On Tue, 17 Feb 2004, Lee Elliott wrote:
> > spoilers are devices designed to reduce lift and also increase drag.
> > they are usually attached to wings. speed brakes are attached to the
> > fuselage and produce drag without affecting lift. airliners have
> > spoilers, fighter jets usually have speed brakes (although the yf-23
> > seems to have spoilers). the gliders i fly have spoilers (even though
> > sometimes we call them speed brakes).
> >
> > --alex--
>
> Speed-brakes are not always attached to the fuselage - they can be found
> pretty much anywhere. On the STS they're in the tail-fin (split-rudder), on
> the Avro Vulcan they extend vertically up through the top of the wing. The
> YF-23 uses the flaps and ailerons in opposition. and the A-10 has split
> ailerons - the top half deflects up and the lower half down.
Even on gliders, there are two substantially different ways of increasing
drag/reducing lift via controls on the wings; these generally go by the
names of 'spoilers' and 'Schempp-Hirth air brakes'. 'Spoilers' are
essentially a part of the wing's surface that is hinged at the front of
the spoiler, and the spoiler raises from the wing's surface at a variable
angle, like so:
/
/
Leading edge ----+------ Trailing edge
Shempp-Hirth Air Brakes, or just 'air brakes' for short, are essentially a
vertical plate that will protrude a variable distance from the wing's
surface. usually the air brake ends with a 'T' piece at the top, which is
in normal flight a part of the wing's surface, but when deployed the air
brakes look like so:
T
|
-----|-----
Schempp-Hirth airbrakes are usually a lot more efficient that spoilers at
reducing the Lift/Drag ratio of the glider, and thus in bringing the
glider safely down on the ground.
> LeeE
Best wishes,
// Christian Brunschen
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