inst wrote:Castlebravo didn't catch that, but neither did I. 3000m is not 15000 feet, it's 9840 feet.

You're also misinterpreting your document, the Su-27 is a high fuel fraction fighter, like the F-35, with about 40% of its weight, fully-loaded, dedicated to fuel. The figure given above is closer to the tested weight, but the Su-27 actually has a higher combat radius than the F-35 by about 300 km, so if you discount its fuel fraction to account for range, the tested 50% would be correct. Other figures also state that the Su-27 has roughly a 16500 kg empty weight, so your figures on the second document seem to be instead for empty weight, 50% weight, and fueled weight.

Here's a chart with the Su-27 at 5000m, or roughly 16000 feet.

http://forumimage.ru/uploads/20110308/1 ... 004937.jpgHere, the Su-27 calculates roughly out to 13.6 deg / sec, but you can't inflate your F-35 STR because both are medium-range high-fuel fraction fighters. It then comes out to 10.8 vs 13.6, giving the Su-27 a 25% superiority.

What you can do, however, is compare the F-35 to the Su-35 instead, which is about 10% heavier loaded, but has superior ITR compared to the base Su-27. Using the thrust change / weight change squared formula, you get about a 6% decrease in sustained turn rate, dropping you down to a 18.7% STR superiority.

Don't know if you are trying to cheat, but you are making a mistake again:

In Su-27 flight manual, the horizontal axis is not true airspeed (or mach number), but indicated airspeed (or mach number). The latter is always smaller than the former. If you do not do the conversion, you will sure over-estimate the turn rate.

I will explain the reason and show the proof.

Reason why indecated airspeed is always smaller than true airspeed:

The pitot tube uses dynamic pressure to caculate airspeed. But when the airplane is flying with some angle of attack, the incoming airflow is deflected inside the pitot tube and thus decelerated, resulting in less dynamic pressure. The viscous force of the wall of the tube also slow the airflow down. That is why the indicated airspeed is always smaller than the true value, even at sea level.

Proof: this is a chart from Su-27 flight manual, Su-27 at 21400kg could pull 2.5G at indicated mach number of 0.2. But given the fact that Su-27's maximum lift coefficient is smaller than 1.9, there is no way it could pull 2.5G below Mach 0.25. There is an 20% deviation. This is not considered an error because that is how a pitot tube works. Each pitot tube has its own convertion table, but that is not always available in flight manuals.

If you don't do the convertion, you will definitely over-estimate Su-27's turn rate significantly. TsAGI has already done the conversion, and showed a sustianed rate of turn of 21deg/sec at sea level, 18920kg. You can ignore the convertion and try the figures on Su-27 manual, you will definitely find something greater than 21deg/sec.