chord However World Record attempts Great Race rules cross-country events require compliance FAI rules also prefer structural integrity inherent such configuration Merlyn very rugged aircraft very encouraging paying wood Construction Merlyn builders beginners difficult cheap no glue Part Part B instructions need dont build general style construction follows Airtronics Aquila structure well-proven well engineered will glad correspond ModelAviation have problem forewarned love talk about airplanes especially Remember airplane size Reynolds Number much larger normal Thus 8-lb Merlyn floater 10-lb Merlyn flies authority Built plans Merlyn should weight 10 lb Modifications described later allow build Merlyn all-up weight about 8 lb Please note since tip panel 36 long trailing edge sheet 37 long Use 4ft wood extra goes roof area Rocket City towhook reliable size Sailplane wrap link wire solder towhook shown plans 24 Model Aviation Airfoil Thickness % chordAspect RatioL/D Maximum Correction Factor2 10%litol17to185% 10%16to1l8tol90% 10%2Otoll9tol95% 13%l6toll7tol85% 13%20to 1175 1875% Table 2 effect Reynolds Number maximum possible L/D various designs 15mph airspeed1 AreaAspect%AverageRN atMax L/D sq inRatioThickness DesignChord15mphPossible2 21001110Merlyn138 in17300038 2100161011Sin 14400035 210020101025 in12800034 2100161311Sin 14400033 210020131025in 12800031 137016613Astro Jeff90 in11300028 Note data Table 1 paper S J Miley titled Design Air foils Low Reynolds Numbers published Massachusetts Institute Technolo gy Proceedings Second International Symposium Technology Science Low-speed Motoriess Flight Note 2 table results data indicating maximum L/D infinite aspect ratios various airfoils functioning Reynolds Number applying correc tion factor Table 1 various aspect ratios thicknesses Table 1 Maximum possible LID various thicknesses flat-bottom air foils Reynolds Number about 500001 Note data article Heinz G Struck Optimum Aspect Ratios RC Sailplanes RCModeier February 1976 Note 2 Percentage compared L/D 20 Reynolds Number 0 infinite aspect ratio FULLSIZEPLANSAVAILABLE E PAGE 140 A- 501 C0-4~ A 0551 GROIN FBI ISBN 31 0B0~Nt 55 BALSA SOOtY TO 55 BALSA NOFRO GOON 151 0Y 80050 ALBCC 005 S00IrA 000~ Frv SSNWA40005NY 0000BL 0 PLY BBLSB BLOCK SBCLLA LBLA%ONA 800505505K BALSAAS SGOBBA ALLOt PLYSYAaAtt RIOGROBBOB-NOLSA BLJ 050030000 --- S NOLBALL BOOLA SOLO PLY OBLY IS 30 SPOOL 300 0004 SPROCA50580 00 OuSAL0G$ AT AUTO PLY OBTOLO AOLJLSYABW OR 005030 BALAKSO YPOS 4000 MAY 80 05W MEN LYN OKORINEBO PRAWN BY SON BOlES -NOW BY Nat Design No 1 Merlyn 10% thickDesign No 22 13% thick airfoil 11 1 ARairfoil 20 1 AR Wing LoadingSinking SpeedWing LoadingSinking Speed ozIsq ft ec ozIsq ft ec 5 111 6119 71287102 81378108 91449115 10121 11127 12133 made aluminum T extrusion purchased local hardware store rearward location preferred 12-volt winch launches weaker winch hi-start i-in rubber would use forward location Please use heavy duty servos 10-lb cross-country Merlyn KPS-15s would good plane can get up 90 mph return downwind putting Quarter Scale power category radio compartment sized four D-size ni-cd cells 4 amp/hour balance bird give about 16 hours operation canopy balsa block have almost never entirely successful gluing blasted plastic canopies straight always get glue wrong place Besides like carve wood comments hear about Merlyn carving Carving fun have right tools project pieces wood large try sharp block plane use Stanley 9 Razor planes have uses big cuts Disston Company makes neat tool called Abrader works like rasp better Abraders really chew wood dont load up leave much better surface final sanding using two tools band saw blank out canopy block entire shaping takes 45 minutes less original Merlyn used blade-type wing joiner Sailplane Factory PO Box 341 Red Lion PA 17356 has heavy duty 14mm blade blade holder brass sleeve can used also have suitable stab bellcrank sake keeping home shop project now use h-in drill rod rod has heat-treated follows austenitize oil quench temper Rockwell C Scale 4245 can get done local heattreatment shop finished wing rod can obtained $500 Ken Bates 738 N Harris St Saline MI 48176 specifications very important Too hard will brittle source doesnt understand dont take chance Make sure rod tempered hardness Rockwell C Scale 42 45 Several variations structure have successfully used have built three Merlyns have used ribs 1/16th tips have also substituted arbon fiber spar Flite-spar Wing sheeting 1/16 balsa tried proved too prone hangar rash Another substitution tct use narrower stock tail surface trailing edges * x i light thermal machine rather rugged cross-country bird desire substitute Lite Ply nose sides bottom a tail boom sides bottom spoiler system shown construction photos new attempt has proven have favorite method use December1981 25 Table 3 effect wing loadings calculated sinking speeds two designs operating Reynolds Numbers around 500001 Note 1 same source table 1 some interpolation necessary Note 2 Hypothetical design optimized lowest minimum sinking speed General Note Reynolds Number calculations done using shortened formula Model Glider Design Frank Zaic RN 0 x chord feet x mph Miller Mod-type bottom leading edge sheet option used prototype feel modification made