Emil Svercl Capacitive Discha Tired happy IL Jack Finn after gruelling flight 16 hours 43 minutes then-new FAI World Record authors CDI system performed flawlessly whole time Full story record flight February 1982 issue tne Ignition components lCtt tne spark plug cover Teflon spacer plug cover left side case lower right has triggerand high-tension components right side hasthe power supply Lithium batteries upper right rigger coil held Dy split ring clamp around front bearing mount crankcase Note magnet mounted prop drive washer just above upper screw holding coil place 48 Model Aviation e Ignition System Plenny Bates Jack Finn crew began plan Duration World Record attempt needed spark igni tion system would work reliably hours weigh little cause little inter ference stateof-the-art system developed author aid Cedar Rapids Skyhawks team story part project THERE IS NEED lightweight efficient trouble-free spark ignition system model aircraft Interest such events Old-Timer Texaco RC Duration record attempts plus sport flying inexpensive fuel should stimu late further development breakless capacitor discharge CD systems CD systems give higher efficiency greater reliability traditional spark ignition systems short-duration spark long tail also results less spark plug electrode erosion construction article rather some hints few details system developed 1. U Q 6VL2 Jn 6V 00l 220 T2 C 0 2N2905 l220 RC Duration record attempt others giving try better sparkers will soon emerge can wind coil have some electronic design background building system should within capabilities Since battery life important record attempts attention given high efficiency reliability Power needed fully shielded system 125 mA 6A 750 mW unshielded 500mW sufficient shielded system should give 30-plus running hours six ounces lithium battery past 50 hours plug inspection has attention given part system usual iron core coil heavy does GV 0 OA 7 47 L r 180K 2 LMIOI 6 38 2 Q P AA 50K CAPS IN UF DIODES 1N4454 have correct electrical characteristics capacitor discharge unit build coil start ferrite rod ofA diameter long Lay 16 tums two parallel *20 wires remove wire will give needed spacing primary winding Hold wire place Q dope Build up end rings equal thicknesss #20 wire is-in wide Mylar tape Cover primary two layers 005 x 75 Teflon tape next part difficult secondary wound 125 layers 15 mil wire used home-brew computer control lead screw Unimat permitting progression tool holder 15 mil per coil revolution Wire 0 1 120V IoJ 001 LTh2N ____a 200VIOKV H3GC 2 SC 1 U ES 1981 Schematic ignition system Part 2N888 no longer available SCR equal greater voltage will substitute can wind coil have some electronic design background building system should within capabilities 120V -o 01 200V 0 August 1982 49 Diagram ignition power supply L2 parallel-wound toroid transformer functions RF choke T2 Collins Radio surplus toroid unknown specification transformers should work T2 Battery life important record attempt Sparkplug coverdetail Note clamp forholding end spark plug wire shield STRINGWRAP 3/4 TURN 12/2 LAYERS 15 MIL WIRE FERR~ 1/4 x 1 IN IGNITION COIL ES 1981 1 005 x 3/4 IN TEFLON TAPE RG18OBU SHIELDS TEFLON TUBES IKzi RNS NO 20 WIRE 15 Mu MYLAR TAPE 1/8 IN WIDE SEAL FINISHED COIL WITH Q DOPE Cutaway view ignition coil Ti hightension cable As shown coil unfinished just four layersi 2layers needed Author used Unimat coil winding red through small hole Teflon block held tool holder wire reel ball bearing support gave just enough drag pull wire down coiL ball bearing rested Teflon sheet wire stuck reel ball bearing reel assembly pulled across Teflon sheet giving time stop lathe before wire broke wire reel would carefully unstuck lathe restarted Hand winding may possible winding jig controls wire tension gives wire guide correct progression both direc tions better way Over wire layer apply layer 005 x 75 Teflon tape potential difference between windings about OOOV need good dielectric spacing between layers msut about 005 correct inductance characteristics Run last layer mid-point let wire protrude two layers Teflon tape end attached conductor RGI 8OBU co-ax cable shield removed wrapped around coil held Teflon tape string wrap shown drawing Covering co-ax way plug three Teflon tubes shielding Continued page 142 Embroidered airplantn quality blue casual shirts choice royal/white Mustang HMUJ navy/white Corsair HCOJ brown white Spitfire HSPJ red/white Pitts H Sweatershirt style VI 520 Golf Shin Istyle Cl $18 Sizes S432-36I M138-40I 1442-44 X1461 Ladles ShIrt Istyle LI $10 Sizes 518-101 M112-141 1416-18 X20-221 Add 10% postage/handling Allow 3-4 weeks delivery Send check money order FlightIlne Shirts Etc Department MA 1781 Johnmark Circle Grants Pass OR 97526 Send SASE new brochure Name Address CityStatezip SizeStyleDesign 50 Model Aviation business end spark plug after 27 hours rich cool running Lean running fori 5 hours left plug perfect tan color ground electrode burned filed point see II sti V Price 2995 NEW FOURMOST PRODUCTS 7 Miter Master Mite Maul, tool designed enable crafts man make perfect joints wood accurately sanding pre-setangles squaring fence allowsforprecise9O angles retracts below surface Any angle can beset triangular guide using adjacent side complement angle mill formed making invaluable fur truss construction new cyanoacrylate adhesives require accurately fitted joints achinue full strength Miter Master will enable make easily FOURMOST PRODUCTS 4040 24th Ave Forest Grove OR 97116 raise enough funds wall new building will carry name permanent display Physical progress building project continues industrial revenue bonds approved Virginia April 20 1982 AMA received construction bids proj ect April 26 general contractor has selected Details construction contract being finalized written lending bank AMA finalizing necessary items go settle ment next installment report hope have date start con struction Contributions Additional names donors Building Fund follows listing current first week May 1982 Room new building dedicated name Bill Semler made pos sible friends Bill Semler Honor Wall recognition contributions $1000 up Romak Iron Works New Charter Members AMA Builders plaques acknowledging donations $500 up Central Jersey Radio Control Club Orange Coast RC Club Somers Radio Con trol Airplane Club Tn-City RC Flyers APrice $750 Assembled booed 503 357-2732 Philip 0 Kiaft memory Howard McEntee Elinor McEntee Clark New Life Members have earmarked membership fees Building Fund James Grier F David McDonald Richard Nelson John Reed Jr Contributing Members Honor Roil listing donated $100 up now includes Aero Sport RC Club Atlanta Hawks RC Bar rons Model Club Bartlesville Falcons Blue Angels Model Airplane Club Brainbusters Club Cape Ann RC Club Capitol Area Radio Drone Squadron CARDS Central Carolina RC Modelers Cobb County RC Club Cos hocton City Cloud Climbers Diablo Valley RC Inc East Side RC Club Flying Tigers Fredericksburg Aero Masters Gold Coast Radio Controllers Grassfield RC Club Hampshire County RC Indianapolis Westside RC Modelers Joint Military RC Flyers Laurel Highlands Model Airplane Club League Silent Flight Manned Spacecraft Center RC Club Midwest Sundowners RC Club North ern Air Modelers Palm Beach Aeronauts Peninsula Channel Commanders Remote Control Association Central Florida Sa linas Area Modelers San Fernando RC Flyers Signal Seekers RC Sky Squires RC Club Suds City Sailplane Team Texas City RC WinstonFUSELAGE FIXTURE FOURMOST FUSELAGE FIXTURE desigsed AatomanicIIy aligo fuselage structures built strings measuring eyeballing Simply slide four centering brackets track until align firewall tail joint two bulkheads clamp fuselage together lightly rubberhands structure will straight th track uneemedflCodfluP ut Salem RC Club Inc Woodbnidge RC Bristol Hobby Center CB Associates Inc Jerry Cowan Steve Crowe Otto Curth NP Curtis Father Dignan Eugene R Field James Harris John Hobson Robert Hockley Philip Lees Robert Lon& Guy Markham Bud Meyers Charles Patterson Rex E Per kins Anthony Ptak Peter Rawlins David Rigotti Salinas Valley Printing Slot Wing Hobhies Bob Wilder Walter Zaharevltz Gold Members donated $50 Building Fund will listed Gold Members Scroll Central Atlantic Academy Leaders Jersey Coast RC Club Kansas City RC Association Pioneer Valley RC Quina poxet Model Flying Club Signal