- 3 NU expensive way determine inflight engine speed CL models RC models flown circle Can also used static tests Richard Porter THE INSPIRATION idea goes back least two sources first article model magazines about Speed flier tape-recorded sound expensive racing engines process burning itself up top rpm later listened tape played notes piano closely matched beautiful sound him racing engine committing hari-kari time felt what would work Speed guy would surely work Stunt flier like second source came found myself middle Trends Science graduate edu cation course taught Dr E Steiner University South Florida made totally open assignment due next week wandered over USF library began browsing through various physics books see could find anything relating frequency various musical notes didnt take long find well-illustrated nomogram text defined musical notes terms cycles per second simply multiplying value 60 cycles per minute could obtained Now could compare musical note sound rpm reasonably smooth-running two-cycling model engine discovered C-to-C pitch pipe worked perfectly musical reference Any instrument will play standard notes can used reference tried couple cheap harmonicas lowest note would play something close high C30000 cycles per minute humming tune engine blowing pitch pipe listening slow beat frequency and/or pitch pipe fre quency very close right same frequency sound engine rpm could easily determined directly nomogram C-to-C pitch pipe gives direct comparison 13 different frequencies 15700 31400 cycles per minute might initially think intervals too large useful consideration given fact possible determine engine rpm between two notesand sometimes noticeably closer note another reasonably accurate measure ment can made scratched frequency-times-60 values Continued page 111 C TCH PIPE lI\I 157K 166K 176K 186K 198K 210K 222K 235K 249K 264K 280K 296K 314K C # 0 9 E F # B C musical notes C-to-C pitch pipe corresponding cycles per minute rpm range 15700 31400 Reasonably accurate rpm can also determined between notes 40 Model Aviation magic pitch pipe disassembled Porter scratched rpm scale piece transparent plastic left next washer nut Other major pieces cover ar right tone reed-bank dark plastic cover pieces bolted together Get pitch pipes music stores author tunes TD-powered Ridiculous 12A Stunter before flightusing musical tech Rich Porter isnt munching sandwich dur ingaClEnduranceflight Hesusingpitchpipe make in-flight rpm check THE chose Waco F-3 biplane flagship because bet represents Golden Era 1930s flying adventure Add easy snag-free building saie gentle flyingthe result thorough kit engineering careful prototype development features Platt Kits have satisfying building flying experience ahead Kit IeaturesTop-quality diecut machined balsa plywood Full size plans Separate instruction book isometrics Decals Injection-moulded vacuum-formed plastic cowl cowl blisters wheel pants required nylon fittings Formed wire langinggear&struts Span 60Area 950 Sq4to6channel Engine good 40 60 j 2657 NE 188th Street Miami Florida 33180 Telephone g35-1436 fellow modelers unorthodox aircraft important designing building un orthodox CL models keep mind presence CL leadouts wires will serve very nicely sort stabilizer functioning both yaw vertical roll longitudinal axes especially true case rotor craft can usually expected have roll stability problem thus observations herein presented may valid model types other CL 1 The flying speed autogiro extent inversely proportional rotor al though number blades area play important role have observed models having large diameter rotors will fly relatively low airspeed makes very susceptible effects wind gusts Furthermore machines will usually exhibit uncontrol lable pitch-up engine stops fortunately will followed parachute-like descent addition large diameter rotors may radially floppy can lead some real control difficulties Another disadvantage large rotor hard landing can cause blades flex downwards far enough strike fuselage tail 2 Other things being equal small rotor will require longer takeoff run attain flying rpm will spin faster have effective control resulting airplane-like flight 3 Number blades two-blade rotor easiest build also easiest handle starting engine obvious blades multiple-bladed rotor can real obstacle enthusiastic prop-flipping other hand multi-blade rotors spin-up faster giving shorter takeoffs will support heavier aircraft appears three-bladed rotor will satisfactory compromise 4 usual practice tilt rotor disc rear absolutely necessary rotor pivot left vertical model will fly quite nose-high attitude takeoff roll will excessive 5 CG model should balanced point about R ahead pivot flight may possible center-of-gravity pivot control will very hairy 6 Wings Although early full-scale auto giros used wings addition rotors appendages