Dont let title throw Its easy-to-read article useful charts yield valuable data comparing designs selecting models build related terms area weight wing/power loading WHEN YOU select new plane en gine what criteria use depends ability fly course also de pends performance expect plane engine experi enced modeler course make choice based experience judgment However relatively inex perienced probably could use some help Hopefully discussion charts will help make proper choices What performance Well can defined formulae too abstract modelers Performance can abstract beautiful sight glider just hanging up maybe gracefully following local hawk Per formance certainly Formula racer turning 115 qualifying heat cham pionship contest no will deny average speed 120 mph performance Performance can moment begin FIGJ CALCULATING W/D AND W/S Jack Burns Empirical RC Model Performance Criteria ner suddenly gets together can take off fly around field make safe landing Thus performance can very technical can subjective judgments form field watching different planes fly What airplane criteria determine per formance Several lets confine discussion three weight wing area engine power designated displace ment little arithmetic weight divided area wing loading W/S perhaps important item Weight divided power power loading W/D know power what makes beast go low W/S means light plane large wing area weight high W/S heavy plane small wing Low W/D means lots power high W/D low power Lets examine manner ratios determine performance full-size airplane calculations pounds square feet horse power used model use keep numbers whole convenient express W/S ounces per square foot W/D pounds per cubic inch displacement assumes horsepower proportional displace ment roughly correct Thus charts marked units En52121 - Q AU0 A'Uk 2 04 - $60 80 WlSozjsonA g %Pq\4AoIAAAm 113 4 F-4M 1T0M -4As AEIF*L0O U W/D LBS /CUIN U As WING LOADING W/S OZISOIN POWER LOADING WtD # iCUIN MCK AIJA AERO TECENECHANIcS .-- .-- IS-- -----4- - S AREA SOIN 5 6 50607060 0 ENGINE DISPLACEMENT Cu IN 14 Model Aviation 10 05 10 15 N gine displacement used instead horse power since actual HP readily avail able Besides never run engines full out maximum potential developed test bench after careful break-in sequence Well maybe pylon racer guys sport flier would rather have engine last longer sacrifice bit performance calculating max speed lines used 167 HP per cubic inch average engines tested Mr Peter Chinn using 5% nitro fuel mufflers sumes horsepower proportional dis placement roughly correct Hotter engines high nitro fuel no mufflers prop will allow engine wind out full rpm will give lower W/D higher speeds shown charts Thus racing 40 has much higher output average much lower W/D Cox TDs also put out average Calculating W/D W/S Fig 1 helps find W/S W/D breaking out calculator W/S W/D radial lines plotted against weight area engine size find W/S locate point left chart weight line intersects area line Simi larly reading right weight scale engine displacement yields direct reading W/D example Senior Falcon shows done Point 810 sq 6 lb equals 17 nice area Point B 6 lb meets 45 displacement line W/D 133 good area plane has characteristics result very nice sport flier also good beginner Although point C W/D ometimes hot satisfactory big bird particularly grassfields Senior Falcons powered 60 fliers want kick plane around sky bit course wing center section has reinforced Another use chart give rough estimate glider performance W/S lines 8 14 labelled Light Heavy glider light glider will have low sink rate will really go up thermal heavy glider will fly faster penetrate head winds better have higher sink rate use engine launch climb field drop down W/D line near line marked Glider Power select engine overpower gliderthose long thin wings just like high speed believe have used 049 10 15 engines progressively larger gliders Big Tat 900 sq W/S 10 15 very nice performer Notice adjective ratings charts-degrees performance impressions after years flying observing model planes Application Empirical Data Now get down specific model planes planes plotted Fig 2 3 ac cording wing power loading Thus can compare planes ideas performance maximum speed lines radiate across Fig 2 3 help relate wing loading speed performance thus separate kites bombs speed lines say faster better vice versa give indication relative performance guide engine selection RC Old-Timers Buzzard Bombshell 850 sq 3 lb 40 eng