Bone1099
Active Member
I recently bought a Ferguson FII-A. If youre not familiar with it. Well it looks exactly like a Kolb. Just dont tell Bill Ferguson that. I beleive it shares some similarities of flight charictaristics with a Kolb from what i have read about them. I have been experiencing what i think is a low frequency aerodynamic flutter. In criuse flight or sometimes in a dive usually 75+ mph i can feel a slight shake in the stick and if i let it go it willl amplify into an oscillation of the tail boom. Looking back while its doing it i cant tell much and never let it go very far before changing pitch or speed or both. It does'nt seem like it wants to run away but i really want to clear this up altogether. I can see the tail pretty good in flight from the cockpit and can see the tail brace wires moving around quite a bit but they are in the propwash and seem to be moving a lot whether its fluttering or not. I have increased the tension on them but it seems to have no affect and do not want to just continue tightening them. Considered going to solid wires instead of stranded cables. I can also see quite a bit of movement in the trim tab (adjustable). The trim tab is about 16 inches span and 4 inches chord. It is very effective i mean very. My first inclination is to shorten the chord of the trim tab by about an inch to see if that helps. Seems to me that it has a long chord for the thickness of material that it is. It also is very effective. Therefore i think trimming it will only increase the amount of movement of the cockpit lever which is'nt much 2 notches maybe in either direction and it has maybe 20 notches. also i have considered adding a balance rod similar to the aileron rods on many Kolbs. Thoughts are apreciated.
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