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Old 12th November 2005, 12:11
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Juha Juha is offline
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Re: Aircraft performance curves

Christer,
Only a few short comments. It is well known that there were speed differences between individual a/c of same type. And for example fully open radiator flap(s) dropped the the max speed of Bf 109G circa 50km/h and that of LaGG-3 c. 15km/h, this info is from Finnish tests. So on warmer day the max speed tended to be lower. So one got usually better figures in Nov. than in July.

It of course clear that the performace curves flown by captured a/c are somewhat doubtful. Much depends how much info the test organisation had.

Acceleration in different situations are possible to calculate, if some basic data is available.

On graphs; there are in Dean's America's Hundred-Thousand some which have both manufacture's and USAAF's/USN's graphs on same type and surprise, surprise, manufactures´ graphs tended to show better performance.

And as I wrote before here in Finland we have a book, Raunio's Lentäjän Näkökulma II, which shows the area where the max. speeds of the FAF's MS-406s were after major overhauls plus the manufacture's speedgraph. The book also gives the variation of max speeds of overhauled FAF's Fiat G.50s, info that Brewster 239s usually were very near to manufacture's figures, Curtiss H75As always clearly slower etc.. So I and surely also Jukka are well aware of the problems and merits of performance graphs and I still think they are very usefull but must be used with care.
BTW all the info in Your message was familiar to me before so I still think the graphs useful.

Juha
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