Chasers Tri-Rivers RC Modelers Bill Bieda DA Carisen Dick Carson Champion Hobbies Samuel R Compton M Cook Jay E Coon Sr Frank Costello Rich ard Dawson Gerald Deneau Jos Dunkis Ervine E Frierson Ronald Ganser John G Haggart Carl Hatrak Bob Johnson John H Krekelberg Juan Livotto Larry Lundy Bud Grace Meyers Richard Palmer Charles Perry John Porter Thelma Harlan Roth Wallace Smith RF Stevenson Robert Strobel Mary Richard Swenson Jim Traw Milo Valencic Grant Wilson Ernest Wrisley Ernest Zam Don Zook Vince Mankowslci Assistant Executive Director CDI System/Svercl Continued page 50 inner two tubes used strain relief insulation Note notch coil ends inner tubes notch fits hole glass-epoxy board also holds end coil middle tubes notch fits hole outer case outer Teflon tube split Teflon tube too small spacer between inner working insulation braided copper shield Ordinary automotive aircraft cable has much capacity will reduce spark half don5t use Blue aircraft cable used outer ground shield ends must unbraided carefully cleaned before soldering copper tube turn soldered case held split clamp spark plug cover spark plug cover shown has Teflon fillers inside reduce chance spark direct ground trigger small single-play tape head pickup removed its metal case small piece ceramic magnet ground round shape correct polarity observed mounted hole aluminum prop-drive sweeps tape head produce trigger pulse circuit shown should positive pulse Any magnet-coil will pro duce pulse few mY will work Breaker points used because may less reliable LED-photocell trigger may used extra current draw important application Some electronics parts now obsolete Use equal higher ratings substitutions cause values shown close minimums Any good DC DC power supply correct voltages 10 mA output will work An alter nator rectifier may make better system Most case 1/32-in single-sided PC board copper outside serving RF shield Two sides use 1/16-in double-sided board outside copper RF shield inside etched form circuit board parts mounted pads no holes parts mounting use etched circuit board 142 Model Aviation sure etching well done slightest film copper will serve conductor high voltages resulting failure op-amp other high-voltage-sensitive parts Leads may pass using Teflon tubes 001 uF capacitors lead ground inside case ground RF needed external leads including trigger wires diodes around op-amp protect stray voltages lost two op-amps before diodes installed Herb WahI Hurleman-type plug has used over 50 hours great success low power engine relation cooling area 27 hours rich running made plug bit black still firing experimenting type spark system interests start coil can wind good coil rest relatively easy Good luck 15 mil wire will need Profiles/SruII Continued page 59 turn becomes too tight etc Use very small thrust changes degree two time since effect large under full power Dihedral angle tail area model cant made fly consistent circle either direction tightening its turn eventu ally diving probably have spiral stability problems especially common lowwing models little dihedral also appears some parasol configurations large vertical tail surfaces such Curtiss Junior case best remedy usually add dihedral abut two three degrees timeuntil problem subsides Another possible solution reduce vertical tail surface usually looks bad can also lead other stability problems Another tricky method worth try certain models add vertical side area above approximate CG position Walt Mooney sometimes does filling open cabane structure like Curtiss Junior has clear sheet thin plastic can hardly see it will sometimes trick another Walts models added large profile pilot figure otherwise empty cockpit added enough lateral area above CG low-wing model fly properly no dihedral Another problem occurs occasionally directional instability case model will tend wander direction somewhat will impossible adjust reliable turn pattern Unlike spiral stability problem men tioned above however model will tend spin fact directional wandering usually means model spirally stable simple cure difficulty increase vertical tail area find need large amount increase would spoil looks Scale creation can borrow another idea Walt Mooney add transparent tab vertical tail flight will hardly visible trying set CG incidence described earlier models flight path erratic pitch difficult get repeat able results horizontal tail surfaces may too small Add 20 30% horizontal tail area try again tinned page 144 COMPLETE THIS FOAM AND ATTACH MAILING LABEL FROM RECE NT E LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept. Model Aviation 815 Fifteenth St. NW. Washington DC. 20005 Check appropriate boxenclose payment 0 NEW SUBSCRIPTION 0 CHANGE OF ADDRESS Non-AMA subscription rates $1800 12 months US Possessions elsewhere Including Canada MexIco $2400 US Schools $gOO US Libraries $1350 NAME ADDRESS CITY/STATE _____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW WASHINGTON DC 20005 August1982 143
Edition: Model Aviation - 1982/08
Page Numbers: 48, 49, 50, 142, 143
Emil Svercl Capacitive Discha Tired happy IL Jack Finn after gruelling flight 16 hours 43 minutes then-new FAI World Record authors CDI system performed flawlessly whole time Full story record flight February 1982 issue tne Ignition components lCtt tne spark plug cover Teflon spacer plug cover left side case lower right has triggerand high-tension components right side hasthe power supply Lithium batteries upper right rigger coil held Dy split ring clamp around front bearing mount crankcase Note magnet mounted prop drive washer just above upper screw holding coil place 48 Model Aviation e Ignition System Plenny Bates Jack Finn crew began plan Duration World Record attempt needed spark igni tion system would work reliably hours weigh little cause little inter ference stateof-the-art system developed author aid Cedar Rapids Skyhawks team story part project THERE IS NEED lightweight efficient trouble-free spark ignition system model aircraft Interest such events Old-Timer Texaco RC Duration record attempts plus sport flying inexpensive fuel should stimu late further development breakless capacitor discharge CD systems CD systems give higher efficiency greater reliability traditional spark ignition systems short-duration spark long tail also results less spark plug electrode erosion construction article rather some hints few details system developed 1. U Q 6VL2 Jn 6V 00l 220 T2 C 0 2N2905 l220 RC Duration record attempt others giving try better sparkers will soon emerge can wind coil have some electronic design background building system should within capabilities Since battery life important record attempts attention given high efficiency reliability Power needed fully shielded system 125 mA 6A 750 mW unshielded 500mW sufficient shielded system should give 30-plus running hours six ounces lithium battery past 50 hours plug inspection has attention given part system usual iron core coil heavy does GV 0 OA 7 47 L r 180K 2 LMIOI 6 38 2 Q P AA 50K CAPS IN UF DIODES 1N4454 have correct electrical characteristics capacitor discharge unit build coil start ferrite rod ofA diameter long Lay 16 tums two parallel *20 wires remove wire will give needed spacing primary winding Hold wire place Q dope Build up end rings equal thicknesss #20 wire is-in wide Mylar tape Cover primary two layers 005 x 75 Teflon tape next part difficult secondary wound 125 layers 15 mil wire used home-brew computer control lead screw Unimat permitting progression tool holder 15 mil per coil revolution Wire 0 1 120V IoJ 001 LTh2N ____a 200VIOKV H3GC 2 SC 1 U ES 1981 Schematic ignition system Part 2N888 no longer available SCR equal greater voltage will substitute can wind coil have some electronic design background building system should within capabilities 120V -o 01 200V 0 August 1982 49 Diagram ignition power supply L2 parallel-wound toroid transformer functions RF choke T2 Collins Radio surplus toroid unknown specification transformers should work T2 Battery life important record attempt Sparkplug coverdetail Note clamp forholding end spark plug wire shield STRINGWRAP 3/4 TURN 12/2 LAYERS 15 MIL WIRE FERR~ 1/4 x 1 IN IGNITION COIL ES 1981 1 005 x 3/4 IN TEFLON TAPE RG18OBU SHIELDS TEFLON TUBES IKzi RNS NO 20 WIRE 15 Mu MYLAR TAPE 1/8 IN WIDE SEAL FINISHED COIL WITH Q DOPE Cutaway view ignition coil Ti hightension cable As shown