Hello Ivan,
Oh well... such is life.
Some are better and/or quicker than others in finding the information needed at a given moment - obviously because some know more than others about the subjects in question, and can thus more easily identify useful from useless information within the quagmire of Internet.
Even Pilotsī Handbooks for similar aircraft supply different and/or inconsistent information, (did the Lycoming engines in question have 220 or 225 HP??) as in the case of Army Corps and Navy Stearmans, or information which is only similar to that required, as in the case of the Orion.
Also, Engine Manuals ommit certain details. For example, there isnīt a military designation for the 240 Hp Continental W670-M, but the Navy had quite a few, but neither do they say how many, nor on what planes. ...and not to mention the 280 Hp Lycoming-engined Stearmans, buried in oblivion largely due to the FAA, although 2 or 3 historical texts do mention 255 units as having them! So, to say Iīm perhaps simply not looking is quite unjust, to say the least.
Anyway, turning back to propellers: After the more thorough method of testing and tuning that you proposed, which yielded almost the same results as Iīd got before, now I am surprised to hear that the Stearman propeller tuning is still not good. Oh, well, such is life... I donīt know any more to do anything further, but I do know where the problem lies.
In real life, 2100 RPM on the Lycoming gave 220 or 225 Hp (we will never know the exact number, will we?), and 2200 RPM, gave 237 Hp. In the Sim, this seems impossible to achieve, at least for me. The positions on the curve are so close that a 100 RPM difference for 12 or 17 Hp is impossible without incorporating a stupid, big step - so again, ...such is life!
My question on how to calculate the point where the propeller curve reaches zero was meant in general.
I have already said that I mentioned the Stearman example only as a check-reference.
You suggested J=0.8 because your calculation results ranged from J=0.7 to J=0.9, and included some working assumptions - and, now why was the J=0.8 out of context? ...and I do apologize for misquoting something or other on the Stearman propeller curve.
Anyway, my aim behind getting this information (that you so generously supplied, thank you very much) is to use for the Lockheed Electra-10īs two-pitch position propeller, which is quite a lot smaller than the Condorīs one you so effectively made.
This business is tedious enough as it is, more so if one adds the CFS and AF99 limitations.
Anyway, it seems that all my questions have been causing you some degree of bother for quite some time already, and I am sorry to hear that. So, the solution is really very simple: I will just reduce the number of questions and interventions to the barest possible, absolute minimum. The last thing I want to do is to be a pain.
Itīs a hobby, and itīs supposed to be fun, so why turn it into such a harsh discipline in so many aspects?
Cheers,
Aleatorylamp
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