M1.2 supercruise + DAS = invincible against Su-35

[mikemag]

I don't dispute any of that. But I can imagine an F-35 somewhere over the Pacific close to the limit of its combat radius. When that Su-35 shows up on radar and you have to chose between taking it down or being conservative with your fuel, the ability to supercruise might suddenly be pretty useful. I'm not saying it can't fight without supercruise - far from. Supercruise is just one additional ability that if it has its all the more lethal and if it doesn't have it's still awfully lethal without it.

[quicksilver]

I don't dispute any of that. But I can imagine an F-35 somewhere over the Pacific close to the limit of its combat radius. When that Su-35 shows up on radar and you have to chose between taking it down or being conservative with your fuel, the ability to supercruise might suddenly be pretty useful. I'm not saying it can't fight without supercruise - far from. Supercruise is just one additional ability that if it has its all the more lethal and if it doesn't have it's still awfully lethal without it.

Any number of hypothetical circumstances exist (similar to the one you present) for all combat aircraft regardless of top end speed. For example, "...I'm at no-shit tanker bingo overhead a TIC...I can't move the tanker track...do I stick around to deliver weapons (and run myself out of gas) or do I go to the tanker now? Hmmm...what transit speed did I assume to get there?"

As for kinematics, a weapon launched at a supersonic speed will enjoy all the kinematics of that speed regardless of whether or not the jet was in mil or ab; it doesn't matter.

[energo]

* I asked about the Mach 1.2 supercruise stat, which I've been reluctant to use in my arguments, given only one source had been found for it. He said the F-35 can't supercruise. He said It can hold .98 or .99 Mach flying level, without burners, but to hold supersonic, it would need to be in a slight dive (1-2 degrees) or use very light burner. He said that could probably change, if they tweaked the software for the engine, giving more thrust, but reducing engine life.

Similar story from a pilot I talked to a while ago. Basically that you punch through Mach with AB, then pull back to MIL and it will hold supersonic "in a very, very shallow dive for a very long time".

[Corsair1963]

A number of sources claim the F-35 can maintain Mach 1.2 dash for extended periods. (only early sources claim 150 miles) I guess some can believe what they like....


Honestly, most F-35's are going to fly around just under supersonic speeds (<.90 Mach) and only accelerate to supersonic speeds briefly during combat. So, really don't see the relevance in the vast majority of the cases.....

[steve2267]

If I'm doing my math correctly...

If a Panther pushes to 1.2M @ 46,000, then throttles back to max MIL, a 1200 fpm descent will be just over a 1° glideslope. At 11.5 nm/minute, it will take 13min to cover 150nm at which point the aircraft will have descended to 30,000ft. Maybe not technically supercruising but a potentially useful trick.

[Corsair1963]

Expect for a quick dash most fighters are rarely going to be flying at supersonic speeds. Just burns up to much fuel and increases your IFR Signature.

[Corsair1963]

It would be interesting to know how the future Adaptive Cycle Engines (ACE) XA100 and/or XA101 would effect the equation?

[optimist]

Expect for a quick dash most fighters are rarely going to be flying at supersonic speeds. Just burns up to much fuel and increases your IFR Signature.

Yep, submarines of the sky, makes more sense. Like a sub, they could slow down when things get interesting. Once out of the immediate battlespace. A high speed dash, back to the tanker for round 2.

[XanderCrews]

I was also very curious, and its worth remembering that the F-35s "standard combat load" includes a pair of 2,000 pound bombs. While most competitors do their "super cruise" with a small complement of AAMs, If the F-35 "super cruise" with just a pair of AAMs would be more possible...

* As for the rest of the Gripen, he has very doubts about some of their claims, as he has spoken with their engineers, and was smelling some bullshit. By that, I mean he said the simulations they ran were so obviously flawed, they can't be taken seriously, and the engineers were clearly saying what the marketing team told them to say, but it didn't hold up under scrutiny.

well yeah, if the engineers are honest then things are over rather quickly

And then no one can figure out why it doesn't win more...

[milosh]

It would be interesting to know how the future Adaptive Cycle Engines (ACE) XA100 and/or XA101 would effect the equation?

Of course they would.

For example F135 is one of hottest turbofans which create problems of its own. In case of B and C we read about limit on AB usage, and for F-35A demo team we read they spend engine much faster then expected.

So for usable quasi supercruise (going AB then "glide" on MIL) you need cooler AB. ACE engines are design to have better cooling.

And ACE as variable cycle engine could in fact allow real supercruise capability no need to use AB and cruise speed could be higher then mentioned M 1.2

[XanderCrews]

In case of B and C we read about limit on AB usage.

Nothing to do with the F135 itself. shorter nozzle on the B was causing higher temps than people wanted on the tail planes. as for the C i understand it was some pretty unique aspects that brought it there and like all things F-35, they'd rather be "safe than sorry"

In these cases this has more to do with the arrangement of the horizontal stabs, and the power of the F135. I don't think its excessively hot. We are dealing with the most powerful fighter engine in the world.

and for F-35A demo team we read they spend engine much faster then expected.

More to do with high hours than high temps.

So for usable quasi supercruise (going AB then "glide" on MIL) you need cooler AB. ACE engines are design to have better cooling.

F135 has an AB with settings for "cooler" AB

If we shoehorned some F135s into some teen fighters who tails are forward or well clear of the exhausts the "excessive heat" issues would be gone.

[element1loop]

If I'm doing my math correctly...

If a Panther pushes to 1.2M @ 46,000, then throttles back to max MIL, a 1200 fpm descent will be just over a 1° glideslope. At 11.5 nm/minute, it will take 13min to cover 150nm at which point the aircraft will have descended to 30,000ft. Maybe not technically supercruising but a potentially useful trick.

Not sure the relevance here but keep in mind also that thrust gradually increases from 46,000 feet down to about 32,000 ft, and so does fuel flow rate, as O2 increases with falling altitude in high-bypass turbofan engines, thus more combustion is available. Thus the thrust rises, as does the speed available as the jet sinks. Speed will max-out around 33,000 feet, at 100% thrust (dry), because drag increases with further sinking, which reduces speed for fuel burned from there.

So there may be a sweet-spot where a supercruise period may be available in an F-35A, where the fuel load is already well burned away, and AoA has reduced and drag also, as it burned off. It's entirely possible an F-35A will supercruise on say 30% fuel loads, at just the right altitude and ISA.

That said, why even bother? I would just fly as high as stably possible, and give it 100% dry, and whatever the resulting KTAS and ground speed is, with best-range altitude for that throttle setting. That will do nicely thanks. Continuous FMS calcs with a bunch of airdata and engine sensors can figure that out better than any human brain can.