SPORT AEROBATICS Ron Van Putte ONE great things about hobby get meet lot nice people what other hobby people willing give time help beginners Aside occasional odd ball radio control fraternity seems draw mostly people pleasant around Thafs gratified really surprised hear about what F Duayne Sims flying buddies did him Duayne moved Indio California January 1976 met group RC fliers welcomed assisted him constructing learning fly first RC airplane After three years flying purchased new business mortuary Unfortunately new business Soda Springs Idaho family move About week prior Duaynes leaving Indio flying buddies wives surprise party presented him one-of-a-kind flying machine flying coffin called Loved designed built Walt Murray Frank Gomez Doug Taylor George Seto felt Duayne should have airplane went along new business Needless say Duayne surprised humbled effort friends made conceiv ing following through such project words Being introduced great men come walks life range ages has really meant lot has great education watching devotion enthusiasm thank fine men friendship will always mean much some details unique airplane Wingspan 66 Wing Chord 10 Stabilizer span 24 Stabilizer chord including elevator 6 Vertical fin height S Fin width 6 Engine K&B 61 Tank 16 oz Weight ready fly 7 lbs 14 oz wing styrofoam covered 1/64 plywood fuselage made foam board balsa plywood empennage balsa Duayne says flies fine real deadstick ship Think about last Thanks sharing great story rest us Duayne beginners look advice about airplane engine propeller selection just about old pros can help However few really under stand propeller theory rely experience recommending right prop job what follows will complete write-up everything know about propellers might tell you already know enable make rational decisions about prop selection Propellers described follows X-Y X usually diameter prop inches Y pitch inches Prop diameter easy understand pitch bit obscure because way different manufacturers produce brands basically two common ways make propellers constant pitch nonconstant pitch constant pitch propeller angle blade varies linearly propeller turned complete revolution tends advance distance equal prop pitch regardless point observed propeller prop constant pitch will twisted angle tip halfthe angle midway out blade non-constant pitch propellers variations constant pitch idea Usually tip angle somewhat reduced blade angle near hub higher propeller pitch usually described point blade reason mentioning kinds pitch found propellers constant-pitch pro peller usually acts like has higher pitch non-constant-pitch propeller may hear certain brand 11-7 prop appears load up engine like another brands 1 l-7 prop reason difference often way prop pitch described Anyone has done work propeller theory will tell large-scale propeller calculations difficult understand often based experimental work Theyll go tell propeller theory small scale propellers like turn over 10000/20000 rpm black art No has bothered develop theory toy airplane fliers would use very little good experimental data exists Thats propeller manufacturers turn out props look different other Formula Pattern fliers sit pits doing modifications commercial props get edge competition So since propeller performance prediction difficult different factors affect no would foolish enough publish arule thumb about propeller selection right Wrong nice thing about rule thumb dont have apologize about errors since looking absolutely top performance sport fliers convenience makes up errors anyway can approximately determine relative Continued page 101 April 1980 23 An airborne Wacky Racer Flying coffin belongs mortuary-owner Duayne Sims Soda Springs ID Dates twin-tombstone empennage commemorate Daves arrival departure lndio CA Hervey Woods has multi-purpose airplane holder baby slumbers lower level Atlas gets cleanup roof Seen first annual Lake Gunteraville ALl RC Club contest Quick nurse sponge Chuck Shade performs surgery planes nose gear Tanger ine contest Orlando FL AT LAST SOME Primer U ndercoeter Nowin Weve taken popular two-part white primer-undercoat formula made gray Just gray enough please have told us want see dents nicks ripples youre sanding Now make little visible just efficient ever course its still available white too Wood Plastic Metal Fiberglass Hobbypoxy primer-undercoater covers well cures fills fast shrinking easy sand provides smooth-as-glass surface. great adhesion wood plastic metal fiberglass Whether youre balsa builder molded plastic buff whether brush spray it. can now put little color life Hobbypoxy gray undercoat. good ever lot visible complete information how-to-do-it Hobbypoxy Finishing Guide write today ARNIIHAUIIvision Pettit Paint Co Inc H UDUIrUAT reooncis Street Rockaway NJ 07866 HOBBYPOXY ct group finishing products especially formulated hobbyists including Epoxy Glues Epoxy-enamel Paints Fillers Primer-undercoaters Resins R2 hole outside lug potentiometer opposite side want 1 