better handling high speeds prefer flat-bottom airfoil Pre cision Duration work thing worse crooked airplane great big expensive crooked airplane make stab bellcrank first can used space stab wire tubes correctly build fin can use stab align bellcrank pivot bushings First glue Lite Ply stab plate make alignment other plate place glued everything correct glue place wings can used align wing rod tubes fuselage Use stab bellcrank mounting wires line up tubes before add top spar root sheeting After clamping lightly final stab sheet place align stab mounting wires carefully use instant glue permanently attach sheeting view wing root shows spoiler servo mount ballast tube front spar tube forthe Thermal Snifflers antenna Note Graupner-type wing hold-down others workable 26 Model Aviation riula piy oreaim Draces competition good results Merlyn can flown too slow wont entirely obvious except stopwatch Keep speed groovy~ area best performanceto produce normal slide Spot landings require planning 8-lbyour normal landing pattern can fooled airplane much wing will difficult toThe Merlyn will farther away moving plant firmly Ground effect mass conspirefaster think might want substitute own favorite spoiler drive mechanics shown lust make sure its strong positive spoiler servo should slide out easily hatch cover holds tThough Merlyns size much ditterent Sagitta author notes place Flange around hole 1/16 plysimilarity proportionseach designed independently other December 1981 27 spoiler servo sits between wing rod tube main spar opumiur rnvu i cessible bottom Note tube tne servo wires cut away avoid rough edges chafe wire servo pushrod shown place surethatthe pushrod doesnt bind against spar bellcrank moves
Edition: Model Aviation - 1981/12
Page Numbers: 20, 21, 22, 23, 24, 25, 26, 27
NO OCR TEXT NO OCR TEXT range airfoils LID values range 18 thick highly-cambered airfoils 24 lowcambered ones Table 1 describes correc tions finite aspect ratios wing thick ness given chord airspeed airfoil increas ing aspect ratio will bring about increase LID Anyone has stretched span model changing airfoil chord weight least much will know relation ship true Also note other things being equal thicker airfoils tend have lower LIDs What happens design around areabased rules like FAI rather span given area increase aspect ratio brings about reduction average chord wing therefore lower Reynolds Number given airspeed Reynolds Number can considered measure scale effect range airspeed also measure relative efficiency Indeed data paper S J Miley demonstrates increase LID Reynolds Numbers upto about 1000000 Using values LID vs Reynolds Number Miley paper correction factor Table 1 maximum value possible LID can cal culated values shown Table 2 various configurations Again keep mind maximum possible LID values will reality less due wing tip losses fuselage drag surface imperfections ever definite trend becomes apparent sufficient increase wing chord can definitely outweigh advantages high aspect ratio Minimum sinking speed also depends wing loading camber aspect ratio Table 3 would seem favor higher aspect ratios However same wing area would very difficult build high aspect ratio aircraft same wing loadings low aspect ratio though feel existing planform near optimum refinements wing tip shape fillets airfoils can still made Merlyn large enough carry instrumentation capable measuring effect design refinements Budder horn made fr, ince Merlyn operating higher Reynolds stock Note blending fuse fin lots Numbers lower lift coefficients suspect sanding means less nose weight needed significant improvements could come inermaionijieriseplybrackets p plate behind Snirner tor cam-bc canopy hold-down 0-cells for4 amps . ing times 16 hours possible Forward end thefuselagesldesshowthetoughbutlightconstmctionIn rear 1/4-in square balsa braces added prevent splitting spruce longeron 1/4-in ply top brace triangle stockThey beveled fit top bottom triangle pieces Wing root area top bulkheads place Note theThis view shows wing root area after top block place box wing tod tube located underthe plytop brace thespoiler servo wiring goes first glass tube second spruce longeron butts up agalns itspare large tube wing rods 22 Model Aviation BALSA TEANDLE OFFiN 3/s SQ STABLIZER1/8 SHEET BALSA 3/BADRILLROOFROM KEN BATESROOT RIB FRAMESSIDES OFFiN BASE3/B SOBALSARUOCER FACES ON HINGE POSiS 1/J/13/8X 3/32 BALSA RIBS 125 DIAMJSIC WIRE7 BALLAST TUBE OPT1ONAL3/BSHEEr FIN FAIRING CLAMP ROD C/S ONLY/2 BALSA BLOCKS VBI D BRASSBALSA BLOCK FAIRINGS VI6PLYVJCCO5/32COLLAR ALLOWS ELIMOL 5/B BALSA BLOCK WITH PLYSKID CLBLER ASBEAI SNIFFER TUBE HOOKS AND BANDSI/B UTE-PLY SICES AFT OF SPliCEL 2 THEWAAL SNIFFER INSTAL CANOPY IS BALSA ROCKI/B BIRO-I PLYWOOD SIDES FWD OF SICE -3/32SHEET BALSA TEl P/ROTFOMELEVATOR PUSHROD TAB-U WING ARTCOMPRESSED TOGETITALL IN-HC --S I/4BARIB 3/32 X 1/4 BALSA CAPSTRPS TOPAND YflOM ALL RIBS PLASTiC 1 I-KDK -- BALSA --TEFILLERS DOWELS 10 LOCATE CANOPY.