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Old February 8th 19, 03:43 AM posted to rec.aviation.soaring
Scott Williams
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Posts: 198
Default Problem with Grob-103

On Thursday, February 7, 2019 at 8:35:08 PM UTC-6, Bob Whelan wrote:
On 2/7/2019 4:47 PM, Elena Malanushenko wrote:
Interesting video with the testing of plane
https://www.youtube.com/watch?v=vel-qoc0UY4


Hmmm...it's been a while since I've looked at a spring-trimmed G-103
specifically, but - assuming no obvious W&B issues muddying the picture -
things I'd look hard at upon noting (in the same flight?!?): a) insufficient
forward trim effect at tow speeds, and b) repeatable step-function-uncommanded
forward trim/stick-inputs at some higher/arbitrary speed would be:

1) "something 'fixed-in-place' not right" in the trim system;

2) "something capable of slipping under tension" in the trim system;

3) the entire primary pitch control system.

Of course, my version of Occam's razor supposes these possibilities have
"long-ago been considered/inspected" (based upon calendar-info in the film
snippet), but inferring as to what - if any - actions have occurred, based
upon the commentary, raises more questions in my mind than it answers.

Me not "doing" YouTube Q&A, my curiosity cat be definitely interested in what
ultimately proves to be the culprit...

Bob W.

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Spring trimmer? our Club grob G 103 twin II has an aerodynamic elevator trim tab.
Scott