Dr DB Mathews UWcK17 2AQ L3T1Llii 1ez SAP IS RISING birds singing grass growing trees budding evenings lengthening Obviously weve survived another winter must spring Just sap rises plants flying sap seems surge within modelers spring stimulating call flying fields renew contacts flying buddies check out old models test new ones determine what mental physical skills have dulled winters cold Shakes Ever wonder hands bodies shake after first few flights new project bodys endocrine system produces excessive amounts adrenaline supercharge metabolism moments high stress commonly referred fight flight run like heck reaction During real stress body burns upor metabolizesthat excessive surge heightened mental activity physical strength Once stress over adrenaline briefly continues spill endocrine system has expended somehow Most commonly happens signaling skeletal muscles flex relax spasmodically heart respiration rates run much above normal other words involuntary muscle contractions increased pulse respiration rates heightened mental acuity feeling euphoria perfectly normal reactions thrill adventure Its nothing ashamed nor should source derision others Frankly euphoric rush adrenaline can become addictive exactly some people skydive bungee jump forth course should flaws cardiovascular system endocrine msh can very hannful Id guess pulse respiration rate us after long free flight recovery challenging thermal flight glider wild Combat session test-flying new model can easily approach levels found after brisk 30minute walk game tennis can fatalor least severely debilitatingfor older overweight out-ofshape men participate high-stress activities heat summer day us heart attacks strokes looking place happen us need get involved conditioning program includes better diets some vigorous physical activities elimination self-destructive habits Think dream projects still built flown alternative growing older unacceptable Autogiros Over years column has featured free flight control line RC autogiro projects times mention has produced large volume correspondence other inputs indicates considerable amount interest models Several RC autogiro articles have recently published US modeling press andas alwaysthe English have continued pioneering Due limited experience Ill critique published designs speculate several should work fairly well however has no chance flying consistently am referring twinrotor autogiros much-more-complex single-shaft type Otto photo attempt blending works David Boddington England several others have apparently ripped him Skip Ruff US simply constructed autogiro Ive obtained successful flightsincluding few public eventspredictably consistent flights have eluded After 18 months messing around project concept far publishable As matter integrity feel design should proven potential builder can assured repeated success project does yet meet criterion So others can benefit errors Ill share what Ive learned Otto absolutely fair Ive seen videos Boddington Ruff designs fly fly well reader should wish build fly autogiro point would recommend rather complex Skipp Ruff Project Model Builder June1994 61 Rotor used Boddington concept Second set rotorsRuff designCurrent rotor Otto uses plywood core April 1975 Please refer previous columns photos information units definition autogiros blades provide lift powered way rotate spinning model moves forward creating lift small wings Boddington designs Otto could possibly support model flight actually just struts booms carry rotors Unlike published design famous designer could possibly fly rotors off Aerodynamic Setups Nearly published designs could find have very similar dynamic setups average lOo 120 rearward 50 inward slant rotor axles relative datum line 5080 downthrust Clark Y airfoiled stabilizers wide variance seems stab incidence ranges 40 to 50 simply understand since balanced slightly ahead rotor axles did find Otto needed full up trim high throttle enough up elevator left reserve good flare landing feel Ottos combination excessive downthrust six degrees airfoiled stab set 40 too much although pitch yaw stability seem pretty good latest version features reduced downthrust stab set zero has flown time writing Rotor Assemblies four bladed rotor photo 1 Boddington concept leading edge blade laid top trailing edge blade two etc blades epoxied inside pair plywood disks hardwood block sandwiched center pitch determined thickness center block also flat horizontal plane Bearings / ID brass eyelets hardware store epoxied center block rotor hub held onto music wire appropriate wheel collars top bottom Machine oil injected bearing after fourth flight Although got repeated flights rotor setup photo model roll instability encountered particularly downwind leg turns models would suddenly dig down side oscillate back same attitude other oscillations would decrease intensity after several swings totally unpredictable both occurrence correction actually resembled tip stalls directly proportional forward speed gained some improvement moving rotor shaft farther aft balance point increasing rearward angle shaft Unfortunately changes required higher angle attack nose up takeoff severely