View Full Version : Slingsby T67 aileron thingy?

8th Apr 2004, 07:52
Just got a T67 MkII in our club. Taking a look round it and see that both ailerons and one side of the elevator (side without the trim tab) have odd 'plates' on the trailing edge of the surface.

The 'plates' are normal to the airflow and extend for about half the span of the ailerons, on the inboard end. They extend above and below the surface by around 6mm.

Does anyone have any idea what they do?

8th Apr 2004, 07:58
Is it balast to stop flutter? I thought most of the aircraft was made from GFRP, so it would make sense.

8th Apr 2004, 09:09
Not sure that it is - would you not balance the control closer to or ahead of the hinge line?

8th Apr 2004, 09:31
Not sure that it is - would you not balance the control closer to or ahead of the hinge line?

Yeah, most types do seem to be that way, but I can't think of what else it could be. I've had a look around for some pictures of the net, but can't find any examples of it.

Maybe it's some kind of repair?

8th Apr 2004, 09:42
They`re "tabs" to give some more feedback to the controls, ie feel, and make them "stiffer". For an authoritative chat, ring Sby., and ask to speak to their flight test engineer, I think it`s John Poole, and they`d be happy to explain.Later a/c have modified "spades" as well.

8th Apr 2004, 10:08
Cheers for that Sycamore! Don't suppose you can explain how they improve feel? I guessed maybe at large deflection/ AoA they would provoke a vortex or something?... If I get hold of the Slingsby guru, I'll post what he says.

8th Apr 2004, 13:53
Pull-up a palm tree, bring a bucket of sand, and a box of dates and we`ll begin!

In the old days,when................................., one used to roll up a piece of cord and tape it on top or underneath a control surface to act as a trim-tab, cutting the tape length to suit the balance you wanted, ie aileron requires constant pull force to hold wings level, add/subtract some tab. So, you can also do the same to both sides to stiffen it up if the control harmonisation needs improving.Some a/c have very blunt trailing edges for the same reason.

8th Apr 2004, 13:56
They'd add more drag, giving a larger moment about the hinge line than would otherwise be there. Since the pilot is the one opposing this moment then the controls would feel 'heavier'.

Analogous to the change in feel from low speed to higher speed.