I have a 35% extra, was running a menz 27-10 2-blade on a DA-100. Rudder trim seemed perfect. Switched to three blade for noise purposes and have done nothing the change the engine thrust but I notice it isn't the same as with the 2-blade, particularly in inverted up or down lines (cuban eights & goldfishes). Here is the test I performed to prove to me something is not right:

Few directly into the wind, away from me, straight and level the plane flies striaght. Pull up to 45° and it continues striaght, roll inverted on the 45° up-line and it goes to my left (planes right) do I need to add or reduce my right thrust? Or could it be something else?

Ryan

I would suggest setting right thrust based on vertical lines, instead of 45's...

I added an extra 2 degrees of right thrust when I went to 3 blades. Plane tracks well.

Be sure to do your pull up right to left, and left to right. This is to make sure its not "weather vaning" into the wind (with respect to the ground).

Don

P.S. Also do this. With the plane inverted (aileron trimmed) cut the throttle and add some down elevator to keep it level (as if entering a spin). If the plane starts heading off (rolling off) to the right then add a couple of clicks of left rudder. Do this test again, and if it still does it, then add negative incidence to the right wing, if you can. This could be contributing to your trim issue.

Thanks guys. I will give both a try.

Ryan

When it's rolling to the right (dropping left wing) when inverted, how is left rudder going to help ? It seems like right rudder trim would be required for that. Also, what's the theory behind setting up a different incidence on each wing ??? What amI missing here ?

I should have been more clear. It yaws to my left (the planes right). No roll.

What about this problem? Full throttle straight & level into the wind. Chop the throttle as to enter into a spin, only using elevator to maintain altitude (no rudder or elevator inputs). As the plane slows it yaws to the left. The slower it gets the harder it seems to yaw. It will yaw a total of 70° or so off of the origional heading before stalling. In competition I can cheat by giving right aileron & right rudder to hold the origional heading, but this makes for a very (and I mean VERY) difficult left spin entry. Any ideas on my problem or how to fix this???????

Ryan

From all your posts, I gather you need some left thrust on the engine. Or, mix some right rudder (slave) with the throttle (master). This will cause you to re-trim the rudder to the right for your up lines to straighten them back up........and that right trim will straighten your off throttle lines by pulling them back to the right.

Good luck.........it takes time to get a set-up right.

CJ