Quote:
So basically the French achieved 494 kph at 600 m with rpm 2400 and 1.303 atm pression d'admission
Extrapolating pessimistically to 0m they got 478 kph with rpm 2400 and 1.289 atm pression d'admission
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Quick ballpark of the data to standard conditions….
478 kph TAS x 0.539956803 nautical miles at +5C = 258KTAS
We don't have a piece of the puzzle which is the atmospheric pressure for that day. I am not looking for it but if somebody finds it, I will refine the calculation.
258KTAS x 1.0299 SMOE for our density altitude Temperature difference = 265 KTAS
265KTAS / 0.539956803 = 492kph
492 kph is within 1% of Mtt stated mean of 500kph over a range of 5%.
If we had the pressure and I wasn't using some quick rules of thumb of a standard atmosphere chart but did the full calcs, I bet it would give even better agreement. The French might have had an optimistic performing Bf-109!!
The French test results give very good agreement with Mtt's published figures for the type.