I respect airplanes as much as I love them, so when they talk to me I listen. Not many things in airplanes scare me, but when they do - I feel compelled to tell fellow aviators.
We have talked about carb ice - I have told you what I know and I will be happy if my input helps one person avoid a bad day. Carb ice (at worst), will turn your airplane into a glider - gliders still fly. Flutter is something very different - it could leave you sitting on a wingless brick. Not many of the folks that have experienced flutter are still around - it is difficult to describe the suddenness and violence of this phenomenon. My concern about flutter has resulted in 15 years of listening, reading, testing and trying. I do not wish to enter into debate on any of this - take it or leave it: (Mark, Dana & Larry exempted) This is KRnet, so my comment applies to everything we are likely to address - however, I would apply the same rationale to a Pietenpol. IN EVERY CASE 1. Mass balance (statically) all control surfaces. This is not critical to the nth degree - just ensure that EVERY completed control surface sort of "hangs level" with the pushrod disconnected. Yes, the rudder is a problem - figure a way to turn the bird on its side - or do the VStab before you mount it. I prefer distributed balance weight where possible - not all in one place. Aerodynamic balance tabs are great - they provide one more place to put some of the counter weight. Get the ballast as far fwd (of the hinge-line) as possible to reduce the amount required. All KR control surfaces are aft of CG, so keep added weight to the essential minimum - it affects CG. 2. Zero slop in the control linkages and hinges (including trim tab). 3. Perfect alignment between the moving control surface and the fixed surface - avoid a step-down between the fixed and the trailing (movable) surface - this introduces turbulence at the TE of the fixed surface, i.e. turbulence over the control surface - I believe that this provokes flutter. If in doubt, make the moving surface a tad thicker than the fixed surface. There has been good advice from some of the netters - viz: = apples and oranges are being mixed here = Flutter can happen at any speed = more factors limiting the Vne than elevator flutter = Flutter can destroy an aircraft in flight! I have also seen information from other netters that makes no sense at all - viz.: = However, any malformation of the elevator, depends on the malformation. Exceeding Vne coupled with excess loading factor and all bets are off. Take care Steve askies(At)microlink.zm
