"Dylan Smith" wrote in message
...
On 2006-05-08, Howard Nelson wrote:
different reasons). I have experienced -500fpm rate of climb in a C182
with
1/2 fuel and two on board 65Knot IAS in May departing Truckee due to

From someone who flies gliders - do NOT fly slowly in sink. It will just
prolong the amount of time you spend in the sink (resulting in a greater
altitude loss). You will of course have to work out the speed to fly for
your particular aircraft -vs- the observed sink rate to determine the
best speed to fly.

For example, imagine a plane that climbs at 1000 fpm in still air at
60kts, and 700 fpm at 120kts.

You're at full power and in sink at 60kts, and you're showing 500fpm
down. Imagine the sink lasts for 4 miles. It'll take you 4 minutes (1
mile per minute) to get through, and you will lose 2000 feet. The air is
sinking at 1500fpm.

If you instead fly this particular plane at 120 knots through the same
sink, you'll only spend 2 minutes to get through it, and your rate of
descent will be 800 fpm - and you'll come out of the sink having lost
1600 feet (and therefore be 400 feet higher than if you'd flown through
the sink slowly).

The example here is obviously contrived (for easy calculation) - but you
can work out some scenarios based on the performance of your plane to
figure out the best speed to fly in sink.

Understand what you are saying but this was on departure at about 1000ft
AGL. Perhaps something could have been done differently but at the time we
were trying to balance rate of climb (which was negative) with stall speed.
Luckily (which is not anything to depend on) after about 30-60 secs the -500
fpm turned into +1500fpm. This was not an especially hot day (maybe 60f).
The point I was making is that any non turbo single in the Tahoe basin may
rapidly reach the limits of it's performance envelope. We were enroute home
from Idaho to the bay area and did not follow a mountain flying rule that
had been taught to me by my mountain flying instructor. That was "in the
summer in the mountains be on the ground between 1000 and 1600hrs".

Howard