On 24 Dec 2004 03:37:31 -0800, "Ramapriya" wrote:

Hi folks,

I've always seen spoilers and flaps being deployed fully upon landing.
While the reason for spoilers is straightforward, I haven't yet figured
why flaps are deployed too.

Isn't the landing roll the time when you'd be wanting all the load of
the craft to be on the main wheels, which is where the brakes are

I find that in the Deb, full flaps help shorten the roll out.
A short field landing is a steep approach with substantial power and
relatively slow. Vso for me alone and partial fuel is only 55 MPH ( ~
48 knots) at roughly 2700#. This is for a pretty slipery airplane.

In the Deb, as soon as the mains are on the runway, let the nose down,
get on the brakes and full up elevator. If you don't get on the
brakes first it's going right back up in ground effect which could
prove to be more than a little inconvenient.

instead of creating lift whereby the load gets transferred onto the
wings and possibly lessening the braking effect? I know the plane would

In many planes with electric flaps there is little if anything to be
gained by raising them as you are slowing to the point where they have
pretty much lost their effect well before they are all the way up.

be decelerating all the time with the engines throttled back fully and
even the forward thrust depolyed, perhaps, yet why create any lift
possibility at all? Wouldn't braking be more effective with no flaps
deployed? Or does the drag produced by the flaps compensate for the
lift?

Aerodynamic braking works great.

OTOH, flying an old Hershey Bar Winged Cherokee 180 with the Johnson
bar flaps, raising the flaps on touchdown on a short sod strip made a
considerable difference.


I suspect I've missed something really fundamental )

I think basically it depends on the plane.
Worked on the Cherokee, doesn't on the Deb.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
Ramapriya