W/S 9 W/D 875 low end wing loading scale BB has predictably fantastic glide oh power Hot word. like destructive power caused stresses failed wing 23rd flight rebuilt will have 19 old 29 wing will reinforced Playboy Senior next BB chart also experienced wing failure according author mag azine article Again apparently too much power low W/S Please use smaller engine OT birds certain reinforce wing center section light structure goes along light wing loading strong enough handle high power radio control can put G-loads plane might encounter free flightturn page January 1977 15 Just handful configurations fly Weight wing area power vary endlessly charts come rescue Photo graph Bruce Robertson RC Model Performance Beginner beginner would well select plane W/S 10-15 W/D 15-20 although models available range Up scale bit several models satisfactory help experienced pilot recommend Falcon 56 Senior Falcon Bridi RCM 400 Old-time fliers planes say use plenty power can always throttle back However power can get novice trouble quicker gets him out cautious Sport Fliers Models sport fliers range W/S 15 24 W/D 10 up depending proficiency models category higher wing loading hotter landing high W/S high W/D just may get off ground does have bear hands Pattern Planes range W/S 23 28 maybe Tony Bon etti named Troublemaker type higher W/S means larger maneuv ers s loops etc An experienced sport pilot can handle pattern ship beginners W/D 10-117 Scale Planes kits Stand-Off true Scale planes available range nice hot beginner insists building scale model hope will sooner later should pick lower W/S area P-SI Me109 F-4 shown chart expert fliers So bought F-4 put away few years until expert pattern flier Akro Master next F-4 W/S 288 too hot lasted five flights Grass takeoffs diffi cult landings hot Biplanes Several available Fleet AeroMaster PT-17 two AcroStars Pitts S-2 Waco-K range good sport flier However biplanes quick responsive controls properly rigged powered definitely acrobatic course tail draggers different trike gear ship Pylon Racers No specific models shown because must conform specifica tions As stated maximum speed lines too low racers because powerful engines used very clean aero dynamic form finish Formula racers 120-mph speed generate performance very special kind flier Quarter Midget racers need expert pilot take care racers dont belong average plane charts because breed own preclude swamping editor correspondence let us make clear wing-loading/power-loading technique does use scale factors dynamic scaling calibrating judges eyeballs square root scale factor scale time etc certain can proved one-fifth scale model Supersonic X-l000 fighter should weigh 25 lbs should powered 50 horses judge should realize model really flying 45% real time. duplicate scale flight full-size plane However average Sunday fliers want know after fourth repair job two pounds epoxy later should change 30 40 can handle hotter land ing higher wing loading simple charts can point us toward answers questions like whole point Conclusion three charts presented show large number models present past fall set FIG 2SPEED VS S/D R/C AIRPLANE PERFORMANCE INDICATORS-AREAENGINEMAX SPEED 336I 3f5CU INI3# VMAX7505 S sa ik4 lr125 C II er150-q--er so/4~ /t U 5560925 0 500636U S 4# 015#4t7# 567 0504p,#~j [ -J5 36050I10 SI 25 042 S 16 ModelAviation z U 2 45 U 40 2 5 2 useful empirically derived curves Some individual adjustments must always made example factor just has added grass takeoff unfortunately means hotter model air hoped discussion charts will assist selecting next two three models after will making own standards event hope will deter beginners visualize four-engine scale bomber weighs 20 lbs first model Meanwhile may flights smooth landings safe Flying scale notorious pitfall unwary know ever tried ease off ground heavy probably under-powered job Richard Smith appears have put together 1976 Nats rather large Citabria charts examples given text enable predict per formance model before flown Per haps engine change order also aid designer pinpointing parameters Assuming adequate prior flying experience can establish feel model will go FIG 3SPEED VS W/D AND W/S R/C MODEL AIRPLANE PERFORMANCE INDICATORS W/S W/D V max tV MAx WtI GLIDEAPOWER C HAND LAUNCH 24/ -I-06C CU IN GRASS TAKEOFF MARGINAL -i-- -re Ii S 18-14 t r 4 314I 12-u 10HOT~ue S 6 acM BOWS PATTERNRACERSMT PILOT January 1977 17 2 WIS OZ/SO FT
Edition: Model Aviation - 1977/01