coil unfinished just four layersi 2layers needed Author used Unimat coil winding red through small hole Teflon block held tool holder wire reel ball bearing support gave just enough drag pull wire down coiL ball bearing rested Teflon sheet wire stuck reel ball bearing reel assembly pulled across Teflon sheet giving time stop lathe before wire broke wire reel would carefully unstuck lathe restarted Hand winding may possible winding jig controls wire tension gives wire guide correct progression both direc tions better way Over wire layer apply layer 005 x 75 Teflon tape potential difference between windings about OOOV need good dielectric spacing between layers msut about 005 correct inductance characteristics Run last layer mid-point let wire protrude two layers Teflon tape end attached conductor RGI 8OBU co-ax cable shield removed wrapped around coil held Teflon tape string wrap shown drawing Covering co-ax way plug three Teflon tubes shielding Continued page 142 Embroidered airplantn quality blue casual shirts choice royal/white Mustang HMUJ navy/white Corsair HCOJ brown white Spitfire HSPJ red/white Pitts H Sweatershirt style VI 520 Golf Shin Istyle Cl $18 Sizes S432-36I M138-40I 1442-44 X1461 Ladles ShIrt Istyle LI $10 Sizes 518-101 M112-141 1416-18 X20-221 Add 10% postage/handling Allow 3-4 weeks delivery Send check money order FlightIlne Shirts Etc Department MA 1781 Johnmark Circle Grants Pass OR 97526 Send SASE new brochure Name Address CityStatezip SizeStyleDesign 50 Model Aviation business end spark plug after 27 hours rich cool running Lean running fori 5 hours left plug perfect tan color ground electrode burned filed point see II sti V Price 2995 NEW FOURMOST PRODUCTS 7 Miter Master Mite Maul, tool designed enable crafts man make perfect joints wood accurately sanding pre-setangles squaring fence allowsforprecise9O angles retracts below surface Any angle can beset triangular guide using adjacent side complement angle mill formed making invaluable fur truss construction new cyanoacrylate adhesives require accurately fitted joints achinue full strength Miter Master will enable make easily FOURMOST PRODUCTS 4040 24th Ave Forest Grove OR 97116 raise enough funds wall new building will carry name permanent display Physical progress building project continues industrial revenue bonds approved Virginia April 20 1982 AMA received construction bids proj ect April 26 general contractor has selected Details construction contract being finalized written lending bank AMA finalizing necessary items go settle ment next installment report hope have date start con struction Contributions Additional names donors Building Fund follows listing current first week May 1982 Room new building dedicated name Bill Semler made pos sible friends Bill Semler Honor Wall recognition contributions $1000 up Romak Iron Works New Charter Members AMA Builders plaques acknowledging donations $500 up Central Jersey Radio Control Club Orange Coast RC Club Somers Radio Con trol Airplane Club Tn-City RC Flyers APrice $750 Assembled booed 503 357-2732 Philip 0 Kiaft memory Howard McEntee Elinor McEntee Clark New Life Members have earmarked membership fees Building Fund James Grier F David McDonald Richard Nelson John Reed Jr Contributing Members Honor Roil listing donated $100 up now includes Aero Sport RC Club Atlanta Hawks RC Bar rons Model Club Bartlesville Falcons Blue Angels Model Airplane Club Brainbusters Club Cape Ann RC Club Capitol Area Radio Drone Squadron CARDS Central Carolina RC Modelers Cobb County RC Club Cos hocton City Cloud Climbers Diablo Valley RC Inc East Side RC Club Flying Tigers Fredericksburg Aero Masters Gold Coast Radio Controllers Grassfield RC Club Hampshire County RC Indianapolis Westside RC Modelers Joint Military RC Flyers Laurel Highlands Model Airplane Club League Silent Flight Manned Spacecraft Center RC Club Midwest Sundowners RC Club North ern Air Modelers Palm Beach Aeronauts Peninsula Channel Commanders Remote Control Association Central Florida Sa linas Area Modelers San Fernando RC Flyers Signal Seekers RC Sky Squires RC Club Suds City Sailplane Team Texas City RC WinstonFUSELAGE FIXTURE FOURMOST FUSELAGE FIXTURE desigsed AatomanicIIy aligo fuselage structures built strings measuring eyeballing Simply slide four centering brackets track until align firewall tail joint two bulkheads clamp fuselage together lightly rubberhands structure will straight th track uneemedflCodfluP ut Salem RC Club Inc Woodbnidge RC Bristol Hobby Center CB Associates Inc Jerry Cowan Steve Crowe Otto Curth NP Curtis Father Dignan Eugene R Field James Harris John Hobson Robert Hockley Philip Lees Robert Lon& Guy Markham Bud Meyers Charles Patterson Rex E Per kins Anthony Ptak Peter Rawlins David Rigotti Salinas Valley Printing Slot Wing Hobhies Bob Wilder Walter Zaharevltz Gold Members donated $50 Building Fund will listed Gold Members Scroll Central Atlantic Academy Leaders Jersey Coast RC Club Kansas City RC Association Pioneer Valley RC Quina poxet Model Flying Club Signal Chasers Tri-Rivers RC Modelers Bill Bieda DA Carisen Dick Carson Champion Hobbies Samuel R Compton M Cook Jay E Coon Sr Frank Costello Rich ard Dawson Gerald Deneau Jos Dunkis Ervine E Frierson Ronald Ganser John G Haggart Carl Hatrak Bob Johnson John H Krekelberg Juan Livotto Larry Lundy Bud Grace Meyers Richard Palmer Charles Perry John Porter Thelma Harlan Roth Wallace Smith RF Stevenson Robert Strobel Mary Richard Swenson Jim Traw Milo Valencic Grant Wilson Ernest Wrisley Ernest Zam Don Zook Vince Mankowslci Assistant Executive Director CDI System/Svercl Continued page 50 inner two tubes used strain relief insulation Note notch coil ends inner tubes notch fits hole glass-epoxy board also holds end coil middle tubes notch fits hole outer case outer Teflon tube split Teflon tube too small spacer between inner working insulation braided copper shield Ordinary automotive aircraft cable has much capacity will reduce spark half don5t use Blue aircraft cable used outer ground shield ends must unbraided carefully cleaned before soldering copper tube turn soldered case held split clamp spark plug cover spark plug cover shown has Teflon fillers inside reduce chance spark direct ground trigger small single-play tape head pickup removed its metal case small piece ceramic magnet ground round shape correct polarity observed mounted hole aluminum prop-drive sweeps tape head produce trigger pulse circuit shown should positive pulse Any magnet-coil will pro duce pulse few mY will work Breaker points used because may less reliable LED-photocell trigger may used extra current draw important application Some electronics parts now obsolete Use equal higher ratings substitutions cause values shown close minimums Any good DC DC power supply correct voltages 10 mA output will work An alter nator rectifier may make better system Most case 1/32-in single-sided PC board copper outside serving RF shield Two sides use 1/16-in double-sided board outside copper RF shield inside etched form circuit board parts mounted pads no holes parts mounting use etched circuit board 142 Model Aviation sure etching well done slightest film copper will serve conductor high voltages resulting failure op-amp other high-voltage-sensitive parts Leads may pass using Teflon tubes 001 uF capacitors lead ground inside case ground RF needed external leads including trigger wires diodes around op-amp protect stray voltages lost two op-amps before diodes installed Herb WahI Hurleman-type plug has used over 50 hours great success low power engine relation cooling area 27 hours rich running made plug bit black still firing experimenting type spark system interests start coil can wind good coil rest relatively easy Good luck 15 mil wire will need Profiles/SruII Continued page 59 turn becomes too tight etc Use very small thrust changes degree two time since effect large under full power Dihedral angle tail area model cant made fly consistent circle either direction tightening its turn eventu ally diving probably have spiral stability problems especially common lowwing models little dihedral also appears some parasol configurations large vertical tail surfaces such Curtiss Junior case best remedy usually add dihedral abut two three degrees timeuntil problem subsides Another possible solution reduce vertical tail surface usually looks bad can also lead