best avoided models winged model giros may find themselves precarious situation having become airborne virtue wing lift before rotor has attained flying rpm As rotor lift becomes factor however attendant rise drag may slow model wing stalls Therefore better far rely entirely rotor Wings may desirable other reasons though fitted should made too small support model flight 7 STOL operations properly constructed giro may relied upon land very small space indeed short takeoff desired may disappointed full-scale autogiros capable near-vertical takeoffs accomplished using power taken engine through system shafts clutches spin up rotor Unless willing undergo sort complexity well have settle takeoff run considered lengthy conventional airplane standards 8 Control Normalairplanetype tail surfaces will produce very good control will provide flight little different airplane long tail moment arm desirable model both elevator authority well conven ience handling launching model 9 Lift Avro C6 weighs 6 oz built will fly very nicely 9 oz two blades manageable 10-mph breeze final point model giros may made much easier transport provision made readily remove rotor sure lubricate rotor pivot inspect rotor security damage between flights Music Tach/Porter Continued page 40 nomogram plastic side pitch pipe Middle C157K C sharp166K D 176K D sharp186K E198K F21 0K F sharp222K G235K G sharp249K A264K sharp2796K B2964K C 314K range can extended both above below range pitch pipe humming lower higher harmonics simultaneously blowing selected note listening low beat frequency determine value unknown harmonic frequency example high C first harmonic above middle C Cto-C pitch pipe humming low C blowing high C very discernible beat frequency can experienced same effect takes place humming high C blowing low C pitch pipe very close toor right ona harmonic beat frequency very low hums higher lower note beat frequency increases humming tune engine sound have now found musical tone representing engine speed find note lower middle C blow B below high C hum frequency lower middle C until very low beat frequency experienced now have frequency exactly half B note lower middle C can hum low enough high enough can cover octaves below above pitch pipe frequencies allow cover range 7800 62800 cycles per minute wider needed recommended fullpower two-cycling rpm almost modern model engine However since human voices limited range does appreciably exceed range pitch pipe practical appli cation seems range available pipe Since fly CL models can make instantaneous in-flight rpm checks scheme hold control handle hand pitch pipe other wanted try RC model would have fly model constant-radius circle around model constant distance iffor exampleit coming toward flying away January1981 111 FUN SCALE IS HERE Easier Fly Yet Very Maneuverable Over 20 step-by-step building illustrations easier follow photos Lands like Trainer Ideal 2nd Trainer Novice 19-25 Engine 19-40 Eng Span 51 Area 490 sq 18-20 oz wing loading 31-4 lbs Upright Engine Can Built Flown 7 Days Due New Construction Techniques WILL FLY AS SLOW AS PIPER CUB MODEL W-i te Jot free Catalog JEMCO 1305 Eoothill Dr Vista CA 92083 714 724-3242 72 Wingspan GUADRA powered DRUINE TURBULENT Gross weight under 20 lbs No foam 1230 sq Simple construction fully detailed Proven design stable aerobatic Shock-absorbing landing gear takes abuse Full-size plans instructions photos best marketS30 pp USA DOUG MAC BRIEN 24 Truhy St Granhy Mass 01033 Send SASE info engine sound wilt have Doppler frequency shift added Youve heard Im sure rpm approaching model car train motorcycle etc appears increase suddenly begins decrease model passes begins retreat time hear true frequency just moment sound stops increasing begins decrease experience pitch pipe prices can range $450 over $600 Expect pay high price local music store low price alma maters campus bookstore should able order directly writing Florida College Bookstore Temple Terrace FL 33617 Enclose $450 plus $109 postage Zeppelin/Grigg Continued page 41 water- condensing radiators four vertical black rows running vertically up sides hull US NAVY lettering main control car carved single piece basswood plastic windows added sailor stood control wheel probably still would unfinished except Tom Scott Wings & Wheels Museum wanted Akron display forced myself get back work eight propeller out riggers made brass tubing piano wire being built separately hull glued soldered together original ship eight German Maybach engines 560-hp drove shafts geared props Ihese props could swiveled up down fore aft Akron could move under its own power direction except sideways 1 put plastic discs six outriggers carved mahogany props other two trapeze Curtiss fighters made piano wire soldered together Sparrowhawk model built Bachmann Boeing F4 B4 Gary Gordon volunteered