Ed, My verbosity has obviously obscured my PRIMARY points in this thread.
1. I strongly affirm that airworthy Ercoupes are safe...that's how they got old! 2. I strongly advocate an immediate power reduction (to that RPM necessary for level flight at 60-70 MPH) in response to any in-flight problem. If sufficiently thought-provoking and convincing I hoped this discussion might someday save someone's life. A pilot probably doesn't actually know what is happening in the instant sense as an in-flight challenge presents itself. Rather than embrace the deceptive simplicity of absolutes, let us consider only in-flight emergencies where pilot action can prevent loss of control and/or catastrophic structural failure. I speculated about "the great majority of flutter encounters...". If there is time for a pilot to act, reducing speed should reduce the destructive effects of flutter. We seem to agree what a pilot does and how soon can literally make the difference between life and death. Of possible courses of action, we seem both interested in discerning which, if any, is BEST to take FIRST. It would appear that your "....resonant vibration..." did NOT go "...to full intensity almost instantly." Had you previously and specifically "pre-programmed" your response to aileron flutter? Did the time elapsing from the initial onset of flutter until your "loading" of the control surfaces had aerodynamic effect take longer than implementing a "pre-programmed" and generic power reduction response?. Only you were there. Would the outcome have been different? Likely not. Immediate power reduction is the easiest logical and effective immediate FIRST response to ANY unfolding in-flight problem of unknown origin. Unusual and unexpected turbulence or wind shear aloft, or a bird strike get a pilot's attention. So does the sudden onset of vibration from a spinner, engine, prop blade, cowling fastener/panel, or flutter. Reducing power makes the situation better in every case possibly excepting of carb ice (you know the drill, right?). This preemptive FIRST step does not preclude further action if a problem is not fully resolved. Any pilot-in-command action that buys more time aloft for specific diagnosis and further action thereby increases one's odds of success. Best regards, WRB -- On Dec 28, 2008, at 14:24, Ed Burkhead wrote: > > Bill, > > Again, great points. > My only difference with you, Bill, on your post is in this comment you > made: >> It is likely that the great majority of flutter encounters >> begin slowly (with the pilot wondering "what is going on") . . . >> and will cease as soon as power is reduced and speed drops. > > That rule may apply to a lot of other things, but I suggest it doesn't > always apply to flutter. Flutter is, as I understand it, a resonance > phenomenon. When the conditions are right and the disturbing stimulus > hits, > the resonant vibration often goes to full intensity almost instantly. > It > was so when I had aileron flutter. > > If you get slow onset, great. I hope it happens. Wheel bounce from an > unbalanced wheel on your car can start with low amplitude and slowly > rise to > a peak at the optimum speed. > > But, if while flying, you feel that driving-on-a-washboard-road > vibration or > wheel badly out of balance vibration, LOAD the control surfaces > instantly. > It doesn't take a huge load. (i.e. I wouldn't have yanked full back > pressure on the elevator at high speed.) But loading the control > surfaces > causes them to press between the air forces and the control > rods/cables. It > stops resonance vibrations very quickly. > > In the SECOND half of the first instant, chop power and reduce speed. > > That driving on a washboard road is a distinct and dramatic thing that > should never happen in the air. If you are not familiar with it, go > find > busy gravel roads and drive around for a while. > > Ed > > > ------------------------------------ > > Yahoo! Groups Links > > >