other stability problems Another tricky method worth try certain models add vertical side area above approximate CG position Walt Mooney sometimes does filling open cabane structure like Curtiss Junior has clear sheet thin plastic can hardly see it will sometimes trick another Walts models added large profile pilot figure otherwise empty cockpit added enough lateral area above CG low-wing model fly properly no dihedral Another problem occurs occasionally directional instability case model will tend wander direction somewhat will impossible adjust reliable turn pattern Unlike spiral stability problem men tioned above however model will tend spin fact directional wandering usually means model spirally stable simple cure difficulty increase vertical tail area find need large amount increase would spoil looks Scale creation can borrow another idea Walt Mooney add transparent tab vertical tail flight will hardly visible trying set CG incidence described earlier models flight path erratic pitch difficult get repeat able results horizontal tail surfaces may too small Add 20 30% horizontal tail area try again tinned page 144 COMPLETE THIS FOAM AND ATTACH MAILING LABEL FROM RECE NT E LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept. Model Aviation 815 Fifteenth St. NW. Washington DC. 20005 Check appropriate boxenclose payment 0 NEW SUBSCRIPTION 0 CHANGE OF ADDRESS Non-AMA subscription rates $1800 12 months US Possessions elsewhere Including Canada MexIco $2400 US Schools $gOO US Libraries $1350 NAME ADDRESS CITY/STATE _____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW WASHINGTON DC 20005 August1982 143
Edition: Model Aviation - 1982/08
Page Numbers: 48, 49, 50, 142, 143
Emil Svercl Capacitive Discha Tired happy IL Jack Finn after gruelling flight 16 hours 43 minutes then-new FAI World Record authors CDI system performed flawlessly whole time Full story record flight February 1982 issue tne Ignition components lCtt tne spark plug cover Teflon spacer plug cover left side case lower right has triggerand high-tension components right side hasthe power supply Lithium batteries upper right rigger coil held Dy split ring clamp around front bearing mount crankcase Note magnet mounted prop drive washer just above upper screw holding coil place 48 Model Aviation e Ignition System Plenny Bates Jack Finn crew began plan Duration World Record attempt needed spark igni tion system would work reliably hours weigh little cause little inter ference stateof-the-art system developed author aid Cedar Rapids Skyhawks team story part project THERE IS NEED lightweight efficient trouble-free spark ignition system model aircraft Interest such events Old-Timer Texaco RC Duration record attempts plus sport flying inexpensive fuel should stimu late further development breakless capacitor discharge CD systems CD systems give higher efficiency greater reliability traditional spark ignition systems short-duration spark long tail also results less spark plug electrode erosion construction article rather some hints few details system developed 1. U Q 6VL2 Jn 6V 00l 220 T2 C 0 2N2905 l220 RC Duration record attempt others giving try better sparkers will soon emerge can wind coil have some electronic design background building system should within capabilities Since battery life important record attempts attention given high efficiency reliability Power needed fully shielded system 125 mA 6A 750 mW unshielded 500mW sufficient shielded system should give 30-plus running hours six ounces lithium battery past 50 hours plug inspection has attention given part system usual iron core coil heavy does GV 0 OA 7 47 L r 180K 2 LMIOI 6 38 2 Q P AA 50K CAPS IN UF DIODES 1N4454 have correct electrical characteristics capacitor discharge unit build coil start ferrite rod ofA diameter long Lay 16 tums two parallel *20 wires remove wire will give needed spacing primary winding Hold wire place Q dope Build up end rings equal thicknesss #20 wire is-in wide Mylar tape Cover primary two layers 005 x 75 Teflon tape next part difficult secondary wound 125 layers 15 mil wire used home-brew computer control lead screw Unimat permitting progression tool holder 15 mil per coil revolution Wire 0 1 120V IoJ 001 LTh2N ____a 200VIOKV H3GC 2 SC 1 U ES 1981 Schematic ignition system Part 2N888 no longer available SCR equal greater voltage will substitute can wind coil have some electronic design background building system should within capabilities 120V -o 01 200V 0 August 1982 49 Diagram ignition power supply L2 parallel-wound toroid transformer functions RF choke T2 Collins Radio surplus toroid unknown specification transformers should work T2 Battery life important record attempt Sparkplug coverdetail Note clamp forholding end spark plug wire shield STRINGWRAP 3/4 TURN 12/2 LAYERS 15 MIL WIRE FERR~ 1/4 x 1 IN IGNITION COIL ES 1981 1 005 x 3/4 IN TEFLON TAPE RG18OBU SHIELDS TEFLON TUBES IKzi RNS NO 20 WIRE 15 Mu MYLAR TAPE 1/8 IN WIDE SEAL FINISHED COIL WITH Q DOPE Cutaway view ignition coil Ti hightension cable As shown coil unfinished just four layersi 2layers needed Author used Unimat coil winding red through small hole Teflon block held tool holder wire reel ball bearing support gave just enough drag pull wire down coiL ball bearing rested Teflon sheet wire stuck reel ball bearing reel assembly pulled across Teflon sheet giving time stop lathe before wire broke wire reel would carefully unstuck lathe restarted Hand winding may possible winding jig controls wire tension gives wire guide correct progression both direc tions better way Over wire layer apply layer 005 x 75 Teflon tape potential difference between windings about OOOV need good dielectric spacing between layers msut about 005 correct inductance characteristics Run last layer mid-point let wire protrude two layers Teflon tape end attached conductor RGI 8OBU co-ax cable shield removed wrapped around coil held Teflon tape string wrap shown drawing Covering co-ax way plug three Teflon tubes shielding Continued page 142 Embroidered airplantn quality blue casual shirts choice royal/white Mustang HMUJ navy/white Corsair HCOJ brown white Spitfire HSPJ red/white Pitts H Sweatershirt style VI 520 Golf Shin Istyle Cl $18 Sizes S432-36I M138-40I 1442-44 X1461 Ladles ShIrt Istyle LI $10 Sizes 518-101 M112-141 1416-18 X20-221 Add 10% postage/handling Allow 3-4 weeks delivery Send check money order FlightIlne Shirts Etc Department MA 1781 Johnmark Circle Grants Pass OR 97526 Send SASE new brochure Name Address CityStatezip SizeStyleDesign 50 Model Aviation business end spark plug after 27 hours rich cool running Lean running fori 5 hours left plug perfect tan color ground electrode burned filed point see II sti V Price 2995 NEW FOURMOST PRODUCTS 7 Miter Master Mite Maul, tool designed enable crafts man make perfect joints wood accurately sanding pre-setangles squaring fence allowsforprecise9O angles retracts below surface Any angle can beset triangular guide using adjacent side complement angle mill formed making invaluable fur truss construction new cyanoacrylate adhesives require accurately fitted joints achinue full strength Miter Master will enable make easily FOURMOST PRODUCTS 4040 24th Ave Forest Grove OR 97116 raise enough funds wall new building will carry name permanent display Physical progress building project continues industrial revenue bonds approved Virginia April 20 1982 AMA received construction bids proj ect April 26 general contractor has selected Details construction contract being finalized written lending bank AMA finalizing necessary items go settle ment next installment report hope have date start con struction Contributions Additional names donors Building Fund follows listing current first week May 1982 Room new building dedicated name Bill Semler made pos sible friends Bill Semler Honor Wall recognition contributions $1000 up Romak Iron Works New Charter Members AMA Builders plaques acknowledging donations $500 up Central Jersey Radio Control Club Orange Coast RC Club Somers Radio Con trol Airplane Club Tn-City RC Flyers APrice $750 Assembled booed 503 357-2732 Philip 0 Kiaft memory Howard McEntee Elinor McEntee Clark New Life Members have earmarked membership fees Building Fund James Grier F David McDonald Richard Nelson John Reed Jr Contributing Members Honor Roil listing donated $100 up now includes Aero Sport RC Club Atlanta