Deep stall recovery procedure
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Read Nasa TP1538 page28 second and last chapter
As I said flaps induce a nose down
In the Turbo Arrow and most Pipers I’ve flown I had to put the yoke forward on lowering the flaps…so it’s not an “always”. Personally, with BMS I haven’t noted any pitch change at all in changing configuration, and I chalk that up to the flight controls doing their job.
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In a RL aircraft, lowering flaps generally produces a nose UP pitching moment (but it can also depend on the configuration of the airplane, I guess)
Generally, lowering flaps in most light aircraft produces a nose DOWN pitching moment. Cant speak for all aircraft ever… but at least the Pipers and Cessnas Ive flown have all been this way.
There is a fairly good chance that if you pay attention in that Turbo Arrow, that you will notice that if you take your hands off the controls, and lower the flaps, that you will nose down (as well as start to climb).
The fact that you need to bunt when lowering flaps is more to control the sudden increase in lift and gain in altitude - i.e., controlling your velocity vector rather than counteracting a pitching moment.
Once you understand the pitch input, pitch moment relationship the MPO “rock out” procedure makes sense and you won’t recover by doing what the book told you to but by doing what you comprehend about the dynamics.
Is there a distinct difference, though? I kinda feel like the book instructions were pretty much how you get the nose down ASAP.
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First comparing a pipper or Cessna to a f16 airframe is a bit strange
Secondly , we are taking about pitch behavior at 60 deg AOA here !!! So I doubt any of Cessna or pipper pilot ever tested that configuration lol
Wind tunnel testing by The nasa is clear : at this AOa , TEF is producing pitch down , this is written black on white in The wind tunnel results table
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Hmm. 60 degree pitch attitude Ive done… but I rather doubt it was 60 degrees angle of attack. Seeing as the control surfaces all responded basically as you would expect. So I cant help there!
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Last month, I made a test flight after an Air to Air refueling in the TE. I think it was the F-16 Bl.50. I tried to get as high as I could in an almost clean configuration (except the AA missiles) and got to 50.000 feet. Up there I made a hard turn without afterburner, got quiqly in a deep stall and let it go. And yes, it was not a big deal to get out there. Just used the standard procedure…
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Jsut as a reminder, the GC position is very evolutive with fuel, interesting article to read again
https://www.benchmarksims.org/forum/content.php?161-Flight-Model-(FM)-Developer-s-Notes-Part-6
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First comparing a pipper or Cessna to a f16 airframe is a bit strange
Secondly , we are taking about pitch behavior at 60 deg AOA here !!! So I doubt any of Cessna or pipper pilot ever tested that configuration lol
Wind tunnel testing by The nasa is clear : at this AOa , TEF is producing pitch down , this is written black on white in The wind tunnel results table
I’m talking in the generic sense about aircraft in genereal…and I DID also say that it can depend on the aircraft. It’s not an “absolute”. And I expect even NASA knows that.
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I’m sure… but I’m also struggling to think of an example where TEFs on a conventional airframe would be located forward of the CG.
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I’m sure… but I’m also struggling to think of an example where TEFs on a conventional airframe would be located forward of the CG.
Mig21 on finnish air force had problems with it rec pod on this. Rec pod located on center station make plane “nose heavy” and flight performance suffer.
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TEFs = Trailing Edge Flap(eron)s.
To clarify, I cant think of terribly many conventional aircraft which have flaps, and by extension, wings, which are forward of the CG - which seems the only straightforward way to have flaps whose deployment causes a nose up moment.
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TEFs = Trailing Edge Flap(eron)s.
To clarify, I cant think of terribly many conventional aircraft which have flaps, and by extension, wings, which are forward of the CG - which seems the only straightforward way to have flaps whose deployment causes a nose up moment.
Tsss tssss
There is not only the torque from the lift vs GC exentricity , there is also the torque generated by the wing itself
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Perhaps I am totally out of my depth, as someone who has done barely any study of aeronautical engineering, but my suspicion is that the wings on conventional aircraft are also typically (mostly) aft of the CG?
I tend to enjoy when you weigh into discussions on aerodynamics, Mav. Your articles on the BMS flight model were my first foray into learning about the subject in any kind of depth, all those years ago.