Air Speed

[ballistx]

I have been looking at different aircraft and trying to get a handle on their air speed. I find it very confusing since most performance specifications don't give the basis for the airspeed.
Using Rising Up as a basis for comparison

First they don't specify whether is it KIAS or KTAS.

If it is KIAS, then at what altitude and atmospheric conditions. Or is there a "quasi-standard" someplace that I am missing?

If it is KTAS, then, again, at what altitude and atmospheric conditions.

An example is an article on a Lance. Says "at 75% power, a Lance cruises at 158 knots while burning 18 GPH". What does that really mean? Is it at its maximum ceiling? Or is that KIAS? Since it doesn't specify altitude, etc. I would presume it is KIAS. Then, at 9500 ft (pressure altitude) and 26 deg C, would that be 192 KTAS?

Hope someone can clear this up for me.

Thanks

[Oracle427]

The vast majority of the time it will be KTAS and should be quoted for a specific temp/altitude. If a specific temp/altitude is not given, then they likely are quoting the best performance at around STP and that will usually be near 8000' on a non-turbocharged engine.

[DHenriques_]

The vast majority of the time it will be KTAS and should be quoted for a specific temp/altitude. If a specific temp/altitude is not given, then they likely are quoting the best performance at around STP and that will usually be near 8000' on a non-turbocharged engine.

I would add that most flight test is done using a standard atmosphere with pressure altitude.
Also, the figures are usually higher then the aircraft in question if the plane has been in use for some time. The manufacturers test pristine aircraft usually picked out for testing during a production run.
I always approach the published numbers with a jaundiced eye.
Really sharp pilots "account" for all this when using the charts........they "subtract a bit here and there. ))

Dudley Henriques

[ballistx]

Thanks.
Went back and was doing some more looking. I was not taking into account the degradation of the N/A engine at elevation. I think I have it figured out now.
Thanks again.