[net.aviation] ROC

normb@tekred.UUCP (Norm Babcock ) (04/18/85)

After reviewing the C-152 handbook, the significance of the
heading of the table I get rate-of-climb, fuel, distance, etc.,
from for various altitudes, hit me. The heading is for MAXIMUM
rate of climb. Even though I make a stab at calculating this and
that, correcting for temp, the actual performance is always less.

I figured out then,(or remembered), that I don't like the deck
angle at max climb, and always lower the nose for better visibility
and cooling. My question is: is there a correction factor which
works for different climb speeds? Is climb performance linear with
speed? ROC would decrease, fuel would increase, time to TOC would
increase, as would distance to TOC. Or does one have to play test
pilot and make new tables?

I realize a lot of pilots gas and go; and I do also, but sometimes
I like to do a precision nav flight just for kicks. I would like to
get a little better at forecasting a/c performance.

Any ideas?

tektronix!tekred!normb

cfiaime@ihnp4.UUCP (Jeff Williams) (04/18/85)

> My question is: is there a correction factor which
> works for different climb speeds? Is climb performance linear with
> speed? ROC would decrease, fuel would increase, time to TOC would
> increase, as would distance to TOC. Or does one have to play test
> pilot and make new tables?
> 
> Any ideas?
> 
As a rule of thumb,  add one mile of enroute distance for each
1000 feet of climb.  As an example, if your distance is 100 miles,
and your climb is 5000 feet, figure time, fuel burn, and the like 
for a trip of 105 miles.  This trick works best for cruise climb,
and is accurate to 1 minute or so and 1 or 2 gallons.  Many precision
pilots use this trick.

However, if you like playing test pilot, you can probably, in enough
flights, build your own tables for your own technique.

				jeff williams
				AT&T Bell Laboratories
				ihnp4!cfiaime

notes@ucf-cs.UUCP (04/21/85)

Unfortunately ROC is nonlinear with speed for a fixed altitude & wt.
ROC is proportional to excess power ie differecce between
what your engine is putting out at your power setting
and the power needed to overcome drag.  Its max at
about middle of the white arc speeds.
Remember also that book figures are one by
factory test pilots on new airplanes at gross wt at sea level
or corrected to sea level.
There is a way of performing an entire climb performance check
in a 1/2 hour flight with on board instruments.
Send mail if you wish to know how.
Good Flying.
.