affected landing angles quickly discovered left rotor should rotate clockwise right counterclockwise Without setup model tended increase roll oscillations just didnt seem fly nearly well Following design Skipp Ruff second set rotors constructed hubs solid piece 3/32-inch medium aircraft-grade aluminum cut shape band saw Individual blades have plywood backing attach point through 4-40 bolts elastic nuts run blades adjusted pitch coning angle tips higher center section using simple wooden jig Bearings brass eyelets soldered fender washers/smaller washer combinations top bottom Since Otto flew well original settings newly increased coning angles roll axis instability associated inadequate dihedral Landings still mess though Unfortunately short length bearing surface available setup caused wallowing eccentric wear brass point after 30 flights rotors began stick flight Skipp uses case crankshaft old Cox reed valve engines rotors attached like propellers Obviously method provides plenty bearing surface works well using system requires totally different complex mast unit fabrication such large chunk metal challenging current rotor design uses 1/4 plywood core straps aluminum bolted blades attached same way previously described units bearings similar original Boddington system except nylon eyelets fender washers substituted Both bolted-on systems use 2 spruce leading edges balsa blades sanded airfoil strips carbon fiber run along blade bottom painted clear epoxy Covering blades heat shrink didnt work well because blades frequently dinged cracked Conclusions limited experience believe principle design problems RC autogiros primarily mechanical ones designs seem fairly tolerant variations balance point rotor pitch decalage lesser extent blade coning angles long-term precise performance weak link seems bearing surface between shafts rotor hub could locate source inexpensive /s ID thrust bearings problem would easily corrected Anyone have ideas Power requirements proportional weight size fuselage tail group rotors look like 25sized conventional airplane use 30 Weight should kept low possible optimum performance Landing gear reaily takes terrible beating should super sturdy easily removable straightening Finally flying skills required held competent aerobatic sport flier Reaction times flying speeds within range average BINGO etc pilot autogiros interesting exciting new challenge also lots fun flight sort look like egg beaters gone mad * 62 Model Aviation ani Taylor Otto K&B power three channels 21st Century film Major Decals markings
Edition: Model Aviation - 1994/06
Page Numbers: 61, 62
Dr DB Mathews UWcK17 2AQ L3T1Llii 1ez SAP IS RISING birds singing grass growing trees budding evenings lengthening Obviously weve survived another winter must spring Just sap rises plants flying sap seems surge within modelers spring stimulating call flying fields renew contacts flying buddies check out old models test new ones determine what mental physical skills have dulled winters cold Shakes Ever wonder hands bodies shake after first few flights new project bodys endocrine system produces excessive amounts adrenaline supercharge metabolism moments high stress commonly referred fight flight run like heck reaction During real stress body burns upor metabolizesthat excessive surge heightened mental activity physical strength Once stress over adrenaline briefly continues spill endocrine system has expended somehow Most commonly happens signaling skeletal muscles flex relax spasmodically heart respiration rates run much above normal other words involuntary muscle contractions increased pulse respiration rates heightened mental acuity feeling euphoria perfectly normal reactions thrill adventure Its nothing ashamed nor should source derision others Frankly euphoric rush adrenaline can become addictive exactly some people skydive bungee jump forth course should flaws cardiovascular system endocrine msh can very hannful Id guess pulse respiration rate us after long free flight recovery challenging thermal flight glider wild Combat session test-flying new model can easily approach levels found after brisk 30minute walk game tennis can fatalor least severely debilitatingfor older overweight out-ofshape men participate high-stress activities heat summer day us heart attacks strokes looking place happen us need get involved conditioning program includes better diets some vigorous physical activities elimination self-destructive habits Think dream projects still built flown alternative growing older unacceptable Autogiros Over years column has featured free flight control line RC autogiro projects times mention has produced large volume correspondence other inputs indicates considerable amount interest models Several RC autogiro articles have recently published US modeling press andas alwaysthe English have continued pioneering Due limited experience Ill critique published designs speculate several should work fairly well however has no chance flying consistently am referring twinrotor autogiros much-more-complex single-shaft type Otto photo attempt blending works David Boddington England several others have apparently ripped him Skip