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JS31 question

Posted: Wed Dec 26, 2012 9:00 am
by arb65912
Keith, off the subject but maybe you can solve my problem.

I know about the control lock etc.

I fly BE33 and have yoke centered.

Then I load JS32 and when I fly on autopilot after a while, I get plane banking to the left a lot like 15 or more degrees.

Then I disconnect autopilot and I ( of course) experience a very hard banking to the right that I can not control to continue to fly or better yet land.

Wind was only 10 degrees from the headwind at 15 KNTS.

I have Saitek yoke and buttons for trim assigned accordingly to elevator and ailerons.

Any idea what I might be doing wrong?

I love the plane, I even flew it on PE recently.

Cheers, AJ

Re: JS31 question

Posted: Wed Dec 26, 2012 9:23 am
by Keith Smith
AJ, I split this off from the pilot training cockpit videos because this is completely unrelated to that topic.

Was the plane flying properly by hand before you engaged the autopilot?

The plane has counter clockwise rotating props, and they're not counter-rotating, so this will generate a strong RIGHT turning tendency as power is applied. You should use aileron trim to be able to fly it hands off at a given power setting. The manual suggests to dots of left aileron trim prior to takeoff if memory serves. I haven't been doing this, and as a result, you can see the momentary right bank on takeoff on the JS31 video.

To find out if this a control system issue vs a power issue, simply try adjusting the power setting and note the difference. If you pull power to just above idle (don't pull power ALL the way, or it goes into beta, which is ugly), I suspect the turning tendency will all but disappear, or might even turn the other way (as a result of built-in twist in the airframe that some designers elect to model).

Re: JS31 question

Posted: Wed Dec 26, 2012 9:34 am
by arb65912
Hi Keith, sorry about posting in the wrong forum and thank you for splitting it.

I took off ( several times the same fashion) and no, plane was not trimmed for level flight before engaging autopilot.

What puzzles me is that after I disengaged autopilot I was not able to trim at all , I used up all aileron trim available, power was set to high but still , I think I should be able to trim the plane for leveled climb...

Hmmm .... I will try tonight to trim for wings level climb and THEN engage autopilot.

I will also see how things will go when I lower the power.

The reason I needed the full power was icing conditions ( as you see in X-Aviation post )

Thank you very much for quick reply.

Cheers, AJ

Re: JS31 question

Posted: Wed Dec 26, 2012 9:52 am
by Keith Smith
Silly question, but did you remove the control lock prior to takeoff?

Re: JS31 question

Posted: Wed Dec 26, 2012 9:54 am
by arb65912
Absolutely. :-)
Another silly question, does it matter when I remove control lock? I do it when I enter the cockpit, should I wait til engines are running?

Re: JS31 question

Posted: Wed Dec 26, 2012 10:29 am
by Keith Smith
If it's incredibly windy, I suppose there would be benefit to leaving in the control lock as late as possible, but most checklists that I've seen call for control lock removal very early on in the process.

Re: JS31 question

Posted: Wed Dec 26, 2012 7:31 pm
by Daddy O
Question: Are you calibrating your hardware before taking off? I found that the more equipment I add to the simulator, the greater the need to calibrate before serious flight. I simply do it where I would normally check visually that control surfaces are free and operate properly (during runup.)

Re: JS31 question

Posted: Thu Dec 27, 2012 6:12 am
by arb65912
Yes, I do. Problem is not solved. I was testing the plane in icing conditions and had the throttle set to max, it caused that heavy wing drop caused by autopilot trying to compensate for a max torque from the engines. Cheers, AJ

Re: JS31 question

Posted: Thu Dec 27, 2012 7:52 am
by Keith Smith
I assume you meant "problem is now solved." ?
To find out if this a control system issue vs a power issue, simply try adjusting the power setting and note the difference. If you pull power to just above idle (don't pull power ALL the way, or it goes into beta, which is ugly), I suspect the turning tendency will all but disappear, or might even turn the other way (as a result of built-in twist in the airframe that some designers elect to model).
So that was it? Or something else?

Re: JS31 question

Posted: Thu Dec 27, 2012 7:56 am
by arb65912
YES, YES, YES, Keith ..lol,lol,lol It was a typo. You were totally right. Awesome plane. Cheers, AJ