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by gargravarr 2775 days ago
That's very informative, I didn't realise the whole horizontal stabiliser itself can be a moving part - I always thought they were fixed and trim was done using the elevator surface. Thanks for the links.

So essentially, trim changes the relative 'zero point' of the elevator, and if past a certain angle, even if the pilot applied full nose-up elevator, the altered airflow over the smaller control surface would be unable to counter the altered airflow by the stabiliser itself having been adjusted. I now see why recovery is so dependent on quickly disabling the trim system and resetting the stabiliser to 'true zero'.

1 comments

> That's very informative, I didn't realise the whole horizontal stabiliser itself can be a moving part

On most, if not all, supersonic aircraft they are like that. It was found that the traditional design didn't work well at supersonic speeds, there is debate as to who developed it but the Miles M52 is a likely candidate.

I've had a quick look for a decent video demonstrating it. This one shows it fairly clearly in the 5-10 second segment.

https://www.youtube.com/watch?v=AFk7kEQ5tVo