seconds/stroke thing found testing servos column new servos arent necessarily fast advertised Some some arent what work theyre fast enough Log values find new look changes fact have changed information really want anyway Keep letters coming George M Myers 70 Froehlich Farm Rd Hicks yule NY 11801 About CG/Powers Continued page 22 I The engine thrust below CG will produce nose-up moment destabilizing tending move N forward 2 The propeller slip stream increases downwash over tail loading up pushing tail down nose up again destabilizing pushes N further ahead 3 The fatter fuselage presenting greater area upflow ahead wingmore instability N moves forward again 4 The fixed landing gear stabilizing tends pull nose down cancel effects other items some extent net result scale models similar basic configuration Neutral Point usually winds up very close 30% chord wing Thus good safe comfortable CG location about 5% forward 30% Neutral Point 25% chord So now understand CG forward beginners can further aft experts As matter fact have several models balanced approximately 25% tickles see little birds recover nicely stall generally forgiving mistakes controlling fliers dont seem pay much attention CG Location just balance airplane about third way back put seem fine because pretty good fliers would guess may struggling against some stability realizing way sure course test fly model varying CG locations Move CG forward little bit time until its hard get nose up can slow down landing move CG aft small increments until becomes sensitive skittish Ease back little both extremes let limits beginners CG location 25% chord good place start have expressing CG location percent chord because have used constant chord rectangular wing example airplanes made way course Some have tapered wings some have elliptical wings some have triangular wings some have two three wings what chord next installment will discuss Mean Aerodynamic Chord find configurations just mentioned Questions comments may addressed author care editor continued RC Aerobatics/Van Putte Continued page 23 thrust two propellers will deliver compar ing load factor props load factor determined multiplying prop pitch cube diameter example 1 1-8 prophas aloadfactorof8 X1 l 8 comparison 11 -7 prop has load factor 7 X1I53 6 According rule thrust developed 11-8 prop should about same 11 -7 prop know small engine will tum large prop So trick using load factor rule determine typical load factor range different engines vary prop characteristics get desired performance What follows table engine sizes versus load factor ranges flier should find displacement engine question read across load factor range engine table presented included article B J Rich Richburg Central Virginia Radio Control Association Virginia Newsletter Engine Displacement 05 10 15 20 25 30 35 40 45 50 60 80 Load Factor Range 400- 680 900- 1500 1500- 2500 2000- 3000 2600- 3650 3350- 4600 4000- 5500 4600- 6200 5200- 7000 6000- 8400 7600- 10800 9900-14000 flier should rate engine compared others same displacement new Schnuerle ported ringed piston engine will able swing higher load factor prop old boostported lapped piston engine ofthe same displace ment Pick out load factor corresponding April 1980 101 TTER FROM HOBBYPOXY ZIF]IhMU EASY 90 NEW HIGH-WING SPORT 90 1/5 Scale 80 Wingspan Flying Weight 101a lbs Fast Building no die-cut parts 15 hrs Inc custom Alum landing Gear$12995 AEROBATIC AIRPLANESprior bending sharply like wing leading BY ROBT C MORRISONIedges Water gave marginally successful results 19 SUPERB ORAWINGSThen day someone suggested use S3 95 P usammon soak balsa Anyone has aoa POS 111111. ~.=used ammonia knows gives fantastic cA OGSRGPLA-1ECHresults never knew However $ 004SO MC k52 .w Leb gh Valley PlC Newsletter edited Tom B Ihe mer short article bending balsa wood went follows bend balsa wood soak ammonia water aqua-ammonia best 15 longer 45 minutes What happens within balsa wood structure orderly assembly arrangement microscopic elongated hollow cellulose tubes held together natural adhesive called lignin temporarily d storted ammonia solution applied balsa wood bent new shape solution water ammonia evapo rates lignin returns its original strength So now know ammonia works About time next column comes out will getting ready fly again after winters hibernation So column will feature suggestions get airplane engine/radio/pilot combination started right foot GET ORGANIZED Hee S set 01 4 stardy tiles holds over 4 years yoa taaolte 5 11 magazInes 4 MAG FILES $495 send $495 pIns $100 postage handling DON INDUSTRIES PO Box 388-K DOVER NH 03820 displacement rating engine intentional some load factor ranges overlap since know hot 35 can swing prop sick 40 After load factor has selected calculations load factors several combinations prop diameter pitch should made determine closest match After initial selection props slight higher lower load factors should tried see satisfies requirements air plane/engine/pilot combination