Thrust vectoring at 400 knots

[Alphacharlie]

I was just asking you---I have asked many of our indian colleagues about the speed at which thrust vectoring can be deployed effectively during flight SAFELY.

Thrust vectoring at speeds can be compared to a high speed collision. The car travelling forward at 60 mph comes to a sudden stop due to impact---but the driver is still moving forward at 60 mph----he gets retrained by his seat belt----but then the internal organs are still travelling at60 miles per hour---sometimes the seat belts break due to force exerted on them.

So---with a sudden change in direction---in case of thrust vectoring---the plane changes direction exerting extreme duress on its structure---the pilots is still moving in a different direction even though being held back by the seat belts---and the body organs and fluids moving in another direction.

Even though pressurized suits are a big help and stronger seat belts work better---human body can take so much.

S---I have yet to get an answer from indian members----what is a safe speed for thrust vectoring?

Janab....

Thrust vectoring cannt be engaged at speed more than 120 Knots. SOP demands to pull Air Brake and Bring A/c to Stall Speed. Stall speed for Clean Configuration SU 30 with 30% fuel and no Armament is about 135-140 Knots. (Incase of Normal weather and No Tail wind)

For Example when ever Sukoi 30/27 does a Pugachev Cobra the A/c first pilot needs to deploy air brake to bring bird to stall speed then pull nose (Alpha) to 70 degrees in azimuth. When this is done throttle is kept at 23-25%. Also, when Cobra is engaged the bird is at stall speed it vertically first stalls then stablizes with speed of about 140-5Kts.

Note 1 - This manoeuvre is at times engaged to Deflect HARMs and Disappear from Radar (MWAS Tactic).

Note 2 - At 400 Knots if Thrust Vectoring is engaged the A/c will experience atleast 12Gs..and Pilot will certainly get Red Out. The Fuselage will get Structural Damage, engine blades will develop stress fractures and Air Brake will be ripped apart. "Natasha Yelling Damage CAT-3"

Note 3 - Cobra manoeuvre is not practised as Often Immelmann as it each time puts massive stress on AIr brakes. Mover Over all Pilots are not Qualified for the same.

 

[SQ8]

BVR is a game changer, no doubt.

In any case, the FCS can rely on any methodology to aid maneuvering as needed, but at all times it must keep the airframe and pilot safe.

BVR apart, the new dogfight missiles is what I refer to. One can see the trend in the F-35 which has focused on just that. See first, and shoot first is the new game rather than dancing around the sky.

 

[VCheng]

BVR apart, the new dogfight missiles is what I refer to. One can see the trend in the F-35 which has focused on just that. See first, and shoot first is the new game rather than dancing around the sky.

Of course. And "see" first means a better radar, not sight. This concept was started by the venerable F-14 Tomcat with its Phoenix system, and is now really hitting its stride. It is only a mater of time this technology goes into the stratosphere with long endurance unmanned platforms.

 

[SQ8]

Of course. And "see" first means a better radar, not sight. This concept was started by the venerable F-14 Tomcat with its Phoenix system, and is now really hitting its stride. It is only a mater of time this technology goes into the stratosphere with long endurance unmanned platforms.

Better sensors is the accurate term. Aircraft like the F-35 may not have the longest ranged radar but it has the best sensor fusion available at this time. So while the enemy jet may have a longer ranged radar, the F-35 will be able to get closer and get information from more sources to paint that picture better than the enemy.

 

[MastanKhan]

Gentlemen,

Thank you for your posts regarding the TV---. That is what I have been saying in my older posts---TV is a very slow speed maneuver---like in the range of 120 to 150 knots---pretty much stall at speeds---.

Stall speeds are a death sentence for any aircraft in combat---.

The airframe and human body can only take so many G forces---either + or - .

 

[Alphacharlie]

Gentlemen,

Thank you for your posts regarding the TV---. That is what I have been saying in my older posts---TV is a very slow speed maneuver---like in the range of 120 to 150 knots---pretty much stall at speeds---.

Stall speeds are a death sentence for any aircraft in combat---.

The airframe and human body can only take so many G forces---either + or - .

However, the same TV in Sea Harrier is a Blessing.

Change the Jet Thrust to 90 from 180 and there is no Red Blindness. Reason being when 6 thrusters are diverted from 180 to 90 it takes few seconds , air brakes kick by 2 jet thrusters thus Vector effect of Positive G is negated.