Page Numbers: 14, 15, 16, 17
Dont let title throw Its easy-to-read article useful charts yield valuable data comparing designs selecting models build related terms area weight wing/power loading WHEN YOU select new plane en gine what criteria use depends ability fly course also de pends performance expect plane engine experi enced modeler course make choice based experience judgment However relatively inex perienced probably could use some help Hopefully discussion charts will help make proper choices What performance Well can defined formulae too abstract modelers Performance can abstract beautiful sight glider just hanging up maybe gracefully following local hawk Per formance certainly Formula racer turning 115 qualifying heat cham pionship contest no will deny average speed 120 mph performance Performance can moment begin FIGJ CALCULATING W/D AND W/S Jack Burns Empirical RC Model Performance Criteria ner suddenly gets together can take off fly around field make safe landing Thus performance can very technical can subjective judgments form field watching different planes fly What airplane criteria determine per formance Several lets confine discussion three weight wing area engine power designated displace ment little arithmetic weight divided area wing loading W/S perhaps important item Weight divided power power loading W/D know power what makes beast go low W/S means light plane large wing area weight high W/S heavy plane small wing Low W/D means lots power high W/D low power Lets examine manner ratios determine performance full-size airplane calculations pounds square feet horse power used model use keep numbers whole convenient express W/S ounces per square foot W/D pounds per cubic inch displacement assumes horsepower proportional displace ment roughly correct Thus charts marked units En52121 - Q AU0 A'Uk 2 04 - $60 80 WlSozjsonA g %Pq\4AoIAAAm 113 4 F-4M 1T0M -4As AEIF*L0O U W/D LBS /CUIN U As WING LOADING W/S OZISOIN POWER LOADING WtD # iCUIN MCK AIJA AERO TECENECHANIcS .-- .-- IS-- -----4- - S AREA SOIN 5 6 50607060 0 ENGINE DISPLACEMENT Cu IN 14 Model Aviation 10 05 10 15 N gine displacement used instead horse power since actual HP readily avail able Besides never run engines full out maximum potential developed test bench after careful break-in sequence Well maybe pylon racer guys sport flier would rather have engine last longer sacrifice bit performance calculating max speed lines used 167 HP per cubic inch average engines tested Mr Peter Chinn using 5% nitro fuel mufflers sumes horsepower proportional dis placement roughly correct Hotter engines high nitro fuel no mufflers prop will allow engine wind out full rpm will give lower W/D higher speeds shown charts Thus racing 40 has much higher output average much lower W/D Cox TDs also put out average Calculating W/D W/S Fig 1 helps find W/S W/D breaking out calculator W/S W/D radial lines plotted against weight area engine size find W/S locate point left chart weight line intersects area line Simi larly reading right weight scale engine displacement yields direct reading W/D example Senior Falcon shows done Point 810 sq 6 lb equals 17 nice area Point B 6 lb meets 45 displacement line W/D 133 good area plane has characteristics result very nice sport flier also good beginner Although point C W/D ometimes hot satisfactory big bird particularly grassfields Senior Falcons powered 60 fliers want kick plane around sky bit course wing center section has reinforced Another use chart give rough estimate glider performance W/S lines 8 14 labelled Light Heavy glider light glider will have low sink rate will really go up thermal heavy glider will fly faster penetrate head winds better have higher sink rate use engine launch climb field drop down W/D line near line marked Glider Power select engine overpower gliderthose long thin wings just like high speed believe have used 049 10 15 engines progressively larger gliders Big Tat 900 sq W/S 10 15 very nice performer Notice adjective ratings charts-degrees performance impressions after years flying observing model planes Application Empirical Data Now get down specific model planes planes plotted Fig 2 3 ac cording wing power loading Thus can compare planes ideas performance maximum speed lines radiate across Fig 2 3 help relate wing loading speed performance thus separate kites bombs speed lines say faster better vice versa give indication relative performance guide engine selection RC Old-Timers Buzzard Bombshell 850 