Full scale... This brings back a piece of memory some 2 years ago when I was in a Pitts and Tiger Moth as a passenger. When I asked the pilot why the control stick didn't return to the center when I released my hand, he looked at me as if I had asked the dumbest question in the world ! He then went on explained to me that once the plane was in the air, the airflow would keep the control surfaces at the trimmed positions. He was right ! he was particularly right about the Tiger Moth. I had to exert some real force on the stick before I could move it . Air flow did keep the stick at the netural position and I could get my hands off the stick without getting any fluttering.
So.... full scale airplanes, at least some of them, do not have any expensive digital servos to nail control surfaces in place and yet they do not have fluttering problems. This had puzzled me for quite I while before I stopped thinking about it. Anyone has got any idea on the reason behind ? Y C Lui --- In [EMAIL PROTECTED], Bill Conkling <[EMAIL PROTECTED]> wrote: > I think that we should take lessons from the full scale guys. Keep > linkages tight, hinges free, miniumize slop, use light weight control > surfaces and make sure they are balanced. > > .........bc ([EMAIL PROTECTED] > > http://www.widomaker.com/~conk > Williamsburg, VA 23185 > > > On Fri, 21 Feb 2003, 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. > > > > 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.