saw still details still add deadline fast approaching must say details could added would give model cluttered appearance tend obscure basic form Akron hanging Wings & Wheels Museum Orlando FL written Come see you can look airplanes too Information full-size Akron diri gible length 785 feet diameter 1329 feet helium capacity 6500000 cubic feet speed 83 mph max first flight Septemher 25 1931 lost April 4 1933 CL Aerobatics/Paul Continued page 42 259 FAI Sporting Code deals weather conditions personal experience wind seemed excess 12 in/sec contest postponed distasteful part rules always seems draw ire competi tors counting highest qualifying flight final standings Sections 428 4214 deal number flights final standings called classification FAI Sporting Code year qualifying flights spread over three full days meant judges comparing flight Bill Werwage 1000 am Monday flight Bob Hunt 930 am Tuesday still same first round may argue judge supposed compare maneuver interpretation perfect maneuver round 69 fliers split over day-and-a-half just too momentous task expect really objective scores day day carry over high score count finals just ridiculous finals should another contest competitors starting out equal flying either two three official flights Actually plenty time fly three official flights count two highest scores especially since 15 competitors Since Precision Aerobatics luck draw has great deal influence outcome instances unfair penalize finalist using qualifying score may have lower relative competitors similar abilities just because flier poor draw can see no advantage carrying-over qualify ing score Certainly everyone will attempt fly best qualifying insure make finals can no question going easy does seem simple solution lengthy qualification procedure especially since flight circle permitted qualifying would expensive provide judges have two circles qualifying would big problem supply two circlesespecially since very difficult come up World Champion ships sites course would make sense have two qualifying circles split number competitors half add two scores obtained two official flights space money limitations foresee possibility Assuming qualifying circle will utilized same procedure selecting 15 finalists should retained except Section 4214 FAI Sporting Code should changed have finals consist best two scores three official flights Another item World Championships asked team manager protest judges did have individual recorder Anybody has ever judged according FAI rules knows difficult score write down scores maneuver Remember three inside loops 1oop awarded score zero 10 As ajudge have option trying write down score looking next loop waiting until three finished writing down what think remember about much falrer procedure able call out softly recorder scores separate part maneuver Unfortunately recorders 1 12 Model Aviation p4695 ALL pares cisC shape UnIque wing construction elinsinates dIhedral braces wing sheeting DesIgned Iron-on coverings 0 liD THE NEW FIREBALL GLOW PLUGS ARE LEAKPROOF AND BLOWOUT PROOF EVEN FOR THE NEW MONSTER ENGINES BUT THEY ARE STILL THE OLD PRICE OF $1 10 WRITE NOW! SWANSO 1/ PO Box 15 Wayne N 07470
Edition: Model Aviation - 1981/01
Page Numbers: 40, 111, 112
Edition: Model Aviation - 1981/01
Page Numbers: 40, 111, 112
- 3 NU expensive way determine inflight engine speed CL models RC models flown circle Can also used static tests Richard Porter THE INSPIRATION idea goes back least two sources first article model magazines about Speed flier tape-recorded sound expensive racing engines process burning itself up top rpm later listened tape played notes piano closely matched beautiful sound him racing engine committing hari-kari time felt what would work Speed guy would surely work Stunt flier like second source came found myself middle Trends Science graduate edu cation course taught Dr E Steiner University South Florida made totally open assignment due next week wandered over USF library began browsing through various physics books see could find anything relating frequency various musical notes didnt take long find well-illustrated nomogram text defined musical notes terms cycles per second simply multiplying value 60 cycles per minute could obtained Now could compare musical note sound rpm reasonably smooth-running two-cycling model engine discovered C-to-C pitch pipe worked perfectly musical reference Any instrument will play standard notes can used reference tried couple cheap harmonicas lowest note would play something close high C30000 cycles per minute humming tune engine blowing pitch pipe listening slow beat frequency and/or pitch pipe fre quency very close right same frequency sound engine rpm could easily determined directly nomogram C-to-C pitch pipe gives direct comparison 13 different frequencies 15700 31400 cycles per minute might initially