F-35 Program - General Discussion

[John Fedup]

The GAO is recommending that the F135 engine upgrade should be separated from the JSF to better gauge the cost. The other issue in addition to the ECU is the thermal management system. These two systems need to be accessed together to make sure block 4 requirements are fully addressed. As for future needs, AETP, although more risky, might still be needed as new tech always seems to need more power and this means even better thermal management. Also, AETP range improvement (30%) is very enticing.

GAO Urges Congress to Separate Engine Upgrade From F-35 Program

Congress should mandate the F-35 fighter engine upgrade become its own major program, a new GAO report states, to increase transparency.

www.airandspaceforces.com

 

[John Fedup]

No more F-35s configured with TR-3 until testing is completed. Starting July, TR-3 equipped F-35s will be stored as they come off the production line. Assuming testing is completed successfully this isn’t a huge setback. I think the ECU is a bigger concern. TR-3 with block 4 software will wear out F135 engines even faster.

Upgraded F-35s won't be accepted by Pentagon come July - Breaking Defense

An unknown number of new F-35s will be held up as a result of ongoing testing for the TR-3 system, with deliveries expected to start between December 2023 and April 2024.

breakingdefense.com

 

[StingrayOZ]

No more F-35s configured with TR-3 until testing is completed. Starting July, TR-3 equipped F-35s will be stored as they come off the production line. Assuming testing is completed successfully this isn’t a huge setback. I think the ECU is a bigger concern. TR-3 with block 4 software will wear out F135 engines even faster.

Bit of an issue, it means that TR-3 isn't the ideal solution.

There was hope that TR-3 could go ahead, with some slightly higher maintenance cycles for now, then when the new engine turns up, they could be easily refitted with the new engines for faster blk IV rollout. That doesn't appear possible now.

As for future needs, AETP, although more risky, might still be needed as new tech always seems to need more power and this means even better thermal management. Also, AETP range improvement (30%) is very enticing.

IF they had chosen the anything but the PW ECU option, its highly likely the F-35B and F-35C would not get the upgrades, and would be stuck at blk III.

IMO there is value in developing both. An immediate ECU upgrade. Also a long term long range AETP program with the efficiency improvements if just for the A model, but coming on stream later.

IMO everyone will want to move to BlkIV, block III limitations as a multirole 5th gen fighter are significant, many weapons and missions would be limited if stuck at block III.

 

[Vivendi]

IF they had chosen the anything but the PW ECU option, its highly likely the F-35B and F-35C would not get the upgrades, and would be stuck at blk III.

AETP engine would work with both the F-35A and C, and should be ready by 2028, however it seems USN was not that interested. Perhaps the extra range does not make sufficient difference in the vast pacific and they would need substantial tanker support anyways?

Tweedie said GE could have an XA100 production model ready for the F-35A and C in 2028—and the engines would integrate “seamlessly” with both aircraft. But making an AETP engine fit the F-35B, which has a unique propulsion system for vertical operations, will require substantially more development work, Tweedie acknowledged. He declined to say how much longer an F-35B-configured engine would take to develop and bring to production. But it can be done, he insisted.

He noted that the F-35A/C and F-35B use different versions of the F135 already; they are “not interchangeable,” although there is some commonality, he said.

The F-35 Joint Program Office asked GE to look at what would be necessary to make the XA100 work with the F-35B’s lift fan, drive shaft and swivel exhaust nozzle, Tweedie said, with emphasis on “how much commonality” and “how much ‘unique’ there would be” between the two versions.

GE was “pleased with the results of the study, in terms of our ability to show a path to make the modifications in a in a B-model derivative that could provide some good capabilities,” he said.

For its part, the JPO agreed “it would be a separate, incremental effort” from the conventional takeoff version, Tweedie continued. “We’ve provided what those incremental costs and timing would be.”

GE gave the JPO and Marine Corps, which operates the F-35B, an estimate of how long a separate AETP engine would take, but Tweedie declined to share it, except that it would be “after” the 2028 target for the conventional takeoff version.

Air Force Secretary Frank Kendall has said the service would like the performance improvements offered by the AETP engines, but USAF would have to bear the development costs alone if the Navy and other partners aren’t interested.