- BRAS5 TIJBE TOP2BALSA~R Bi I/BPIYWOOD%EN ---- WOODBALSA TOPSAME FOR 82-3AND BOTTOMWEBS END HERE LOW NOSENOSE BLOCK BLOCK 3/32 SHEEV BALSAVBX 1/4 SPRUCE V4 PLYWOOD FORMS AT JOINTLE SKIN FULL SPANSPAR TCP ONLY TO END OF SPOILER3/850 BALSA OF FUSELAGE AND CANOPYLEFULL N 1/4K 1/2 SPRUCE 1/4K 1/2 SPRUCE1/2 BALSA TRIAN3LESPARS TOPAND BOTTOM PiT RAILBOlTOM CORNERS FULLLENGTUREINFORCING FROM3/B BALSA SPOILER ADE WITH -ROOT TO BELLCRANKPUSH ROD-TOBELLCRANKANDSBWOL16 PLYWOOD JOINS WING SPARS I/B WEBS FROM SPOILER OUTWARD 3BRIRPW EBOP 0 3 WIWIT BBSWROk RLL RIBS 10 W B MLSA RIIcRPT RIB O tRY BA BR 83 NEAR TRIMRWART PInUP ORB TT -4WLRff1R-- BALSA RLRSRROT NBYBRIRUTB RI I--4i-VRRTRBRRRERTCRBB RSECTION 0-B SPEAR CROCIIII -ml CR10 BROSSILBOtB IL YUBA SBPR PLUSIIIXIA SOBER DU1RR3WRRS ORIj-BR BAlSAIBXRI1BI II CrOP B ROT COPUSTIBB W4Y IBPBv~PAIPAp IIIIII Ii II I Ii I II LII RWROT WUOB 00 ICC 8150 OBhIRT PBJURB BAlSa WIll RIRASS TORITRPRROC BR SQ BALSABAlSA FILSOR lEERPRL WOO BRORT B 1pBRAISS R00C1 ASSRRBAVP45AlERt ROALWOIS BAl BALSA %SIIRAT BALSA BLURBAR IRABROC SBCTORR OB A 54 BALSA BlOCK BALLRRWR/SPRIER PARER 51501 RTOR P0044000k RLLRAP&W4L~z1 PR TO BRASS IA RANSULAR WA R75450IIPREPI -BRA o RPQDy PS WA ARISE WARBALSA SECTION A-AcRUSIIINA TULYUR0RAL FORMER U PLY[1 airfoils normally considered Design game compromise have designed Merlyn according preferences handling indications higher possible efficiency Obviously constrained PAl size limits could better using higher aspect ratio wing same chord However World Record attempts Great Race rules cross-country events require compliance FAI rules also prefer structural integrity inherent such configuration Merlyn very rugged aircraft very encouraging paying wood Construction Merlyn builders beginners difficult cheap no glue Part Part B instructions need dont build general style construction follows Airtronics Aquila structure well-proven well engineered will glad correspond ModelAviation have problem forewarned love talk about airplanes especially Remember airplane size Reynolds Number much larger normal Thus 8-lb Merlyn floater 10-lb Merlyn flies authority Built plans Merlyn should weight 10 lb Modifications described later allow build Merlyn all-up weight about 8 lb Please note since tip panel 36 long trailing edge sheet 37 long Use 4ft wood extra goes roof area Rocket City towhook reliable size Sailplane wrap link wire solder towhook shown plans 24 Model Aviation Airfoil Thickness % chordAspect RatioL/D Maximum Correction Factor2 10%litol17to185% 10%16to1l8tol90% 10%2Otoll9tol95% 13%l6toll7tol85% 13%20to 1175 1875% Table 2 effect Reynolds Number maximum possible L/D various designs 15mph airspeed1 AreaAspect%AverageRN atMax L/D sq inRatioThickness DesignChord15mphPossible2 21001110Merlyn138 in17300038 2100161011Sin 14400035 210020101025 in12800034 2100161311Sin 14400033 210020131025in 12800031 137016613Astro Jeff90 in11300028 Note data Table 1 paper S J Miley titled Design Air foils Low Reynolds Numbers published Massachusetts Institute Technolo gy Proceedings Second International Symposium Technology Science Low-speed Motoriess Flight Note 2 table results data indicating maximum L/D infinite aspect ratios various airfoils functioning Reynolds Number applying correc tion factor Table 1 various aspect ratios thicknesses Table 1 Maximum possible LID various thicknesses flat-bottom air foils Reynolds Number about 500001 Note data article Heinz G Struck Optimum Aspect Ratios RC Sailplanes RCModeier February 1976 Note 2 Percentage compared L/D 20 Reynolds Number 0 infinite aspect ratio FULLSIZEPLANSAVAILABLE E PAGE 140 A- 501 C0-4~ A 0551 GROIN FBI ISBN 31 0B0~Nt 55 BALSA SOOtY TO 55 BALSA NOFRO GOON 151 0Y 80050 ALBCC 005 S00IrA 000~ Frv SSNWA40005NY 0000BL 0 PLY BBLSB BLOCK SBCLLA LBLA%ONA 800505505K BALSAAS SGOBBA ALLOt PLYSYAaAtt RIOGROBBOB-NOLSA BLJ 050030000 --- S NOLBALL BOOLA SOLO PLY OBLY IS 30 SPOOL 300 0004 SPROCA50580 00 OuSAL0G$ AT AUTO PLY OBTOLO AOLJLSYABW OR 005030 BALAKSO YPOS 4000 MAY 80 05W MEN LYN OKORINEBO PRAWN BY SON BOlES -NOW BY Nat Design No 1 Merlyn 10% thickDesign No 22 13% thick airfoil 11 1 ARairfoil 20 1 AR Wing LoadingSinking SpeedWing LoadingSinking Speed ozIsq ft ec ozIsq ft ec 5 111 6119 71287102 81378108 91449115 10121 11127 12133 made aluminum T extrusion purchased local hardware store rearward location preferred 12-volt winch launches weaker winch hi-start i-in rubber would use forward location Please use heavy duty servos 10-lb cross-country Merlyn KPS-15s would good plane can get up 90 mph return downwind putting Quarter Scale power category radio compartment sized four D-size ni-cd cells 4 amp/hour balance bird give about 16 hours operation canopy balsa block have almost never entirely successful gluing blasted plastic canopies straight always get glue wrong place Besides like carve wood comments hear about Merlyn carving Carving fun have right tools project pieces wood large try sharp block plane use Stanley 9 Razor planes have uses big cuts Disston Company makes neat tool called Abrader works like rasp better Abraders really chew wood dont load up leave much better surface final sanding using two tools band saw blank out canopy block entire shaping takes 45 minutes less original Merlyn used blade-type wing joiner Sailplane Factory PO Box 341 Red Lion PA 17356 has heavy duty 14mm blade blade holder brass sleeve can used also have suitable stab bellcrank sake keeping home shop project now use h-in drill rod rod has heat-treated follows austenitize oil quench temper Rockwell C Scale 4245 can get done local heattreatment shop