think intervals too large useful consideration given fact possible determine engine rpm between two notesand sometimes noticeably closer note another reasonably accurate measure ment can made scratched frequency-times-60 values Continued page 111 C TCH PIPE lI\I 157K 166K 176K 186K 198K 210K 222K 235K 249K 264K 280K 296K 314K C # 0 9 E F # B C musical notes C-to-C pitch pipe corresponding cycles per minute rpm range 15700 31400 Reasonably accurate rpm can also determined between notes 40 Model Aviation magic pitch pipe disassembled Porter scratched rpm scale piece transparent plastic left next washer nut Other major pieces cover ar right tone reed-bank dark plastic cover pieces bolted together Get pitch pipes music stores author tunes TD-powered Ridiculous 12A Stunter before flightusing musical tech Rich Porter isnt munching sandwich dur ingaClEnduranceflight Hesusingpitchpipe make in-flight rpm check THE chose Waco F-3 biplane flagship because bet represents Golden Era 1930s flying adventure Add easy snag-free building saie gentle flyingthe result thorough kit engineering careful prototype development features Platt Kits have satisfying building flying experience ahead Kit IeaturesTop-quality diecut machined balsa plywood Full size plans Separate instruction book isometrics Decals Injection-moulded vacuum-formed plastic cowl cowl blisters wheel pants required nylon fittings Formed wire langinggear&struts Span 60Area 950 Sq4to6channel Engine good 40 60 j 2657 NE 188th Street Miami Florida 33180 Telephone g35-1436 fellow modelers unorthodox aircraft important designing building un orthodox CL models keep mind presence CL leadouts wires will serve very nicely sort stabilizer functioning both yaw vertical roll longitudinal axes especially true case rotor craft can usually expected have roll stability problem thus observations herein presented may valid model types other CL 1 The flying speed autogiro extent inversely proportional rotor al though number blades area play important role have observed models having large diameter rotors will fly relatively low airspeed makes very susceptible effects wind gusts Furthermore machines will usually exhibit uncontrol lable pitch-up engine stops fortunately will followed parachute-like descent addition large diameter rotors may radially floppy can lead some real control difficulties Another disadvantage large rotor hard landing can cause blades flex downwards far enough strike fuselage tail 2 Other things being equal small rotor will require longer takeoff run attain flying rpm will spin faster have effective control resulting airplane-like flight 3 Number blades two-blade rotor easiest build also easiest handle starting engine obvious blades multiple-bladed rotor can real obstacle enthusiastic prop-flipping other hand multi-blade rotors spin-up faster giving shorter takeoffs will support heavier aircraft appears three-bladed rotor will satisfactory compromise 4 usual practice tilt rotor disc rear absolutely necessary rotor pivot left vertical model will fly quite nose-high attitude takeoff roll will excessive 5 CG model should balanced point about R ahead pivot flight may possible center-of-gravity pivot control will very hairy 6 Wings Although early full-scale auto giros used wings addition rotors appendages best avoided models winged model giros may find themselves precarious situation having become airborne virtue wing lift before rotor has attained flying rpm As rotor lift becomes factor however attendant rise drag may slow model wing stalls Therefore better far rely entirely rotor Wings may desirable other reasons though fitted should made too small support model flight 7 STOL operations properly constructed giro may relied upon land very small space indeed short takeoff desired may disappointed full-scale autogiros capable near-vertical takeoffs accomplished using power taken engine through system shafts clutches spin up rotor Unless willing undergo sort complexity well have settle takeoff run considered lengthy conventional airplane standards 8 Control Normalairplanetype tail surfaces will produce very good control will provide flight little different airplane long tail moment arm desirable model both elevator authority well conven ience handling launching model 9 Lift Avro C6 weighs 6 oz built will fly very nicely 9 oz two blades manageable 10-mph breeze final point model giros may made much easier transport provision made readily remove rotor sure lubricate rotor pivot inspect rotor security damage between flights Music Tach/Porter Continued page 40 nomogram plastic side pitch pipe Middle C157K C sharp166K D 176K D sharp186K E198K F21 0K F sharp222K G235K G sharp249K A264K sharp2796K B2964K C 314K range can extended both above below range pitch pipe humming lower higher harmonics simultaneously blowing selected note listening low