example speed desired prop higher load factor should tried Conversely better low speed thrust will generally obtained using prop lower load factor Unfortunately load factor chart wont tell whether would have better luck manufacturers prop anothers However easy determine everything no would expert Give chart try next time beginner asks what prop put first airplane might think about way go get better vertical performance latest airplane too long time used water soak balsa sheet Ron Van Putte 12 Connie Drive Shalimar FL 32579 RC Helicopters/Chesney Continued page 25 utility variety semi-scale Hughes 300 available Du-Bro number years can fashioned very respectable stand-off scale model Look back few months ago July 1979 MA photo Grady Howards Hughes 300 example what can done Du-Bros Shark Hughes part executive military types full fuselages seem popular guess because chances really doll up fuselage paint schemes recent executive helicopters modeled Bell 222 very sleek business aircraft retractable tricycle landing gear rather usual landing skids Schlueter first offered 222 scale fuselage Heliboy recently Bell 222 fuse lage offered Kavan Jet Ranger mechanics Central Hobby Supply 35 Woodberry Little Rock AR 72212 Centrals Bell 222 may also modified accept Heliboy Revolution Commander Graupner mechanics leaflet photos fiberglass kit looked great wish photo present So far looks like Bell helicopter would have likely full scale helicopter represented model helicopter flying field continue trend Graupner intro duced Bell 212 47G models few years ago Graupner 47G 25 size machine never seemed make over Graupner Bell 212s did Im sure Graupner kits still available 212 fliers Ive talked still find desirable model Graupoer 212 seems very smooth scale-like flying ma chine Other fuselage kits Bell helicopters will modeled instance Bell 212 214 205 slated future releases Central Hobby Supply Bell 204 UH lB IROQUOIS helicopter kit Hirobo available through Consumers Hobby Corp rounds out Bell Helicopter family available RC fliers What about representation other fullscale American helicopter manufacturers have single rotor designs Well excep tion Enstrom Im sure few years ago Du-Bro presented 40 size TnStar Enstrom fuselage re cently Hirobo offers Enstrom Shark 40 size far know model helicopter manufacturers have ignored other full scale american helicopter designs So Sikorsky fans will have scratch-build few other models full scale birds available about Kavans Alouette II 40 size engines Hirobos Aero spatiale Gazelle 60s Schlueters Bolkow B0105 four blade head other helicopters available kit form models European helicopters quite well known American skywatchers beautiful ships very pretty helicopter European design Aerospatiale AS350 have opportunity walk around photo course full scale machine fuselage kit will soon available fit Heliboy mechanics So variety scale helicopter kits fuselage kits availablenow about some 102 Model Aviation 1/5 Scale Size 80 Wingspan 1126 Wing Area Price $12995 CHIPSHIP k Fast Super Aerobatic Ohio TWO EASYt Truly Aerobatic Twin 40 Model High Quality Throughout Price $8995 Diesel Conversion Scale Power Quiet Smooth Economical Send 25 & Stamped Addressed Envelope Dealer Inquiry Invited Diesel Development Inc Dads ox 141 Miltord CT 06460
Edition: Model Aviation - 1980/04
Page Numbers: 23, 101, 102
SPORT AEROBATICS Ron Van Putte ONE great things about hobby get meet lot nice people what other hobby people willing give time help beginners Aside occasional odd ball radio control fraternity seems draw mostly people pleasant around Thafs gratified really surprised hear about what F Duayne Sims flying buddies did him Duayne moved Indio California January 1976 met group RC fliers welcomed assisted him constructing learning fly first RC airplane After three years flying purchased new business mortuary Unfortunately new business Soda Springs Idaho family move About week prior Duaynes leaving Indio flying buddies wives surprise party presented him one-of-a-kind flying machine flying coffin called Loved designed built Walt Murray Frank Gomez Doug Taylor George Seto felt Duayne should have airplane went along new business Needless say Duayne surprised humbled effort friends made conceiv ing following through such project words Being introduced great men come walks life range ages has really meant lot has great education watching devotion enthusiasm thank fine men friendship will always mean much some details unique airplane Wingspan 66 Wing Chord 10 Stabilizer span 24 Stabilizer chord including elevator 6 Vertical fin height S Fin width 6 Engine K&B 61 Tank 16 oz Weight ready fly 7 lbs 14 oz wing styrofoam covered 1/64 plywood fuselage made foam board balsa plywood empennage balsa Duayne says flies fine real deadstick ship Think about last Thanks sharing great story rest us Duayne beginners look advice about airplane engine propeller selection just about old pros can help However few really under stand propeller theory rely