Hawks RC Bar rons Model Club Bartlesville Falcons Blue Angels Model Airplane Club Brainbusters Club Cape Ann RC Club Capitol Area Radio Drone Squadron CARDS Central Carolina RC Modelers Cobb County RC Club Cos hocton City Cloud Climbers Diablo Valley RC Inc East Side RC Club Flying Tigers Fredericksburg Aero Masters Gold Coast Radio Controllers Grassfield RC Club Hampshire County RC Indianapolis Westside RC Modelers Joint Military RC Flyers Laurel Highlands Model Airplane Club League Silent Flight Manned Spacecraft Center RC Club Midwest Sundowners RC Club North ern Air Modelers Palm Beach Aeronauts Peninsula Channel Commanders Remote Control Association Central Florida Sa linas Area Modelers San Fernando RC Flyers Signal Seekers RC Sky Squires RC Club Suds City Sailplane Team Texas City RC WinstonFUSELAGE FIXTURE FOURMOST FUSELAGE FIXTURE desigsed AatomanicIIy aligo fuselage structures built strings measuring eyeballing Simply slide four centering brackets track until align firewall tail joint two bulkheads clamp fuselage together lightly rubberhands structure will straight th track uneemedflCodfluP ut Salem RC Club Inc Woodbnidge RC Bristol Hobby Center CB Associates Inc Jerry Cowan Steve Crowe Otto Curth NP Curtis Father Dignan Eugene R Field James Harris John Hobson Robert Hockley Philip Lees Robert Lon& Guy Markham Bud Meyers Charles Patterson Rex E Per kins Anthony Ptak Peter Rawlins David Rigotti Salinas Valley Printing Slot Wing Hobhies Bob Wilder Walter Zaharevltz Gold Members donated $50 Building Fund will listed Gold Members Scroll Central Atlantic Academy Leaders Jersey Coast RC Club Kansas City RC Association Pioneer Valley RC Quina poxet Model Flying Club Signal Chasers Tri-Rivers RC Modelers Bill Bieda DA Carisen Dick Carson Champion Hobbies Samuel R Compton M Cook Jay E Coon Sr Frank Costello Rich ard Dawson Gerald Deneau Jos Dunkis Ervine E Frierson Ronald Ganser John G Haggart Carl Hatrak Bob Johnson John H Krekelberg Juan Livotto Larry Lundy Bud Grace Meyers Richard Palmer Charles Perry John Porter Thelma Harlan Roth Wallace Smith RF Stevenson Robert Strobel Mary Richard Swenson Jim Traw Milo Valencic Grant Wilson Ernest Wrisley Ernest Zam Don Zook Vince Mankowslci Assistant Executive Director CDI System/Svercl Continued page 50 inner two tubes used strain relief insulation Note notch coil ends inner tubes notch fits hole glass-epoxy board also holds end coil middle tubes notch fits hole outer case outer Teflon tube split Teflon tube too small spacer between inner working insulation braided copper shield Ordinary automotive aircraft cable has much capacity will reduce spark half don5t use Blue aircraft cable used outer ground shield ends must unbraided carefully cleaned before soldering copper tube turn soldered case held split clamp spark plug cover spark plug cover shown has Teflon fillers inside reduce chance spark direct ground trigger small single-play tape head pickup removed its metal case small piece ceramic magnet ground round shape correct polarity observed mounted hole aluminum prop-drive sweeps tape head produce trigger pulse circuit shown should positive pulse Any magnet-coil will pro duce pulse few mY will work Breaker points used because may less reliable LED-photocell trigger may used extra current draw important application Some electronics parts now obsolete Use equal higher ratings substitutions cause values shown close minimums Any good DC DC power supply correct voltages 10 mA output will work An alter nator rectifier may make better system Most case 1/32-in single-sided PC board copper outside serving RF shield Two sides use 1/16-in double-sided board outside copper RF shield inside etched form circuit board parts mounted pads no holes parts mounting use etched circuit board 142 Model Aviation sure etching well done slightest film copper will serve conductor high voltages resulting failure op-amp other high-voltage-sensitive parts Leads may pass using Teflon tubes 001 uF capacitors lead ground inside case ground RF needed external leads including trigger wires diodes around op-amp protect stray voltages lost two op-amps before diodes installed Herb WahI Hurleman-type plug has used over 50 hours great success low power engine relation cooling area 27 hours rich running made plug bit black still firing experimenting type spark system interests start coil can wind good coil rest relatively easy Good luck 15 mil wire will need Profiles/SruII Continued page 59 turn becomes too tight etc Use very small thrust changes degree two time since effect large under full power Dihedral angle tail area model cant made fly consistent circle either direction tightening its turn eventu ally diving probably have spiral stability problems especially common lowwing models little dihedral also appears some parasol configurations large vertical tail surfaces such Curtiss Junior case best remedy usually add dihedral abut two three degrees timeuntil problem subsides Another possible solution reduce vertical tail surface usually looks bad can also lead other stability problems Another tricky method worth try certain models add vertical side area above approximate CG position Walt Mooney sometimes does filling open cabane structure like Curtiss Junior has clear sheet thin plastic can hardly see it will sometimes trick another Walts models added large profile pilot figure otherwise empty cockpit added enough lateral area above CG low-wing model fly properly no dihedral Another problem occurs occasionally directional instability case model will tend wander direction somewhat will impossible adjust reliable turn pattern Unlike spiral stability problem men tioned above however model will tend spin fact directional wandering usually means model spirally stable simple cure difficulty increase vertical tail area find need large amount increase would spoil looks Scale creation can borrow another idea Walt Mooney add transparent tab vertical tail flight will hardly visible trying set CG incidence described earlier models flight path erratic pitch difficult get repeat able results horizontal tail surfaces may too small Add 20 30% horizontal tail area try again tinned page 144 COMPLETE THIS FOAM AND ATTACH MAILING LABEL FROM RECE NT E LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept. Model Aviation 815 Fifteenth St. NW. Washington DC. 20005 Check appropriate boxenclose payment 0 NEW SUBSCRIPTION 0 CHANGE OF ADDRESS Non-AMA subscription rates $1800 12 months US Possessions elsewhere Including Canada MexIco $2400 US Schools $gOO US Libraries $1350 NAME ADDRESS CITY/STATE _____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW WASHINGTON DC 20005 August1982 143
Edition: Model Aviation - 1982/08
Page Numbers: 48, 49, 50, 142, 143
Emil Svercl Capacitive Discha Tired happy IL Jack Finn after gruelling flight 16 hours 43 minutes then-new FAI World Record authors CDI system performed flawlessly whole time Full story record flight February 1982 issue tne Ignition components lCtt tne spark plug cover Teflon spacer plug cover left side case lower right has triggerand high-tension components right side hasthe power supply Lithium batteries upper right rigger coil held Dy split ring clamp around front bearing mount crankcase Note magnet mounted prop drive washer just above upper screw holding coil place 48 Model Aviation e Ignition System Plenny Bates Jack Finn crew began plan Duration World Record attempt needed spark igni tion system would work reliably hours weigh little cause little inter ference stateof-the-art system developed author aid Cedar Rapids Skyhawks team story part project THERE IS NEED lightweight efficient trouble-free spark ignition system model aircraft Interest such events Old-Timer Texaco RC Duration record attempts plus sport flying inexpensive fuel should stimu late further development breakless capacitor discharge CD systems CD systems give higher efficiency greater reliability traditional spark ignition systems short-duration spark long tail also results less spark plug electrode erosion construction article rather some hints few details system developed 1. U Q 6VL2 Jn 6V 00l 220 T2 C 0 2N2905 l220 RC Duration record attempt others giving try better sparkers will soon emerge can wind coil have some electronic design background building system should within capabilities Since battery life important record attempts attention