GE Aims to Steal F-35 Engine Production!

All about the Pratt & Whitney F135 and the (cancelled) General Electric/Rolls-Royce F136
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Corsair1963

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Unread post12 Jul 2016, 08:07

FARNBOROUGH, England — As it continues development of its Adaptive Engine Transition Program (AETP) design, General Electric is not being shy about its target: the massive F-35 joint strike fighter fleet.............


http://www.defensenews.com/story/defens ... /86953686/
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Unread post13 Jul 2016, 09:28

:devil:

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sferrin

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Unread post13 Jul 2016, 13:12

P&W has their own equivalent they're working on, three streams and all.
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sprstdlyscottsmn

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Unread post13 Jul 2016, 13:35

Lighter weight, major thrust increase, and major fuel economy gains? That's a lot to promise.
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Unread post13 Jul 2016, 13:49

Let us divide by 10.
2%, 2.5% and 3% range increase

I think that is more realistic.
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Unread post13 Jul 2016, 13:54

Spurts, any chance you could work a hypothetical F-35 with an adaptive engine into the analyses you've done? I'd love to get an idea what the increased performance would mean for turn rate and acceleration.
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Unread post13 Jul 2016, 13:57

vilters wrote:Let us divide by 10.
2%, 2.5% and 3% range increase

I think that is more realistic.


These aren't just tweaked F135s, they're completely new engines with new cycles. I would be astonished if the "realistic" numbers weren't much closer to GE's claims than yours.
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Unread post13 Jul 2016, 14:16

sferrin wrote:
vilters wrote:Let us divide by 10.
2%, 2.5% and 3% range increase

I think that is more realistic.


These aren't just tweaked F135s, they're completely new engines with new cycles. I would be astonished if the "realistic" numbers weren't much closer to GE's claims than yours.


My understanding is it's basically a new type of engine overall. Rather than a fixed bypass ratio it can change so that one engine can alter from being very high bypass for high efficiency cruise and go to quite low bypass for high speed turbojet like work. So you can basically have greater than F135 like efficiency when you want it and then have F119 like high speed performance when you want that.

Overall the new engine tech being worked on is the most crucial thing for steps forward in military aviation. Fighters are going to get heavier and longer ranged and need this. Plus this feeds into a parallel program for rotorcraft which see an even greater direct benefit from the power and efficiency. In 15 years any program that doesn't have this will seem hopelessly outclassed in my view.
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Unread post13 Jul 2016, 14:27

bigjku wrote:
My understanding is it's basically a new type of engine overall. Rather than a fixed bypass ratio it can change so that one engine can alter from being very high bypass for high efficiency cruise and go to quite low bypass for high speed turbojet like work. So you can basically have greater than F135 like efficiency when you want it and then have F119 like high speed performance when you want that.

Overall the new engine tech being worked on is the most crucial thing for steps forward in military aviation. Fighters are going to get heavier and longer ranged and need this. Plus this feeds into a parallel program for rotorcraft which see an even greater direct benefit from the power and efficiency. In 15 years any program that doesn't have this will seem hopelessly outclassed in my view.

I was thinking that such an engine would also allow considerably higher top-speed for the F-35. The high bypass-ratio of the engine is the main reason for the current Mach 1.6 ceiling right? I mean even with the current thrust F-35 would otherwise be capable of more. With more thrust aswell, it should also allow supercruise, let alone faster top-speed.
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Unread post13 Jul 2016, 14:37

How many F-35 users will have the money to swap out F135s for the new adaptive engines and logistics tail? Maybe for new-build F-35s but operating a mixed fleet will complicate things. The F135 Block 1 upgrade may be a more compelling option.
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Unread post13 Jul 2016, 17:25

gideonic wrote:I was thinking that such an engine would also allow considerably higher top-speed for the F-35. The high bypass-ratio of the engine is the main reason for the current Mach 1.6 ceiling right? I mean even with the current thrust F-35 would otherwise be capable of more. With more thrust aswell, it should also allow supercruise, let alone faster top-speed.

With all streams open (lower cruise speeds, .8M or lower I imagine) you would have the most afterburn thrust gain as that cycle has the most unburned air passing into the afterburner. With only one stream open the afterburner would have very little, if any, gain in thrust as now a greater portion of the engine air has already gone through the combustion chamber. Military power at high speed would go way up as the overall pressure ratio (or the whole airflow) should increase (relative to all streams open). I guess that could negate the air issue. Less oxygen to burn but it's already moving faster and with more pressure.
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Unread post13 Jul 2016, 20:19

gideonic wrote:...

I was thinking that such an engine would also allow considerably higher top-speed for the F-35. The high bypass-ratio of the engine is the main reason for the current Mach 1.6 ceiling right? I mean even with the current thrust F-35 would otherwise be capable of more. With more thrust as well, it should also allow supercruise, let alone faster top-speed.


One thing we must always be mindful of, is that the inlet shape, volume, and airframe shapes, drag at speeds, are all carefully designed for the current performance requirements. Shoving a Hoover vacuum cleaner in is no guarantee of additional air volume once installed with the fixed inlet . Likewise, an engine installed with twice the power, doesn't necessarily do well up against the drag curves beyond requirements.

However, even so, improved engine efficiency (range / durability) at the same performance is definitely real, and acceleration can be significantly improved up to any design drag barriers.

(although I am made mindful that the F-4 Phantom was pretty much proof that even a brick can hit Mach 2 if you have enough thrust, and the T-33 sort of proved that just changing something here and there can accidently make the plane faster than the original design)

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Unread post13 Jul 2016, 21:02

blindpilot wrote:(although I am made mindful that the F-4 Phantom was pretty much proof that even a brick can hit Mach 2 if you have enough thrust,
BP


The other lesson from the F-4 is that more power could end up meaning less speed (see F-4K vs the J79 powered models).
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Unread post13 Jul 2016, 21:35

sferrin wrote:
blindpilot wrote:(although I am made mindful that the F-4 Phantom was pretty much proof that even a brick can hit Mach 2 if you have enough thrust,
BP


The other lesson from the F-4 is that more power could end up meaning less speed (see F-4K vs the J79 powered models).

J79 was a high speed engine. The faster it went the more thrust it made. During operation skyburner the F-4 finished the second run accelerating through ~M2.7 (or 2.67, something like that) with the modified J79-GE-17 ( I imagine the -19 would have done the same). Rated Thrust and Dynamic Thrust are not the same thing.
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Unread post13 Jul 2016, 21:50

sprstdlyscottsmn wrote:
sferrin wrote:
blindpilot wrote:(although I am made mindful that the F-4 Phantom was pretty much proof that even a brick can hit Mach 2 if you have enough thrust,
BP


The other lesson from the F-4 is that more power could end up meaning less speed (see F-4K vs the J79 powered models).

J79 was a high speed engine. The faster it went the more thrust it made. During operation skyburner the F-4 finished the second run accelerating through ~M2.7 (or 2.67, something like that) with the modified J79-GE-17 ( I imagine the -19 would have done the same). Rated Thrust and Dynamic Thrust are not the same thing.


Likewise the B-58's speed limit was only how close to melting the aluminum the pilot felt comfortable with. Not sure I believed him but I had a B-58 pilot report that they could break Mach 3, but then the melted parts would come apart. ("It could, but then it would have to kill you")

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