sq 3 lb 40 eng W/S 9 W/D 875 low end wing loading scale BB has predictably fantastic glide oh power Hot word. like destructive power caused stresses failed wing 23rd flight rebuilt will have 19 old 29 wing will reinforced Playboy Senior next BB chart also experienced wing failure according author mag azine article Again apparently too much power low W/S Please use smaller engine OT birds certain reinforce wing center section light structure goes along light wing loading strong enough handle high power radio control can put G-loads plane might encounter free flightturn page January 1977 15 Just handful configurations fly Weight wing area power vary endlessly charts come rescue Photo graph Bruce Robertson RC Model Performance Beginner beginner would well select plane W/S 10-15 W/D 15-20 although models available range Up scale bit several models satisfactory help experienced pilot recommend Falcon 56 Senior Falcon Bridi RCM 400 Old-time fliers planes say use plenty power can always throttle back However power can get novice trouble quicker gets him out cautious Sport Fliers Models sport fliers range W/S 15 24 W/D 10 up depending proficiency models category higher wing loading hotter landing high W/S high W/D just may get off ground does have bear hands Pattern Planes range W/S 23 28 maybe Tony Bon etti named Troublemaker type higher W/S means larger maneuv ers s loops etc An experienced sport pilot can handle pattern ship beginners W/D 10-117 Scale Planes kits Stand-Off true Scale planes available range nice hot beginner insists building scale model hope will sooner later should pick lower W/S area P-SI Me109 F-4 shown chart expert fliers So bought F-4 put away few years until expert pattern flier Akro Master next F-4 W/S 288 too hot lasted five flights Grass takeoffs diffi cult landings hot Biplanes Several available Fleet AeroMaster PT-17 two AcroStars Pitts S-2 Waco-K range good sport flier However biplanes quick responsive controls properly rigged powered definitely acrobatic course tail draggers different trike gear ship Pylon Racers No specific models shown because must conform specifica tions As stated maximum speed lines too low racers because powerful engines used very clean aero dynamic form finish Formula racers 120-mph speed generate performance very special kind flier Quarter Midget racers need expert pilot take care racers dont belong average plane charts because breed own preclude swamping editor correspondence let us make clear wing-loading/power-loading technique does use scale factors dynamic scaling calibrating judges eyeballs square root scale factor scale time etc certain can proved one-fifth scale model Supersonic X-l000 fighter should weigh 25 lbs should powered 50 horses judge should realize model really flying 45% real time. duplicate scale flight full-size plane However average Sunday fliers want know after fourth repair job two pounds epoxy later should change 30 40 can handle hotter land ing higher wing loading simple charts can point us toward answers questions like whole point Conclusion three charts presented show large number models present past fall set FIG 2SPEED VS S/D R/C AIRPLANE PERFORMANCE INDICATORS-AREAENGINEMAX SPEED 336I 3f5CU INI3# VMAX7505 S sa ik4 lr125 C II er150-q--er so/4~ /t U 5560925 0 500636U S 4# 015#4t7# 567 0504p,#~j [ -J5 36050I10 SI 25 042 S 16 ModelAviation z U 2 45 U 40 2 5 2 useful empirically derived curves Some individual adjustments must always made example factor just has added grass takeoff unfortunately means hotter model air hoped discussion charts will assist selecting next two three models after will making own standards event hope will deter beginners visualize four-engine scale bomber weighs 20 lbs first model Meanwhile may flights smooth landings safe Flying scale notorious pitfall unwary know ever tried ease off ground heavy probably under-powered job Richard Smith appears have put together 1976 Nats rather large Citabria charts examples given text enable predict per formance model before flown Per haps engine change order also aid designer pinpointing parameters Assuming adequate prior flying experience can establish feel model will go FIG 3SPEED VS W/D AND W/S R/C MODEL AIRPLANE PERFORMANCE INDICATORS W/S W/D V max tV MAx WtI GLIDEAPOWER C HAND LAUNCH 24/ -I-06C CU IN GRASS TAKEOFF MARGINAL -i-- -re Ii S 18-14 t r 4 314I 12-u 10HOT~ue S 6 acM BOWS PATTERNRACERSMT PILOT January 1977 17 2 WIS OZ/SO FT
Edition: Model Aviation - 1977/01