experience recommending right prop job what follows will complete write-up everything know about propellers might tell you already know enable make rational decisions about prop selection Propellers described follows X-Y X usually diameter prop inches Y pitch inches Prop diameter easy understand pitch bit obscure because way different manufacturers produce brands basically two common ways make propellers constant pitch nonconstant pitch constant pitch propeller angle blade varies linearly propeller turned complete revolution tends advance distance equal prop pitch regardless point observed propeller prop constant pitch will twisted angle tip halfthe angle midway out blade non-constant pitch propellers variations constant pitch idea Usually tip angle somewhat reduced blade angle near hub higher propeller pitch usually described point blade reason mentioning kinds pitch found propellers constant-pitch pro peller usually acts like has higher pitch non-constant-pitch propeller may hear certain brand 11-7 prop appears load up engine like another brands 1 l-7 prop reason difference often way prop pitch described Anyone has done work propeller theory will tell large-scale propeller calculations difficult understand often based experimental work Theyll go tell propeller theory small scale propellers like turn over 10000/20000 rpm black art No has bothered develop theory toy airplane fliers would use very little good experimental data exists Thats propeller manufacturers turn out props look different other Formula Pattern fliers sit pits doing modifications commercial props get edge competition So since propeller performance prediction difficult different factors affect no would foolish enough publish arule thumb about propeller selection right Wrong nice thing about rule thumb dont have apologize about errors since looking absolutely top performance sport fliers convenience makes up errors anyway can approximately determine relative Continued page 101 April 1980 23 An airborne Wacky Racer Flying coffin belongs mortuary-owner Duayne Sims Soda Springs ID Dates twin-tombstone empennage commemorate Daves arrival departure lndio CA Hervey Woods has multi-purpose airplane holder baby slumbers lower level Atlas gets cleanup roof Seen first annual Lake Gunteraville ALl RC Club contest Quick nurse sponge Chuck Shade performs surgery planes nose gear Tanger ine contest Orlando FL AT LAST SOME Primer U ndercoeter Nowin Weve taken popular two-part white primer-undercoat formula made gray Just gray enough please have told us want see dents nicks ripples youre sanding Now make little visible just efficient ever course its still available white too Wood Plastic Metal Fiberglass Hobbypoxy primer-undercoater covers well cures fills fast shrinking easy sand provides smooth-as-glass surface. great adhesion wood plastic metal fiberglass Whether youre balsa builder molded plastic buff whether brush spray it. can now put little color life Hobbypoxy gray undercoat. good ever lot visible complete information how-to-do-it Hobbypoxy Finishing Guide write today ARNIIHAUIIvision Pettit Paint Co Inc H UDUIrUAT reooncis Street Rockaway NJ 07866 HOBBYPOXY ct group finishing products especially formulated hobbyists including Epoxy Glues Epoxy-enamel Paints Fillers Primer-undercoaters Resins R2 hole outside lug potentiometer opposite side want 1 seconds/stroke thing found testing servos column new servos arent necessarily fast advertised Some some arent what work theyre fast enough Log values find new look changes fact have changed information really want anyway Keep letters coming George M Myers 70 Froehlich Farm Rd Hicks yule NY 11801 About CG/Powers Continued page 22 I The engine thrust below CG will produce nose-up moment destabilizing tending move N forward 2 The propeller slip stream increases downwash over tail loading up pushing tail down nose up again destabilizing pushes N further ahead 3 The fatter fuselage presenting greater area upflow ahead wingmore instability N moves forward again 4 The fixed landing gear stabilizing tends pull nose down cancel effects other items some extent net result scale models similar basic configuration Neutral Point usually winds up very close 30% chord wing Thus good safe comfortable CG location about 5% forward 30% Neutral Point 25% chord So now understand CG forward beginners can further aft experts As matter fact have several models balanced approximately 25% tickles see little birds recover nicely stall generally forgiving mistakes controlling fliers dont seem pay much attention CG Location just balance airplane about third way back put seem fine because pretty good fliers would guess may struggling against some stability realizing way sure course test fly model varying CG locations Move CG forward little bit time until its hard get nose up can slow down landing move CG aft small increments until becomes sensitive skittish Ease back little both extremes let limits beginners CG location 25% chord good place start have