Landing Flap Video

Check out...

http://www.youtube.com/watch?v=PXwy7dsLndM

....for a nice/useful/short video of two flapped landings in an HP-14,
owned/flown/filmed by Wayne Paul (and posted here with his permission).
Curious reader-pilots may find the following information helpful, should they
attempt to extract directly-/potentially-useful-to-them-information from the
video:
- "The tow pilot confirms my estimate that the winds were less than five knots."
- The distance from the beginning of asphalt to the start of the first stripe
is 120 feet.
- The stripe length is 120 feet.
- The stripe spacing is 80 feet. (Hence the distance from the start of one
stripe to the start of the next is 200 feet.)
- I have no idea where the roundout-aiming-point was for either landing.

For curious readers perhaps not terribly familiar with the traits/benefits of
large-deflection landing flaps, this video nicely illustrates some 'you can
bank on it' aspects of 'em.

1) When I estimate both landings' touchdown points and further estimate the
landing rolls, I come up with ~300 feet in both cases. The reason the landing
roll doesn't decrease from the 60-degree-flapped touchdown to the
90-degree-flapped touchdown, is because (for all practical purposes) flaps
stop adding lift after about 30-45 degrees of deflection; beyond that they add
only drag. But the short rollout distance nicely illustrates the
speed-reducing benefits of flaps.

2) Though it's impossible to tell from the video at what point the
60-/90-degrees of flap are deployed, one *can* get a sense for the drag
increment of those last 30-degrees by contrasting the approach angles on short
final, prior to roundout initiation. Steep approach without speed
increase...very nice; also very stable, wonderful visibility, simple to judge
one's roundout point, and great fun!

HP-14's land at ~5.5psf wing loading. It's an accurate statement that - when
Joe Pilot is using full flaps - they can easily/safely be put into fields
unavailable to 1-26 drivers, simply because they can approach more steeply
over field-bordering obstacles. As for the rollout, how many 1-26 drivers
routinely roll no more than 300 feet on a hard surface after touchdown? (And
how long does your skid plate last?)

IMHO, large deflection landing flaps on gliders are the best kept sailplane
secret in the last half century.

Enjoy!
Bob W.