If Sea Harrier is at 400 Knts you can move to stationary but when, by the time this happens it takes about 7 seconds from moving knob till "Ground speed "changing to near zero, and you have moved 4 km.... This Tactic was massively used in Falkland

Bottom Line TV in Su is Good when you have time.
But in a Sea Harrier is "All Pleasure"

 

[Viper0011.]

Better sensors is the accurate term. Aircraft like the F-35 may not have the longest ranged radar but it has the best sensor fusion available at this time.

The -35 introduces new kinds of sensors vs. the traditional radars (it still has a powerful, long range AESA radar) but the new tech DAS in it, can detect and track anything out by 800 miles with images. So per your post is incorrect about -35 not having the longest radars, in terms of visibility and situational awareness. I don't think any Jet today is capable of scanning out to 800 mile for a very small missile engine burn. The -35 can do that.....

This is your future generation of sensors that will become the future 3D image based situational awareness technology to replace today's Radars. Radars in my opinion are almost part of the past. May be ten more years and it'll be stuff like the DAS.

Thrust vectoring can be used at any speed, provided the transitions are managed smoothly to keep down peak and sustained g-forces.

Here are the comments I was responding to...compare these to my post above and you'll see where you were incorrect

 

[Donatello]

However, the same TV in Sea Harrier is a Blessing.

Change the Jet Thrust to 90 from 180 and there is no Red Blindness. Reason being when 6 thrusters are diverted from 180 to 90 it takes few seconds , air brakes kick by 2 jet thrusters thus Vector effect of Positive G is negated.

If Sea Harrier at 400 Knts you con move to stationary but when the time this happens it takes about 7 seconds from moving knob till "Ground speed "changing to near zero, and you have moved 4 km.... This Tactic was massively used in Faland

Bottom Line TV in Su is Good when you have time.
But in a Sea Harrier is "All Pleasure"

The Sea Harrier was designed to be a VTOL aircraft, meaning with it's thrust nozzles at 90 degrees, it can have zero airspeed/ground speed and still hover in the air. Skhoi cannot do that. If you reduce the speed too much to change direction, you will stall. Depending on your aircraft's configuration and hence the resulting thrust/weight ratio, pilot will have a hard time recovering from stall.

I would love to see a fully fueled and fully loaded Su30 pull off a near stall cobra.

 

[MastanKhan]

However, the same TV in Sea Harrier is a Blessing.

Change the Jet Thrust to 90 from 180 and there is no Red Blindness. Reason being when 6 thrusters are diverted from 180 to 90 it takes few seconds , air brakes kick by 2 jet thrusters thus Vector effect of Positive G is negated.

If Sea Harrier at 400 Knts you con move to stationary but when the time this happens it takes about 7 seconds from moving knob till "Ground speed "changing to near zero, and you have moved 4 km.... This Tactic was massively used in Faland

Bottom Line TV in Su is Good when you have time.
But in a Sea Harrier is "All Pleasure"

Hi,

Let me throw in another curve ball-----would the distance between the position of the pilot to the distance of thrust nozzles exert higher G forces on the pilot------would the distance of the thrust nozzles to the nose have any effect of differences in G forces on the frame as well----when the same change of angle is achieved---ie---from 0 deg to 90 deg.

The length of sea harrier being 46 ft approx.---and pilot to TVC nozzle distance being around 30 ft ----otoh the length of su30 is around 76 ft and approx. distance from the tv nozzles to pilot around 65 ft approx.

To me----it looks like---the same change of angle even withinthe same time frame and speed would have two different sets of g forces acting on the pilot of these two aircraft----.

Any physics majors want to jump in----.

 

[DrWatson775]

Hi,

Let me throw in another curve ball-----would the distance between the position of the pilot to the distance of thrust nozzles exert higher G forces on the pilot------would the distance of the thrust nozzles to the nose have any effect of differences in G forces on the frame as well----when the same change of angle is achieved---ie---from 0 deg to 90 deg.

The length of sea harrier being 46 ft approx.---and pilot to TVC nozzle distance being around 30 ft ----otoh the length of su30 is around 76 ft and approx. distance from the tv nozzles to pilot around 65 ft approx.

To me----it looks like---the same change of angle even withinthe same time frame and speed would have two different sets of g forces acting on the pilot of these two aircraft----.

Any physics majors want to jump in----.

Yes two different values of g force depending on the distance of the pilot seat to the point on the plane that remains "stationary " in terms of pitch or the hinge point. This distance would be more in larger aircraft. The g force would also depend on the RATE at which the pitch changes(hence a very high rate with TVC).

