Flying Technique Question of the Day

In article , Judy Ruprecht
writes
At 03:24 01 September 2003, Shirley wrote:

One (side slip) is used to adjust for drift in a
crosswind

.. best used on final approach, both the ground track
and the glider's longitudinal axis are aligned on runway
heading. (Useful in a 2-33 with x-winds of 15 kts &
higher - not a swell option on low-wing gliders in
strong crosswinds.)

the other (forward slip) is used to increase the angle
of descent...

.. the ground track is aligned on runway heading,
while the glider's longitudinal axis is decidedly off-kilter.
(Useful in some gliders to further steepen a full-spoiler
approach to a short field or deal with spoiler failure.)
Too much speed and a delayed recovery, however, can
leave you with a glider cum lawn dart.


I see. So the two ideas are aerodynamically the same, but what you call
a sideslip is used for cross wind landings and a forward slip for
steepening the glidepath?




--
Mike Lindsay

Mike Lindsay wrote in message ...
In article , Judy Ruprecht
writes
At 03:24 01 September 2003, Shirley wrote:

One (side slip) is used to adjust for drift in a
crosswind

.. best used on final approach, both the ground track
and the glider's longitudinal axis are aligned on runway
heading. (Useful in a 2-33 with x-winds of 15 kts &
higher - not a swell option on low-wing gliders in
strong crosswinds.)

the other (forward slip) is used to increase the angle
of descent...

.. the ground track is aligned on runway heading,
while the glider's longitudinal axis is decidedly off-kilter.
(Useful in some gliders to further steepen a full-spoiler
approach to a short field or deal with spoiler failure.)
Too much speed and a delayed recovery, however, can
leave you with a glider cum lawn dart.


I see. So the two ideas are aerodynamically the same, but what you call
a sideslip is used for cross wind landings and a forward slip for
steepening the glidepath?

Yes, they are aerodynamically the same. Judy's description is
dead-on. Both of them will steepen the glide path, but the latter one
is much more dramatic than the former. I admit to writing a bit of a
troll; it annoys me that the one that keeps the fuselage and the
course line the same is called a side slip, and especially so that the
one in which one is travelling sideways is called a forward slip.

I still insist that the airplane doesn't know the difference except
that one is slipping a greater amount, usually, than the other. A
very gentle "forward slip" will feel just like a healthy "side slip"
if you have your eyes closed.-

Mike Lindsay wrote in message ...
snip

I see. So the two ideas are aerodynamically the same, but what you call
a sideslip is used for cross wind landings and a forward slip for
steepening the glidepath?





In the US, the term "sidelslip" is shorthand for a forward slip to
landing.

A forward slip can be properly done with the low wing into the wind or
not. A sideslip (forward slip to landing), must obviously be done
with the low wing into the wind or you will be unable to align the
longitudinal axis of the glider with the ground track.

Fred