expressing CG location percent chord because have used constant chord rectangular wing example airplanes made way course Some have tapered wings some have elliptical wings some have triangular wings some have two three wings what chord next installment will discuss Mean Aerodynamic Chord find configurations just mentioned Questions comments may addressed author care editor continued RC Aerobatics/Van Putte Continued page 23 thrust two propellers will deliver compar ing load factor props load factor determined multiplying prop pitch cube diameter example 1 1-8 prophas aloadfactorof8 X1 l 8 comparison 11 -7 prop has load factor 7 X1I53 6 According rule thrust developed 11-8 prop should about same 11 -7 prop know small engine will tum large prop So trick using load factor rule determine typical load factor range different engines vary prop characteristics get desired performance What follows table engine sizes versus load factor ranges flier should find displacement engine question read across load factor range engine table presented included article B J Rich Richburg Central Virginia Radio Control Association Virginia Newsletter Engine Displacement 05 10 15 20 25 30 35 40 45 50 60 80 Load Factor Range 400- 680 900- 1500 1500- 2500 2000- 3000 2600- 3650 3350- 4600 4000- 5500 4600- 6200 5200- 7000 6000- 8400 7600- 10800 9900-14000 flier should rate engine compared others same displacement new Schnuerle ported ringed piston engine will able swing higher load factor prop old boostported lapped piston engine ofthe same displace ment Pick out load factor corresponding April 1980 101 TTER FROM HOBBYPOXY ZIF]IhMU EASY 90 NEW HIGH-WING SPORT 90 1/5 Scale 80 Wingspan Flying Weight 101a lbs Fast Building no die-cut parts 15 hrs Inc custom Alum landing Gear$12995 AEROBATIC AIRPLANESprior bending sharply like wing leading BY ROBT C MORRISONIedges Water gave marginally successful results 19 SUPERB ORAWINGSThen day someone suggested use S3 95 P usammon soak balsa Anyone has aoa POS 111111. ~.=used ammonia knows gives fantastic cA OGSRGPLA-1ECHresults never knew However $ 004SO MC k52 .w Leb gh Valley PlC Newsletter edited Tom B Ihe mer short article bending balsa wood went follows bend balsa wood soak ammonia water aqua-ammonia best 15 longer 45 minutes What happens within balsa wood structure orderly assembly arrangement microscopic elongated hollow cellulose tubes held together natural adhesive called lignin temporarily d storted ammonia solution applied balsa wood bent new shape solution water ammonia evapo rates lignin returns its original strength So now know ammonia works About time next column comes out will getting ready fly again after winters hibernation So column will feature suggestions get airplane engine/radio/pilot combination started right foot GET ORGANIZED Hee S set 01 4 stardy tiles holds over 4 years yoa taaolte 5 11 magazInes 4 MAG FILES $495 send $495 pIns $100 postage handling DON INDUSTRIES PO Box 388-K DOVER NH 03820 displacement rating engine intentional some load factor ranges overlap since know hot 35 can swing prop sick 40 After load factor has selected calculations load factors several combinations prop diameter pitch should made determine closest match After initial selection props slight higher lower load factors should tried see satisfies requirements air plane/engine/pilot combination example speed desired prop higher load factor should tried Conversely better low speed thrust will generally obtained using prop lower load factor Unfortunately load factor chart wont tell whether would have better luck manufacturers prop anothers However easy determine everything no would expert Give chart try next time beginner asks what prop put first airplane might think about way go get better vertical performance latest airplane too long time used water soak balsa sheet Ron Van Putte 12 Connie Drive Shalimar FL 32579 RC Helicopters/Chesney Continued page 25 utility variety semi-scale Hughes 300 available Du-Bro number years can fashioned very respectable stand-off scale model Look back few months ago July 1979 MA photo Grady Howards Hughes 300 example what can done Du-Bros Shark Hughes part executive military types full fuselages seem popular guess because chances really doll up fuselage paint schemes recent executive helicopters modeled Bell 222 very sleek business aircraft retractable tricycle landing gear rather usual landing skids Schlueter first offered 222 scale fuselage Heliboy recently Bell 222 fuse lage offered Kavan Jet Ranger mechanics Central Hobby Supply 35 Woodberry Little Rock AR 72212 Centrals Bell 222 may also modified accept Heliboy Revolution Commander Graupner mechanics leaflet photos fiberglass kit looked great wish photo present So far looks like Bell helicopter would have likely full scale helicopter represented model helicopter flying field continue trend Graupner intro duced Bell 212 47G models few years ago Graupner 47G 25 size machine never seemed make over Graupner Bell 212s did Im sure