Keep in mind that it will not be a 180 degree turn but more like 210 degrees
(unless you plan to make your power-off landing parallel to runway surface).
There have been many, many studies of the "Impossible Turn." Google that
term and you will learn a lot.

Bob Gardner

"Harold" wrote in message
...
If a small single engine plane can out-climb its engine-out glide ratio
from
take off through the top of climb point, wouldn't it follow that it can
always theoretically make it back to the departure airport in the event of
engine failure ? Assuming straight out departure, no wind, and the
altitude
loss in the 180 turnback is offset by the runway portion you didn't use.
If
my best glide is 85 KTAS and it loses 700 fpm at that speed, shouldn't I
be
guaranteed I can make it back if I climb at 84 KTAS and 701 fpm ?