Orma wrote: >>Perhaps I'm missing the point. If the pivot for the elevator and the pivot >>for the aileron is attached at the same point, as mine are, the elevator >>cables will try to twist forward of the aft spar mounted pulley assembly, >>any time the stick is moved for aileron input. As the stick is pulled for >>and aft, the aileron cable or push/pull rod set will move for and aft. In >>both cases, the stick movement in one direction does not affect the movement >>of the other control surface. I guess I fail to see how the bias is induced. >> Help me out <<
You are correct that as you move the stick fore and aft, the ailerons are not deflected. However, since the pivot point for the elevator action is about 3" ABOVE the aileron cable axis, you have to deflect the aileron cable itself to make the elevator work. The tighter the aileron cable, the more the elevator wants to stay in one certain place, which is wherever the stick ends up when the aileron cable is straight through the cockpit. Now if your elevator doesn't happen to be at the optimal position for cruise at this point, you're going to have to trim it out to maintain altitude. That's where the drag comes from. The aileron cable acts as a "centering spring" to keep the elevator in that certain place. The elevator wants to be wherever the stick is "biased" to, whether or not it's optimal for your cruise condition. If you were careful enough and liked to experiment, you could find the sweet spot where the elevator trim was neutral, and the aileron cable was undeflected through the cockpit (at one speed and load condition, anyway). Picture this. You're 10 year-old kid is pushing on the stick and you don't notice. You add trim to keep the plane flying level. Now you've increased your trim drag. Same thing. That was my point. Probably not a big enough deal for most people to worry about. Just us anal retentive types. But I'll bet it makes a measurable difference. It just goes against my grain to stretch the aileron cable every time I deflect the elevator. I'm just that way... Mark Langford, Huntsville, AL N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mylist.net/private/krnet/attachments/20030530/1dc02156/attachment.htm
