gliding back to your departure airport

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 ?

Well obviously, but I'm not talking about in the pattern area like the
Impossible Turn is. I'm talking about 10 minutes after departure at 7k feet
where the departure airport, if you can make it, is the best landing option.
Then for all intents and purposes its a 180 degree turn.

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 ?

"Harold" wrote in message
...
Well obviously, but I'm not talking about in the pattern area like the
Impossible Turn is. I'm talking about 10 minutes after departure at 7k
feet
where the departure airport, if you can make it, is the best landing
option.
Then for all intents and purposes its a 180 degree turn.

To my knowledge, no one has ever said you can't. Other than aircraft that
cannot climb as steeply as they descend (and there are a number of aircraft
that are like that), obviously after a 10 minute climb, it would be very
likely you could make it back to your original departure airport.

I would never say "guaranteed". Other than aircraft performance, there are
still other reasons you wouldn't be able to make it. For example, climbing
with a tailwind will hinder your ability to make it back to the airport
(just because you take off into the wind, that doesn't mean you'll be
climbing out into the wind, even if you depart straight out).

So, a literal answer to your question is "no", you cannot guarantee that you
can make it back. However, it's true that for many aircraft, once you've
climbed that far, the original departure airport is often going to be a very
good choice for an emergency landing site, at least shortly after takeoff.

Does *that* answer your question?

Pete

That wasn't implicit in your post (although "top of climb" is a heck of a
hint). Most such questions deal with failure during the initial climb.

Bob Gardner

"Harold" wrote in message
...
Well obviously, but I'm not talking about in the pattern area like the
Impossible Turn is. I'm talking about 10 minutes after departure at 7k
feet
where the departure airport, if you can make it, is the best landing
option.
Then for all intents and purposes its a 180 degree turn.

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 ?

"Harold" wrote in message ...

Well obviously, but I'm not talking about in the pattern area like the
Impossible Turn is. I'm talking about 10 minutes after departure at 7k feet
where the departure airport, if you can make it, is the best landing option.
Then for all intents and purposes its a 180 degree turn.


Absolutely. As long as you have continued climbing at a higher rate
than the descent will be.

About 2 years ago I got to practice this. On an early morning
takeoff for a 300 mile cross-country flight, the OAT was cool and the
plane was light, so I climbed out at 900 ft./min. to reach my cruising
altitude quickly. At around 9K ft. the engine got real loud and I
realized I had broken something in the exhaust. I shut down the
engine so as not to catch the cowl on fire. I was 6 miles away from
the airport and knew I had climbed at much better than the 750 ft./min
descent rate, so the return glide was really a no-stress event. When
I got back to the pattern, I actually had about 1K ft. too much
altitude and had to circle to lose it before deadsticking on to the
same runway I had departed.

John Galban=====N4BQ (PA28-180)

"Harold" wrote in message
...
Well obviously, but I'm not talking about in the pattern area like the
Impossible Turn is. I'm talking about 10 minutes after departure at 7k
feet
where the departure airport, if you can make it, is the best landing
option.
Then for all intents and purposes its a 180 degree turn.


In that case you might want to use ft/nm as a better measurement.

jerry