Power Chart Creation?

Some flight plan software requires one to enter a power chart for the aircraft. This
is used to calculate time enroute at different altitudes and temperatures. The chart
has TAS for various combinations of altitude and power. Given the single
airspeed/altitude/power setting provided by the aircraft manufacturer, can one of
these charts be created mathmatically?

If so, how?

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

"G.R. Patterson III" wrote:

Some flight plan software requires one to enter a power chart for the aircraft. This
is used to calculate time enroute at different altitudes and temperatures. The chart
has TAS for various combinations of altitude and power. Given the single
airspeed/altitude/power setting provided by the aircraft manufacturer, can one of
these charts be created mathmatically?

This sounds unclear to me, so it probably is to you. I need to enter power
percentage, GPH, and TAS figures for several rpm settings at, say 3,000' and the same
info for 10,000'. I can get the percentage and GPH figures from the Lycoming engine
data charts. Maule, however, just says that TAS is 103 knots at 8,500' at 75% power.
How can I derive the TAS values I need?

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

"G.R. Patterson III" wrote in message
...


"G.R. Patterson III" wrote:

Some flight plan software requires one to enter a power chart for the
aircraft. This
is used to calculate time enroute at different altitudes and
temperatures. The chart
has TAS for various combinations of altitude and power. Given the
single
airspeed/altitude/power setting provided by the aircraft
manufacturer, can one of
these charts be created mathmatically?

This sounds unclear to me, so it probably is to you. I need to enter
power
percentage, GPH, and TAS figures for several rpm settings at, say
3,000' and the same
info for 10,000'. I can get the percentage and GPH figures from the
Lycoming engine
data charts. Maule, however, just says that TAS is 103 knots at 8,500'
at 75% power.
How can I derive the TAS values I need?

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to
have
been looking for it.

At a minimum, you'll need your airplane's drag polar, which requires
numbers CD0 (parasite drag coefficient) and e (airplane efficiency
factor), which in turn requires only a fairly simple glide test. It's
all outlined in Performance of Light Aircraft. Other things you might or
might not need are in there too.

John Lowry
Flight Physics