beat frequency determine value unknown harmonic frequency example high C first harmonic above middle C Cto-C pitch pipe humming low C blowing high C very discernible beat frequency can experienced same effect takes place humming high C blowing low C pitch pipe very close toor right ona harmonic beat frequency very low hums higher lower note beat frequency increases humming tune engine sound have now found musical tone representing engine speed find note lower middle C blow B below high C hum frequency lower middle C until very low beat frequency experienced now have frequency exactly half B note lower middle C can hum low enough high enough can cover octaves below above pitch pipe frequencies allow cover range 7800 62800 cycles per minute wider needed recommended fullpower two-cycling rpm almost modern model engine However since human voices limited range does appreciably exceed range pitch pipe practical appli cation seems range available pipe Since fly CL models can make instantaneous in-flight rpm checks scheme hold control handle hand pitch pipe other wanted try RC model would have fly model constant-radius circle around model constant distance iffor exampleit coming toward flying away January1981 111 FUN SCALE IS HERE Easier Fly Yet Very Maneuverable Over 20 step-by-step building illustrations easier follow photos Lands like Trainer Ideal 2nd Trainer Novice 19-25 Engine 19-40 Eng Span 51 Area 490 sq 18-20 oz wing loading 31-4 lbs Upright Engine Can Built Flown 7 Days Due New Construction Techniques WILL FLY AS SLOW AS PIPER CUB MODEL W-i te Jot free Catalog JEMCO 1305 Eoothill Dr Vista CA 92083 714 724-3242 72 Wingspan GUADRA powered DRUINE TURBULENT Gross weight under 20 lbs No foam 1230 sq Simple construction fully detailed Proven design stable aerobatic Shock-absorbing landing gear takes abuse Full-size plans instructions photos best marketS30 pp USA DOUG MAC BRIEN 24 Truhy St Granhy Mass 01033 Send SASE info engine sound wilt have Doppler frequency shift added Youve heard Im sure rpm approaching model car train motorcycle etc appears increase suddenly begins decrease model passes begins retreat time hear true frequency just moment sound stops increasing begins decrease experience pitch pipe prices can range $450 over $600 Expect pay high price local music store low price alma maters campus bookstore should able order directly writing Florida College Bookstore Temple Terrace FL 33617 Enclose $450 plus $109 postage Zeppelin/Grigg Continued page 41 water- condensing radiators four vertical black rows running vertically up sides hull US NAVY lettering main control car carved single piece basswood plastic windows added sailor stood control wheel probably still would unfinished except Tom Scott Wings & Wheels Museum wanted Akron display forced myself get back work eight propeller out riggers made brass tubing piano wire being built separately hull glued soldered together original ship eight German Maybach engines 560-hp drove shafts geared props Ihese props could swiveled up down fore aft Akron could move under its own power direction except sideways 1 put plastic discs six outriggers carved mahogany props other two trapeze Curtiss fighters made piano wire soldered together Sparrowhawk model built Bachmann Boeing F4 B4 Gary Gordon volunteered saw still details still add deadline fast approaching must say details could added would give model cluttered appearance tend obscure basic form Akron hanging Wings & Wheels Museum Orlando FL written Come see you can look airplanes too Information full-size Akron diri gible length 785 feet diameter 1329 feet helium capacity 6500000 cubic feet speed 83 mph max first flight Septemher 25 1931 lost April 4 1933 CL Aerobatics/Paul Continued page 42 259 FAI Sporting Code deals weather conditions personal experience wind seemed excess 12 in/sec contest postponed distasteful part rules always seems draw ire competi tors counting highest qualifying flight final standings Sections 428 4214 deal number flights final standings called classification FAI Sporting Code year qualifying flights spread over three full days meant judges comparing flight Bill Werwage 1000 am Monday flight Bob Hunt 930 am Tuesday still same first round may argue judge supposed compare maneuver interpretation perfect maneuver round 69 fliers split over day-and-a-half just too momentous task expect really objective scores day day carry over high score count finals just ridiculous finals should another contest competitors starting out equal flying either two three official flights Actually plenty time fly three official flights count two highest scores especially since 15 competitors Since Precision Aerobatics luck draw has great deal influence outcome instances unfair penalize finalist using qualifying score may have lower relative competitors similar abilities just because