My understanding is that Spoliers spoil the lift of a portion of the wing
and to achieve this are usually mounted well forward on the top surface of
the wing. They are also often hinged at the leading edge.

Airbrakes are mounted well back on the top (and sometimes bottom surface
and therefore have much reduced effect on lift whilst increasing drag.

Having flown gliders fitted with both of these devices the effect is quite
different.

I believe that here in the UK that is the accepted explanation and few
modern gliders have spoilers. It seems that the US definition is much less
clearly defined and the two terms are interchangeable.


Terry Walsh

At 11:47 01 October 2013, Kevin Neave wrote:
According to the flight manual my glider has "Airbrakes" and they extend
from the top surface only.

I suspect the same is true of the vast majority of modern gliders

KN

At 22:01 30 September 2013, Jim Kellett wrote:
On Wednesday, September 25, 2013 2:42:08 PM UTC-4, Tom wrote:

Figure 2-9 indicates dive brakes extend top and bottom of wing, while
spo=
ilers are top only.



Um, that's correct. The distinction has been common knowledge for over
a
h=
alf-century, but lots of smart people (including some who write POHs!)
stil=
l misunderstand the distinction. Glad to see a proper definition in
what
c=
ould become a widely used manual.

See also http://en.wikipedia.org/wiki/Dive_brakes