Graupner kits still available 212 fliers Ive talked still find desirable model Graupoer 212 seems very smooth scale-like flying ma chine Other fuselage kits Bell helicopters will modeled instance Bell 212 214 205 slated future releases Central Hobby Supply Bell 204 UH lB IROQUOIS helicopter kit Hirobo available through Consumers Hobby Corp rounds out Bell Helicopter family available RC fliers What about representation other fullscale American helicopter manufacturers have single rotor designs Well excep tion Enstrom Im sure few years ago Du-Bro presented 40 size TnStar Enstrom fuselage re cently Hirobo offers Enstrom Shark 40 size far know model helicopter manufacturers have ignored other full scale american helicopter designs So Sikorsky fans will have scratch-build few other models full scale birds available about Kavans Alouette II 40 size engines Hirobos Aero spatiale Gazelle 60s Schlueters Bolkow B0105 four blade head other helicopters available kit form models European helicopters quite well known American skywatchers beautiful ships very pretty helicopter European design Aerospatiale AS350 have opportunity walk around photo course full scale machine fuselage kit will soon available fit Heliboy mechanics So variety scale helicopter kits fuselage kits availablenow about some 102 Model Aviation 1/5 Scale Size 80 Wingspan 1126 Wing Area Price $12995 CHIPSHIP k Fast Super Aerobatic Ohio TWO EASYt Truly Aerobatic Twin 40 Model High Quality Throughout Price $8995 Diesel Conversion Scale Power Quiet Smooth Economical Send 25 & Stamped Addressed Envelope Dealer Inquiry Invited Diesel Development Inc Dads ox 141 Miltord CT 06460
Edition: Model Aviation - 1980/04
Page Numbers: 23, 101, 102
SPORT AEROBATICS Ron Van Putte ONE great things about hobby get meet lot nice people what other hobby people willing give time help beginners Aside occasional odd ball radio control fraternity seems draw mostly people pleasant around Thafs gratified really surprised hear about what F Duayne Sims flying buddies did him Duayne moved Indio California January 1976 met group RC fliers welcomed assisted him constructing learning fly first RC airplane After three years flying purchased new business mortuary Unfortunately new business Soda Springs Idaho family move About week prior Duaynes leaving Indio flying buddies wives surprise party presented him one-of-a-kind flying machine flying coffin called Loved designed built Walt Murray Frank Gomez Doug Taylor George Seto felt Duayne should have airplane went along new business Needless say Duayne surprised humbled effort friends made conceiv ing following through such project words Being introduced great men come walks life range ages has really meant lot has great education watching devotion enthusiasm thank fine men friendship will always mean much some details unique airplane Wingspan 66 Wing Chord 10 Stabilizer span 24 Stabilizer chord including elevator 6 Vertical fin height S Fin width 6 Engine K&B 61 Tank 16 oz Weight ready fly 7 lbs 14 oz wing styrofoam covered 1/64 plywood fuselage made foam board balsa plywood empennage balsa Duayne says flies fine real deadstick ship Think about last Thanks sharing great story rest us Duayne beginners look advice about airplane engine propeller selection just about old pros can help However few really under stand propeller theory rely experience recommending right prop job what follows will complete write-up everything know about propellers might tell you already know enable make rational decisions about prop selection Propellers described follows X-Y X usually diameter prop inches Y pitch inches Prop diameter easy understand pitch bit obscure because way different manufacturers produce brands basically two common ways make propellers constant pitch nonconstant pitch constant pitch propeller angle blade varies linearly propeller turned complete revolution tends advance distance equal prop pitch regardless point observed propeller prop constant pitch will twisted angle tip halfthe angle midway out blade non-constant pitch propellers variations constant pitch idea Usually tip angle somewhat reduced blade angle near hub higher propeller pitch usually described point blade reason mentioning kinds pitch found propellers constant-pitch pro peller usually acts like has higher pitch non-constant-pitch propeller may hear certain brand 11-7 prop appears load up engine like another brands 1 l-7 prop reason difference often way prop pitch described Anyone has done work propeller theory will tell large-scale propeller calculations difficult understand often based experimental work Theyll go tell propeller theory small scale propellers like turn over 10000/20000 rpm black art No has bothered develop theory toy airplane fliers would use very little good experimental data exists Thats propeller manufacturers turn out props look different other Formula Pattern fliers sit pits doing modifications commercial props get edge competition So since propeller performance prediction