finished wing rod can obtained $500 Ken Bates 738 N Harris St Saline MI 48176 specifications very important Too hard will brittle source doesnt understand dont take chance Make sure rod tempered hardness Rockwell C Scale 42 45 Several variations structure have successfully used have built three Merlyns have used ribs 1/16th tips have also substituted arbon fiber spar Flite-spar Wing sheeting 1/16 balsa tried proved too prone hangar rash Another substitution tct use narrower stock tail surface trailing edges * x i light thermal machine rather rugged cross-country bird desire substitute Lite Ply nose sides bottom a tail boom sides bottom spoiler system shown construction photos new attempt has proven have favorite method use December1981 25 Table 3 effect wing loadings calculated sinking speeds two designs operating Reynolds Numbers around 500001 Note 1 same source table 1 some interpolation necessary Note 2 Hypothetical design optimized lowest minimum sinking speed General Note Reynolds Number calculations done using shortened formula Model Glider Design Frank Zaic RN 0 x chord feet x mph Miller Mod-type bottom leading edge sheet option used prototype feel modification made better handling high speeds prefer flat-bottom airfoil Pre cision Duration work thing worse crooked airplane great big expensive crooked airplane make stab bellcrank first can used space stab wire tubes correctly build fin can use stab align bellcrank pivot bushings First glue Lite Ply stab plate make alignment other plate place glued everything correct glue place wings can used align wing rod tubes fuselage Use stab bellcrank mounting wires line up tubes before add top spar root sheeting After clamping lightly final stab sheet place align stab mounting wires carefully use instant glue permanently attach sheeting view wing root shows spoiler servo mount ballast tube front spar tube forthe Thermal Snifflers antenna Note Graupner-type wing hold-down others workable 26 Model Aviation riula piy oreaim Draces competition good results Merlyn can flown too slow wont entirely obvious except stopwatch Keep speed groovy~ area best performanceto produce normal slide Spot landings require planning 8-lbyour normal landing pattern can fooled airplane much wing will difficult toThe Merlyn will farther away moving plant firmly Ground effect mass conspirefaster think might want substitute own favorite spoiler drive mechanics shown lust make sure its strong positive spoiler servo should slide out easily hatch cover holds tThough Merlyns size much ditterent Sagitta author notes place Flange around hole 1/16 plysimilarity proportionseach designed independently other December 1981 27 spoiler servo sits between wing rod tube main spar opumiur rnvu i cessible bottom Note tube tne servo wires cut away avoid rough edges chafe wire servo pushrod shown place surethatthe pushrod doesnt bind against spar bellcrank moves
Edition: Model Aviation - 1981/12
Page Numbers: 20, 21, 22, 23, 24, 25, 26, 27
NO OCR TEXT NO OCR TEXT range airfoils LID values range 18 thick highly-cambered airfoils 24 lowcambered ones Table 1 describes correc tions finite aspect ratios wing thick ness given chord airspeed airfoil increas ing aspect ratio will bring about increase LID Anyone has stretched span model changing airfoil chord weight least much will know relation ship true Also note other things being equal thicker airfoils tend have lower LIDs What happens design around areabased rules like FAI rather span given area increase aspect ratio brings about reduction average chord wing therefore lower Reynolds Number given airspeed Reynolds Number can considered measure scale effect range airspeed also measure relative efficiency Indeed data paper S J Miley demonstrates increase LID Reynolds Numbers upto about 1000000 Using values LID vs Reynolds Number Miley paper correction factor Table 1 maximum value possible LID can cal culated values shown Table 2 various configurations Again keep mind maximum possible LID values will reality less due wing tip losses fuselage drag surface imperfections ever definite trend becomes apparent sufficient increase wing chord can definitely outweigh advantages high aspect ratio Minimum sinking speed also depends wing loading camber aspect ratio Table 3 would seem favor higher aspect ratios However same wing area would very difficult build high aspect ratio aircraft same wing loadings low aspect ratio though feel existing planform near optimum refinements wing tip shape fillets airfoils can still made Merlyn large enough carry instrumentation capable measuring effect design refinements Budder horn made fr, ince Merlyn operating higher Reynolds stock Note blending fuse fin lots Numbers lower lift coefficients suspect sanding means less nose weight needed significant improvements could come inermaionijieriseplybrackets p plate behind Snirner tor cam-bc canopy hold-down 0-cells for4 amps . ing times 16 hours possible Forward end thefuselagesldesshowthetoughbutlightconstmctionIn rear 1/4-in square balsa braces added prevent splitting spruce longeron 1/4-in ply top brace triangle stockThey beveled fit top bottom triangle pieces Wing root area top bulkheads place Note theThis view shows wing root area after top block place box wing tod tube located