UK's new Tempest fighter !

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I do not deny that US are probably building the best fighter engines. But adaptative cycle is far from being a revolution. However, from "off " info (believe me or not), next engine for NGF will be 14-15T thrust for a 20T empty aircraft. The aim is also to better master hot parts (being tested at DGA propulseurs in Saclay atm at about 2400K.), so as to use the hot section for civilian engines.

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all of them have adaptative cycle using different systems. Kaveri being a special case, its third flux being used ot have a flat rate whatever speed or altitude.

can you explained further
What system do they use?

I do not deny that US are probably building the best fighter engines. But adaptative cycle is far from being a revolution. However, from "off " info (believe me or not), next engine for NGF will be 14-15T thrust for a 20T empty aircraft. The aim is also to better master hot parts (being tested at DGA propulseurs in Saclay atm at about 2400K.), so as to use the hot section for civilian engines.

Let's see nobody can touch the current P&W F135 in performance. While, the new ACE provide significant gains on top of that......hmm, sounds pretty revolutionary to me.

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https://www.geaviation.com/military/engines/ge-adaptive-cycle-engine

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It might sound it but it isn't. It's a variable bypass ratio, it's not new.

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[USER="1416"]Scooter[/USER] :if you base your judgement about a new item using as your main source the promotional brochure of the producer itself, EVERYTHING would seems revolutionary independently by who the producer is and from what county it came from.

In this case they are using the usual trick of publishing only a partial data: the 25% better fuel, 20% higher thrust consumption refers to SUPERSONIC regime, not to the overall one.

Variable bypass ratio or adaptative cycle if you prefer to use such a term is something though to divert and reroute the air flow between the cold and the hot section of a turbofan.
in the case of ACE it work though the use of a third ,intermediate stage that can swap its own flow between the two.
In the subsonic cruise mode it will act as a high bypass turbofan, with the most of air flowing through the cold section, in transonic flow woud be partially diverted, so to still have some in the cold one in order to use afterburner, in full supersonic it would go for the most part through the hot one making the engine a quasi-turbojet or better said, a leaky turbofan.
It is precisely at that range speed that you get the highlighted advantages, in subsonic one it will be almost the same that today, with just the few gains that one can expect with adopting a newer engine.
It will be a great advancement, above all or certain type of planes or missions, so I expect that about all the main producers would head trough it.
In the case of F-35 however , I expect that it would be much more useful for expanding its own performances in A2A missions than in the A2G one that will still remain its main role.

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It's a simple principle. Run a higher BPR for cruise and take-off, getting better fuel consumption and take-off thrust, then reduce the BPR when you want to go supersonic. So basically you run a BPR of maybe 1-2:1 at take-off and when cruising and then 0.3-0.4 when going supersonic.

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Reduction of bypass provides the most payoff at extremely high altitudes, say >40K feet.

You get the best thrust improvement when using an afterburner to energize low temperature bypass air.

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I heard it can use third stream for cooling, that will be useful against IR sensor, or help with future DEW

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Reduction of bypass provides the most payoff at extremely high altitudes, say >40K feet.

You get the best thrust improvement when using an afterburner to energize low temperature bypass air.


Reduction of the BPR mainly benefits high speed thrust, because at high speed you need a faster jet velocity to produce thrust.

Higher BPR is generally better at everything up to about M0.8ish. It also gives a less hot exhaust as moon_light says.

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It will be a great advancement, above all or certain type of planes or missions, so I expect that about all the main producers would head trough it.

It will be for aircraft that can be modified or designed with an engine bay large enough to incorporate three airstreams. Designers aren't going to scale this technology for an F414 sized engine very soon.

One small caveat, as people have been saying VCE technology isn't new, the YF-120 had variable area bypass ejectors, basically valves that could direct more airstream into the core or bypass duct. The AETP engines add annular duct third stream, very high pressure ratio compressor. It isn't just about variable cycle, the engine program is testing new materials that are lighter and run at very high temps.

Another point, many like to focus on the potential increased power, but the USAF is more interested in the range improvements and extra cooling potential. Both the F-35 and the F-22 have pushed right to the edge of current thermal management technologies in LO aircraft. Without AETP cooling advances, future growth in the F-35 or sixth generation avionics and DEW wouldn't be possible. The added benefit is that it will remove some of the supersonic low altitude time limitations on the F-35 as well.

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It isn't just about variable cycle, the engine program is testing new materials that are lighter and run at very high temps.

Yup. It is the recent advancements in materials and fabrication methods that makes the predicted benefits of GE's VCE engine possible.

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https://matmatch.com/blog/the-future...-gas-turbines/

https://www.compositesworld.com/blog...rix-composites

Another point, many like to focus on the potential increased power, but the USAF is more interested in the range improvements and extra cooling potential. Both the F-35 and the F-22 have pushed right to the edge of current thermal management technologies in LO aircraft. Without AETP cooling advances, future growth in the F-35 or sixth generation avionics and DEW wouldn't be possible. The added benefit is that it will remove some of the supersonic low altitude time limitations on the F-35 as well.

This is spot on. Although characteristics such as total thrust and TWR are still important, it will be efficiency, thermal signature management, and electrical power generation which will be of primary importance going into the coming decades.

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Looking at that graph, could you explain how the EJ200 (developed in the '80s) is already operating at 1,800K (1527degC)?