flier poor draw can see no advantage carrying-over qualify ing score Certainly everyone will attempt fly best qualifying insure make finals can no question going easy does seem simple solution lengthy qualification procedure especially since flight circle permitted qualifying would expensive provide judges have two circles qualifying would big problem supply two circlesespecially since very difficult come up World Champion ships sites course would make sense have two qualifying circles split number competitors half add two scores obtained two official flights space money limitations foresee possibility Assuming qualifying circle will utilized same procedure selecting 15 finalists should retained except Section 4214 FAI Sporting Code should changed have finals consist best two scores three official flights Another item World Championships asked team manager protest judges did have individual recorder Anybody has ever judged according FAI rules knows difficult score write down scores maneuver Remember three inside loops 1oop awarded score zero 10 As ajudge have option trying write down score looking next loop waiting until three finished writing down what think remember about much falrer procedure able call out softly recorder scores separate part maneuver Unfortunately recorders 1 12 Model Aviation p4695 ALL pares cisC shape UnIque wing construction elinsinates dIhedral braces wing sheeting DesIgned Iron-on coverings 0 liD THE NEW FIREBALL GLOW PLUGS ARE LEAKPROOF AND BLOWOUT PROOF EVEN FOR THE NEW MONSTER ENGINES BUT THEY ARE STILL THE OLD PRICE OF $1 10 WRITE NOW! SWANSO 1/ PO Box 15 Wayne N 07470
Edition: Model Aviation - 1981/01
Page Numbers: 40, 111, 112
- 3 NU expensive way determine inflight engine speed CL models RC models flown circle Can also used static tests Richard Porter THE INSPIRATION idea goes back least two sources first article model magazines about Speed flier tape-recorded sound expensive racing engines process burning itself up top rpm later listened tape played notes piano closely matched beautiful sound him racing engine committing hari-kari time felt what would work Speed guy would surely work Stunt flier like second source came found myself middle Trends Science graduate edu cation course taught Dr E Steiner University South Florida made totally open assignment due next week wandered over USF library began browsing through various physics books see could find anything relating frequency various musical notes didnt take long find well-illustrated nomogram text defined musical notes terms cycles per second simply multiplying value 60 cycles per minute could obtained Now could compare musical note sound rpm reasonably smooth-running two-cycling model engine discovered C-to-C pitch pipe worked perfectly musical reference Any instrument will play standard notes can used reference tried couple cheap harmonicas lowest note would play something close high C30000 cycles per minute humming tune engine blowing pitch pipe listening slow beat frequency and/or pitch pipe fre quency very close right same frequency sound engine rpm could easily determined directly nomogram C-to-C pitch pipe gives direct comparison 13 different frequencies 15700 31400 cycles per minute might initially think intervals too large useful consideration given fact possible determine engine rpm between two notesand sometimes noticeably closer note another reasonably accurate measure ment can made scratched frequency-times-60 values Continued page 111 C TCH PIPE lI\I 157K 166K 176K 186K 198K 210K 222K 235K 249K 264K 280K 296K 314K C # 0 9 E F # B C musical notes C-to-C pitch pipe corresponding cycles per minute rpm range 15700 31400 Reasonably accurate rpm can also determined between notes 40 Model Aviation magic pitch pipe disassembled Porter scratched rpm scale piece transparent plastic left next washer nut Other major pieces cover ar right tone reed-bank dark plastic cover pieces bolted together Get pitch pipes music stores author tunes TD-powered Ridiculous 12A Stunter before flightusing musical tech Rich Porter isnt munching sandwich dur ingaClEnduranceflight Hesusingpitchpipe make in-flight rpm check THE chose Waco F-3 biplane flagship because bet represents Golden Era 1930s flying adventure Add easy snag-free building saie gentle flyingthe result thorough kit engineering careful prototype development features Platt Kits have satisfying building flying experience ahead Kit IeaturesTop-quality diecut machined balsa plywood Full size plans Separate instruction book isometrics Decals Injection-moulded vacuum-formed plastic cowl cowl blisters wheel pants required nylon fittings Formed wire langinggear&struts Span 60Area 950 Sq4to6channel Engine good 40 60 j 2657 NE 188th Street Miami Florida 33180 Telephone g35-1436 fellow modelers unorthodox aircraft important designing building un orthodox CL