Mike is correct. Only "close in" obstacles are best cleared with flaps in
any GA airplane.

That is because all GA aircraft have only one Vx and Vy and they are ALWAYS
attained with ZERO flaps.

Climbing at a lower speed with flaps to clear obstacles is a compromise. In
order to get off the ground in the shortest distance flaps are used. But one
has to then climb at a speed that is lower than Vx. There becomes a point at
which you are better off to accelerate to Vx and retract the flaps. Then you
will be climbing at BEST angle, which is impossible to do with any flap out.

For instance, say you are taking off from a short strip in the Snake River
canyon. There are trees at the end of the runway. Most likely you will use
the short field procedure in the POH for takeoff, which will probably
include flaps. But, once clear of the trees you will want to get rid of the
flaps in order to clear the distant obstacles, such as a ridge five miles
away. Best angle is WITHOUT flaps.

On the kind of Cessna, Piper and Beechcraft airplanes discussed here, Vx and
Vy are "clean wing" numbers. The exceptions are some VERY unusual STOL wings
like on a DHC-2 Beaver, which does use some flap for all normal climbs.

Karl
"curator" Cessna A185F, N185KG


"BTIZ" wrote in message
news:%tcnd.106330$bk1.58516@fed1read05...
Well Mike, I do not have a PA-28-181 POH handy so I checked my old
PA-32-300
At sea level, At Max GW
Normal take off, 10degree flap setting, Ground Roll, 1050ft, 50ft
clearance 1500ft
Short Field take off, 25degree flap setting, Ground Roll, 950ft, 50ft
clearance, 1400ft.

Say again?

BT

"Mike Rapoport" wrote in message
ink.net...
The problem with this logic is that the 50' obstical distance is
genarally greater with the short field flap setting. Only the ground run
is shorter.

Mike
MU-2