Page Numbers: 14, 15, 16, 17
Dont let title throw Its easy-to-read article useful charts yield valuable data comparing designs selecting models build related terms area weight wing/power loading WHEN YOU select new plane en gine what criteria use depends ability fly course also de pends performance expect plane engine experi enced modeler course make choice based experience judgment However relatively inex perienced probably could use some help Hopefully discussion charts will help make proper choices What performance Well can defined formulae too abstract modelers Performance can abstract beautiful sight glider just hanging up maybe gracefully following local hawk Per formance certainly Formula racer turning 115 qualifying heat cham pionship contest no will deny average speed 120 mph performance Performance can moment begin FIGJ CALCULATING W/D AND W/S Jack Burns Empirical RC Model Performance Criteria ner suddenly gets together can take off fly around field make safe landing Thus performance can very technical can subjective judgments form field watching different planes fly What airplane criteria determine per formance Several lets confine discussion three weight wing area engine power designated displace ment little arithmetic weight divided area wing loading W/S perhaps important item Weight divided power power loading W/D know power what makes beast go low W/S means light plane large wing area weight high W/S heavy plane small wing Low W/D means lots power high W/D low power Lets examine manner ratios determine performance full-size airplane calculations pounds square feet horse power used model use keep numbers whole convenient express W/S ounces per square foot W/D pounds per cubic inch displacement assumes horsepower proportional displace ment roughly correct Thus charts marked units En52121 - Q AU0 A'Uk 2 04 - $60 80 WlSozjsonA g %Pq\4AoIAAAm 113 4 F-4M 1T0M -4As AEIF*L0O U W/D LBS /CUIN U As WING LOADING W/S OZISOIN POWER LOADING WtD # iCUIN MCK AIJA AERO TECENECHANIcS .-- .-- IS-- -----4- - S AREA SOIN 5 6 50607060 0 ENGINE DISPLACEMENT Cu IN 14 Model Aviation 10 05 10 15 N gine displacement used instead horse power since actual HP readily avail able Besides never run engines full out maximum potential developed test bench after careful break-in sequence Well maybe pylon racer guys sport flier would rather have engine last longer sacrifice bit performance calculating max speed lines used 167 HP per cubic inch average engines tested Mr Peter Chinn using 5% nitro fuel mufflers sumes horsepower proportional dis placement roughly correct Hotter engines high nitro fuel no mufflers prop will allow engine wind out full rpm will give lower W/D higher speeds shown charts Thus racing 40 has much higher output average much lower W/D Cox TDs also put out average Calculating W/D W/S Fig 1 helps find W/S W/D breaking out calculator W/S W/D radial lines plotted against weight area engine size find W/S locate point left chart weight line intersects area line Simi larly reading right weight scale engine displacement yields direct reading W/D example Senior Falcon shows done Point 810 sq 6 lb equals 17 nice area Point B 6 lb meets 45 displacement line W/D 133 good area plane has characteristics result very nice sport flier also good beginner Although point C W/D ometimes hot satisfactory big bird particularly grassfields Senior Falcons powered 60 fliers want kick plane around sky bit course wing center section has reinforced Another use chart give rough estimate glider performance W/S lines 8 14 labelled Light Heavy glider light glider will have low sink rate will really go up thermal heavy glider will fly faster penetrate head winds better have higher sink rate use engine launch climb field drop down W/D line near line marked Glider Power select engine overpower gliderthose long thin wings just like high speed believe have used 049 10 15 engines progressively larger gliders Big Tat 900 sq W/S 10 15 very nice performer Notice adjective ratings charts-degrees performance impressions after years flying observing model planes Application Empirical Data Now get down specific model planes planes plotted Fig 2 3 ac cording wing power loading Thus can compare planes ideas performance maximum speed lines radiate across Fig 2 3 help relate wing loading speed performance thus separate kites bombs speed lines say faster better vice versa give indication relative performance guide engine selection RC Old-Timers Buzzard