models keep mind presence CL leadouts wires will serve very nicely sort stabilizer functioning both yaw vertical roll longitudinal axes especially true case rotor craft can usually expected have roll stability problem thus observations herein presented may valid model types other CL 1 The flying speed autogiro extent inversely proportional rotor al though number blades area play important role have observed models having large diameter rotors will fly relatively low airspeed makes very susceptible effects wind gusts Furthermore machines will usually exhibit uncontrol lable pitch-up engine stops fortunately will followed parachute-like descent addition large diameter rotors may radially floppy can lead some real control difficulties Another disadvantage large rotor hard landing can cause blades flex downwards far enough strike fuselage tail 2 Other things being equal small rotor will require longer takeoff run attain flying rpm will spin faster have effective control resulting airplane-like flight 3 Number blades two-blade rotor easiest build also easiest handle starting engine obvious blades multiple-bladed rotor can real obstacle enthusiastic prop-flipping other hand multi-blade rotors spin-up faster giving shorter takeoffs will support heavier aircraft appears three-bladed rotor will satisfactory compromise 4 usual practice tilt rotor disc rear absolutely necessary rotor pivot left vertical model will fly quite nose-high attitude takeoff roll will excessive 5 CG model should balanced point about R ahead pivot flight may possible center-of-gravity pivot control will very hairy 6 Wings Although early full-scale auto giros used wings addition rotors appendages best avoided models winged model giros may find themselves precarious situation having become airborne virtue wing lift before rotor has attained flying rpm As rotor lift becomes factor however attendant rise drag may slow model wing stalls Therefore better far rely entirely rotor Wings may desirable other reasons though fitted should made too small support model flight 7 STOL operations properly constructed giro may relied upon land very small space indeed short takeoff desired may disappointed full-scale autogiros capable near-vertical takeoffs accomplished using power taken engine through system shafts clutches spin up rotor Unless willing undergo sort complexity well have settle takeoff run considered lengthy conventional airplane standards 8 Control Normalairplanetype tail surfaces will produce very good control will provide flight little different airplane long tail moment arm desirable model both elevator authority well conven ience handling launching model 9 Lift Avro C6 weighs 6 oz built will fly very nicely 9 oz two blades manageable 10-mph breeze final point model giros may made much easier transport provision made readily remove rotor sure lubricate rotor pivot inspect rotor security damage between flights Music Tach/Porter Continued page 40 nomogram plastic side pitch pipe Middle C157K C sharp166K D 176K D sharp186K E198K F21 0K F sharp222K G235K G sharp249K A264K sharp2796K B2964K C 314K range can extended both above below range pitch pipe humming lower higher harmonics simultaneously blowing selected note listening low beat frequency determine value unknown harmonic frequency example high C first harmonic above middle C Cto-C pitch pipe humming low C blowing high C very discernible beat frequency can experienced same effect takes place humming high C blowing low C pitch pipe very close toor right ona harmonic beat frequency very low hums higher lower note beat frequency increases humming tune engine sound have now found musical tone representing engine speed find note lower middle C blow B below high C hum frequency lower middle C until very low beat frequency experienced now have frequency exactly half B note lower middle C can hum low enough high enough can cover octaves below above pitch pipe frequencies allow cover range 7800 62800 cycles per minute wider needed recommended fullpower two-cycling rpm almost modern model engine However since human voices limited range does appreciably exceed range pitch pipe practical appli cation seems range available pipe Since fly CL models can make instantaneous in-flight rpm checks scheme hold control handle hand pitch pipe other wanted try RC model would have fly model constant-radius circle around model constant distance iffor exampleit coming toward flying away January1981 111 FUN SCALE IS HERE Easier Fly Yet Very Maneuverable Over 20 step-by-step building illustrations easier follow photos Lands like Trainer Ideal 2nd Trainer Novice 19-25 Engine 19-40 Eng Span 51 Area 490 sq 18-20 oz wing loading 31-4 lbs Upright Engine Can Built Flown 7 Days Due New Construction Techniques WILL FLY AS SLOW AS PIPER CUB MODEL W-i te Jot free Catalog JEMCO 1305 Eoothill Dr Vista CA 