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Pulling to the left

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Pulling to the left

Postby Steevo » Tue Dec 08, 2015 4:51 pm

I am after a bit of advice regarding my Jab UL-450 year 2000. Someone may have a few clues on this issue.

Ever since I have owned it, it has always wanted to pull to the left during cruise. I cannot quite work out whether it is yaw or roll but either way, without control input I cannot get it to fly straight in the cruise. By the end of a long flight you can easily have a tired arm or foot as you have either have to hold the stick constantly a little to the right or apply a little right rudder.

Adjusting the flaps has made absolutely no difference. I have tried adjusting them right to the end of the thread (or as close as is safe to do so). Earlier in the year, I fitted a trim tab to the rudder which, at first, seemed to work, but after further flying, it is still noticeably pulling to the left in cruise. The aircraft has wingfold so the bushes cannot be replaced with a different type as has been suggested in the past.

Asking other people I have had suggestions such as 'Is the rudder peddle adjusted correctly' and 'Is the engine offset correct'. Most of these comments coming from non-Jabiru owners. Looking through the manuals, I cannot find anything about engine offset and the pictures for the rudder adjustment are confusing so have not tried it. Plus I don't have any templates for the aircraft.

Does anyone else have any other suggestions?
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Re: Pulling to the left

Postby MikeL » Tue Dec 08, 2015 8:27 pm

I had a similar problem with my SPL. It has been partially resolved by tweaking the rudder setting to the right, just one turn on the cable end fitting (so far) to see how it affected performance.
It has not fully cured the problem, but the handling is much more relaxed.
I initially thought the left-ward pull was due to my flying predominantly solo, with the weight on the left seat putting things out of balance. I have yet to fly two-up to see what happens since tweaking, but hope that I have found a reasonable compromise.
I think the engine mount has some offset built in to counteract the torque, so doubt that it will be contributing to your problem unless, of course, it has been built incorrectly.
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Re: Pulling to the left

Postby Steevo » Wed Dec 09, 2015 9:11 am

It seems like this is going to be a case of trial and error and maybe never fixed.

I will give the rudder adjustment a try first. It may be best to go back to basics and start with the flaps completely level and then try things a bit at a time and see if there is any improvement.
Jabiru J160 & Jabiru SPL-450
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Re: Pulling to the left

Postby Garyo » Thu Dec 10, 2015 7:37 pm

Have you tried a wing trim tab?
Also has 1 wing been built a lot heavier than the other?

Clive james has a template set for an SP

Failing this and your other suggestions give Gary C or Erik Bently a call
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Re: Pulling to the left

Postby Steevo » Thu Dec 10, 2015 8:34 pm

Would be prepared to try anything except anything that needs to have LAA involvement. I actually want to use the aircraft next year.

Not weighed the wings but going to spend a bit of time on it over the xmas period. Gary C has had a look at it a few times but it seems every time he gets in it, it doesn't want to do it. I thought it must be me until 2 other people who flew it commented on the pull to the left.
Jabiru J160 & Jabiru SPL-450
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Funke THT800H OLED/Trig TT22
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Re: Pulling to the left

Postby Garyo » Fri Dec 11, 2015 9:57 am

you could duct tape a trim tab on to test it

assume you looked down the fuz to see if the fin is actually square. there is a jab floating around that was built with the fin Male chicken eyed a bit and used to do what you are saying pending the power setting
does yours change at different power settings, i.e when you are on finals for instance it flies straight, at cruise it does not etc
Former Owner of
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No bells and whistles
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Re: Pulling to the left

Postby Gleee » Wed Dec 16, 2015 11:15 pm

There was a thread on another forum where a jab fitted with wheel spats was having the same issue. A small trim tab fitted to the nose wheel spat cured the problem.


http://www.recreationalflying.com/threa ... ats.40475/
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