Bombshell 850 sq 3 lb 40 eng W/S 9 W/D 875 low end wing loading scale BB has predictably fantastic glide oh power Hot word. like destructive power caused stresses failed wing 23rd flight rebuilt will have 19 old 29 wing will reinforced Playboy Senior next BB chart also experienced wing failure according author mag azine article Again apparently too much power low W/S Please use smaller engine OT birds certain reinforce wing center section light structure goes along light wing loading strong enough handle high power radio control can put G-loads plane might encounter free flightturn page January 1977 15 Just handful configurations fly Weight wing area power vary endlessly charts come rescue Photo graph Bruce Robertson RC Model Performance Beginner beginner would well select plane W/S 10-15 W/D 15-20 although models available range Up scale bit several models satisfactory help experienced pilot recommend Falcon 56 Senior Falcon Bridi RCM 400 Old-time fliers planes say use plenty power can always throttle back However power can get novice trouble quicker gets him out cautious Sport Fliers Models sport fliers range W/S 15 24 W/D 10 up depending proficiency models category higher wing loading hotter landing high W/S high W/D just may get off ground does have bear hands Pattern Planes range W/S 23 28 maybe Tony Bon etti named Troublemaker type higher W/S means larger maneuv ers s loops etc An experienced sport pilot can handle pattern ship beginners W/D 10-117 Scale Planes kits Stand-Off true Scale planes available range nice hot beginner insists building scale model hope will sooner later should pick lower W/S area P-SI Me109 F-4 shown chart expert fliers So bought F-4 put away few years until expert pattern flier Akro Master next F-4 W/S 288 too hot lasted five flights Grass takeoffs diffi cult landings hot Biplanes Several available Fleet AeroMaster PT-17 two AcroStars Pitts S-2 Waco-K range good sport flier However biplanes quick responsive controls properly rigged powered definitely acrobatic course tail draggers different trike gear ship Pylon Racers No specific models shown because must conform specifica tions As stated maximum speed lines too low racers because powerful engines used very clean aero dynamic form finish Formula racers 120-mph speed generate performance very special kind flier Quarter Midget racers need expert pilot take care racers dont belong average plane charts because breed own preclude swamping editor correspondence let us make clear wing-loading/power-loading technique does use scale factors dynamic scaling calibrating judges eyeballs square root scale factor scale time etc certain can proved one-fifth scale model Supersonic X-l000 fighter should weigh 25 lbs should powered 50 horses judge should realize model really flying 45% real time. duplicate scale flight full-size plane However average Sunday fliers want know after fourth repair job two pounds epoxy later should change 30 40 can handle hotter land ing higher wing loading simple charts can point us toward answers questions like whole point Conclusion three charts presented show large number models present past fall set FIG 2SPEED VS S/D R/C AIRPLANE PERFORMANCE INDICATORS-AREAENGINEMAX SPEED 336I 3f5CU INI3# VMAX7505 S sa ik4 lr125 C II er150-q--er so/4~ /t U 5560925 0 500636U S 4# 015#4t7# 567 0504p,#~j [ -J5 36050I10 SI 25 042 S 16 ModelAviation z U 2 45 U 40 2 5 2 useful empirically derived curves Some individual adjustments must always made example factor just has added grass takeoff unfortunately means hotter model air hoped discussion charts will assist selecting next two three models after will making own standards event hope will deter beginners visualize four-engine scale bomber weighs 20 lbs first model Meanwhile may flights smooth landings safe Flying scale notorious pitfall unwary know ever tried ease off ground heavy probably under-powered job Richard Smith appears have put together 1976 Nats rather large Citabria charts examples given text enable predict per formance model before flown Per haps engine change order also aid designer pinpointing parameters Assuming adequate prior flying experience can establish feel model will go FIG 3SPEED VS W/D AND W/S R/C MODEL AIRPLANE PERFORMANCE INDICATORS W/S W/D V max tV MAx WtI GLIDEAPOWER C HAND LAUNCH 24/ -I-06C CU IN GRASS TAKEOFF MARGINAL -i-- -re Ii S 18-14 t r 4 314I 12-u 10HOT~ue S 6 acM BOWS PATTERNRACERSMT PILOT January 1977 17 2 WIS OZ/SO FT