given high efficiency reliability Power needed fully shielded system 125 mA 6A 750 mW unshielded 500mW sufficient shielded system should give 30-plus running hours six ounces lithium battery past 50 hours plug inspection has attention given part system usual iron core coil heavy does GV 0 OA 7 47 L r 180K 2 LMIOI 6 38 2 Q P AA 50K CAPS IN UF DIODES 1N4454 have correct electrical characteristics capacitor discharge unit build coil start ferrite rod ofA diameter long Lay 16 tums two parallel *20 wires remove wire will give needed spacing primary winding Hold wire place Q dope Build up end rings equal thicknesss #20 wire is-in wide Mylar tape Cover primary two layers 005 x 75 Teflon tape next part difficult secondary wound 125 layers 15 mil wire used home-brew computer control lead screw Unimat permitting progression tool holder 15 mil per coil revolution Wire 0 1 120V IoJ 001 LTh2N ____a 200VIOKV H3GC 2 SC 1 U ES 1981 Schematic ignition system Part 2N888 no longer available SCR equal greater voltage will substitute can wind coil have some electronic design background building system should within capabilities 120V -o 01 200V 0 August 1982 49 Diagram ignition power supply L2 parallel-wound toroid transformer functions RF choke T2 Collins Radio surplus toroid unknown specification transformers should work T2 Battery life important record attempt Sparkplug coverdetail Note clamp forholding end spark plug wire shield STRINGWRAP 3/4 TURN 12/2 LAYERS 15 MIL WIRE FERR~ 1/4 x 1 IN IGNITION COIL ES 1981 1 005 x 3/4 IN TEFLON TAPE RG18OBU SHIELDS TEFLON TUBES IKzi RNS NO 20 WIRE 15 Mu MYLAR TAPE 1/8 IN WIDE SEAL FINISHED COIL WITH Q DOPE Cutaway view ignition coil Ti hightension cable As shown coil unfinished just four layersi 2layers needed Author used Unimat coil winding red through small hole Teflon block held tool holder wire reel ball bearing support gave just enough drag pull wire down coiL ball bearing rested Teflon sheet wire stuck reel ball bearing reel assembly pulled across Teflon sheet giving time stop lathe before wire broke wire reel would carefully unstuck lathe restarted Hand winding may possible winding jig controls wire tension gives wire guide correct progression both direc tions better way Over wire layer apply layer 005 x 75 Teflon tape potential difference between windings about OOOV need good dielectric spacing between layers msut about 005 correct inductance characteristics Run last layer mid-point let wire protrude two layers Teflon tape end attached conductor RGI 8OBU co-ax cable shield removed wrapped around coil held Teflon tape string wrap shown drawing Covering co-ax way plug three Teflon tubes shielding Continued page 142 Embroidered airplantn quality blue casual shirts choice royal/white Mustang HMUJ navy/white Corsair HCOJ brown white Spitfire HSPJ red/white Pitts H Sweatershirt style VI 520 Golf Shin Istyle Cl $18 Sizes S432-36I M138-40I 1442-44 X1461 Ladles ShIrt Istyle LI $10 Sizes 518-101 M112-141 1416-18 X20-221 Add 10% postage/handling Allow 3-4 weeks delivery Send check money order FlightIlne Shirts Etc Department MA 1781 Johnmark Circle Grants Pass OR 97526 Send SASE new brochure Name Address CityStatezip SizeStyleDesign 50 Model Aviation business end spark plug after 27 hours rich cool running Lean running fori 5 hours left plug perfect tan color ground electrode burned filed point see II sti V Price 2995 NEW FOURMOST PRODUCTS 7 Miter Master Mite Maul, tool designed enable crafts man make perfect joints wood accurately sanding pre-setangles squaring fence allowsforprecise9O angles retracts below surface Any angle can beset triangular guide using adjacent side complement angle mill formed making invaluable fur truss construction new cyanoacrylate adhesives require accurately fitted joints achinue full strength Miter Master will enable make easily FOURMOST PRODUCTS 4040 24th Ave Forest Grove OR 97116 raise enough funds wall new building will carry name permanent display Physical progress building project continues industrial revenue bonds approved Virginia April 20 1982 AMA received construction bids proj ect April 26 general contractor has selected Details construction contract being finalized written lending bank AMA finalizing necessary items go settle ment next installment report hope have date start con struction Contributions Additional names donors Building Fund follows listing current first week May 1982 Room new building dedicated name Bill Semler made pos sible friends Bill Semler Honor Wall recognition contributions $1000 up Romak Iron Works New Charter Members AMA Builders plaques acknowledging donations $500 up Central Jersey Radio Control Club Orange Coast RC Club Somers Radio Con trol Airplane Club Tn-City RC Flyers APrice $750 Assembled booed 503 357-2732 Philip 0 Kiaft memory Howard McEntee Elinor McEntee Clark New Life Members have earmarked membership fees Building Fund James Grier F David McDonald Richard Nelson John Reed Jr Contributing Members Honor Roil listing donated $100 up now includes Aero Sport RC Club Atlanta Hawks RC Bar rons Model Club Bartlesville Falcons Blue Angels Model Airplane Club Brainbusters Club Cape Ann RC Club Capitol Area Radio Drone Squadron CARDS Central Carolina RC Modelers Cobb County RC Club Cos hocton City Cloud Climbers Diablo Valley RC Inc East Side RC Club Flying Tigers Fredericksburg Aero Masters Gold Coast Radio Controllers Grassfield RC Club Hampshire County RC Indianapolis Westside RC Modelers Joint Military RC Flyers Laurel Highlands Model Airplane Club League Silent Flight Manned Spacecraft Center RC Club Midwest Sundowners RC Club North ern Air Modelers Palm Beach Aeronauts Peninsula Channel Commanders Remote Control Association Central Florida Sa linas Area Modelers San Fernando RC Flyers Signal Seekers RC Sky Squires RC Club Suds City Sailplane Team Texas City RC WinstonFUSELAGE FIXTURE FOURMOST FUSELAGE FIXTURE desigsed AatomanicIIy aligo fuselage structures built strings measuring eyeballing Simply slide four centering brackets track until align firewall tail joint two bulkheads clamp fuselage together lightly rubberhands structure will straight th track uneemedflCodfluP ut Salem RC Club Inc Woodbnidge RC Bristol Hobby Center CB Associates Inc Jerry Cowan Steve Crowe Otto Curth NP Curtis Father Dignan Eugene R Field James Harris John Hobson Robert Hockley Philip Lees Robert Lon& Guy Markham Bud Meyers Charles Patterson Rex E Per kins Anthony Ptak Peter Rawlins David Rigotti Salinas Valley Printing Slot Wing Hobhies Bob Wilder Walter Zaharevltz Gold Members donated $50 Building Fund will listed Gold Members Scroll Central Atlantic Academy Leaders Jersey Coast RC Club Kansas City RC Association Pioneer Valley RC Quina poxet Model Flying Club Signal Chasers Tri-Rivers RC Modelers Bill Bieda DA Carisen Dick Carson Champion Hobbies Samuel R Compton M Cook Jay E Coon Sr Frank Costello Rich ard Dawson Gerald Deneau Jos Dunkis Ervine E Frierson Ronald Ganser John G Haggart Carl Hatrak Bob Johnson John H Krekelberg Juan Livotto Larry Lundy Bud Grace Meyers Richard Palmer Charles Perry John Porter Thelma Harlan Roth Wallace Smith RF Stevenson Robert Strobel Mary Richard Swenson Jim Traw Milo Valencic Grant Wilson Ernest Wrisley Ernest Zam Don Zook Vince Mankowslci Assistant Executive Director CDI System/Svercl Continued page 50 inner two tubes used strain relief insulation Note notch coil ends inner tubes notch fits hole glass-epoxy board also holds end coil middle tubes notch fits hole outer case outer Teflon tube split Teflon tube too small spacer between inner working insulation braided copper shield Ordinary automotive aircraft cable has much capacity will reduce spark half don5t use Blue aircraft cable used outer ground shield ends must unbraided carefully cleaned before soldering copper tube turn soldered case held split clamp spark plug cover spark plug cover shown has Teflon fillers inside reduce chance spark direct ground trigger small single-play tape head pickup removed its metal case small piece ceramic magnet ground round shape correct polarity observed mounted hole aluminum prop-drive sweeps tape head produce trigger pulse circuit shown should positive pulse Any magnet-coil will pro duce pulse few mY will work Breaker points used because may less reliable LED-photocell trigger may used extra current draw important application Some electronics parts now