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Old 07-27-2014, 05:16 AM   #51
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Re: twin engine

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Most important, throttle up SLOWLY when taking off!
MAAC # 51283
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Old 07-27-2014, 08:19 AM   #52
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Re: twin engine

A slight twist in the wing could also cause it.
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Old 07-27-2014, 08:57 AM   #53
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Re: twin engine

Originally Posted by OLD PRAIRIE RED NECK View Post
Here is something I would try. Take it up a couple mistakes high and trim the rudder for straight flight. Now do another pass, same direction(to cancel wind drift effects) but with power off and see if it still tracks straight. If the rudder trim changes with power off then the problem is engine torque/side thrust angle. If it tracks true power off or on then there is a misalignment in the airframe.

I built a trainer once that took about 3 degrees left rudder trim to get it to track straight. I measured it from every possible angle and never did figure out why.
Yup ,, looked at that... had her trimmed well for half throttle cruise.. then up to full ,, and throttle cut on a landing approach with mid flap.. tracked straight except for the minor rudder corrections for wind drift on approach.. now here is another funny thing.. after I land.. you look at the fuse.. the right side will be plastered with bug guts... the left side nothing.. indicating that the prop wash is coming off to the left when looking forward from the tail.. there is nothing in the way of the left engine so the air just washes off.. but the right side has that big fuse in the way to deflect the air down the side.. this would bring me back to the idea of this "P" factor effect.. and the other thing is that once she breaks ground effect ,, flies like it is on rails..

Originally Posted by hitechflyer View Post
Most important, throttle up SLOWLY when taking off!
Yup... got that one figured out by the second flight.. go don't dare take this thing full throttle.. it will turn left and depart ,, much like my little skybolt.. 40 size airframe with 91 engine.. you better be holding right rudder and don't even think about much over half before she is well in the air..

the wings where assembled in a jig and engine mounts clamped to a straight edge.. so everything was built straight.. maybe too straight.. and checked with digital incident meters.. two of them.. It is straight..
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