92083 714 724-3242 72 Wingspan GUADRA powered DRUINE TURBULENT Gross weight under 20 lbs No foam 1230 sq Simple construction fully detailed Proven design stable aerobatic Shock-absorbing landing gear takes abuse Full-size plans instructions photos best marketS30 pp USA DOUG MAC BRIEN 24 Truhy St Granhy Mass 01033 Send SASE info engine sound wilt have Doppler frequency shift added Youve heard Im sure rpm approaching model car train motorcycle etc appears increase suddenly begins decrease model passes begins retreat time hear true frequency just moment sound stops increasing begins decrease experience pitch pipe prices can range $450 over $600 Expect pay high price local music store low price alma maters campus bookstore should able order directly writing Florida College Bookstore Temple Terrace FL 33617 Enclose $450 plus $109 postage Zeppelin/Grigg Continued page 41 water- condensing radiators four vertical black rows running vertically up sides hull US NAVY lettering main control car carved single piece basswood plastic windows added sailor stood control wheel probably still would unfinished except Tom Scott Wings & Wheels Museum wanted Akron display forced myself get back work eight propeller out riggers made brass tubing piano wire being built separately hull glued soldered together original ship eight German Maybach engines 560-hp drove shafts geared props Ihese props could swiveled up down fore aft Akron could move under its own power direction except sideways 1 put plastic discs six outriggers carved mahogany props other two trapeze Curtiss fighters made piano wire soldered together Sparrowhawk model built Bachmann Boeing F4 B4 Gary Gordon volunteered saw still details still add deadline fast approaching must say details could added would give model cluttered appearance tend obscure basic form Akron hanging Wings & Wheels Museum Orlando FL written Come see you can look airplanes too Information full-size Akron diri gible length 785 feet diameter 1329 feet helium capacity 6500000 cubic feet speed 83 mph max first flight Septemher 25 1931 lost April 4 1933 CL Aerobatics/Paul Continued page 42 259 FAI Sporting Code deals weather conditions personal experience wind seemed excess 12 in/sec contest postponed distasteful part rules always seems draw ire competi tors counting highest qualifying flight final standings Sections 428 4214 deal number flights final standings called classification FAI Sporting Code year qualifying flights spread over three full days meant judges comparing flight Bill Werwage 1000 am Monday flight Bob Hunt 930 am Tuesday still same first round may argue judge supposed compare maneuver interpretation perfect maneuver round 69 fliers split over day-and-a-half just too momentous task expect really objective scores day day carry over high score count finals just ridiculous finals should another contest competitors starting out equal flying either two three official flights Actually plenty time fly three official flights count two highest scores especially since 15 competitors Since Precision Aerobatics luck draw has great deal influence outcome instances unfair penalize finalist using qualifying score may have lower relative competitors similar abilities just because flier poor draw can see no advantage carrying-over qualify ing score Certainly everyone will attempt fly best qualifying insure make finals can no question going easy does seem simple solution lengthy qualification procedure especially since flight circle permitted qualifying would expensive provide judges have two circles qualifying would big problem supply two circlesespecially since very difficult come up World Champion ships sites course would make sense have two qualifying circles split number competitors half add two scores obtained two official flights space money limitations foresee possibility Assuming qualifying circle will utilized same procedure selecting 15 finalists should retained except Section 4214 FAI Sporting Code should changed have finals consist best two scores three official flights Another item World Championships asked team manager protest judges did have individual recorder Anybody has ever judged according FAI rules knows difficult score write down scores maneuver Remember three inside loops 1oop awarded score zero 10 As ajudge have option trying write down score looking next loop waiting until three finished writing down what think remember about much falrer procedure able call out softly recorder scores separate part maneuver Unfortunately recorders 1 12 Model Aviation p4695 ALL pares cisC shape UnIque wing construction elinsinates dIhedral braces wing sheeting DesIgned Iron-on coverings 0 liD THE NEW FIREBALL GLOW PLUGS ARE LEAKPROOF AND BLOWOUT PROOF EVEN FOR THE NEW MONSTER ENGINES BUT THEY ARE STILL THE OLD PRICE OF $1 10 WRITE NOW! SWANSO 1/ PO Box 15 Wayne N 07470
