based on this, I was always told that 10degree flaps on take off where to
get up off that wet grassy runway and accelerate in ground effect, slower
climb rate to be expected, so make sure there are no trees at the other end.

BT

" Blueskies" wrote in message
. ..

"Michelle P" wrote in message
nk.net...
An interesting dilemma.
The manual for the 172 N tells you that 0-10 degrees is acceptable for
takeoff. However it does not tell you what affect it has at low altitude
300 feet MSL Density altitude around 2500 MSL. It only states that it
will have a detrimental affect at high altitude on a hot day. It also
does not give an airspeed for Vy flaps 10 degrees.

In talking to another pilot who has an 172 L has states that his manual
says if 10 degrees flaps are used it will decrease ground roll and
decrease climb rate. Having an overall detrimental affect.

The only definitive number the 172N manual states for flaps 10 degrees is
Vx.

First hand experience seems to confirm what the 172 L manual says.

What do you all think?
Michelle


1975 C172M manual...

"Normal and obstacle clearance take-offs are performed with wing flaps up.
The use of 10° flaps will shorten the ground run approximately 10%, but
this advantage is lost in the climb to a 50-foot obstacle. Therefore, the
use of 10° flaps is reserved for minimum ground runs or for take-off from
soft or rough fields. If 10° of flaps are used for minimum ground runs, it
is preferable to leave them extended rather than retract them in the climb
to the obstacle. In this case, use an obstacle clearance speed of 65 mph.
As soon as the obstacle is cleared, the flaps may be retracted as the
aircraft accelerates to the normal flaps up climb speed of 80 to 90 mph.

During a high altitude take-off in hot weather where the climb would be
marginal with 10° flaps, it is recommended that flaps not be used for
take-off. Flap settings greater than 10° are not recommended at any time
for takeoff."

The Take-off checklist has a normal and a maximum performance set of
items. Both say Flaps up. The only real difference is the brakes are held
until full power is applied and the run is with the tail slightly low for
the max performance T-O...

The old C-172A book says pretty much the same thing.

From my experience the use of flaps should be reserved for those really
rough or rain soaked grass fields with low obstacles.