Subtle right turn tendency in cruise

[taildraggin68]

Starting this thread as this topic has been just comments in other topic threads.

In cruise configuration, with one pilot, 10 percent more fuel in left tank, there is an ever so slight, but noticeable creep to the right.

No weather add ons and FSX with UTX USA

[Dooga]

Might have seen this as well, but... trim.

[Mazo]

Rudder trim not centered?

[taildraggin68]

Rudder trim centered.....it's just enough on my system anyway, that it's just perceptible. And with the weights to the left side?

[Dooga]

Rudder trim centered.....it's just enough on my system anyway, that it's just perceptible. And with the weights to the left side?

Well then, trim it away. These old airframes...

[taildraggin68]

Rudder trim centered.....it's just enough on my system anyway, that it's just perceptible. And with the weights to the left side?

Well then, trim it away. These old airframes...

Lol, I have but the creep still persists It's only just enough to mention and no big deal, but as it was mentioned by another in another thread, I figured I would post it up........me, I have no problem in just reaching over and turning on the AP

[Nick - A2A]

I haven't done much in the way of cruise flight yet Scott, but a quick experiment with the aircraft loaded laterally balanced did result in this slight right turn tendency (I was using a power setting of 20" MP and 2000 RPM). -6 to -7 % rudder trim seemed to counteract the effect...

Cheers,
Nick

[taildraggin68]

Thanks Nick. Maybe I didn't put enough rudder trim in lol Heck it could even be that I didn't hold my tongue just right, while pouring my coffee, and you can never trust that Heidi chick Just took it up for a quick test again myself, and dang if it didn't fly just like it should.....maybe that little trip into the back country scared it a little Bear Gulch Aviation at gross is pushing it a touch

[Nick - A2A]

For what it's worth, I just tried another flight with cruise at much higher power settings (23" and 2300 RPM) and the right-turning tendency is definitely more pronounced (rate of turn settled at about 1° per second). Again, a fairly liberal dose of left rudder trim seemed to sort it out. I'm certainly not qualified to comment on whether this is true to the real aircraft - any thoughts?

I guess the rudder trim is there for a reason, but from my limited understanding, I'd expect the turn to be in the opposite direction?

Cheers,
Nick

[taildraggin68]

That's what was boggling me Nick....my weights to the left of CG as well as the torque should be gently influencing the aircraft to the left? Maybe Rob or Esa can chime in.....

[Bruce Hamilton]

Have you checked control calibration?

[taildraggin68]

Sure have Bruce...just my habit to check that regularly as well after installing new aircraft...

[Nick - A2A]

All controls checked here, and weight and balance double-checked Bruce!

Taildraggin' - I've just tried another flight. During take-off there's certainly a left-turning tendency as you'd expect and quite a bit of right rudder is needed to stay on the centreline (OK - near the centreline in my case ). During climb-out that left-turning tendency remains, but as I roll in nose-down elevator trim with increasing airspeed, the left-turning tendency seems to gradually reverse into a right-turning one. It's almost as if the act of trimming the nose down is causing the drift to the right.

As far as I'm aware, torque, P-factor and propwash (and to some extent gyro effect) should all be causing a yaw to the left in the Skylane. Interested to hear what the experts have to say...

Cheers,
Nick

[Nick - A2A]

Hi guys - a further observation. Just carried-out another flight in the C182 and the issue seemed to have magically cured itself! "Hang on a minute" I though - "surely I'm not that daft!" Then I remembered that I'd ticked 'auto-rudder' whilst experimenting with slow speed flight in the C172 just beforehand.

With auto-rudder selected, the C182 develops a slight left-turning tendency at cruise as you'd expect. However, when I un-ticked auto-rudder, the pronounced right-turning behaviour at cruise power settings was definitely back.

Anyone else seeing this other than Scott (taildraggin68) and I?
Nick

P.S. To prove it wasn't noisy rudder hardware (twisty joystick) which was causing this, I deleted my rudder axis altogether for part of the flight. The right-turning tendency remained...

[taildraggin68]

EnDSchultz spoke of it first I believe and when I read that we were buried in another topic, so I started this one. Maybe he will see this and jump in