On 8/2/2011 4:35 AM, Scott wrote:
On 8-2-2011 02:15, BobW wrote:


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

Enjoy!
Bob W.

As a noob to gliders (coming from powered airplanes), I always thought that
spoilers were "the bomb" One thing I like about spoilers over flaps is that
you can go from full spoilers to no spoilers instantly without bad effects.

A comforting - if not terribly accurate (see next para.) - theoretical thought
indeed. However, in the real world, there are precious few times when Joe
Clued-in Glider Pilot would actually want to or *need* to go from full
spoilers/flaps to none... assuming any halfway-decent landing pattern that
didn't also involve some sort of arcane practice.

Can't do that with flaps...if you misjudge and put on too much, too early,
there isn't much you can do except undershoot...but maybe you can dump some
flaps since gliders tend to have more wing to work with than their powered
brothers.

At the risk of starting a religious war, Joe Glider Pilot indeed *can* go
from full flap to zero flap w/o any ill/negatively-dramatic issues in gliders
(BTDT many times, just 'playing around')...with one
theoretical/possibly-real-world exception. The exception, of course, is
getting low and slow on a short final approach with gobs of flap hanging down,
in which case you *are* going to land short, the only question being whether
you do it at a higher speed (i.e. after you've retracted the flaps), or a
slower/lower-energy speed (i.e. playing the hand you've dealt yourself and
hoping for the best while contacting the ground as slowly as
theoretically/practically as is possible for whatever amount of 'too much'
flap you've hanging down). That noted, this exception is meaningful ONLY if
Joe Not-so-clued-in Glider Pilot gets a final approach horribly wrong and
waits until he's completely out of options to do something about it. (Extra
Credit Test Questions: Are you more likely to wind up on a low approach in a
glider with effective drag devices, or one with ineffective ones? Why?

Sure, it's fun - and quite possibly a useful learning exercise - to 'mentally
play with' these sorts of scenarios, but the fact of the matter is Joe Glider
Pilot should *never* 'suddenly' and 'shockingly' find himself hung out to dry
on any normal approach. In fact, I'd argue the only time the possibility of
being 'hung out to dry' should ever even rear its 'might-could-happen' head
are those times when JXCGP has reason to utilize his/the plane's fullest
capabilities shoehorning into a short/obstructed field (which skills of course
shoulda/woulda been safely practiced/determined beforehand)...and even then
the 'need' to do so should've been the result of an active *series* of choices
(maybe not all of them good! ).

Not picking on you...just hypothesizing about possible future realities in any
XC glider pilot's future! As for 'horribly screwing up' a routine approach at
JGP's home field...should never happen, just as a departure from controlled
flight (i.e. the dreaded stall/spin turning base to final) should never
happen. Why would any of us want to go to these places? Yeah, the newer JGP
is, the more likely he is to be making massively large drag device settings
changes in any normal approach (kinda like a new bicycle rider's
easily-detectable large changes to maintain balance, contrasted with an
experienced rider's multitude of 'invisible' corrections), but there's no
'routinely defensible' reason for him to be *aiming* at the absolute near end
of the runway, even when practicing short field approaches.

But it does make sense that you can probably land shorter with these
type of flaps over just spoilers. Now I'll have to go watch the video

Good on you...and may your flying experiences always occur on a happily
expanding palette!


Regards,
Bob W.