 

[John Fedup]

Bit of an issue, it means that TR-3 isn't the ideal solution.

There was hope that TR-3 could go ahead, with some slightly higher maintenance cycles for now, then when the new engine turns up, they could be easily refitted with the new engines for faster blk IV rollout. That doesn't appear possible now.


IF they had chosen the anything but the PW ECU option, its highly likely the F-35B and F-35C would not get the upgrades, and would be stuck at blk III.

IMO there is value in developing both. An immediate ECU upgrade. Also a long term long range AETP program with the efficiency improvements if just for the A model, but coming on stream later.

IMO everyone will want to move to BlkIV, block III limitations as a multirole 5th gen fighter are significant, many weapons and missions would be limited if stuck at block III.

Agree, merit in doing both engines for the F-35.

 

[John Fedup]

AETP engine would work with both the F-35A and C, and should be ready by 2028, however it seems USN was not that interested. Perhaps the extra range does not make sufficient difference in the vast pacific and they would need substantial tanker support anyways?

Tweedie said GE could have an XA100 production model ready for the F-35A and C in 2028—and the engines would integrate “seamlessly” with both aircraft. But making an AETP engine fit the F-35B, which has a unique propulsion system for vertical operations, will require substantially more development work, Tweedie acknowledged. He declined to say how much longer an F-35B-configured engine would take to develop and bring to production. But it can be done, he insisted.

He noted that the F-35A/C and F-35B use different versions of the F135 already; they are “not interchangeable,” although there is some commonality, he said.

The F-35 Joint Program Office asked GE to look at what would be necessary to make the XA100 work with the F-35B’s lift fan, drive shaft and swivel exhaust nozzle, Tweedie said, with emphasis on “how much commonality” and “how much ‘unique’ there would be” between the two versions.

GE was “pleased with the results of the study, in terms of our ability to show a path to make the modifications in a in a B-model derivative that could provide some good capabilities,” he said.

For its part, the JPO agreed “it would be a separate, incremental effort” from the conventional takeoff version, Tweedie continued. “We’ve provided what those incremental costs and timing would be.”

GE gave the JPO and Marine Corps, which operates the F-35B, an estimate of how long a separate AETP engine would take, but Tweedie declined to share it, except that it would be “after” the 2028 target for the conventional takeoff version.

Air Force Secretary Frank Kendall has said the service would like the performance improvements offered by the AETP engines, but USAF would have to bear the development costs alone if the Navy and other partners aren’t interested.

It is rather strange the USN had no interest in AETP for the F-35C given the significant range improvement. Also, AETP will be likely be in their NGAD fighter. Perhaps the AETP for the C is seen as a delay for their NGAD.

 

[Vivendi]

It is rather strange the USN had no interest in AETP for the F-35C given the significant range improvement. Also, AETP will be likely be in their NGAD fighter. Perhaps the AETP for the C is seen as a delay for their NGAD.

You may be onto something.

Perhaps I am wrong, but I think I have sensed a not always very high enthusiasm for F-35C at the USN. At one point I thought they would ultimately replace all their SH with F-35C, now it looks like the SH will be replaced by the NGAD. And they do have quite a larger number of SH.

 

[John Fedup]

You may be onto something.

Perhaps I am wrong, but I think I have sensed a not always very high enthusiasm for F-35C at the USN. At tone point I thought they would ultimately replace all their SH with F-35C, now it looks like the SH will be replaced by the NGAD. And they do have quite a larger number of SH.

It appears the USN hasn’t been very enthusiastic about the F-35C but given the likely cost of their NGAD, it can’t replace all the SHs. The F-35C will still need to be a significant part of the replacement fleet.

 

[Vivendi]

It appears the USN hasn’t been very enthusiastic about the F-35C but given the likely cost of their NGAD, it can’t replace all the SHs. The F-35C will still need to be a significant part of the replacement fleet.

Well, there is a third component -- the future unmanned "loyal wingman" that supposedly will work in tandem with both F-35 and NGAD. I think it may replace some of the SH...?

 

[StingrayOZ]

I think when people talk about range improvement, there is this fear that it will cut into USAF or USN refuelling assets projects.

