Pitch stability

[Skybrd]

I have a early 201 J model and noticed that the pitch stability doesn't seem to be very good. After leveling off and stabilizing power and trim, I notice that it climbs and goes down on it's own. The airspeed changes a small amount but not bad. Could this be caused by having a forward CG since I normally don't have rear seat passengers. I like to set the heading on the autopilot and let the plane fly itself. The pitch changes are annoying.

[Guest]

Throw a case of oil in the baggage area at least in my model and you will notice a difference. 

My model is rock solid once trimmed, sometimes I don't set the Alt hold cause it's so good. 

[jetdriven]

I have noticed that as well. A tiny movement and the airplane climbs or dives a lot. The crazy expensive solution is an STEC 30ALT altitude hold unit.  The other is just constant, micro corrections in pitch.

[kerry]

My plane does the same.  A alt hold would be nice.

[Skybrd]

Quote: BluSky

Throw a case of oil in the baggage area at least in my model and you will notice a difference. 

My model is rock solid once trimmed, sometimes I don't set the Alt hold cause it's so good. 

[jetdriven]

I dont see how moving the C.G. aft increases pitch stability.  Every airplane I have flown has increasing sensitivity as the CG moves aft.

 

Your Century III definately needs adjustment. it should return to level flight when displaced.

[Guest]

Sky Bird, I once had a Piper with the Century and it was all over the place in very light turbulence.  I had it tweaked (serviced ) and it was night and day in performance. 

 

Of course moving CG farther aft makes the aircraft  ( little less unstable ) it's what we do for aerobatics, we are always playing with CG. Finding the perfect balance point in cruise can help and may change your point of view of how your aircraft currently handles.  Some have picked up a couple knots. 

[201er]

Quote: Skybrd

I have a early 201 J model and noticed that the pitch stability doesn't seem to be very good. After leveling off and stabilizing power and trim, I notice that it climbs and goes down on it's own. The airspeed changes a small amount but not bad. Could this be caused by having a forward CG since I normally don't have rear seat passengers. I like to set the heading on the autopilot and let the plane fly itself. The pitch changes are annoying.

[Skybrd]

Quote: 201er

Have you tried flying at night? That solved all my pitching problems! Holds perfect pitch/altitude hands off!

[201er]

My point was that mine will bounce around in the daytime even when it doesn't feel turbulent. At night (or in truly calm air) it will hold altitude hands off easily. So I think it's more a matter of turbulence and not mechanics.

As for the strobe lights... first had the power supply go on me. Then was back in a few months cause the bulb went too! What a pain.