I'm doing some analysis of various powerplant options and would like to know
if there is data available that documents cruising TAS vs. altitude:

1.  For a conventional Naturally-Aspirated engine configuration with
standard magnetos.  This needs to be at a fixed rpm and fixed percent power
below 8,000 ft.  75 percent power and 2500 rpm would be a representative
condition.  I have some data like this, but only up to about 12,000 feet.  I
would like to get data up to 18,000.

2.  For a Naturally-Aspirated engine equipped with dual electronic ignition
that automatically advances the timing at low manifold pressures under the
same conditions as above.  I have a suspicion that the slope of the airspeed
line above 8,000 feet is much lower than with fixed timing, but I have
little data.

3.  A turbo-normalized engine (any turbocharged engine will do) run at a
fixed rpm and fixed percent power at all altitudes to at least 18,000 ft.  I
have reasonably good data (C-TR182) for this that shows a straight line with
an 8 percent increase from 8,000 to 18,000.

It would be nice if all three configurations were on an ES, but other
airframes will also produce usable data.  I have found that the above data
for certified aircraft closely matches each other, but I only have anecdotal
information for the dual electronic ignition version.

Thanks,

Gary Casey