obsolete Use equal higher ratings substitutions cause values shown close minimums Any good DC DC power supply correct voltages 10 mA output will work An alter nator rectifier may make better system Most case 1/32-in single-sided PC board copper outside serving RF shield Two sides use 1/16-in double-sided board outside copper RF shield inside etched form circuit board parts mounted pads no holes parts mounting use etched circuit board 142 Model Aviation sure etching well done slightest film copper will serve conductor high voltages resulting failure op-amp other high-voltage-sensitive parts Leads may pass using Teflon tubes 001 uF capacitors lead ground inside case ground RF needed external leads including trigger wires diodes around op-amp protect stray voltages lost two op-amps before diodes installed Herb WahI Hurleman-type plug has used over 50 hours great success low power engine relation cooling area 27 hours rich running made plug bit black still firing experimenting type spark system interests start coil can wind good coil rest relatively easy Good luck 15 mil wire will need Profiles/SruII Continued page 59 turn becomes too tight etc Use very small thrust changes degree two time since effect large under full power Dihedral angle tail area model cant made fly consistent circle either direction tightening its turn eventu ally diving probably have spiral stability problems especially common lowwing models little dihedral also appears some parasol configurations large vertical tail surfaces such Curtiss Junior case best remedy usually add dihedral abut two three degrees timeuntil problem subsides Another possible solution reduce vertical tail surface usually looks bad can also lead other stability problems Another tricky method worth try certain models add vertical side area above approximate CG position Walt Mooney sometimes does filling open cabane structure like Curtiss Junior has clear sheet thin plastic can hardly see it will sometimes trick another Walts models added large profile pilot figure otherwise empty cockpit added enough lateral area above CG low-wing model fly properly no dihedral Another problem occurs occasionally directional instability case model will tend wander direction somewhat will impossible adjust reliable turn pattern Unlike spiral stability problem men tioned above however model will tend spin fact directional wandering usually means model spirally stable simple cure difficulty increase vertical tail area find need large amount increase would spoil looks Scale creation can borrow another idea Walt Mooney add transparent tab vertical tail flight will hardly visible trying set CG incidence described earlier models flight path erratic pitch difficult get repeat able results horizontal tail surfaces may too small Add 20 30% horizontal tail area try again tinned page 144 COMPLETE THIS FOAM AND ATTACH MAILING LABEL FROM RECE NT E LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept. Model Aviation 815 Fifteenth St. NW. Washington DC. 20005 Check appropriate boxenclose payment 0 NEW SUBSCRIPTION 0 CHANGE OF ADDRESS Non-AMA subscription rates $1800 12 months US Possessions elsewhere Including Canada MexIco $2400 US Schools $gOO US Libraries $1350 NAME ADDRESS CITY/STATE _____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW WASHINGTON DC 20005 August1982 143
Edition: Model Aviation - 1982/08
Page Numbers: 48, 49, 50, 142, 143
Emil Svercl Capacitive Discha Tired happy IL Jack Finn after gruelling flight 16 hours 43 minutes then-new FAI World Record authors CDI system performed flawlessly whole time Full story record flight February 1982 issue tne Ignition components lCtt tne spark plug cover Teflon spacer plug cover left side case lower right has triggerand high-tension components right side hasthe power supply Lithium batteries upper right rigger coil held Dy split ring clamp around front bearing mount crankcase Note magnet mounted prop drive washer just above upper screw holding coil place 48 Model Aviation e Ignition System Plenny Bates Jack Finn crew began plan Duration World Record attempt needed spark igni tion system would work reliably hours weigh little cause little inter ference stateof-the-art system developed author aid Cedar Rapids Skyhawks team story part project THERE IS NEED lightweight efficient trouble-free spark ignition system model aircraft Interest such events Old-Timer Texaco RC Duration record attempts plus sport flying inexpensive fuel should stimu late further development breakless capacitor discharge CD systems CD systems give higher efficiency greater reliability traditional spark ignition systems short-duration spark long tail also results less spark plug electrode erosion construction article rather some hints few details system developed 1. U Q 6VL2 Jn 6V 00l 220 T2 C 0 2N2905 l220 RC Duration record attempt others giving try better sparkers will soon emerge can wind coil have some electronic design background building system should within capabilities Since battery life important record attempts attention given high efficiency reliability Power needed fully shielded system 125 mA 6A 750 mW unshielded 500mW sufficient shielded system should give 30-plus running hours six ounces lithium battery past 50 hours plug inspection has attention given part system usual iron core coil heavy does GV 0 OA 7 47 L r 180K 2 LMIOI 6 38 2 Q P AA 50K CAPS IN UF DIODES 1N4454 have correct electrical characteristics capacitor discharge unit build coil start ferrite rod ofA diameter long Lay 16 tums two parallel *20 wires remove wire will give needed spacing primary winding Hold wire place Q dope Build up end rings equal thicknesss #20 wire is-in wide Mylar tape Cover primary two layers 005 x 75 Teflon tape next part difficult secondary wound 125 layers 15 mil wire used home-brew computer control lead screw Unimat permitting progression tool holder 15 mil per coil revolution Wire 0 1 120V IoJ 001 LTh2N ____a 200VIOKV H3GC 2 SC 1 U ES 1981 Schematic ignition system Part 2N888 no longer available SCR equal greater voltage will substitute can wind coil have some electronic design background building system should within capabilities 120V -o 01 200V 0 August 1982 49 Diagram ignition power supply L2 parallel-wound toroid transformer functions RF choke T2 Collins Radio surplus toroid unknown specification transformers should work T2 Battery life important record attempt Sparkplug coverdetail Note clamp forholding end spark plug wire shield STRINGWRAP 3/4 TURN 12/2 LAYERS 15 MIL WIRE FERR~ 1/4 x 1 IN IGNITION COIL ES 1981 1 005 x 3/4 IN TEFLON TAPE RG18OBU SHIELDS TEFLON TUBES IKzi RNS NO 20 WIRE 15 Mu MYLAR TAPE 1/8 IN WIDE SEAL FINISHED COIL WITH Q DOPE Cutaway view ignition coil Ti hightension cable As shown coil unfinished just four layersi 2layers needed Author used Unimat coil winding red through small hole Teflon block held tool holder wire reel ball bearing support gave just enough drag pull wire down coiL ball bearing rested Teflon sheet wire stuck reel ball bearing reel assembly pulled across Teflon sheet giving time stop lathe before wire broke wire reel would carefully unstuck lathe restarted Hand winding may possible winding jig controls wire tension gives wire guide correct progression both direc tions better way Over wire layer apply layer 005 x 75 Teflon tape potential difference between windings about OOOV need good dielectric spacing between layers msut about 005 correct inductance characteristics Run last layer mid-point let wire protrude two layers Teflon tape end attached conductor RGI 8OBU co-ax cable shield removed wrapped around coil held Teflon tape string wrap shown drawing Covering co-ax way plug three Teflon tubes shielding Continued page 142 Embroidered airplantn quality blue casual shirts choice royal/white Mustang HMUJ navy/white Corsair HCOJ brown white Spitfire HSPJ red/white Pitts H Sweatershirt style VI 520 Golf Shin Istyle Cl $18 Sizes S432-36I M138-40I 1442-44 X1461 Ladles ShIrt Istyle LI $10 Sizes 518-101 M112-141 1416-18 X20-221 Add 10% postage/handling Allow 3-4 weeks delivery Send check money order FlightIlne Shirts Etc Department MA 1781 Johnmark Circle Grants Pass OR 97526 Send SASE new brochure Name Address CityStatezip SizeStyleDesign 50 Model Aviation business end spark plug after 27 hours rich cool running Lean running fori 5 hours left plug perfect tan color ground