US fighters IMO have a range issue, for the pacific. I'm not sure any other region is as important. The Chinese have a range of long range aircraft now, and long range munitions for those aircraft. They need this range improvement to get close to matching range of the generally bigger aircraft that carry more fuel.

It may not be a priority for the US, but for Japan, Australia, South Korea, etc F-35 range is very much a thing.

 

[John Fedup]

I think when people talk about range improvement, there is this fear that it will cut into USAF or USN refuelling assets projects.

US fighters IMO have a range issue, for the pacific. I'm not sure any other region is as important. The Chinese have a range of long range aircraft now, and long range munitions for those aircraft. They need this range improvement to get close to matching range of the generally bigger aircraft that carry more fuel.

It may not be a priority for the US, but for Japan, Australia, South Korea, etc F-35 range is very much a thing.

Yes, I agree it is a big issue for allies but it should be for the USN as well. Sure the MQ-25 helps but a 30% range increase for the F-35A/C does add some safety margin for those future 14 billion dollar CVNs.

 

[John Fedup]

Interesting news, LM has come out in favour of AETP. Will be interesting to see if this changes things. There is a lot of merit in the AETP being a solution that will work for the entire lifetime of the F-35A and likely C as well. Hopefully a solution for the B is found eventually.

Lockheed backs new AETP engine for F-35 - Breaking Defense

“I’m going to advocate, and I do advocate, for [the Adaptive Engine Transition Program, or AETP],” said Lockheed Martin aeronautics chief Greg Ulmer, who labeled “some” current approaches to the fighter's engine modernization as “short-sighted.”

breakingdefense.com

 

[John Fedup]

Well it didn’t take P&W very long to respond to LM’s remarks about AETP. Looks like the JSF marriage might be heading into troubled waters.

Pratt blasts Lockheed's 'confusing and misleading' adaptive engine advocacy (Exclusive) - Breaking Defense

In a high-profile public spat with little precedence between the airframe and engine giants, Pratt & Whitney executives are formally accusing Lockheed Martin of prioritizing its own bottom line by seeking an adaptive engine solution for the Joint Strike Fighter.

breakingdefense.com

 

[Terran]

Just my opinion here.
I think both have a point and it’s healthy that they are having a bit of a debate.
Lockheed Martin’s perspective seems to be a rational one. They see F35 and they see F16. Today over 44 years after IOC new F16 are still being built and entering service meaning F16 is likely to have over a 70 year service.
F35 is the new kid on the block, the replacement for F16 and as such it might have a lifespan out into the year 2090. As such they are looking at the F35 and saying okay people this is good butwe can do more what’s after the next TR. Block 5 when do we get F35 D/E/F?


Pratt and Whitney is on the other hand trying to reign them in a bit. Hold on there we haven’t gotten TR3 done let alone Block 5. Let’s eat what’s on our plates before we plan dessert, for next year. P&W knows that it will eventually have to deal with GE’s ambitions and they know they will have to fight for NGAD’s hearts but that’s down the line.

 

[John Fedup]

Just my opinion here.
I think both have a point and it’s healthy that they are having a bit of a debate.
Lockheed Martin’s perspective seems to be a rational one. They see F35 and they see F16. Today over 44 years after IOC new F16 are still being built and entering service meaning F16 is likely to have over a 70 year service.
F35 is the new kid on the block, the replacement for F16 and as such it might have a lifespan out into the year 2090. As such they are looking at the F35 and saying okay people this is good butwe can do more what’s after the next TR. Block 5 when do we get F35 D/E/F?


Pratt and Whitney is on the other hand trying to reign them in a bit. Hold on there we haven’t gotten TR3 done let alone Block 5. Let’s eat what’s on our plates before we plan dessert, for next year. P&W knows that it will eventually have to deal with GE’s ambitions and they know they will have to fight for NGAD’s hearts but that’s down the line.

Both engine programs should happen despite the cost. One important advantage of AETP is the estimated range for increase of 30%, a significant gain that minimizes risk to CVNs. Continuing the ECU minimizes risk and AETP is needed for the NGAD anyway. If it can fit into the A and C then operators who want the extra range can buy it.