underthe plytop brace thespoiler servo wiring goes first glass tube second spruce longeron butts up agalns itspare large tube wing rods 22 Model Aviation BALSA TEANDLE OFFiN 3/s SQ STABLIZER1/8 SHEET BALSA 3/BADRILLROOFROM KEN BATESROOT RIB FRAMESSIDES OFFiN BASE3/B SOBALSARUOCER FACES ON HINGE POSiS 1/J/13/8X 3/32 BALSA RIBS 125 DIAMJSIC WIRE7 BALLAST TUBE OPT1ONAL3/BSHEEr FIN FAIRING CLAMP ROD C/S ONLY/2 BALSA BLOCKS VBI D BRASSBALSA BLOCK FAIRINGS VI6PLYVJCCO5/32COLLAR ALLOWS ELIMOL 5/B BALSA BLOCK WITH PLYSKID CLBLER ASBEAI SNIFFER TUBE HOOKS AND BANDSI/B UTE-PLY SICES AFT OF SPliCEL 2 THEWAAL SNIFFER INSTAL CANOPY IS BALSA ROCKI/B BIRO-I PLYWOOD SIDES FWD OF SICE -3/32SHEET BALSA TEl P/ROTFOMELEVATOR PUSHROD TAB-U WING ARTCOMPRESSED TOGETITALL IN-HC --S I/4BARIB 3/32 X 1/4 BALSA CAPSTRPS TOPAND YflOM ALL RIBS PLASTiC 1 I-KDK -- BALSA --TEFILLERS DOWELS 10 LOCATE CANOPY.- BRAS5 TIJBE TOP2BALSA~R Bi I/BPIYWOOD%EN ---- WOODBALSA TOPSAME FOR 82-3AND BOTTOMWEBS END HERE LOW NOSENOSE BLOCK BLOCK 3/32 SHEEV BALSAVBX 1/4 SPRUCE V4 PLYWOOD FORMS AT JOINTLE SKIN FULL SPANSPAR TCP ONLY TO END OF SPOILER3/850 BALSA OF FUSELAGE AND CANOPYLEFULL N 1/4K 1/2 SPRUCE 1/4K 1/2 SPRUCE1/2 BALSA TRIAN3LESPARS TOPAND BOTTOM PiT RAILBOlTOM CORNERS FULLLENGTUREINFORCING FROM3/B BALSA SPOILER ADE WITH -ROOT TO BELLCRANKPUSH ROD-TOBELLCRANKANDSBWOL16 PLYWOOD JOINS WING SPARS I/B WEBS FROM SPOILER OUTWARD 3BRIRPW EBOP 0 3 WIWIT BBSWROk RLL RIBS 10 W B MLSA RIIcRPT RIB O tRY BA BR 83 NEAR TRIMRWART PInUP ORB TT -4WLRff1R-- BALSA RLRSRROT NBYBRIRUTB RI I--4i-VRRTRBRRRERTCRBB RSECTION 0-B SPEAR CROCIIII -ml CR10 BROSSILBOtB IL YUBA SBPR PLUSIIIXIA SOBER DU1RR3WRRS ORIj-BR BAlSAIBXRI1BI II CrOP B ROT COPUSTIBB W4Y IBPBv~PAIPAp IIIIII Ii II I Ii I II LII RWROT WUOB 00 ICC 8150 OBhIRT PBJURB BAlSa WIll RIRASS TORITRPRROC BR SQ BALSABAlSA FILSOR lEERPRL WOO BRORT B 1pBRAISS R00C1 ASSRRBAVP45AlERt ROALWOIS BAl BALSA %SIIRAT BALSA BLURBAR IRABROC SBCTORR OB A 54 BALSA BlOCK BALLRRWR/SPRIER PARER 51501 RTOR P0044000k RLLRAP&W4L~z1 PR TO BRASS IA RANSULAR WA R75450IIPREPI -BRA o RPQDy PS WA ARISE WARBALSA SECTION A-AcRUSIIINA TULYUR0RAL FORMER U PLY[1 airfoils normally considered Design game compromise have designed Merlyn according preferences handling indications higher possible efficiency Obviously constrained PAl size limits could better using higher aspect ratio wing same chord However World Record attempts Great Race rules cross-country events require compliance FAI rules also prefer structural integrity inherent such configuration Merlyn very rugged aircraft very encouraging paying wood Construction Merlyn builders beginners difficult cheap no glue Part Part B instructions need dont build general style construction follows Airtronics Aquila structure well-proven well engineered will glad correspond ModelAviation have problem forewarned love talk about airplanes especially Remember airplane size Reynolds Number much larger normal Thus 8-lb Merlyn floater 10-lb Merlyn flies authority Built plans Merlyn should weight 10 lb Modifications described later allow build Merlyn all-up weight about 8 lb Please note since tip panel 36 long trailing edge sheet 37 long Use 4ft wood extra goes roof area Rocket City towhook reliable size Sailplane wrap link wire solder towhook shown plans 24 Model Aviation Airfoil Thickness % chordAspect RatioL/D Maximum Correction Factor2 10%litol17to185% 10%16to1l8tol90% 10%2Otoll9tol95% 13%l6toll7tol85% 13%20to 1175 1875% Table 2 effect Reynolds Number maximum possible L/D various designs 15mph airspeed1 AreaAspect%AverageRN atMax L/D sq inRatioThickness DesignChord15mphPossible2 21001110Merlyn138 in17300038 2100161011Sin 14400035 210020101025 in12800034 2100161311Sin 14400033 210020131025in 12800031 137016613Astro Jeff90 in11300028 Note data Table 1 paper S J Miley titled Design Air foils Low Reynolds Numbers published Massachusetts Institute Technolo gy Proceedings Second International Symposium Technology Science Low-speed Motoriess Flight Note 2 table results data indicating maximum L/D infinite aspect ratios various airfoils functioning Reynolds Number applying correc tion factor Table 1 various aspect ratios thicknesses Table 1 Maximum possible LID various thicknesses flat-bottom air foils Reynolds Number about 500001 Note data article Heinz G Struck Optimum Aspect Ratios RC Sailplanes RCModeier February 1976 Note 2 Percentage compared L/D 20 Reynolds Number 0 infinite aspect ratio FULLSIZEPLANSAVAILABLE E PAGE 140 A- 501 C0-4~ A 0551 GROIN FBI ISBN 31 0B0~Nt 55 BALSA SOOtY TO 55 BALSA NOFRO GOON 151 0Y 80050 ALBCC 005 S00IrA 000~ Frv SSNWA40005NY 0000BL 0 PLY BBLSB BLOCK SBCLLA LBLA%ONA 800505505K BALSAAS SGOBBA ALLOt PLYSYAaAtt RIOGROBBOB-NOLSA BLJ 050030000 --- S NOLBALL BOOLA SOLO PLY OBLY IS 30 SPOOL 300 0004 SPROCA50580 00 OuSAL0G$ AT AUTO PLY OBTOLO AOLJLSYABW OR 005030 BALAKSO YPOS 4000 MAY 80 05W MEN LYN OKORINEBO PRAWN BY SON BOlES -NOW BY Nat Design No 1 Merlyn 10% thickDesign No 22 13% thick airfoil 11 1 ARairfoil 20 1 AR Wing LoadingSinking SpeedWing LoadingSinking Speed ozIsq ft ec ozIsq ft ec 5 111 6119 71287102 81378108 91449115 10121 11127 12133 made aluminum T extrusion purchased local hardware store rearward location preferred 12-volt winch launches weaker winch hi-start i-in