electrode burned filed point see II sti V Price 2995 NEW FOURMOST PRODUCTS 7 Miter Master Mite Maul, tool designed enable crafts man make perfect joints wood accurately sanding pre-setangles squaring fence allowsforprecise9O angles retracts below surface Any angle can beset triangular guide using adjacent side complement angle mill formed making invaluable fur truss construction new cyanoacrylate adhesives require accurately fitted joints achinue full strength Miter Master will enable make easily FOURMOST PRODUCTS 4040 24th Ave Forest Grove OR 97116 raise enough funds wall new building will carry name permanent display Physical progress building project continues industrial revenue bonds approved Virginia April 20 1982 AMA received construction bids proj ect April 26 general contractor has selected Details construction contract being finalized written lending bank AMA finalizing necessary items go settle ment next installment report hope have date start con struction Contributions Additional names donors Building Fund follows listing current first week May 1982 Room new building dedicated name Bill Semler made pos sible friends Bill Semler Honor Wall recognition contributions $1000 up Romak Iron Works New Charter Members AMA Builders plaques acknowledging donations $500 up Central Jersey Radio Control Club Orange Coast RC Club Somers Radio Con trol Airplane Club Tn-City RC Flyers APrice $750 Assembled booed 503 357-2732 Philip 0 Kiaft memory Howard McEntee Elinor McEntee Clark New Life Members have earmarked membership fees Building Fund James Grier F David McDonald Richard Nelson John Reed Jr Contributing Members Honor Roil listing donated $100 up now includes Aero Sport RC Club Atlanta Hawks RC Bar rons Model Club Bartlesville Falcons Blue Angels Model Airplane Club Brainbusters Club Cape Ann RC Club Capitol Area Radio Drone Squadron CARDS Central Carolina RC Modelers Cobb County RC Club Cos hocton City Cloud Climbers Diablo Valley RC Inc East Side RC Club Flying Tigers Fredericksburg Aero Masters Gold Coast Radio Controllers Grassfield RC Club Hampshire County RC Indianapolis Westside RC Modelers Joint Military RC Flyers Laurel Highlands Model Airplane Club League Silent Flight Manned Spacecraft Center RC Club Midwest Sundowners RC Club North ern Air Modelers Palm Beach Aeronauts Peninsula Channel Commanders Remote Control Association Central Florida Sa linas Area Modelers San Fernando RC Flyers Signal Seekers RC Sky Squires RC Club Suds City Sailplane Team Texas City RC WinstonFUSELAGE FIXTURE FOURMOST FUSELAGE FIXTURE desigsed AatomanicIIy aligo fuselage structures built strings measuring eyeballing Simply slide four centering brackets track until align firewall tail joint two bulkheads clamp fuselage together lightly rubberhands structure will straight th track uneemedflCodfluP ut Salem RC Club Inc Woodbnidge RC Bristol Hobby Center CB Associates Inc Jerry Cowan Steve Crowe Otto Curth NP Curtis Father Dignan Eugene R Field James Harris John Hobson Robert Hockley Philip Lees Robert Lon& Guy Markham Bud Meyers Charles Patterson Rex E Per kins Anthony Ptak Peter Rawlins David Rigotti Salinas Valley Printing Slot Wing Hobhies Bob Wilder Walter Zaharevltz Gold Members donated $50 Building Fund will listed Gold Members Scroll Central Atlantic Academy Leaders Jersey Coast RC Club Kansas City RC Association Pioneer Valley RC Quina poxet Model Flying Club Signal Chasers Tri-Rivers RC Modelers Bill Bieda DA Carisen Dick Carson Champion Hobbies Samuel R Compton M Cook Jay E Coon Sr Frank Costello Rich ard Dawson Gerald Deneau Jos Dunkis Ervine E Frierson Ronald Ganser John G Haggart Carl Hatrak Bob Johnson John H Krekelberg Juan Livotto Larry Lundy Bud Grace Meyers Richard Palmer Charles Perry John Porter Thelma Harlan Roth Wallace Smith RF Stevenson Robert Strobel Mary Richard Swenson Jim Traw Milo Valencic Grant Wilson Ernest Wrisley Ernest Zam Don Zook Vince Mankowslci Assistant Executive Director CDI System/Svercl Continued page 50 inner two tubes used strain relief insulation Note notch coil ends inner tubes notch fits hole glass-epoxy board also holds end coil middle tubes notch fits hole outer case outer Teflon tube split Teflon tube too small spacer between inner working insulation braided copper shield Ordinary automotive aircraft cable has much capacity will reduce spark half don5t use Blue aircraft cable used outer ground shield ends must unbraided carefully cleaned before soldering copper tube turn soldered case held split clamp spark plug cover spark plug cover shown has Teflon fillers inside reduce chance spark direct ground trigger small single-play tape head pickup removed its metal case small piece ceramic magnet ground round shape correct polarity observed mounted hole aluminum prop-drive sweeps tape head produce trigger pulse circuit shown should positive pulse Any magnet-coil will pro duce pulse few mY will work Breaker points used because may less reliable LED-photocell trigger may used extra current draw important application Some electronics parts now obsolete Use equal higher ratings substitutions cause values shown close minimums Any good DC DC power supply correct voltages 10 mA output will work An alter nator rectifier may make better system Most case 1/32-in single-sided PC board copper outside serving RF shield Two sides use 1/16-in double-sided board outside copper RF shield inside etched form circuit board parts mounted pads no holes parts mounting use etched circuit board 142 Model Aviation sure etching well done slightest film copper will serve conductor high voltages resulting failure op-amp other high-voltage-sensitive parts Leads may pass using Teflon tubes 001 uF capacitors lead ground inside case ground RF needed external leads including trigger wires diodes around op-amp protect stray voltages lost two op-amps before diodes installed Herb WahI Hurleman-type plug has used over 50 hours great success low power engine relation cooling area 27 hours rich running made plug bit black still firing experimenting type spark system interests start coil can wind good coil rest relatively easy Good luck 15 mil wire will need Profiles/SruII Continued page 59 turn becomes too tight etc Use very small thrust changes degree two time since effect large under full power Dihedral angle tail area model cant made fly consistent circle either direction tightening its turn eventu ally diving probably have spiral stability problems especially common lowwing models little dihedral also appears some parasol configurations large vertical tail surfaces such Curtiss Junior case best remedy usually add dihedral abut two three degrees timeuntil problem subsides Another possible solution reduce vertical tail surface usually looks bad can also lead other stability problems Another tricky method worth try certain models add vertical side area above approximate CG position Walt Mooney sometimes does filling open cabane structure like Curtiss Junior has clear sheet thin plastic can hardly see it will sometimes trick another Walts models added large profile pilot figure otherwise empty cockpit added enough lateral area above CG low-wing model fly properly no dihedral Another problem occurs occasionally directional instability case model will tend wander direction somewhat will impossible adjust reliable turn pattern Unlike spiral stability problem men tioned above however model will tend spin fact directional wandering usually means model spirally stable simple cure difficulty increase vertical tail area find need large amount increase would spoil looks Scale creation can borrow another idea Walt Mooney add transparent tab vertical tail flight will hardly visible trying set CG incidence described earlier models flight path erratic pitch difficult get repeat able results horizontal tail surfaces may too small Add 20 30% horizontal tail area try again tinned page 144 COMPLETE THIS FOAM AND ATTACH MAILING LABEL FROM RECE NT E LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept. Model Aviation 815 Fifteenth St. NW. Washington DC. 20005 Check appropriate boxenclose payment 0 NEW SUBSCRIPTION 0 CHANGE OF ADDRESS Non-AMA subscription rates $1800 12 months US Possessions elsewhere Including Canada MexIco $2400 US Schools $gOO US Libraries $1350 NAME ADDRESS CITY/STATE _____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW WASHINGTON DC 20005 August1982 143