Prospects for a light Stealth Fighter

[Elysium]

I kind of have to question the wisdom of pursuing a lightweight fighter, considering the major driver of costs nowadays are the electronics and sensors. Putting them on a small plane, might even make it worse, considering the lack of cooling, power and space puts higher demand on those systems for a given amount of capability.
Afaik, the F-35 delays were partly responsible because of the aforementioned issues.

Case in point - the Gripen E is said to cost $85 million, hardly a 'lightweight' in terms of wallet impact, comfortably in the F-35 price range, with a lot less payload.

 

[H_K]

kind of have to question the wisdom of pursuing a lightweight fighter, considering the major driver of costs nowadays are the electronics and sensors.

Would be interesting to see how much money could be saved with slightly downgraded, off-the-shelf components. Avoid buying the most expensive, bleeding edge gear and go with well amortized « current gen » gear. I believe the Israeli and Turkish companies are very good at this.

 

[Scott Kenny]

I kind of have to question the wisdom of pursuing a lightweight fighter, considering the major driver of costs nowadays are the electronics and sensors. Putting them on a small plane, might even make it worse, considering the lack of cooling, power and space puts higher demand on those systems for a given amount of capability.
Afaik, the F-35 delays were partly responsible because of the aforementioned issues.

Case in point - the Gripen E is said to cost $85 million, hardly a 'lightweight' in terms of wallet impact, comfortably in the F-35 price range, with a lot less payload.

Agreed.

Also, I think that the F-35 has about the smallest realistic payload, 6x BVRAAMs in the bays, or 2x BVRAAMs and 2x 2000lb class, or 2x BVRAAMs and 8x SDBs.

You might end up with an aircraft somewhat smaller than an F-35 if you don't have that VTOL Liftfan volume to deal with, but I strongly suspect that the inlet shaping will end up making a space in the center of the airframe that would make a decent 3rd payload bay.

I mean, the Liftfan is 50" in diameter, plus the length of the gearbox and clutch pack (disregarding the drive shaft as that's in the inlet). A 2000lb class weapon is ~155" long and 25" wide which means that it's theoretically possible to make an FB-35 by stretching the forward fuselage until the space where the liftfan was is long enough for 2000lb bombs, probably a 72"-80" stretch. I'd also stretch the side payload bays that amount to carry big standoff weapons internally in those bays, or pack some extra SDB-sized weapons in there along with a "halfraam". The question for the center bay is then depth: do you leave it only deep enough for one 2000lber, or do you make it deep enough to carry 2x or 3x? If you leave the bay one weapon deep you put a fuel tank on top of it and will probably have more range than the basic F-35, especially since this would require larger wings than even the F-35C to shift the center of lift that far forward.

 

[T. A. Gardner]

From the Design Challenge thread:

That's definitely an interesting idea. Already has internal weapons bays (for 51mm FFARs) and is a pretty light aircraft overall. 17,500lbs empty and that's with a 5100lb J57, not a 2450lb F414. The F414 is 90" shorter than the J57, so depending on where exactly the engine needs to end up for CG purposes it may open up some significant length in the weapons bays. Also, the F414 is 35" in diameter, not 39" like the J57, which should open up more internal volume.

You'd be looking at a ~16000lb fighter empty, and could maybe mess around with a wet wing outboard of the existing wing tanks to make them into weapons bays.

I'd think it could be even lighter with modern materials and design technology over what the 50's offered. Plenty of room in the nose for a radar and associated electronics, the wing provides lots of room for fuel and 'stuff.' The original F4D had a phenomenal rate of climb for the day and I could see that copied here and bettered.
You have room for a weapons bay, and if you are updating the cannon armament, there's more room in the wings from that at about mid span.
So, let's say you end up with modern construction, design, and materials a plane empty at around 15,000 lbs. that is carrier capable as well as operates from land bases.

 

[kqcke for you]

Maybe take an YF-120 engine. A little bit bigger than F414 but got mutch more power. And with a modern spin on it we can expect to cut some weight as well as boost power. If done right you got 2x the dry power or that what f414 gives you with afterburner dry.

 

[Desertfox]

If you want a light fighter you don't need internal 2,000lb bomb capability, when SDBs exist... If you can fit 4 SDBs and a couple of AAMs that should be good enough. You can always go external once the threat has been reduced.

 

[Jackonicko]

I agree on limited success. But isn't that because it's "worse", more expensive, and less available than F-16 rather than any ITAR issues? I mean which competitions has it lost or not been entered in due to ITAR?

I thought you were suggesting that had it been ITAR free then success would have been its due...

Whereas, as you suggest, what Saab have faced is marketing an expensive F-16 with superior sensors and MMI but significantly worse kinematic performance