rubber would use forward location Please use heavy duty servos 10-lb cross-country Merlyn KPS-15s would good plane can get up 90 mph return downwind putting Quarter Scale power category radio compartment sized four D-size ni-cd cells 4 amp/hour balance bird give about 16 hours operation canopy balsa block have almost never entirely successful gluing blasted plastic canopies straight always get glue wrong place Besides like carve wood comments hear about Merlyn carving Carving fun have right tools project pieces wood large try sharp block plane use Stanley 9 Razor planes have uses big cuts Disston Company makes neat tool called Abrader works like rasp better Abraders really chew wood dont load up leave much better surface final sanding using two tools band saw blank out canopy block entire shaping takes 45 minutes less original Merlyn used blade-type wing joiner Sailplane Factory PO Box 341 Red Lion PA 17356 has heavy duty 14mm blade blade holder brass sleeve can used also have suitable stab bellcrank sake keeping home shop project now use h-in drill rod rod has heat-treated follows austenitize oil quench temper Rockwell C Scale 4245 can get done local heattreatment shop finished wing rod can obtained $500 Ken Bates 738 N Harris St Saline MI 48176 specifications very important Too hard will brittle source doesnt understand dont take chance Make sure rod tempered hardness Rockwell C Scale 42 45 Several variations structure have successfully used have built three Merlyns have used ribs 1/16th tips have also substituted arbon fiber spar Flite-spar Wing sheeting 1/16 balsa tried proved too prone hangar rash Another substitution tct use narrower stock tail surface trailing edges * x i light thermal machine rather rugged cross-country bird desire substitute Lite Ply nose sides bottom a tail boom sides bottom spoiler system shown construction photos new attempt has proven have favorite method use December1981 25 Table 3 effect wing loadings calculated sinking speeds two designs operating Reynolds Numbers around 500001 Note 1 same source table 1 some interpolation necessary Note 2 Hypothetical design optimized lowest minimum sinking speed General Note Reynolds Number calculations done using shortened formula Model Glider Design Frank Zaic RN 0 x chord feet x mph Miller Mod-type bottom leading edge sheet option used prototype feel modification made better handling high speeds prefer flat-bottom airfoil Pre cision Duration work thing worse crooked airplane great big expensive crooked airplane make stab bellcrank first can used space stab wire tubes correctly build fin can use stab align bellcrank pivot bushings First glue Lite Ply stab plate make alignment other plate place glued everything correct glue place wings can used align wing rod tubes fuselage Use stab bellcrank mounting wires line up tubes before add top spar root sheeting After clamping lightly final stab sheet place align stab mounting wires carefully use instant glue permanently attach sheeting view wing root shows spoiler servo mount ballast tube front spar tube forthe Thermal Snifflers antenna Note Graupner-type wing hold-down others workable 26 Model Aviation riula piy oreaim Draces competition good results Merlyn can flown too slow wont entirely obvious except stopwatch Keep speed groovy~ area best performanceto produce normal slide Spot landings require planning 8-lbyour normal landing pattern can fooled airplane much wing will difficult toThe Merlyn will farther away moving plant firmly Ground effect mass conspirefaster think might want substitute own favorite spoiler drive mechanics shown lust make sure its strong positive spoiler servo should slide out easily hatch cover holds tThough Merlyns size much ditterent Sagitta author notes place Flange around hole 1/16 plysimilarity proportionseach designed independently other December 1981 27 spoiler servo sits between wing rod tube main spar opumiur rnvu i cessible bottom Note tube tne servo wires cut away avoid rough edges chafe wire servo pushrod shown place surethatthe pushrod doesnt bind against spar bellcrank moves
Edition: Model Aviation - 1981/12
Page Numbers: 20, 21, 22, 23, 24, 25, 26, 27
NO OCR TEXT NO OCR TEXT range airfoils LID values range 18 thick highly-cambered airfoils 24 lowcambered ones Table 1 describes correc tions finite aspect ratios wing thick ness given chord airspeed airfoil increas ing aspect ratio will bring about increase LID Anyone has stretched span model changing airfoil chord weight least much will know relation ship true Also note other things being equal thicker airfoils tend have lower LIDs What happens design around areabased rules like FAI rather span given area increase aspect ratio brings about reduction average chord wing therefore lower Reynolds Number given airspeed Reynolds Number can considered measure scale effect range airspeed also measure relative efficiency Indeed data paper S J Miley demonstrates increase LID Reynolds Numbers upto about 1000000 Using values LID vs Reynolds Number Miley paper correction factor Table 1 maximum value possible LID can cal culated values shown Table 2 various configurations Again keep mind maximum possible LID values will reality less due wing tip losses fuselage drag surface imperfections ever definite trend