What's a Highspeed stall?

[i fight by 1 0]

I remember seeing it somewhere, but I have no idea what it is.

[+DoctorQuest 107]

If I understand your question this might help....

 

http://www.grc.nasa.gov/WWW/K-12/airplane/incline.html

 

Basically a wing can stall at any speed given a high enough angle of attack.

[Fubar512 1,350]

A high speed stall is when your pitch surfaces, even at maximum deflection, cannot overcome the aircraft's inertia at a high airspeed, usually while in a dive at too low an altitude to pull out from. This brings about two interesting effects: First, the high speed stall. Second, a deep, smoking, hole in the ground.

 

Hope this clarifies things for you

[i fight by 1 0]

What do you do when you get into one?

 

...Or was that crater thing implying you'd be SOL?

Edited May 27, 2009 by i fight by 1

[maverickHR 0]

I ve heard somewhere that cobra manuver is offten called "high speed stall"

[+76.IAP-Blackbird 3,545]

A high speed stall is when the airflow over the wings start to approach the speed of sound. When this happens the shockwaves/compression produced by the airflow makes the air separate from the aircraft earlier and therefore produce less lift. The aircraft goes into 'Mach Tuck' which is a nose down pitching movement (as opposed to a slow speed stall where the nose pitches up) and eventually the loss of lift is so great that the aircraft stalls. At high altitudes above the optimum level the high speed and low speed stalls meet eachother. This is known as 'coffin corner'. As you climb your high speed stall starts to come down and your low speed stall starts to go up. Eventually they will meet if you keep climbing. Climbing above your optimum is not recommended because of this and especially in turbulent conditions where you may be flying with only 10knots separation from those stall speeds

 

think this is the best answer

[i fight by 1 0]

A high speed stall is when the airflow over the wings start to approach the speed of sound. When this happens the shockwaves/compression produced by the airflow makes the air separate from the aircraft earlier and therefore produce less lift. The aircraft goes into 'Mach Tuck' which is a nose down pitching movement (as opposed to a slow speed stall where the nose pitches up) and eventually the loss of lift is so great that the aircraft stalls. At high altitudes above the optimum level the high speed and low speed stalls meet eachother. This is known as 'coffin corner'. As you climb your high speed stall starts to come down and your low speed stall starts to go up. Eventually they will meet if you keep climbing. Climbing above your optimum is not recommended because of this and especially in turbulent conditions where you may be flying with only 10knots separation from those stall speeds

 

think this is the best answer

 

Yahoo Answers? xD

[+76.IAP-Blackbird 3,545]

google is the best friend XD

[i fight by 1 0]

yep^^

Edited May 27, 2009 by i fight by 1

[i fight by 1 0]

http://www.youtube.com/watch?v=YBPMmO6RsHA <--- (A SU-30 Recovering from Highspeed stalls)

 

So that's what it looks like when a plane goes into that kind of stall?

[Fubar512 1,350]

The definition of a high speed stall (at least as far as crash investigators are concerned) is pretty much as I posted it. An aircraft in a dive accelerates (under dry power) until it reaches a speed where the center of lift has moved so far aft on its lifting surfaces, that the stabs or elevators cannot supply sufficient lift (leverage) to pull out of that dive., even at full deflection. Laden F-4s were known to achieve that state at speeds as low as 550 kias in shallow dives at low altitude. Early MiG-21s also suffered from that, as did F-105s.

 

And no, that Flanker was never in a high speed stall. Modern aircraft have HUGE stabilators that pretty much prevent that.

[MAKO69 186]

Compression stall is what it is called. The bell X-1 had issues with this, late prop fighters, and early jets were saseptable to this. Me-262 was very saseptable "Ve had to be carefull ve had no dive brakes".Late model P-38s had a dive spoiler under the wings that would deter such issues. The all moving tail surfaces and fly by wire systems help solve these problems, but if you push an aircraft past its envelope it still can happen.

Edited May 27, 2009 by MAKO69

[i fight by 1 0]

How do you get out of that stall?

[+Viggen 516]

Eject. From how Fubar described it, that's the only way I can think of getting out of one, well, apart from avoiding falling in to a high speed stall in the first place.

[zmatt 2]

If you have enough altitude you could always try cutting the power and using the air brakes. If you are lucky that may give you control back, but if you are anywhere under 20k feet I would punch out.

[i fight by 1 0]

Has this ever happened to anyobdy in WoX?

[Stretch32 0]

A high speed stall is really just a different name for an accelerated stall. Like was mentioned above an aircraft can be stalled at any airspeed and in any attitude provided the AoA (angle of attack) is high enough for the given weight and wing design of the aircraft. When an accelerated stall occurs a pilot will normally unload the aircraft (normally just release elevator back stick pressures) and add power if available and the aircraft will resume normal flight. Things like critical mach and mach tuck don't normally refer to a stall. Older aircraft that flew into the ground during high speed dives normally did so because the pilot lacked the physical strength to overcome the aerodynamic forces acting on the control surfaces (compressibility is an exception and in this case the aircraft wasn't "stalled" but the aircraft's control surfaces weren't in the airstream because of airflow seperation caused by reaching critical mach, the wing was still producing lift). Also, it's not uncommon to pull like crazy near the ground when your pointed straight at it. This can very easily cause an accelerated stall with a resultant "smoking hole." The grinding noise one hears in TW's jet sims when manuevering and pulling hard turns at high AoA is the noise a jet makes when the pilot is approaching an accelerated stall, a high speed stall, normally beyond optimum AoA.

