F-22 sustained and instantantenous turn rates question

[raptorzilla22]

I have no question that it can generate the lift, but does it have the thrust? With a nine ton fuel load it can make a big difference how much are left in the tanks.

Hm, in its air to air combat configuration the F-22 has T/W of 1.26 which is higher than any other fighter, the Typhoon has 1.15 in its interceptor configuration and has an exceptional turn rate. The second point is that we don't even know how much thrust the Raptors engines really produce (again classified), so I dont think thrust should be the problem.

[basher54321]

I have no question that it can generate the lift, but does it have the thrust? With a nine ton fuel load it can make a big difference how much are left in the tanks.

Hm, in its air to air combat configuration the F-22 has T/W of 1.26 which is higher than any other fighter, the Typhoon has 1.15 in its interceptor configuration and has an exceptional turn rate. The second point is that we don't even know how much thrust the Raptors engines really produce (again classified), so I dont think thrust should be the problem.

You will probably find that the given thrust ratings (from Lockheed Martin) are not that far off - but they are only sea level uninstalled thrust figures.

With the available data - At Max AB a T/W of 1.26 is with about 13K lbs fuel for the F-22.

At full fuel (18K lbs) its T/W is now around 1.12 (the weight point also mentioned)

That's not the issue though - comparing it to data from another turbo fan (F100-PW-220) we can see that if you calculated 28 degrees p/s at ~M0.75 (350KIAS) - the engine is putting out about 17% more thrust there at sea level. However when it goes to 20,000 ft it loses about 40% of its thrust due to thinner air.

If the F-22 thrust was relative at 20,000ft its engines would now only give it a T/W of about 0.84 in max AB with 13k lbs fuel.

Just a rough example really......

[raptorzilla22]

I have no question that it can generate the lift, but does it have the thrust? With a nine ton fuel load it can make a big difference how much are left in the tanks.

Hm, in its air to air combat configuration the F-22 has T/W of 1.26 which is higher than any other fighter, the Typhoon has 1.15 in its interceptor configuration and has an exceptional turn rate. The second point is that we don't even know how much thrust the Raptors engines really produce (again classified), so I dont think thrust should be the problem.

You will probably find that the given thrust ratings (from Lockheed Martin) are not that far off - but they are only sea level uninstalled thrust figures.

With the available data - At Max AB a T/W of 1.26 is with about 13K lbs fuel for the F-22.

At full fuel (18K lbs) its T/W is now around 1.12 (the weight point also mentioned)

That's not the issue though - comparing it to data from another turbo fan (F100-PW-220) we can see that if you calculated 28 degrees p/s at ~M0.75 (350KIAS) - the engine is putting out about 17% more thrust there at sea level. However when it goes to 20,000 ft it loses about 40% of its thrust due to thinner air.

If the F-22 thrust was relative at 20,000ft its engines would now only give it a T/W of about 0.84 in max AB with 13k lbs fuel.

Just a rough example really......

Well but the 28deg/sec figure is stated for 20,000 ft, not sea level.

[basher54321]

Well but the 28deg/sec figure is stated for 20,000 ft, not sea level.

Yes and the example shows you exactly why the claim is dubious...........

[raptorzilla22]

Well but the 28deg/sec figure is stated for 20,000 ft, not sea level.

Yes and the example shows you exactly why the claim is dubious...........

So what do you think would be realistic?

[basher54321]

So what do you think would be realistic?

If it can sustain 28 degrees p/s in a horizontal turn anywhere it would be near Sea Level - that's still far better than every other fighter out there in that regards (AFAIK).

When the flight manual comes out you can prove me other wise and I will eat my hat....

[raptorzilla22]

So what do you think would be realistic?

If it can sustain 28 degrees p/s in a horizontal turn anywhere it would be near Sea Level - that's still far better than every other fighter out there in that regards (AFAIK).

When the flight manual comes out you can prove me other wise and I will eat my hat....

Hahaha I think I can get along with that.

[uclass]

Because the F-22 has TVC it wouldnt be higher at sea level (as it doesnt really get lower at high altitude)and there arent any em diagrams for the F-22 (classified of course).

TVC doesn't help you sustain any turn without bleeding energy - well not where I am talking about.

Surely that's incorrect, thrust can be vectored in the lift direction and only marginally reduce tangential thrust, while also reducing the drag created by aerodynamic lifting.

[count_to_10]

Surely that's incorrect, thrust can be vectored in the lift direction and only marginally reduce tangential thrust, while also reducing the drag created by aerodynamic lifting.

If you vector the thrust to the lift direction, the force will pitch the aircraft away from the direction of the turn. Also consider that a standard aircraft makes turns at significant angle of attack, with purely axial engine thrust going in the lift direction.

[uclass]

Surely that's incorrect, thrust can be vectored in the lift direction and only marginally reduce tangential thrust, while also reducing the drag created by aerodynamic lifting.

If you vector the thrust to the lift direction, the force will pitch the aircraft away from the direction of the turn. Also consider that a standard aircraft makes turns at significant angle of attack, with purely axial engine thrust going in the lift direction.

Surely that depends if the thrust vector is pointing under or over the CoG. It could still be pointing under or through the CoG and vectored at maybe a few degrees. Even at 3 degrees it would add >3000lbf of lift and the loss in axial thrust is irrelevant in a maximum deg/s turn at S/L, since it's lift-dependent. I guess the advantage is small when you consider a 9g turn requiring 9 times the aircraft's weight in lift.

I suppose the problem is pretty complicated and depends on lift distribution. E.g. with relaxed stability the CoP is in front of the CoG. So is the wing the limiting factor in the lift or the tail plane being used to balance the moment generated by the wing lift preventing the plane flipping? If the latter then even a TVC vector pointing over the CoG will allow the wing to produce more lift, because the balancing moment is greater.