Quote:
Originally Posted by MadBlaster
hmm, before I read further, I think we need zero lift drag coefficient for 190 to say that weight is the deciding factor. wiki says 27.87 m² for p47 wing area and 18.30 m² for 190A. Agree with you that denominator (i.e., weight) is almost twice as large for p47 verses 190, but numerator? To keep simple math, assume zero drag coeff=1 for both planes, 190 weighs "1" and p47 weighs "2" (weight on relative basis to each other). Then drag coefficient portion of numerator
-dragcoefficentX(speed)^2/weight
where you did this -> P-47D-27 = 0.0256 * 25.87 = 0.662272 (i assume your using 25.87 for wing area)
(i.e., use 1 instead of .0256 and 1 for speed since same for both planes and 2 for weight p47 and 1 for weight of 190)
27.87/2 (p47) or 18.3/1 (190) is bigger??? The latter is bigger, and since it is a subtraction from this gXcos(60), wing area and/or differences in zero drag coeff may be the deciding factor in the calculation of dive acceleration, not the weight. And if this is the case, dive acceleration is less for 190 than p47. Sorry,if this is confusing. It's late here.
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27.87/2=13.93 much smaller than 18.3, so P47 has smaller subtraction from this g*cos(60).
BTW, this link says VDM 3m diametre has a 0.54 prop reduction gearing. Fw190A8 :VDM 9-12176A10 ft, 11 ¾ in. diameter 390 lbs
BMW-801D 2700rpm
So in 1943's test, @10000ft ,250mph IAS, fw190A4's propeller tip speed=(254^2+130^2)^0.5=286m/s=0.87Mach, less than 0.95 Mach of P47's.
Some P47's has 16:9 reduction which provides higher Mach number (1.05Mach ).
In conclusion, My opinion is that when p47 and fw190a4 at full engine 2700rpm dive from @10000ft ,250mph IAS, fw190's tip speed is about 0.87mach while p47's is around 0.945-1.05 Mach. Probably at that time P47's propeller's efficiency is quite lower than fw190, so p47 was outdove rapidly at initial diving stage.
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