difficult different factors affect no would foolish enough publish arule thumb about propeller selection right Wrong nice thing about rule thumb dont have apologize about errors since looking absolutely top performance sport fliers convenience makes up errors anyway can approximately determine relative Continued page 101 April 1980 23 An airborne Wacky Racer Flying coffin belongs mortuary-owner Duayne Sims Soda Springs ID Dates twin-tombstone empennage commemorate Daves arrival departure lndio CA Hervey Woods has multi-purpose airplane holder baby slumbers lower level Atlas gets cleanup roof Seen first annual Lake Gunteraville ALl RC Club contest Quick nurse sponge Chuck Shade performs surgery planes nose gear Tanger ine contest Orlando FL AT LAST SOME Primer U ndercoeter Nowin Weve taken popular two-part white primer-undercoat formula made gray Just gray enough please have told us want see dents nicks ripples youre sanding Now make little visible just efficient ever course its still available white too Wood Plastic Metal Fiberglass Hobbypoxy primer-undercoater covers well cures fills fast shrinking easy sand provides smooth-as-glass surface. great adhesion wood plastic metal fiberglass Whether youre balsa builder molded plastic buff whether brush spray it. can now put little color life Hobbypoxy gray undercoat. good ever lot visible complete information how-to-do-it Hobbypoxy Finishing Guide write today ARNIIHAUIIvision Pettit Paint Co Inc H UDUIrUAT reooncis Street Rockaway NJ 07866 HOBBYPOXY ct group finishing products especially formulated hobbyists including Epoxy Glues Epoxy-enamel Paints Fillers Primer-undercoaters Resins R2 hole outside lug potentiometer opposite side want 1 seconds/stroke thing found testing servos column new servos arent necessarily fast advertised Some some arent what work theyre fast enough Log values find new look changes fact have changed information really want anyway Keep letters coming George M Myers 70 Froehlich Farm Rd Hicks yule NY 11801 About CG/Powers Continued page 22 I The engine thrust below CG will produce nose-up moment destabilizing tending move N forward 2 The propeller slip stream increases downwash over tail loading up pushing tail down nose up again destabilizing pushes N further ahead 3 The fatter fuselage presenting greater area upflow ahead wingmore instability N moves forward again 4 The fixed landing gear stabilizing tends pull nose down cancel effects other items some extent net result scale models similar basic configuration Neutral Point usually winds up very close 30% chord wing Thus good safe comfortable CG location about 5% forward 30% Neutral Point 25% chord So now understand CG forward beginners can further aft experts As matter fact have several models balanced approximately 25% tickles see little birds recover nicely stall generally forgiving mistakes controlling fliers dont seem pay much attention CG Location just balance airplane about third way back put seem fine because pretty good fliers would guess may struggling against some stability realizing way sure course test fly model varying CG locations Move CG forward little bit time until its hard get nose up can slow down landing move CG aft small increments until becomes sensitive skittish Ease back little both extremes let limits beginners CG location 25% chord good place start have expressing CG location percent chord because have used constant chord rectangular wing example airplanes made way course Some have tapered wings some have elliptical wings some have triangular wings some have two three wings what chord next installment will discuss Mean Aerodynamic Chord find configurations just mentioned Questions comments may addressed author care editor continued RC Aerobatics/Van Putte Continued page 23 thrust two propellers will deliver compar ing load factor props load factor determined multiplying prop pitch cube diameter example 1 1-8 prophas aloadfactorof8 X1 l 8 comparison 11 -7 prop has load factor 7 X1I53 6 According rule thrust developed 11-8 prop should about same 11 -7 prop know small engine will tum large prop So trick using load factor rule determine typical load factor range different engines vary prop characteristics get desired performance What follows table engine sizes versus load factor ranges flier should find displacement engine question read across load factor range engine table presented included article B J Rich Richburg Central Virginia Radio Control Association Virginia Newsletter Engine Displacement 05 10 15 20 25 30 35 40 45 50 60 80 Load Factor Range 400- 680 900- 1500 1500- 2500 2000- 3000 2600- 3650 3350- 4600 4000- 5500 4600- 6200 5200- 7000 6000- 8400 7600- 10800 9900-14000 flier should rate engine compared others same displacement new Schnuerle ported ringed piston engine will able swing higher load factor prop old boostported lapped piston engine ofthe same displace ment Pick out load factor corresponding April 1980 101 TTER FROM HOBBYPOXY ZIF]IhMU EASY 90 NEW HIGH-WING SPORT 90 1/5 Scale 80 Wingspan Flying Weight 101a lbs Fast Building no die-cut parts 15 hrs Inc custom Alum landing Gear$12995 AEROBATIC AIRPLANESprior bending sharply like wing leading BY ROBT C MORRISONIedges Water gave marginally successful results 19 SUPERB ORAWINGSThen day someone suggested use S3 95 P usammon soak balsa Anyone has aoa POS 111111. ~.