becomes apparent sufficient increase wing chord can definitely outweigh advantages high aspect ratio Minimum sinking speed also depends wing loading camber aspect ratio Table 3 would seem favor higher aspect ratios However same wing area would very difficult build high aspect ratio aircraft same wing loadings low aspect ratio though feel existing planform near optimum refinements wing tip shape fillets airfoils can still made Merlyn large enough carry instrumentation capable measuring effect design refinements Budder horn made fr, ince Merlyn operating higher Reynolds stock Note blending fuse fin lots Numbers lower lift coefficients suspect sanding means less nose weight needed significant improvements could come inermaionijieriseplybrackets p plate behind Snirner tor cam-bc canopy hold-down 0-cells for4 amps . ing times 16 hours possible Forward end thefuselagesldesshowthetoughbutlightconstmctionIn rear 1/4-in square balsa braces added prevent splitting spruce longeron 1/4-in ply top brace triangle stockThey beveled fit top bottom triangle pieces Wing root area top bulkheads place Note theThis view shows wing root area after top block place box wing tod tube located underthe plytop brace thespoiler servo wiring goes first glass tube second spruce longeron butts up agalns itspare large tube wing rods 22 Model Aviation BALSA TEANDLE OFFiN 3/s SQ STABLIZER1/8 SHEET BALSA 3/BADRILLROOFROM KEN BATESROOT RIB FRAMESSIDES OFFiN BASE3/B SOBALSARUOCER FACES ON HINGE POSiS 1/J/13/8X 3/32 BALSA RIBS 125 DIAMJSIC WIRE7 BALLAST TUBE OPT1ONAL3/BSHEEr FIN FAIRING CLAMP ROD C/S ONLY/2 BALSA BLOCKS VBI D BRASSBALSA BLOCK FAIRINGS VI6PLYVJCCO5/32COLLAR ALLOWS ELIMOL 5/B BALSA BLOCK WITH PLYSKID CLBLER ASBEAI SNIFFER TUBE HOOKS AND BANDSI/B UTE-PLY SICES AFT OF SPliCEL 2 THEWAAL SNIFFER INSTAL CANOPY IS BALSA ROCKI/B BIRO-I PLYWOOD SIDES FWD OF SICE -3/32SHEET BALSA TEl P/ROTFOMELEVATOR PUSHROD TAB-U WING ARTCOMPRESSED TOGETITALL IN-HC --S I/4BARIB 3/32 X 1/4 BALSA CAPSTRPS TOPAND YflOM ALL RIBS PLASTiC 1 I-KDK -- BALSA --TEFILLERS DOWELS 10 LOCATE CANOPY.- BRAS5 TIJBE TOP2BALSA~R Bi I/BPIYWOOD%EN ---- WOODBALSA TOPSAME FOR 82-3AND BOTTOMWEBS END HERE LOW NOSENOSE BLOCK BLOCK 3/32 SHEEV BALSAVBX 1/4 SPRUCE V4 PLYWOOD FORMS AT JOINTLE SKIN FULL SPANSPAR TCP ONLY TO END OF SPOILER3/850 BALSA OF FUSELAGE AND CANOPYLEFULL N 1/4K 1/2 SPRUCE 1/4K 1/2 SPRUCE1/2 BALSA TRIAN3LESPARS TOPAND BOTTOM PiT RAILBOlTOM CORNERS FULLLENGTUREINFORCING FROM3/B BALSA SPOILER ADE WITH -ROOT TO BELLCRANKPUSH ROD-TOBELLCRANKANDSBWOL16 PLYWOOD JOINS WING SPARS I/B WEBS FROM SPOILER OUTWARD 3BRIRPW EBOP 0 3 WIWIT BBSWROk RLL RIBS 10 W B MLSA RIIcRPT RIB O tRY BA BR 83 NEAR TRIMRWART PInUP ORB TT -4WLRff1R-- BALSA RLRSRROT NBYBRIRUTB RI I--4i-VRRTRBRRRERTCRBB RSECTION 0-B SPEAR CROCIIII -ml CR10 BROSSILBOtB IL YUBA SBPR PLUSIIIXIA SOBER DU1RR3WRRS ORIj-BR BAlSAIBXRI1BI II CrOP B ROT COPUSTIBB W4Y IBPBv~PAIPAp IIIIII Ii II I Ii I II LII RWROT WUOB 00 ICC 8150 OBhIRT PBJURB BAlSa WIll RIRASS TORITRPRROC BR SQ BALSABAlSA FILSOR lEERPRL WOO BRORT B 1pBRAISS R00C1 ASSRRBAVP45AlERt ROALWOIS BAl BALSA %SIIRAT BALSA BLURBAR IRABROC SBCTORR OB A 54 BALSA BlOCK BALLRRWR/SPRIER PARER 51501 RTOR P0044000k RLLRAP&W4L~z1 PR TO BRASS IA RANSULAR WA R75450IIPREPI -BRA o RPQDy PS WA ARISE WARBALSA SECTION A-AcRUSIIINA TULYUR0RAL FORMER U PLY[1 airfoils normally considered Design game compromise have designed Merlyn according preferences handling indications higher possible efficiency Obviously constrained PAl size limits could better using higher aspect ratio wing same chord However World Record attempts Great Race rules cross-country events require compliance FAI rules also prefer structural integrity inherent such configuration Merlyn very rugged aircraft very encouraging paying wood Construction Merlyn builders beginners difficult cheap no glue Part Part B instructions need dont build general style construction follows Airtronics Aquila structure well-proven well engineered will glad correspond ModelAviation have problem forewarned love talk about airplanes especially Remember airplane size Reynolds Number much larger normal Thus 8-lb Merlyn floater 10-lb Merlyn flies authority Built plans Merlyn should weight 10 lb Modifications described later allow build Merlyn all-up weight about 8 lb Please note since tip panel 36 long trailing edge sheet 37 long Use 4ft wood extra goes roof area Rocket City towhook reliable size Sailplane wrap link wire solder towhook shown plans 24 Model Aviation Airfoil Thickness % chordAspect RatioL/D Maximum Correction Factor2 10%litol17to185% 10%16to1l8tol90% 10%2Otoll9tol95% 13%l6toll7tol85% 13%20to 1175 1875% Table 2 effect Reynolds Number maximum possible L/D various designs 15mph airspeed1 AreaAspect%AverageRN atMax L/D sq inRatioThickness DesignChord15mphPossible2 21001110Merlyn138 in17300038 2100161011Sin 14400035 210020101025 in12800034 2100161311Sin 14400033 210020131025in 12800031 137016613Astro Jeff90 in11300028 Note data Table 1 paper S J Miley titled Design Air foils Low Reynolds Numbers published Massachusetts Institute Technolo gy Proceedings Second International Symposium Technology Science Low-speed Motoriess Flight Note 2 table results data indicating maximum L/D infinite aspect ratios various airfoils