Auto Pilot flies one wing low.

[Chunky]

I ahve managed to sortout the rocking of the wings. Dont know what I changed but its not doing it anymore, but now I have a one wing low scenario.

I am sure there is a setting on the D10 that sorts out the AH on the D10. Could it bethatthe remote compass has been fitted at an angle not aligned to the head unit.

I didnt do the instalation this time so I suspect that could be a possibility.

Shawn

 

[lindsayj]

I ahve managed to sortout the rocking of the wings. Dont know what I changed but its not doing it anymore, but now I have a one wing low scenario.

I am sure there is a setting on the D10 that sorts out the AH on the D10. Could it bethatthe remote compass has been fitted at an angle not aligned to the head unit.

I didnt do the instalation this time so I suspect that could be a possibility.

Shawn

Make sure the ball's in the middle before doing something with the AP. You may have a rudder trim problem the AP's trying to defeat by banking. "Step on the ball" and see if the AP levels the wings.

 

[PhantomPholly]

Yeah - and even if the ball appears to be centered, watch and see if the airplane holds course over a period of time with the wing consistently low. It may be an out-of-rig condition, or there could even be twist in one or more of the surfaces causing "straight ahead" to be slightly wing-low.

 

[dynonsupport]

If the autopilot is holding one wing low, but the aircraft is staying on the same (desired) heading or course, then you're most likely looking at an out of rig condition. The other advice here is sound.

 

[Alfio]

With the autopilot ON (track), fly your airplane and note the wing low condition. Turn back 180 deg. and note if the same wing is low. If the opposite wing is low then you probably have a crosswind. You are not using any rudder for correction, so the autopilot only has the ailerons for correcting this yaw, and will place the airplane in a bank. Of course, the ball will not be centered.

All other advice above is valid as well. Go out and fly....

 

[PhantomPholly]

With the autopilot ON (track), fly your airplane and note the wing low condition. Turn back 180 deg. and note if the same wing is low. If the opposite wing is low then you probably have a crosswind. You are not using any rudder for correction, so the autopilot only has the ailerons for correcting this yaw, and will place the airplane in a bank. Of course, the ball will not be centered.

All other advice above is valid as well. Go out and fly....

A cross-wind would not cause that symptom. If the airplane is in a constant bank while holding a steady ground track, then it is because it is compensating for some other condition causing the nose to want to drift the opposite direction (yaw, rig, etc.). Turning 180 degrees and repeating on the opposite track will result in exactly the same bank towards the same side.

 

[Alfio]

Sorry Phantom, I am not convinced. It would be true if you held your foot on the rudder to compensate for yaw, but with an autopilot, you would not be holding your foot on the rudder pedals through a cross country.

 

[skysailor]

Alfio,

Phantom is right about the crosswind. The autopilot will lower the upwind wing to turn into the wind so as to correct for drift. However, when the correct drift correction is found and applied (delta heading) the plane will return to wings level with the proper course correction applied.

 

[Alfio]

....guess I'll have to mull this one over some more  :

Alfio

 

[PhantomPholly]

Yeah, Skysailor may have stooped to flying girlie Navy jets, but he knows his stuff anyway.  And, he has WAAAAYYYYY more hours than me with the autopilot turned on...  

Think about it this way:  Once you are airborne, the plane doesn't know anything about wind.  It can only fly "straight ahead" through the air, or turn.  If the wind speed is constant, a constant heading = a constant ground track (but not necessarily where the nose is pointing).  Only if the nose drifts left or right will the ground track change.

Now, in a properly rigged plane if the wings are level the nose will not drift left or right.  But, if you add rudder or something is not right (engine pointed to one side, for example) the nose will drift unless you lower one wing to compensate.

Most piston planes actually have the engine pointed not quite straight ahead to compensate for P-factor and other propeller stuff I don't pretend to understand, and then generally have a rudder trim tab as well.

Try bending your rudder trim tab a bit towards the high wing so it pushes the ruder towards the low wing and then go fly and see if it doesn't fly straighter.

Cheers!

 

[Alfio]

Well... I've mulled it over, and the advice given is bang on. A few weeks ago I had the opportunity to fly with a 60kt cross-wind. Wings were level all the time.

Thanks for the correction/enlightenment.

Alfio

 

[PhantomPholly]

There's not one of us here that doesn't learn something new every day.

Aside from that, growing older is highly overrated...

 

[skysailor]

Aside from that, growing older is highly overrated...

But it sure beats the alternative!