 

[Alphacharlie]

Hi,

Let me throw in another curve ball-----would the distance between the position of the pilot to the distance of thrust nozzles exert higher G forces on the pilot------would the distance of the thrust nozzles to the nose have any effect of differences in G forces on the frame as well----when the same change of angle is achieved---ie---from 0 deg to 90 deg.

The length of sea harrier being 46 ft approx.---and pilot to TVC nozzle distance being around 30 ft ----otoh the length of su30 is around 76 ft and approx. distance from the tv nozzles to pilot around 65 ft approx.

To me----it looks like---the same change of angle even withinthe same time frame and speed would have two different sets of g forces acting on the pilot of these two aircraft----.

Any physics majors want to jump in----.

Gentlemen - In simplest language

a) The TV Giant has 2TV Nozzles in Tail
Where as, Sea Harrier has 4 Major Thrusters, with 2 control Thrusters Pitch and Yaw Control.

b)The TVs of Su 30 MKI with Nozzle control in 2D will give Pitching control Only SU35 with 3D will Give Yaw Control as well.

c) Bottom Line - Each System has its Limitation and Merits :-
1) if some Joker comes and Says- In Dog Fight we will engage Cobra - Rubbish. Shoot from Distance & Scoot.
2) In case HARM engaged at your "Alpha". The MAWs gives time to prepare here Cobra will be useful. Please note Radar Homing Missiles have over 90% Kill Ratio in First Launch Itself.
3) If Scissors engagement is on then Kulbit can be used Never Cobra. Professionals are very careful when they speak of Limitations and uses of Cobra.

Note - FYI Even F16, Mirage 2000 Can also do Cobra.

 

[HariPrasad]

illuminatidinesh said: ↑
Anything that exceeds 9 or sustained 9 will make the pilot faint is it not?

Yes 9 G is a human endurance Limit.

It is more accurate to say that the g-force is related to the rate of change of speed, not the speed itself. So it does not matter whether the change happens at 200 knots or 500, as long as the rate of change is the same, nothing adverse will happen.

Very True. People often fail to understand the difference between the velocity and change in velocity.

 

[MastanKhan]

It is more accurate to say that the g-force is related to the rate of change of speed, not the speed itself. So it does not matter whether the change happens at 200 knots or 500, as long as the rate of change is the same, nothing adverse will happen.

Hi,

It maybe related to rate of change of speed----but that is not what we are addressing----. We are talking about a rapid change in the direction of the aircraft and what transpires during that rapid process---.

We are talking about a snap shot---a quick draw---the strike of a cobra or a mamba or a rattler---so speed does matter----because time is of essence.

 

[Hyperion]

Exactly....... what's the point!!! It's like humanity already can build working stable wormholes and then they start designing warp engines..............

The Indians were looking into it last I sniffed around. However, in the manner safe for the pilot and plane may not essentially get you the performance you expect. With the advent of weapons like the AIM-9X-II, IRIS-T and others which literally chase you down at 60g+, its pointless.

 

[SQ8]

The -35 introduces new kinds of sensors vs. the traditional radars (it still has a powerful, long range AESA radar) but the new tech DAS in it, can detect and track anything out by 800 miles with images. So per your post is incorrect about -35 not having the longest radars, in terms of visibility and situational awareness. I don't think any Jet today is capable of scanning out to 800 mile for a very small missile engine burn. The -35 can do that.....

This is your future generation of sensors that will become the future 3D image based situational awareness technology to replace today's Radars. Radars in my opinion are almost part of the past. May be ten more years and it'll be stuff like the DAS.



Here are the comments I was responding to...compare these to my post above and you'll see where you were incorrect

Well, my post may not be incorrect in what I meant to say. Which is exactly that the F-35 had much more than Radar at its disposal to create its situational picture.

Exactly....... what's the point!!! It's like humanity already can build working stable wormholes and then they start designing warp engines..............

The warp engine is useful, but essentially the cost/benefit analysis is no longer what it used to be. Had TV been introduced back in the 70's and 80's. It would have made the fighter a deadly system, being able to point and shoot the missiles of those days Aim-9L/M at with deadly effect. As much as the Russians like carrying the banner of TVC, its the Americans who did the serious work on. the X-31 program was a fairly prolonged one along with the F-18HARV . At the end of it, it was found that while TVC is a great luxury and really does provide a great advantage especially in 1vs1 combat; in a normal combat scenarios with multiple bogies and the advent of high off boresight missiles that can essentially outfly the fighter.. its just not worth it.