functioning Reynolds Number applying correc tion factor Table 1 various aspect ratios thicknesses Table 1 Maximum possible LID various thicknesses flat-bottom air foils Reynolds Number about 500001 Note data article Heinz G Struck Optimum Aspect Ratios RC Sailplanes RCModeier February 1976 Note 2 Percentage compared L/D 20 Reynolds Number 0 infinite aspect ratio FULLSIZEPLANSAVAILABLE E PAGE 140 A- 501 C0-4~ A 0551 GROIN FBI ISBN 31 0B0~Nt 55 BALSA SOOtY TO 55 BALSA NOFRO GOON 151 0Y 80050 ALBCC 005 S00IrA 000~ Frv SSNWA40005NY 0000BL 0 PLY BBLSB BLOCK SBCLLA LBLA%ONA 800505505K BALSAAS SGOBBA ALLOt PLYSYAaAtt RIOGROBBOB-NOLSA BLJ 050030000 --- S NOLBALL BOOLA SOLO PLY OBLY IS 30 SPOOL 300 0004 SPROCA50580 00 OuSAL0G$ AT AUTO PLY OBTOLO AOLJLSYABW OR 005030 BALAKSO YPOS 4000 MAY 80 05W MEN LYN OKORINEBO PRAWN BY SON BOlES -NOW BY Nat Design No 1 Merlyn 10% thickDesign No 22 13% thick airfoil 11 1 ARairfoil 20 1 AR Wing LoadingSinking SpeedWing LoadingSinking Speed ozIsq ft ec ozIsq ft ec 5 111 6119 71287102 81378108 91449115 10121 11127 12133 made aluminum T extrusion purchased local hardware store rearward location preferred 12-volt winch launches weaker winch hi-start i-in rubber would use forward location Please use heavy duty servos 10-lb cross-country Merlyn KPS-15s would good plane can get up 90 mph return downwind putting Quarter Scale power category radio compartment sized four D-size ni-cd cells 4 amp/hour balance bird give about 16 hours operation canopy balsa block have almost never entirely successful gluing blasted plastic canopies straight always get glue wrong place Besides like carve wood comments hear about Merlyn carving Carving fun have right tools project pieces wood large try sharp block plane use Stanley 9 Razor planes have uses big cuts Disston Company makes neat tool called Abrader works like rasp better Abraders really chew wood dont load up leave much better surface final sanding using two tools band saw blank out canopy block entire shaping takes 45 minutes less original Merlyn used blade-type wing joiner Sailplane Factory PO Box 341 Red Lion PA 17356 has heavy duty 14mm blade blade holder brass sleeve can used also have suitable stab bellcrank sake keeping home shop project now use h-in drill rod rod has heat-treated follows austenitize oil quench temper Rockwell C Scale 4245 can get done local heattreatment shop finished wing rod can obtained $500 Ken Bates 738 N Harris St Saline MI 48176 specifications very important Too hard will brittle source doesnt understand dont take chance Make sure rod tempered hardness Rockwell C Scale 42 45 Several variations structure have successfully used have built three Merlyns have used ribs 1/16th tips have also substituted arbon fiber spar Flite-spar Wing sheeting 1/16 balsa tried proved too prone hangar rash Another substitution tct use narrower stock tail surface trailing edges * x i light thermal machine rather rugged cross-country bird desire substitute Lite Ply nose sides bottom a tail boom sides bottom spoiler system shown construction photos new attempt has proven have favorite method use December1981 25 Table 3 effect wing loadings calculated sinking speeds two designs operating Reynolds Numbers around 500001 Note 1 same source table 1 some interpolation necessary Note 2 Hypothetical design optimized lowest minimum sinking speed General Note Reynolds Number calculations done using shortened formula Model Glider Design Frank Zaic RN 0 x chord feet x mph Miller Mod-type bottom leading edge sheet option used prototype feel modification made better handling high speeds prefer flat-bottom airfoil Pre cision Duration work thing worse crooked airplane great big expensive crooked airplane make stab bellcrank first can used space stab wire tubes correctly build fin can use stab align bellcrank pivot bushings First glue Lite Ply stab plate make alignment other plate place glued everything correct glue place wings can used align wing rod tubes fuselage Use stab bellcrank mounting wires line up tubes before add top spar root sheeting After clamping lightly final stab sheet place align stab mounting wires carefully use instant glue permanently attach sheeting view wing root shows spoiler servo mount ballast tube front spar tube forthe Thermal Snifflers antenna Note Graupner-type wing hold-down others workable 26 Model Aviation riula piy oreaim Draces competition good results Merlyn can flown too slow wont entirely obvious except stopwatch Keep speed groovy~ area best performanceto produce normal slide Spot landings require planning 8-lbyour normal landing pattern can fooled airplane much wing will difficult toThe Merlyn will farther away moving plant firmly Ground effect mass conspirefaster think might want substitute own favorite spoiler drive mechanics shown lust make sure its strong positive spoiler servo should slide out easily hatch cover holds tThough Merlyns size much ditterent Sagitta author notes place Flange around hole 1/16 plysimilarity proportionseach designed independently other December 1981 27 spoiler servo sits between wing rod tube main spar opumiur rnvu i cessible bottom Note tube tne servo wires cut away avoid rough edges chafe wire servo pushrod shown place surethatthe pushrod doesnt bind against spar bellcrank moves