Flaps and V-Tails of Death

(Mark James Boyd) wrote in message news:3fbc8231$1@darkstar...

I was always under the impression that Fowler flaps
reduced stall speed, but didn't think plain flaps
did much other than just add drag. On the
Katana, AA-1 Grumman, and Tomahawk (all power planes)
they seem to do nothing but add drag. Interesting
to hear these experiences, and I'll certainly
look at the next HP I come across more carefully.

All flaps will lower stall speed at small settings - even split flaps.
That's why you usually have a takeoff setting for soft and/or short
fields.

Boy, I havn't flown an AA-1 (the original, American Aviation Yankee,
with the "hot" wing) in a LONG time (32 years!) but I seem to remember
it's flaps didn't do much at all - at least compared to any Cessna.
Sure was a fun little thing to buzz around in, though!

As far as V-tails go, anything to reduce wetted area
is good, right? ;-P

This is a bit of a myth, I think. You still need the same tail volume
regardless of tail configuration, so you end up with basically the
same wetted area. If you cut down the size of the tails, you start
having stability problems (the Bonanza was originally a bit marginal,
I think), which is probably how V-tails on gliders got their bad
reputation in the first place. HPs apparently got it right from the
start. The theoretical saving is in reduced interference drag due to
fewer intersections (less of an advantage compared to T-tails) and
reduced weight (a big advantage compared to T-tails). Then there is
the rudder-elevator mixer issue...

They do look nicely retro, though. And the Fouga Magister proves that
the V tail can work beautifully in a relatively high performance fully
aerobatic jet trainer.

Finally, let's face it, V-tails were a fashion for a while in the late
40s and 50s (Bonanza, Magister, SHKs, Sisu, HPs, etc.) Now, T-tails
are the "cool" tail - which probably has a lot to do with why the poor
little PW-5 is dissed so much.

Kirk