Ruff US simply constructed autogiro Ive obtained successful flightsincluding few public eventspredictably consistent flights have eluded After 18 months messing around project concept far publishable As matter integrity feel design should proven potential builder can assured repeated success project does yet meet criterion So others can benefit errors Ill share what Ive learned Otto absolutely fair Ive seen videos Boddington Ruff designs fly fly well reader should wish build fly autogiro point would recommend rather complex Skipp Ruff Project Model Builder June1994 61 Rotor used Boddington concept Second set rotorsRuff designCurrent rotor Otto uses plywood core April 1975 Please refer previous columns photos information units definition autogiros blades provide lift powered way rotate spinning model moves forward creating lift small wings Boddington designs Otto could possibly support model flight actually just struts booms carry rotors Unlike published design famous designer could possibly fly rotors off Aerodynamic Setups Nearly published designs could find have very similar dynamic setups average lOo 120 rearward 50 inward slant rotor axles relative datum line 5080 downthrust Clark Y airfoiled stabilizers wide variance seems stab incidence ranges 40 to 50 simply understand since balanced slightly ahead rotor axles did find Otto needed full up trim high throttle enough up elevator left reserve good flare landing feel Ottos combination excessive downthrust six degrees airfoiled stab set 40 too much although pitch yaw stability seem pretty good latest version features reduced downthrust stab set zero has flown time writing Rotor Assemblies four bladed rotor photo 1 Boddington concept leading edge blade laid top trailing edge blade two etc blades epoxied inside pair plywood disks hardwood block sandwiched center pitch determined thickness center block also flat horizontal plane Bearings / ID brass eyelets hardware store epoxied center block rotor hub held onto music wire appropriate wheel collars top bottom Machine oil injected bearing after fourth flight Although got repeated flights rotor setup photo model roll instability encountered particularly downwind leg turns models would suddenly dig down side oscillate back same attitude other oscillations would decrease intensity after several swings totally unpredictable both occurrence correction actually resembled tip stalls directly proportional forward speed gained some improvement moving rotor shaft farther aft balance point increasing rearward angle shaft Unfortunately changes required higher angle attack nose up takeoff severely affected landing angles quickly discovered left rotor should rotate clockwise right counterclockwise Without setup model tended increase roll oscillations just didnt seem fly nearly well Following design Skipp Ruff second set rotors constructed hubs solid piece 3/32-inch medium aircraft-grade aluminum cut shape band saw Individual blades have plywood backing attach point through 4-40 bolts elastic nuts run blades adjusted pitch coning angle tips higher center section using simple wooden jig Bearings brass eyelets soldered fender washers/smaller washer combinations top bottom Since Otto flew well original settings newly increased coning angles roll axis instability associated inadequate dihedral Landings still mess though Unfortunately short length bearing surface available setup caused wallowing eccentric wear brass point after 30 flights rotors began stick flight Skipp uses case crankshaft old Cox reed valve engines rotors attached like propellers Obviously method provides plenty bearing surface works well using system requires totally different complex mast unit fabrication such large chunk metal challenging current rotor design uses 1/4 plywood core straps aluminum bolted blades attached same way previously described units bearings similar original Boddington system except nylon eyelets fender washers substituted Both bolted-on systems use 2 spruce leading edges balsa blades sanded airfoil strips carbon fiber run along blade bottom painted clear epoxy Covering blades heat shrink didnt work well because blades frequently dinged cracked Conclusions limited experience believe principle design problems RC autogiros primarily mechanical ones designs seem fairly tolerant variations balance point rotor pitch decalage lesser extent blade coning angles long-term precise performance weak link seems bearing surface between shafts rotor hub could locate source inexpensive /s ID thrust bearings problem would easily corrected Anyone have ideas Power requirements proportional weight size fuselage tail group rotors look like 25sized conventional airplane use 30 Weight should kept low possible optimum performance Landing gear reaily takes terrible beating should super sturdy easily removable straightening Finally flying skills required held competent aerobatic sport flier Reaction times flying speeds within range average BINGO etc pilot autogiros interesting exciting new challenge also lots fun flight sort look like egg beaters gone mad * 62 Model Aviation ani Taylor Otto K&B power three channels 21st Century film Major Decals markings