"yclui_hk " wrote: > So full-size airplanes are flown with the most springy "servo" - > human hands. How come they don't flutter ? Do they all have balanced > control surfaces ? If they do, is the balance done weight wise ( CG > of the control surface at the hinge point ), aerodynamic wise ( line > of aerodynamic force on the control surface going through the hinge > point ) or in some other fashions ?
Full sized airplanes can and do flutter if pushed beyond their specified speed limits. There's all sorts of mass balances, from wieghts hidden just forward of the leading edge of the aileron, to big tear-drop shaped chunks of lead hung from the control surfaces on a strut that places them forward of the hinge line. > > Y C Lui > > --- In [EMAIL PROTECTED], Simon Van Leeuwen <[EMAIL PROTECTED]> > wrote: > > As Bill S. put it, the stiffer the control surface, the less linkage > > slop, the tighter the gear lash...the higher you push the (resonant) > > frequency required to initialize flutter. No rocket science here. > > > > Craig Toutolmin wrote: > > > > > > I want to run this by everyone for confirmation or correction. > > > > > > I have talked to several engineer types and have been told that > what we are > > > working with is a mass/spring system. The mass is the control > surface and > > > the spring is the give in the servo - assuming the linkage and > hinge are > > > tight, arranged to minimize the effect of gear slop and > positioned to > > > minimize torsional flex. The system will flutter at some > harmonic. Large > > > amplitude is destructive. A very small amplitude is the goal. > The softer > > > the spring and the heavier the surface (aft of the hinge line) > the larger > > > the amplitude of the harmonic. Smaller surfaces minimize > amplitude. > > > Lighter surfaces minimize amplitude. Surfaces counterbalanced to > the hinge > > > line will minimize the amplitude. Servos with a higher spring > constant > > > (firmer) will minimize amplitude. > > > > > > Whatdayathink? > > > > > > Craig Toutolmin > > > > > > RCSE-List facilities provided by Model Airplane News. > Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] > Please note that subscribe and unsubscribe messages must be sent in > text only format with MIME turned off. > > > > -- > > *~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~* > > Simon Van Leeuwen, Calgary, Alberta > > RADIUS SYSTEMS > > Cogito-Ergo-Zoom > > IAC25233*MAAC12835*IMAC1756*LSF5953*IMAA20209 > > *~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~* > > RCSE-List facilities provided by Model Airplane News. > Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] > Please note that subscribe and unsubscribe messages must be sent in > text only format with MIME turned off. > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and > "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and > unsubscribe messages must be sent in text only format with MIME turned off. -- _____________________________________________________________ Brett Jaffee [EMAIL PROTECTED] R/C Slope and Power Homepage http://home.earthlink.net/~jaffee The Unoffical Extra 300 Home Page http://members.nbci.com/bjaffee/extra300/ OnTheWay Quake 3 Server Utility http://www.planetquake.com/ontheway _____________________________________________________________ RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
