• The Biplane Forum is a large global active community of biplane builders, owners and pilots. From Pitts to Skybolts, to older barnstormers, all types are welcome. In addition to our active community, our content boasts exhaustive technical information which is often sought after for projects and maintenance. This information has accumulated over the 12+ years the forum has been in existence.

    The Biplane Forum is a private community. Subscriptions are only $49.99/year or $6.99/month to gain access to this great community and unmatched source of information not found anywhere else on the web. We are also a great resource for non biplane users, since many GA aircraft are built the same way (fabric and tube construction).

Trim/Servo Tab Adjustment

JoeyC

JoeyC
*
Joined
Aug 28, 2007
Messages
105
Reaction score
1
OK Gang, a little input requested: Got the bird out of its long and detailed (all winter) condition inspection and had an enjoyable and pretty successful 1.4test hop Wednesday. Only one problem noted; When it went in this winter, one of the squawks my A&P wrote up was that the servo tab pushrod was rusted and slightly bent. So I dutifully cleaned, painted, and straightened it, and reinstalled in the original horn holes at the original thread adjustments.


During the test flight, it was immediately apparent that there was now a pronounced pitch up tendency requiring forward pressure on the stick, even with full nose-down trim. Not so bad at 80-90 knots, but more and more pressure required at 110-120 (as you'd expect). Should note that it flew pretty much hands off before I screwed around with the pushrod.


I expected straightening the rod would have some effect but not to this extent. I know, the obvious fix is probably to just bend the rod again, but looking for more education on how the trim should be set up properly.


Thanks-
Joe C.
 

Latest posts

Top