In article ,
David Lednicer writes:

When Hawker developed the Hunter, the prototype had the airbrakes
mounted in such a way that they could be moved forward and aft, to find
the place where they produced no pitch change. It turned out that the
first location tried was the best.

This is why the Hunter's airbrakes are mounted out of contour.

It's a little more complicated than that. Originally, the Hunter was
going to use its flaps as speedbrakes. This cased a lot more pitching
moment than the specifications, or, more importantly, the Ministry of
Supply (I _think_ it was Ministry of Supply it might have still been
the Air Ministry) would tolerate. The Logical Move would have been to
restring the rear fuselage for Sabre/F-84F type lateral brakes, but
for some reason, this was deemed to hold up production too
much. (Although one was prototyped, so _somebody_ did the drawings and
bent the metal). The Last Best Desparate Move was the brake scabbed
on under the aft fuselage. As you say, they got the position right
the first time they tried it, But that position has some
disadvantages. It's vulnerable to damage from stuff like ejected
ammunition links, and you can't have the brake open when landing.

A pity, really. The Hunter is just about the perfect shape. If you
can lose the speedbrake under the tail, and the "Sabrina fairings"
tacked under the gun bay to hold the spent links, so that they didn't
damage the speedbrake.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster