Dale


This is what David Gladwin posted on the subject.... i am sure he won't mind me reposting..

The strips were placed on the wing to produce pre-stall buffet, essntial on a trainer without a stick shaker and/or pusher. However these stall strip wWILL produce an earlier stall in the area of the wing to which they are attached (the Chipmunk is a classic example of this application) and thats good in that it stalls the root section before the tips, thus retaining aileron control and miniimsing unpleaant wing drop at the stall.

They may well work at the Reynolds numbers we are working at with models BUT how would we FEEL the buffet if we are not IN the aircraft ?

However, because the strips produce this earlier stall the penalty on the Hawk was a small increase in stall speed, around 4-5 knots, considered acceptable in view of the enhanced stall warning.

On the Hawk, spanwise flow contol was achieved by optimising the wing fence design.

If you think the Hawk had to be "fiddled" to achieve accptable handling take a look at all the aerodynamic fixes on the Jet Provost Mk 5 , roughened leading edges, spin strakes on the nose, root slats, all to make it fly, stall and spin like a trainer ! In the final form (although many changes in wing dressings were made to later Hawks and Goshawks) they were both a delight to fly !

Regards, David Gladwin.