=used ammonia knows gives fantastic cA OGSRGPLA-1ECHresults never knew However $ 004SO MC k52 .w Leb gh Valley PlC Newsletter edited Tom B Ihe mer short article bending balsa wood went follows bend balsa wood soak ammonia water aqua-ammonia best 15 longer 45 minutes What happens within balsa wood structure orderly assembly arrangement microscopic elongated hollow cellulose tubes held together natural adhesive called lignin temporarily d storted ammonia solution applied balsa wood bent new shape solution water ammonia evapo rates lignin returns its original strength So now know ammonia works About time next column comes out will getting ready fly again after winters hibernation So column will feature suggestions get airplane engine/radio/pilot combination started right foot GET ORGANIZED Hee S set 01 4 stardy tiles holds over 4 years yoa taaolte 5 11 magazInes 4 MAG FILES $495 send $495 pIns $100 postage handling DON INDUSTRIES PO Box 388-K DOVER NH 03820 displacement rating engine intentional some load factor ranges overlap since know hot 35 can swing prop sick 40 After load factor has selected calculations load factors several combinations prop diameter pitch should made determine closest match After initial selection props slight higher lower load factors should tried see satisfies requirements air plane/engine/pilot combination example speed desired prop higher load factor should tried Conversely better low speed thrust will generally obtained using prop lower load factor Unfortunately load factor chart wont tell whether would have better luck manufacturers prop anothers However easy determine everything no would expert Give chart try next time beginner asks what prop put first airplane might think about way go get better vertical performance latest airplane too long time used water soak balsa sheet Ron Van Putte 12 Connie Drive Shalimar FL 32579 RC Helicopters/Chesney Continued page 25 utility variety semi-scale Hughes 300 available Du-Bro number years can fashioned very respectable stand-off scale model Look back few months ago July 1979 MA photo Grady Howards Hughes 300 example what can done Du-Bros Shark Hughes part executive military types full fuselages seem popular guess because chances really doll up fuselage paint schemes recent executive helicopters modeled Bell 222 very sleek business aircraft retractable tricycle landing gear rather usual landing skids Schlueter first offered 222 scale fuselage Heliboy recently Bell 222 fuse lage offered Kavan Jet Ranger mechanics Central Hobby Supply 35 Woodberry Little Rock AR 72212 Centrals Bell 222 may also modified accept Heliboy Revolution Commander Graupner mechanics leaflet photos fiberglass kit looked great wish photo present So far looks like Bell helicopter would have likely full scale helicopter represented model helicopter flying field continue trend Graupner intro duced Bell 212 47G models few years ago Graupner 47G 25 size machine never seemed make over Graupner Bell 212s did Im sure Graupner kits still available 212 fliers Ive talked still find desirable model Graupoer 212 seems very smooth scale-like flying ma chine Other fuselage kits Bell helicopters will modeled instance Bell 212 214 205 slated future releases Central Hobby Supply Bell 204 UH lB IROQUOIS helicopter kit Hirobo available through Consumers Hobby Corp rounds out Bell Helicopter family available RC fliers What about representation other fullscale American helicopter manufacturers have single rotor designs Well excep tion Enstrom Im sure few years ago Du-Bro presented 40 size TnStar Enstrom fuselage re cently Hirobo offers Enstrom Shark 40 size far know model helicopter manufacturers have ignored other full scale american helicopter designs So Sikorsky fans will have scratch-build few other models full scale birds available about Kavans Alouette II 40 size engines Hirobos Aero spatiale Gazelle 60s Schlueters Bolkow B0105 four blade head other helicopters available kit form models European helicopters quite well known American skywatchers beautiful ships very pretty helicopter European design Aerospatiale AS350 have opportunity walk around photo course full scale machine fuselage kit will soon available fit Heliboy mechanics So variety scale helicopter kits fuselage kits availablenow about some 102 Model Aviation 1/5 Scale Size 80 Wingspan 1126 Wing Area Price $12995 CHIPSHIP k Fast Super Aerobatic Ohio TWO EASYt Truly Aerobatic Twin 40 Model High Quality Throughout Price $8995 Diesel Conversion Scale Power Quiet Smooth Economical Send 25 & Stamped Addressed Envelope Dealer Inquiry Invited Diesel Development Inc Dads ox 141 Miltord CT 06460