Question on rudders

[Foam Addict]

Hey all, Sorry to start a thread with a question, but no one else seems to know. I have two scratch built Piper senecas of my own design, and they both fly great. Unfortunately they both share a quirk. Left, and only left rudder, results in a lightning fast pitch down, and if held, behaves as an elevator on steroids. Out side loops are possible with this! right rudder behaves as normal.
Any thoughts?

 

[earthsciteach]

Weird mix on your tx?

 

[Carbon]

I'm guessing accidental mix or the rudder is catching on the elevator. Do you have a video of you applying right rudder that could show us what is wrong?

 

[Ak Flyer]

Well, check it out on the ground. When you apply the rudder, does any other control surface move? Does it move at the same speed and proportion in both directions? During normal flight, where is the rudder trimmed? Are you using a lot of rudder in one direction to correct for an improper thrust angle? Pictures or video would help immensely. Pic of everything turned on, mid stick just like it would be in flight. Then apply full right rudder and snap a pic, then apply full left rudder and snap a pic. Rudder pics from above will help as well. Looking for uneven throws, accidental mixing etc.

 

[Foam Addict]

Thanks for all the tips! Carbon, I am taking the plane flying(lost one) I will post a vid. of it. No it isn't mixings, I do have Elevator-flap, and light aileron-rudder mixing, but all other mixes are clear, and all control movements check out, no down to left rudder, no rubbing or catching, not even a slightly bent surface! I will be checking this power off today, as they have massive motors for their size, and could have centripetal redirection(aka 90 degree force application from intended, thanks, I'll post a Vid. later today. AK flyer, I'll post pics and a Video later, after it stops being windy. The plane has an Intentional twist to counter act motor torque, similar to the super fast micro's that Josh and Josh reviewed some time ago. so please don't freak on that. Thanks again.

 

[Ak Flyer]

Understood. Stock supercubs have a lot of motor angle as well. It's normal.

 

[Foam Addict]

Okay, so after a slight mod to the wing, a couple of tweaks to the prop size, and twisting the thrust angle 15 degrees right... It Flies! I will be posting video after I load it, but it wasn't bad especially for a 25 MPH wind. Not half as fast as I thought, but still respectable. The plane has about 560 watts of power on it, but it flies very slowly, take offs at 1/4 throttle are cool though!
The rudder issue went away when I turned the tail about three degrees right.
It glides like a brick, but hey, vertical comes with a price!
Thanks all, I'll post a video soon!
P.S. I hate Flaperons!

 

[Ak Flyer]

Flaperons are better than no flaps but not as good as regular flaps. Glad to hear it's gotten better.

 

[Foam Addict]

I crashed on the runway due to a flaperon induced vtol takeoff and landing. You know, nose as landing gear!:black_eyed:

 

[Ak Flyer]

Ah, the old familiar nose skid. I'm quite versed in this maneuver.