Westchester County Center White Plains New York Dont miss 12th annual show Itll biggest best ever Keep last weekend February open 1980 WRAMs Show going largest yet Well over 150 manufacturers other ex hibiters have already signed up bring everything thats new hobby--- kits engines radi os accessories everything between famous Swap Shop will full operation thousands items including built-up planes almost new radios engines on something just about everyone Westchester County Center centrally located city White Plains N intersection RI 110 Central Park Ace. Oronx Ricer Parkway White Plains lust 22 miles north VC Static Competition Make sure latest creation finished up polished youll have chance take home dozens trophies fered events Ww POST AMI Military POST I/RN NOc-MiIituyI PAtTERN SPORT BIPLANE OLD TIMERS SPORT PYLON GLIDERS HELICOPTERS SCALE RIC BOATS RACING RJC BOATS STAND-OFF SCALE JUNIOR EVENTS RIC CARS REST-IN-SHOW Judging takes place Sunday afternoon Entries accepted until 12Noon Sunday Openers/Winter continued page 6 center its side area lies sufficiently behind CG make tracklike feathers arrow profile weathervane traditional argument CLA too far above CG plane would forced spiral dive banked turned because skidding effect airflow outside circle exerting leverage proportion moment arm between CG CLA came Goldberg Zipper pylon gas model spiraled upward under power shook up hardline tradi tionalists long theory revised account two CLAs froffltthe CG andihetttherbehind line drawn between two would impart nose up SWAP SHOP WRAMs Swap Shop has become malor show attractions thousands individual items changing hands help eliminate registration crush 1980 Swap Shop will have special pre-registra lion line have com pleted pre-registration form receive forms send selfaddressed stamped envelope John Isbister 4 Devon Rd Larchmont NY 10528 SPECIAL NOTE Because increased volume items being brought Swap Shop combined space limita tions built-up model will accepted Swap Shop regis trant further informalion write Lam OiRubbo 16 Lindsey Ace Buchanan NY 10511 914 739-2827 WESTCHESTER RADIO AEROMODELERS INC February 23/21i 10AM 6 PM attitude forward CLA higher rearward inclination line barometer might say emphasis ward profile pattern airplane improve knife-edge example revised theory account Walt Mooneys comic free flights have no dihedral have huge funny pilot profile really fin sticking up cockpit really just same Low-speed aerodynamics never developed remotely compare full-scale knowledge cant make up minds smooth wing rough better fiddle turbulators multispars turbulate airflow over model wing presume keep flow breaking away prematurely top surface airfoiL So sounds contradic tory spanking new little scale model seems improve age patches dinks dents begin appear may fast once appears become flying carpet Reynolds Number mighty factor stern task master world indoor different youll agree fast pattern job RN goes up its best glass-like wings seems true FAI RC sailplanes full-scale world deals well-defined set rulesalthough reality great void between Cub ajet liner far wing efficiency lifting capacity concerned world appears level upon level note majestic flight 1/4 scale design parameters stretched like rubber bands seems tell us comparison full-scale aerody namics laws nature have left us modelers worlds still explore believe know everything know basic rules determine configur ation Consider fact awing must somehow stabilized hold its optimum position flight have ever seen free-flight wing depart model high sky rotate around some spanwise axis know what lack such stabilizing force really means As angle attack loose wing increases first pitch-up know thatthe center pressure lift moves forward airfoil destabilize flat plate like sheet balsa wing CL moves rearward Convex sections reduce distance CL will shift So can wing made stable no stabilizer present incorporate sweepback still have supply further stabilization wing twistex aggerated washout tips providing uptilted surfaces tips same purpose possible through airfoil variations other tricky stuff too devious consider limited space have stable flying plank Without hoopla will agree orthodox wing simply must stabilizing force stabilizer winglike horizontal area taiL Some years ago Mr Norman K Walker gave lecture members DC/RC entitled Stability Control Model Air craft long intriguing lecture presented diagrams variety strange models make points Among strange beastie shown accompanying photo graph Instead conventional stabilizer achieved necessary stability small flat plate mounted front high fin After have figured out will perceive notion ways skinning scat laws aerodynamics may fixed thing however strange confirming end employment model designer eloquently suggests adventures lie future draw precise airfoils yet majority sport models rubber gas radio otThand zip can perform just well better speak downwash angles put stab really knows downwash given model may slow molasses fast enough duplicate homebuilt speeds typical indoor model may weigh gram two rubber Consider wing loading would bet life model has tip vortices air pressure thing tip borders non-existent Would agitate tissue streamer aerodynamics science itmeanders still waters low Reynolds Numbers work some cases Low speed aerodynamics know proves mans educated guess good anothers may Continued page 96 72 Model Aviation assou,c ao,c/TONES EN0AN0 aC es0EOss N rare 55551W 4t 00 ii-0 4 0 0