Not again!

Nitpicking over whether an aircraft obeys the Lockheed-Martin Divine Laws of Supercruising, as revealed in the Book of F-22, is silly. If “supercruise” means anything, other than marketing hype, it is supersonic cruising.

BTW, Concorde could & did (in tests) accelerate to M2 on dry thrust, but. In service, reheat was usually used to get over M1.5 (to about M1.7, I think), then dry thrust up to cruising speed of M2.

I think SOC’s definition of supercruise is technically merited. It helps to distinguish between different capabilities. Mig-31/25 have great supersonic persistence – but they don’t “supercruise”. Aircraft that can sustain supersonic speeds, but can’t punch through the sound barrier in dry thrust are not “supercruisers” – as part of their supersonic profile is dependent on the afterburner. Whether it is more efficient to use the burner or not is irrelavent – it still entails a rather large IR signature increase – which becomes especially relevant in the BVR game. It also highlights the aircraft’s transonic kinermatics and aerodyanmics.

Where I do believe the jargon/semantics gets painfull – is where LM says SC is only Mach 1.5 +; even if this demonstrates a more significant dry thrust supersonic capability.

Agree. Although my comparison was more or less aimed at hypothetical 2xEJ200 powered Gripen vs F-35. The thrust and fuel consumption would come out roughly equal, the former would have more space occupied by the engines and would be more maintenance intensive, the later would be less reliable. There would be differences but I don’t think they would be overall that decisive. Which makes me think of a 5th gen Gripen as a viable option (in case someone pays for it)

I feel engines are just the tip of the iceberg. R&D for a real VLO fighter will be massive. It’s a PR stunt – that won’t come to fruition – unless they redefine the the requirements.
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Oh I see what you are saying – you refering to the twin arrangement of EJ200s vs a single F135. There won’t be that much noticable difference pound for pound if they have the same SFCs. Yet its very likely that the F135 is superior by some margin in the subsonic SFC realm. The large single engine configuration also allows for more internal fuel to be stored in an equally efficient manner.
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SFC is given in kg/h/kN (kg of fuel per hour per kN of thrust). Having identical SFC does not equal having identical fuel consumption. An EJ200 engine running at full military thrust (60 kN dry) will consume around 4800kg of fuel per hour while F119 swallows up around 9200 kg of fuel (assuming dry static thrust of 115 kN – according to Sweetman).

That means a twinpack of EJ200 will need 9600kg of fuel per hour producing 120 kN. I don’t see any reasonable differences here… :confused: Which basically proves what Schorsch has said.

Yes – there won’t be a noticable difference between the engines as they have a comparable SFC. The however F119 is most likely running closer to 178 kN in full burner and around 120-134 kN in Dry – if the ATF blokes are correct. An advantage in favour of the F-22 is in operational configuration – it will likely need less relative net force to achieve the same speed an EF would – especially in the supersonic realm. As such the F119 engines can probably operate at more favourable SFCs.
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You couldn’t give an idea of how EJ200 and GE-F414 SFC’s compare, could you please?

Sure: according to the 10/2000 edition of Military Technology magazine the EJ200 has an SFC of around 0.8. According to a declassified Rand document this is about the same for the F119-100. The thirsty F414-GE-400 on the other hand is 0.84.
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Lm

That has already been done in 1999. The BAE Replica was designed around two up rated EJ200 and a bloody big “bomb?s bay” between them (the objective was a “hole” big enough that it could carry one Storm Shadow!).

Cheers

That may well be the case – and I’d be interested to read about it :). But that doesn’t mean it meets the requirement specifications set out –

Current European powerplants are most likely insufficient in powering an aircraft that has the combination of F-35 kinematics + F-35 internal weapons load + F-35 LO + F-35 internal fuel.

– which is where engineering efficiency comes into it. Nor does it mean BAE were capable of fielding an operational version at the time – far to much about Replica remains speculation – at least with online sources.

I have no doubt the current European engines would be fine in making a F-117 type aircraft. Not so much an F-22 type – especially if you want the combination of wideband VLO which adds a lot of structural weight and F-22esq performance and internal room for fuel + passive sensor farms – it would be a lot more efficient to use engines that give an extra 20000lb of thrust +-. For a multirole type – like F-35 – you really need a single engine in the F119/135/136 class.

Additionally the F135 promises to have a lower SFC than the EJ200 and a much lower SFC compared to the F414.
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Basically, its doable but less efficient…………………:o

It’s possible – technically of course, but it’s an inferior solution. Using the larger F135 turbofan – which produces 43000lb thrust + at static sea level affords the same or more thrust as two EJ200s while using a smaller cross-sectional area. This allows for a lot more space around the under curve of the F135 for the bombs + missiles. If the jet just needs to fire BVRAAMs internally – then by all means go for the dual EJ200 combo – as in that case you can make it more aerodynamically efficient – and most likely stealthier as is the case with F-22 vs F-35.
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Well, why couldn’t you install two EJ-200’s or F414’s in a Stealthy Platform very much like the F-35. (i.e. two small turbo fans vs one large turbo fan)

Because if you want an internal weapons load capability as volumous as that of the F-35 – using a larger single engine solution is much more efficient. Having two smaller turbofans in the EJ200 class and 2x2000lb Bombs + 2 BVRAAMs internally = considerably larger + heavier aircraft. It means less internal fuel capacity, added drag and increased weight – which translates to poorer kinematics – less range – higher procurement price and operating costs.
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