Hello Ivan, hello Smilo,
Well, I didnīt think the flight model stuff was so uninteresting, otherwise I wouldnīt have spent so much ink on it in the posts... but of course it depends on a personīs taste for it.
At the beginning it seemed quite straight forward, but quite soon it got more and more complicated because of the strange way the information was presented by the different sources.
After all if Ivanīs explanations on propellers, which I didnīt fully understand at the beginning, at the end, and BECAUSE of the posts in this public forum, most issues were clarified. So, the forum fulfills its purpose!
Some things are not too clear yet, and will probably stay unclear, because of the fact that many sources followed the FAAīs way of bundling everything up into normalized post-war HP standards. This way, the very probable over 200 units of 280 Hp stock Stearmans with a wooden propeller have been buried and forgotten about in the mists of time.
Also, the R-680-5 is most widely quoted as having 215 Hp, but a document stating engine certificates, shows is as equivalent to a -B5 with 240 Hp. I find that quite disconcerting. Maybe the -5 and the -B5 werenīt the same engine and that could be the mistake: There could have been a -5 with 5.5:1 compression, and a -B5 with 6.5:1. The early PT-13 production run of 26 units without letter had the R-680-5 series engine, without letter. So probably the 225 Hp is correct there, and a stock Stearman never had the -B5 = -5 engine with 240 Hp.
But who knows? ...and who cares? Even if I think itīs annoying that itīs so hard to find out for sure whatīs correct, I know that complaining about it in a public forum is no use, but we are human, and humans err.
Anyway, we are trying to have fun, arenīt we all?
Cheers,
Aleatorylamp
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