Edition: Model Aviation - 1977/01
Page Numbers: 14, 15, 16, 17
Dont let title throw Its easy-to-read article useful charts yield valuable data comparing designs selecting models build related terms area weight wing/power loading WHEN YOU select new plane en gine what criteria use depends ability fly course also de pends performance expect plane engine experi enced modeler course make choice based experience judgment However relatively inex perienced probably could use some help Hopefully discussion charts will help make proper choices What performance Well can defined formulae too abstract modelers Performance can abstract beautiful sight glider just hanging up maybe gracefully following local hawk Per formance certainly Formula racer turning 115 qualifying heat cham pionship contest no will deny average speed 120 mph performance Performance can moment begin FIGJ CALCULATING W/D AND W/S Jack Burns Empirical RC Model Performance Criteria ner suddenly gets together can take off fly around field make safe landing Thus performance can very technical can subjective judgments form field watching different planes fly What airplane criteria determine per formance Several lets confine discussion three weight wing area engine power designated displace ment little arithmetic weight divided area wing loading W/S perhaps important item Weight divided power power loading W/D know power what makes beast go low W/S means light plane large wing area weight high W/S heavy plane small wing Low W/D means lots power high W/D low power Lets examine manner ratios determine performance full-size airplane calculations pounds square feet horse power used model use keep numbers whole convenient express W/S ounces per square foot W/D pounds per cubic inch displacement assumes horsepower proportional displace ment roughly correct Thus charts marked units En52121 - Q AU0 A'Uk 2 04 - $60 80 WlSozjsonA g %Pq\4AoIAAAm 113 4 F-4M 1T0M -4As AEIF*L0O U W/D LBS /CUIN U As WING LOADING W/S OZISOIN POWER LOADING WtD # iCUIN MCK AIJA AERO TECENECHANIcS .-- .-- IS-- -----4- - S AREA SOIN 5 6 50607060 0 ENGINE DISPLACEMENT Cu IN 14 Model Aviation 10 05 10 15 N gine displacement used instead horse power since actual HP readily avail able Besides never run engines full out maximum potential developed test bench after careful break-in sequence Well maybe pylon racer guys sport flier would rather have engine last longer sacrifice bit performance calculating max speed lines used 167 HP per cubic inch average engines tested Mr Peter Chinn using 5% nitro fuel mufflers sumes horsepower proportional dis placement roughly correct Hotter engines high nitro fuel no mufflers prop will allow engine wind out full rpm will give lower W/D higher speeds shown charts Thus racing 40 has much higher output average much lower W/D Cox TDs also put out average Calculating W/D W/S Fig 1 helps find W/S W/D breaking out calculator W/S W/D radial lines plotted against weight area engine size find W/S locate point left chart weight line intersects area line Simi larly reading right weight scale engine displacement yields direct reading W/D example Senior Falcon shows done Point 810 sq 6 lb equals 17 nice area Point B 6 lb meets 45 displacement line W/D 133 good area plane has characteristics result very nice sport flier also good beginner Although point C W/D ometimes hot satisfactory big bird particularly grassfields Senior Falcons powered 60 fliers want kick plane around sky bit course wing center section has reinforced Another use chart give rough estimate glider performance W/S lines 8 14 labelled Light Heavy glider light glider will have low sink rate will really go up thermal heavy glider will fly faster penetrate head winds better have higher sink rate use engine launch climb field drop down W/D line near line marked Glider Power select engine overpower gliderthose long thin wings just like high speed believe have used 049 10 15 engines progressively larger gliders Big Tat 900 sq W/S 10 15 very nice performer Notice adjective ratings charts-degrees performance impressions after years flying observing model planes Application Empirical Data Now get down specific model planes planes plotted Fig 2 3 ac cording wing power loading Thus can compare planes ideas performance maximum speed lines radiate across Fig 2 3 help relate wing loading speed performance thus separate kites bombs speed lines say faster better vice versa give indication relative performance guide engine selection RC