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Old 09-22-2015, 01:46 AM
Gordon W
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Originally Posted by Dave Wilshere View Post
Only the FO 144 two seater. The Mk1 single seat is quite different, needs elevator compensation on landing and other changes.
Hi Dave, along with the factory drawings, have the guys also got copies of the aircrew manual and pilots notes. Why I ask is that the trainer does need elevator compensation, and this is dealt with automatically by what's called Tail Datum Shift, which dials in 3.5deg up elevator when the gear is lowered. This is to avoid the pilot running out of back stick movement. If the tail datum shift system becomes inoperative, the pilot needs to manually set the trim before landing.

There's also a need for the pilot to achieve 6deg of up-elevator trim at take-off and landing, apparently by adding an extra 2.5deg up-trim manually, which is gradually removed as the gear and flaps are retracted and airspeed is increased. Presumably the guys will have spoken with one of the Gnat teams so will know this already, but I'm just making these comments as one large-ish Gnat prototype has already bitten the dust. Plus John Carpenter found that lowering flaps generated a huge and unexpected nose-down couple when he fitted flaps to one of his prototypes all those years ago - this was before computer mixing in Tx's and he said he never used the flaps again!

Pim's ancient Gnat doesn't have flaps so he doesn't get the effect.

It occurred to me that these elevator trim settings will most likely require programming into the Tx as this huge model will behave more like the real one.

The AP's mentioned above along with those for the fighter variant are available as an online download from http://www.flight-manuals-on-cd.com/Home10.html , and I got them as I'm making a Carpenter Gnat and will fit flaps.

Just trying to help.


Last edited by Gordon W; 09-22-2015 at 01:58 AM. Reason: typo