Scale Bud Atkinson THIS MONTH want talk about subject have requests questions about some time dont remember seeing too much written about flaps install oper ate properly have some mis givings doubts about proper use flaps Have no fear no mystery secrets about flaps must understand use intended just same ailerons elevator can remember way back before ailerons old Smog Hog days flaps thought no-no RC model Flaps fall three categories First full flaps portion trailing edge section say about ed commonly used US WW II airplanes light planes lower section trailing edge hinged upper part flap area stationary British use split flap Spitfires Hurricanes others Two well-known airplanes using full flaps hut split flaps P-39 P-40 Next split flaps Third Fowler flaps used multi-engined planes bomb ers transports P-38 B-24 used Fowler flaps flaps glided rearward track extend beyond trailing edge thus also adding wing area FULL FLAP 60 SPUT FLAP FOWLER FLAP Fowler flaps seldom used scale models Up now problem construction alignment track flap ride troublesome because thinness aver age scale wing exception Jack Staffords B-24 large model hope hear some have built flown B-24 Fowler flaps see just react type flap new scale models Lets little theorizing just what flaps work Full-size aircraft generally designed speed maneuverabil ity load-lifting capacity airfoils entire aerodynamics airplane de signed performance So say fighter plane will fast maneuverable problem now slow down land safely such carrier plane Flaps might say air brake Lets take airfoil model such 2412 used lot scale models good lift stability section Assume wing set two-degrees incidence also good round figure incidence scale model center line drawn center leading edge center trailing edge measuring center line airfoil positive two-degree refer ence center line fuselage setting airplane will fly best aerodynami cally other functions being proper engine thrust line stab incidence etc slow down airplane can two things other reduce power course pro duce drag provide lift say can slow bird down producing lift dropping flaps say 30-degrees split full-section flaps trailing edge say /2 lower flaps up position other words draw line center leading edge trailing edge see incidence now about six degreesthis what wing flying drag six de grees two degrees also increase incidence nose will come up trying stay two degrees So full-size airplane some down trim needed hold glide path same true scale model cases just little forward down elevator will job like use down ele vator model say foot IS touchdown neutral elevator will flare about right smooth landing can compare action high-Wing pattern model Im sure have seen flown especially smaller-size engine / airplane class has too much incidence nose wants come up stay up after take-off stay up almost stall full power flaps down same thing occurs As power reduced nose will drop level flight Also forward speed will proportion ally reduced what after slower glide path smoother slower touchdown using flaps take-off take-off run can somewhat shorter steeper climb-out Care must taken bring up flaps slowly once because nose will drop climb-out less level flight slightly below level can rather hairy too low flying strong wind also true lowering flaps landing flaps dumped once will balloon glide path desirable drop half flaps say down-wind leg about r power final lower full flaps have used both full split flaps several scale models really cant tell much difference between above true both factor have contend old hug-a-boo scale effect cannot use same amount degrees flaps cases does full-size airplane P-5 will drop much 70 degrees flaps will fighter aircraft WW II era 50 degrees flaps scale model will almost stop mid-air Ive seen happen About 30 degrees sufficient scale models believe important first test flight use small amount flaps start until airplane trimmed out Should bird tail heavy too much flaps first could disastrous hope have explained suitably flaps function asset scale model cases can get easy points well slow down hot bird Rigging simple just would rig ailerons either bellcranks strip ailerons hope have some feed back some scale contests next time sure send results want mentioned scale contest address 734 N 6th St Terrace Blue Springs Missouri 64015 October 1975 27 Above What could RAF Spitfire awaiting Messerschmitts WW Ills Jim Bonannos realistic model Below Bob Jennings Playboy authors plans has well over 200 flights