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Simple. Military hardware isn't required to last as long as civilian hardware. You can stress the materials further but it will cost you in the longevity department. The graph and articles are more civilian oriented, but they point to the qualitative jump in coming military hardware too.

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Don't forget that the aetp would be an electrical power generation source at an unseen level today. And you won't get the needed reliably with a shaft mounted starter generator ;)

Also, the number and conformity with the 35's engine bay dimension means only one thing: the outer diameter of the core will be smaller meaning that the engine will reach better performances with less fuel. So you can draw from that, that a proper engine developed without any geo constraints will even have a better overall efficiency than what is announced in every domain or could be operated in a less stressful domain (more range, more durability etc...).

[USER="1416"]Scooter[/USER] :if you base your judgement about a new item using as your main source the promotional brochure of the producer itself, EVERYTHING would seems revolutionary independently by who the producer is and from what county it came from.

In this case they are using the usual trick of publishing only a partial data: the 25% better fuel, 20% higher thrust consumption refers to SUPERSONIC regime, not to the overall one.

Variable bypass ratio or adaptative cycle if you prefer to use such a term is something though to divert and reroute the air flow between the cold and the hot section of a turbofan.
in the case of ACE it work though the use of a third ,intermediate stage that can swap its own flow between the two.
In the subsonic cruise mode it will act as a high bypass turbofan, with the most of air flowing through the cold section, in transonic flow woud be partially diverted, so to still have some in the cold one in order to use afterburner, in full supersonic it would go for the most part through the hot one making the engine a quasi-turbojet or better said, a leaky turbofan.
It is precisely at that range speed that you get the highlighted advantages, in subsonic one it will be almost the same that today, with just the few gains that one can expect with adopting a newer engine.
It will be a great advancement, above all or certain type of planes or missions, so I expect that about all the main producers would head trough it.
In the case of F-35 however , I expect that it would be much more useful for expanding its own performances in A2A missions than in the A2G one that will still remain its main role.

Actually, your remarks are contradictory? As one hand me make sound like it is no big deal. Then it's a "great advancement"??? Simple fact while the concept it generally not new. The simple fact is nobody has been able to make it "work". So, if the US can deliver it would be a major break thru.....many would call that "revolutionary".

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Actually, your remarks are contradictory? As one hand me make sound like it is no big deal. Then it's a "great advancement"??? Simple fact while the concept it generally not new. The simple fact is nobody has been able to make it "work". So, if the US can deliver it would be a major break thru.....many would call that "revolutionary".

Scooter, the contradiction exist only in your chauvinistic mindset.

You are mixing two different topics into one.
First one is the innate unreliability of promotional brochures send out by the producers as a way to judge a defense related item and that's I repeat, INDEPENDENTLY from the producer in itself and the country from which it came from.
What that eventually change is the level of lack of critical sense, chauvinism and the gullibility of the audience they relate to... :rolleyes:

I tried so to explain you how to critically read what is really written in the promotional leaflet you posted, hope you have almost tried to read it but given the tone of your reply I have not a great hope on it.

In a second part, after that I have limited the claims contained in this propaganda leaflet, in the sense of reducing them to their real dimensions, I eagerly concede that such space for performance enhancements (obviously in the above highlighted speed range) trough the use of the variable bypass technologies (not just ACE) really exist and so it is pursued (and it was previously, see F-120 and Al-41F) by all the major engine producers.

ATM, it is certain that no one such engines is even near to operativity (although I would, with the same eagerness i talked above, bet on some american firm to come first to it),
So sorry, maybe it's just a little too early to begin your usual chestbeating routine basing yourself just on your own partial understanding of a corporate propaganda piece.

Scooter, the contradiction exist only in your chauvinistic mindset.

You are mixing two different topics into one.
First one is the innate unreliability of promotional brochures send out by the producers as a way to judge a defense related item and that's I repeat, INDEPENDENTLY from the producer in itself and the country from which it came from.
What that eventually change is the level of lack of critical sense, chauvinism and the gullibility of the audience they relate to... :rolleyes:

I tried so to explain you how to critically read what is really written in the promotional leaflet you posted, hope you have almost tried to read it but given the tone of your reply I have not a great hope on it.

In a second part, after that I have limited the claims contained in this propaganda leaflet, in the sense of reducing them to their real dimensions, I eagerly concede that such space for performance enhancements (obviously in the above highlighted speed range) trough the use of the variable bypass technologies (not just ACE) really exist and so it is pursued (and it was previously, see F-120 and Al-41F) by all the major engine producers.

ATM, it is certain that no one such engines is even near to operativity (although I would, with the same eagerness i talked above, bet on some american firm to come first to it),
So sorry, maybe it's just a little too early to begin your usual chestbeating routine basing yourself just on your own partial understanding of a corporate propaganda piece.

I am sure you think your an expert on the designs of Advance Military Engines. Yet, I think the leaders like P&W and General Electric. May know a little more than you............:rolleyes:

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I predict breakthroughs in sound dampening will find the way into next generation of engines.

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Not sure about the other engines mentioned.
But the very limited variable cycle capability of the M53 was to make up for its other shortcomings.
The M53 was a single spool turbofan. That means neither its lo-pressure compressor, or hi-pressure compressor was optimized to run at the best available efficiency.
How could they if they had to run at the same speed ?
Variable cycle ( limited ) mitigated some of these problems.