is TVC used here???

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f-16adf

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Unread post01 May 2017, 01:57

I really don't know much about the F-22. I have always been more of a teen series/F-4/F-106 fan.

However, in this aerial demo compilation, does anyone know just how much Thrust Vectoring is playing a part in these VERY hard turns?

https://www.youtube.com/watch?v=j9DNMI5JsM8



From slowing the video down, I don't see hardly any horizontal stab deflection in these turns. However, it looks like the engine nozzles are pitching slightly up (TVC is being engaged)????


Or maybe part TVC + part horizontal stab are both being used in these hard turns??
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mixelflick

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Unread post01 May 2017, 13:28

Great question/observation...

I didn't see much in the way of horizontal stabilizer movement either, so presumably it was thrust vectoring and chines doing most of the work. You could surmise they were "holding back" using all control surfaces plus TV, in an effort not to reveal its true capabilities.

And if that's the case, it's downright scary. The severity of those turns with TV alone is... eye watering.
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rhoads56

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Unread post01 May 2017, 17:18

I agree, great observation/question. I always thought that due to the negative/relaxed static stability inherent of the F-22, those hard pitch-up maneuvers required very little control surface deflection so as to not over-G the jet. Though it's a good point that this could be simply a cover-up to not reveal its full maneuverability envelope.
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f-16adf

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Unread post02 May 2017, 01:43

And both ailerons are slightly deflected upwards.
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f-16adf

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Unread post02 May 2017, 14:31

Possibly for pitch or to unload?
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gta4

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Unread post03 May 2017, 20:37

Without Thrust Vectoring, the raptor has been tested under 80+ deg AOA. It could recover from that angle (generating sufficient nose down moment). Under 60 deg AOA, it could generate both nose up and nose down moment, making an accurate nose pointing control. It employs nose-up inertia to exceed 60 deg AOA without thrust vectoring (just like normal cobra)
Image

Most of the F-22's high-g turns at airshows does not engage into thrust vectoring at all: F-22 rely on its aerodynamics only to perform the turn.
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https://www.youtube.com/watch?v=N_3m5Zx-6Kc
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f-16adf

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Unread post03 May 2017, 20:53

I'm not trying to start an argument here, but in the 3rd frame if you zoom on in it actually does look like the nozzles are canted slightly upwards.
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gta4

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Unread post04 May 2017, 00:43

1. If you take a look at the first pic, the horizontal stab is actually deflecting upward. It could contribute to the total lift and thus improving the turn rate.

2. You suspect the 3rd pic shows a TVC slightly deflected (the 1st, 2nd and 4th pic shows no sign of deflection). But given that the time interval between each picture frame is at the order of magnitude of 0.01 second, it is impossible to enable/disable deflection in such short interval, so your hypothesis does not hold.
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rheonomic

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Unread post14 May 2017, 06:07

Don't underestimate the effectiveness of the aerodynamic control effectors...
u = (CB)⁻¹(cvdt_des - CAx)
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mixelflick

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Unread post14 May 2017, 15:51

There so much at work here we DON'T see...

For example, the chines. It's my understanding both the F-22 and 35 make use of these, to the point where no canards are needed (although certainly must have been studied for the ATF). Clearly, we're not seeing its max capabilities though, and seeing the abruptness and severity of this turn, that should be downright frightening to adversaries.
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Scorpion1alpha

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Unread post14 May 2017, 20:08

Those are considered "gentle" turns for the F-22...
I'm watching...

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