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What is behind it that they did a couple of stall speed trials with the Spit earlier, and from the stall speed they deducted Clmax (which in itself lends some room for error, recall those lenghty discussions about what 'stall speed' really is'?). Based on the date, they calculated a doghouse turn chart for the Spi. When the 109E-3 was handed over by the French for testing, the British wanted a similiar graphical comparison made. They made a similiar test procedure to establish 109E stall speeds, based on that, the Clmax. ![]() at http://www.kurfurst.org/Tactical_tri...ls/Morgan.html Quote:
It gives the turn time for 109E as 18.92 secs on the deck, a fairly believable number IMHO. What complicates things that appearantly we have (ca. 50HP higher) DB 601Aa ratings present, not DB 601A the report assumes. Well say 18-18.5 secs in this case. Actually it should be possible to calculate it precisly using the report. Quote:
The conditions of the Wrk.Nr. 1792 test are not known for certain, as the report aimed for relative speeds w. and w/o MG FF barrels in the wing, and not absolute figures. Even boost is uncertain, a the report mentions that the figures are not corrected for nominal engine output etc. The Baubescreibung is the official performance specs for the 109E, which the manufacturer guaranteed to be met withon +/- 5% tolerenace. Those Emils that could not satisfy the specs were not accepted by BAL, the LW's quality control organisation. Even at the war's end! Moreover the 500/570 specifications laid down in the Bbschr. 109E paper were confirmed with the detailed report of the Emil prototype: http://www.kurfurst.org/Performance_...w_109V15a.html ![]() and by French testing of Bf 109E-3 WNr. 1340 (same aircraft as tested by the Brits later) also seem to confirm that the level speed figures laid down in the in German specs can be confirmed: http://www.kurfurst.org/Performance_...formanceT.html (beware of the bewildering combination of open/closed raditors, RPMs and manifold pressures used.. its a bit of a pity that the French used Hgmm for boost instead of ata. Confusing..) Besides if one uses simple common sense, its quite easy to see. If you look at the Spitfire and Bf 109E speeds and powers at rated altitude, you'll find that that both do around 570 km/h, but the Spit has actually quite a bit of more power at this altitude (as opposed to popular knowledge, the Merlin III was pretty good at alt). It follows that it has more drag. Now, at SL the Spit does, iirc some 282 mph at +6 1/4 boost, which is 890 HP. And the 109 there has 990 (601A-1) to 1050 HP (601Aa). It follows that should be a good deal faster than 282 mph (454 kph), with 150 HP extra in less draggy airframe..
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Il-2Bugtracker: Feature #200: Missing 100 octane subtypes of Bf 109E and Bf 110C http://www.il2bugtracker.com/issues/200 Il-2Bugtracker: Bug #415: Spitfire Mk I, Ia, and Mk II: Stability and Control http://www.il2bugtracker.com/issues/415 Kurfürst - Your resource site on Bf 109 performance! http://kurfurst.org ![]() Last edited by Kurfürst; 04-12-2011 at 04:07 PM. Reason: I was wrong about that the UK 109E CLmax figures are guesstimates, having just re-read Morgan's report,there was a stall test |
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