 

[StingrayOZ]

It should really be a tic-tok strategy a small upgrade, followed up a much larger one. The ticks and the tocks can be separate programs.

While there are some 6th gen fighter programs being thrown around, there aren't any cheap 6th gen fighter programs AFAIK. The F-35 is likely to have a long life span, and should have a series of upgrades in a pipeline. There are what? 1000 F-35's currently flying around, that is already a huge fleet.

Money should be provided for both programs, the priority can be PW for low risk and the easiest upgrade for the existing fleet. If they want to keep selling F-35 going forward, they will need to incorporate newer technologies and capabilities.

Increasing the flight endurance of the F-35 would be a great way to lower cost per flight hour and get more hours out of the fleet.

Pratt and Whitney is on the other hand trying to reign them in a bit. Hold on there we haven’t gotten TR3 done let alone Block 5. Let’s eat what’s on our plates before we plan dessert, for next year. P&W knows that it will eventually have to deal with GE’s ambitions and they know they will have to fight for NGAD’s hearts but that’s down the line.

Ultimately I think while you may be right, this PW thinking is flawed. China doesn't care about GE or PW. In the Pacific the F-35 is short ranged, all western fighters are. Carriers alone is not enough to fight China. In 10 years China will be approaching or matching US carrier capabilities in the Pacific. USS Ford sitting 200km off the Chinese coast isn't a threat, its a target.

The US is locked in competition with China. China isn't the soviet union, they have an economy, they have technologies and they a spending big money. They aren't on the other side of the iron curtain either, so the US MUST keep developing its technological edge.

Coasting is no longer a strategy for the US industrial complex. They are being outproduced for the first time, basically ever. The US has a technological edge, but its eroding and the quantitively edge is disappearing very fast.

The F-35 Market is a big one, it has sold well, everyone is on the band wagon. Failing to continue to develop this aircraft would be pretty much a collapse of allied airpower.

 

[vonnoobie]

Off hand how much would the R&D cost? PW makes a claim it would cost tens of billions but provide nothing to back that statement up beyond saying the main cost would be duplication... which would only apply to forces operating both engine types so that to me sounds like they are stretching the truth quite a bit. Dont know why they dont see if they can get other F-35 partners that would be interested in it to chip in on the cost, Be easier to get past congress.

 

[John Fedup]

Off hand how much would the R&D cost? PW makes a claim it would cost tens of billions but provide nothing to back that statement up beyond saying the main cost would be duplication... which would only apply to forces operating both engine types so that to me sounds like they are stretching the truth quite a bit. Dont know why they dont see if they can get other F-35 partners that would be interested in it to chip in on the cost, Be easier to get past congress.

One issue P&W has that GE does not is the R&D costs for the ECU and its XA101 AETP engine. Guessing GE’s XA100 is much further developed than P&W’s XA101. The XA100 could end P&W’s F135 ECU down the road.

 

[StingrayOZ]

One issue P&W has that GE does not is the R&D costs for the ECU and its XA101 AETP engine. Guessing GE’s XA100 is much further developed than P&W’s XA101. The XA100 could end P&W’s F135 ECU down the road.

Well the F-35 was meant to have multiple engine options. Even if XA100 was basically ready today, there is a 1000 PW powered aircraft existing. There is a problem now, and a different future problem.

This is going to be a big issue rolling out blk IV upgrades, which some countries are absolutely desperate for, and will be essential for any high end conflict.

It may come to a development point where countries/services want different priorities in engines. I am almost certain USN/USMC want different things than the USAF. Having a fairly common airframe and interchangeable engines isn't the worst thing in the world if that is required to meet those niche needs. If the USAF went GE and USN/USMC went PW, you are still talking about thousands of aircraft in either pool with international customers choosing.

 

[John Fedup]

Actually you would think the USN should be enthusiastic about a AETP engine that provides all the power requirements for TR3/block 4 plus improves range by 30%, a good thing for F-35Cs operating off CVNs. The F-35B is likely only going to get the ECU. For many of the European F-35A users, the ECU is likely all they require. The USAF and Asian operators would probably be interested in AETP as long as the price isn’t excessive. Even if AETP is fully developed, probably won’t get into F-35A/Cs until the late 2030s.