Old-Timers Buzzard Bombshell 850 sq 3 lb 40 eng W/S 9 W/D 875 low end wing loading scale BB has predictably fantastic glide oh power Hot word. like destructive power caused stresses failed wing 23rd flight rebuilt will have 19 old 29 wing will reinforced Playboy Senior next BB chart also experienced wing failure according author mag azine article Again apparently too much power low W/S Please use smaller engine OT birds certain reinforce wing center section light structure goes along light wing loading strong enough handle high power radio control can put G-loads plane might encounter free flightturn page January 1977 15 Just handful configurations fly Weight wing area power vary endlessly charts come rescue Photo graph Bruce Robertson RC Model Performance Beginner beginner would well select plane W/S 10-15 W/D 15-20 although models available range Up scale bit several models satisfactory help experienced pilot recommend Falcon 56 Senior Falcon Bridi RCM 400 Old-time fliers planes say use plenty power can always throttle back However power can get novice trouble quicker gets him out cautious Sport Fliers Models sport fliers range W/S 15 24 W/D 10 up depending proficiency models category higher wing loading hotter landing high W/S high W/D just may get off ground does have bear hands Pattern Planes range W/S 23 28 maybe Tony Bon etti named Troublemaker type higher W/S means larger maneuv ers s loops etc An experienced sport pilot can handle pattern ship beginners W/D 10-117 Scale Planes kits Stand-Off true Scale planes available range nice hot beginner insists building scale model hope will sooner later should pick lower W/S area P-SI Me109 F-4 shown chart expert fliers So bought F-4 put away few years until expert pattern flier Akro Master next F-4 W/S 288 too hot lasted five flights Grass takeoffs diffi cult landings hot Biplanes Several available Fleet AeroMaster PT-17 two AcroStars Pitts S-2 Waco-K range good sport flier However biplanes quick responsive controls properly rigged powered definitely acrobatic course tail draggers different trike gear ship Pylon Racers No specific models shown because must conform specifica tions As stated maximum speed lines too low racers because powerful engines used very clean aero dynamic form finish Formula racers 120-mph speed generate performance very special kind flier Quarter Midget racers need expert pilot take care racers dont belong average plane charts because breed own preclude swamping editor correspondence let us make clear wing-loading/power-loading technique does use scale factors dynamic scaling calibrating judges eyeballs square root scale factor scale time etc certain can proved one-fifth scale model Supersonic X-l000 fighter should weigh 25 lbs should powered 50 horses judge should realize model really flying 45% real time. duplicate scale flight full-size plane However average Sunday fliers want know after fourth repair job two pounds epoxy later should change 30 40 can handle hotter land ing higher wing loading simple charts can point us toward answers questions like whole point Conclusion three charts presented show large number models present past fall set FIG 2SPEED VS S/D R/C AIRPLANE PERFORMANCE INDICATORS-AREAENGINEMAX SPEED 336I 3f5CU INI3# VMAX7505 S sa ik4 lr125 C II er150-q--er so/4~ /t U 5560925 0 500636U S 4# 015#4t7# 567 0504p,#~j [ -J5 36050I10 SI 25 042 S 16 ModelAviation z U 2 45 U 40 2 5 2 useful empirically derived curves Some individual adjustments must always made example factor just has added grass takeoff unfortunately means hotter model air hoped discussion charts will assist selecting next two three models after will making own standards event hope will deter beginners visualize four-engine scale bomber weighs 20 lbs first model Meanwhile may flights smooth landings safe Flying scale notorious pitfall unwary know ever tried ease off ground heavy probably under-powered job Richard Smith appears have put together 1976 Nats rather large Citabria charts examples given text enable predict per formance model before flown Per haps engine change order also aid designer pinpointing parameters Assuming adequate prior flying experience can establish feel model will go FIG 3SPEED VS W/D AND W/S R/C MODEL AIRPLANE PERFORMANCE INDICATORS W/S W/D V max tV MAx WtI GLIDEAPOWER C HAND LAUNCH 24/ -I-06C CU IN GRASS TAKEOFF MARGINAL -i-- -re Ii S 18-14 t r 4 314I 12-u 10HOT~ue S 6 acM BOWS PATTERNRACERSMT PILOT January 1977 17 2 WIS OZ/SO FT