 

Stretch

[zmatt 2]

Has this ever happened to anyobdy in WoX?

 

high speed stall? All the time. Just fly really high. If you are in a good and fast jet like a Viper, you can stall at 70k feet going mach 1. As for the compression stall, only when I have really messed with the aircraft. It has never happened in a normal plane, but some of my modified ones have done it in deep high speed dives. By deep I mean diving from 80k feet and pulling out at 1000 feet. Even then it never full locks up, the controls are just very sluggish, I'm not even sure if its a proper compression stall. I just cut the power and apply air brakes. I can usually pull out without blacking out.

[Fubar512 1,350]

How do you get out of that stall?

 

 

Chop the throttle, pop out the speed brakes, dump your tanks, bombs, or rocket pods, try to "break" the aircraft loose by barrel-rolling using both the ailerons and the rudder. Believe it or not, some aircraft in real life (the P-38 comes to mind), were sometimes able to get out of a compression-stall by applying negative pitch! That means pushing the stick forward, even if it sounds like the last thing you'd want to do in that situation.

[FastCargo 412]

Most pilots I know tend to view the terms exactly as Streched said...mach tuck and accelerated stall.

 

Speaking of mach tuck, you can get into it in the stock TW B-57 pretty easily...which makes perfect sense...

 

Fubar's solution is pretty much right on the nose...you've got to slow down...

 

FC

[i fight by 1 0]

Wow lot of answers, thanks guys.

[zzHOOTERzz 0]

Chop the throttle, pop out the speed brakes, dump your tanks, bombs, or rocket pods, try to "break" the aircraft loose by barrel-rolling using both the ailerons and the rudder. Believe it or not, some aircraft in real life (the P-38 comes to mind), were sometimes able to get out of a compression-stall by applying negative pitch! That means pushing the stick forward, even if it sounds like the last thing you'd want to do in that situation.

 

Some aircraft needed aileron in the direction of the spin to stop a spin by use of adverse yaw from the ailerons. (P-38 as well?) The T-38 for example. Some jets you momentarliy pull aft stick in a spin as well with full opposite rudder to stop the spinning but then you release back stick pressure and neutralize rudder to recover from the stall.

 

My 2 bits... a high speed stall as mentioned earlier, you are demanding more AOA out of the jet than it can give you, pulling to many G's, the nose stops tracking. This is bad when your nose is pointed at the ground. The only way to break any stall is to decrease your AOA, that is release back stick. You are still trying to maximize your turn so I say DO NOT chop throttles, DO jet your junk... speed brakes.... hmmmm.... I"d say if STALLED, do not use SB. In that case you are still trying to maximize available G, turn rate/radius. Go Max power.... maybe roll some flaps if the jet will allow... that can decrease your stall speed (at the cost of more drag but if you need to turn NOW... well)

 

If doing a nose low recovery but not stalled, then DO use speed brakes to minimize your turn radius. (You are probably going to fast... Cut throttle too). I've packed it in simming in a 550kt dive.... earlier words about Mach and compressability are true, you will be unable to pull as much G. Watch what happens as you pull and slow though, your nose rate will increase at a certain point and then begin to decrease again. In the WOI Shahak above around 550 are so it's a fast brick, around 450 she's awesome with much G, down around 250 to 200... back to a slow brick but with a tight turn radius abeit a slow nose rate. (Go for a one-circle fight)

 

STALL = exceeding critical AOA. To break a stall.... reduce AOA (reduce back stick pressure) NOTE: you can stall while pointing straight up or down by pulling to much... your nose stops tracking and your jet begins to mush towards the ground... yep you will eventually stop going up and go down (STS) all the while in a stall if you keep the stick buried in your lap.

 

DIVE recovery = inadvertantly pointed down hill going too FAST to turn. Fan boards, chop throtts, Jet your junk

 

Respectfully,

HOOTER

[Stretch32 0]

Most pilots I know tend to view the terms exactly as Streched said...mach tuck and accelerated stall.

 

That's because the Navy and Chairforce teach their SMA's the same aerodynamics curriculum essentially. We all come from the same school of thought For some reason though, Navy guys just end up making better pilots.......

 

@ HOOTER "Some aircraft needed aileron in the direction of the spin to stop a spin by use of adverse yaw from the ailerons. (P-38 as well?) The T-38 for example."

 

T-45C Goshawk has the same recovery techniques in terms of aileron use. In an inverted spin you use aileron away from the spin and in an upright spin you apply pro-spin aileron. In each case you want the outboard aileron to be pointed at the ground. This generates the adverse yaw you mention. You leave the longitudinal stick neutral since the elevators in this case don't aid in recovery. It's very backward to what your taught early on where the ailerons remain neutral and you use rudder and elevator.

 

Stretch