Radiator drag

[Kurfürst]

Originally Posted by Crumpp

If you line up the altitudes and look at the manifold pressures the French recorded, they used higher manifold pressure's when the closed radiator test was conducted.

That means the speed gap between open and closed due to radiator drag is not as wide as their results.

I don't think 10 Hgmm boost difference would change anything. In real life, that's well inside measurement/manufacturing/modelling tolerance.

From the practical standpoint its not too relevant either, since 1/4 open is the speed referenced point, the temperature is stable. Fully open position has only relevance as a speed break or on the ground for example, in prolonged run up.

In short, technically it might not reach up to modern engineering standards, but its more than good enough to model a flightsim with apprx. good values.