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Kwiatos
04-29-2006, 03:34 AM
Has someone information about critical angle of attack for Bf 109 and Spitfrie? I need it for BoB2 VOW stall and spin testing?

Kwiatos
04-29-2006, 03:34 AM
Has someone information about critical angle of attack for Bf 109 and Spitfrie? I need it for BoB2 VOW stall and spin testing?

Kwiatos
04-29-2006, 10:21 AM
noone?

Spinnetti
04-29-2006, 06:37 PM
This isn't a fixed value, so your question doesn't make much sense.

At what airspeed, altitude, air density and rate of change of AOA? http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Owlsphone
04-29-2006, 07:13 PM
What Spinetti said...you can stall an airplane at any speed.

NonWonderDog
04-29-2006, 07:50 PM
I'm not sure what you two are on about... stall angle varies very little over a wide range of airspeeds. There's a bit of variance with Reynolds number, and everything goes out the window at Mach 1, but asking about stall angle is a very valid question.

If you know the numerical designation of the Spitfire and Bf-109 airfoils or you can work it out, you can look up the stall angle in NACA 824, here:

http://naca.larc.nasa.gov/reports/1945/naca-report-824/

The relevant charts are in the back -- meaning, the last 135 of the 265 pages. All of them have Cl v. alpha curves on the left. Most charts have several curves, corresponding to several Reynolds numbers, both flaps up and flaps down. The two curves above and to the left of the big cluster are flaps down (see Timmy, that's what flaps do!). Just pick the average maxima of either group of curves, you don't really need to figure a Reynolds number for your uses.

If you don't know the NACA airfoil number, or they're "special" (which is likely), you *will* be able to find a similar airfoil.... you most likely *will not* know when you have. There are a lot of pages there.

The automatic slats on the 109 will make this difficult to look up, as will its Germanness. As a guess, add 1-2 degrees to anything you find that's similar. A German aviation equivalent of this listing almost certainly existed at one point, but the chances of finding it are quite low.


If you just want an off the wall guess, I would say, for both aircraft flaps up and normallish conditions, the Spitfire would have a stall angle of attack of about 14-17 degrees, the Me-109 would have a stall angle of 15-18 degrees with the slats out.