F-135 Block Upgrade

All about the Pratt & Whitney F135 and the (cancelled) General Electric/Rolls-Royce F136
  • Author
  • Message
Offline

bring_it_on

Forum Veteran

Forum Veteran

  • Posts: 929
  • Joined: 30 Apr 2014, 14:32

Unread post22 Jun 2015, 00:22

From AIR , 6.15

The F135 Block Upgrade Plan

Under the F135 Block Upgrade Plan, a series of initial ‘Block 1’ improvements might potentially be available for new-production examples and for retrofit into existing ones from as early as 2018. Then a second series of AETD project-derived, more substantial ‘Block 2’ improvements could be put “into production in the very early 2020s”, depending on “funding and the requirement pool”, according to Kenyon.Although Kenyon points out this plan is “not part of the F135 programme proper”,
he said “it is an opportunity looking ahead to demonstrate fuel-burn cost savings” to F-35 operators – and particularly to the US Navy, with which P&W is working to try to get the Block 1 F135 upgrades into production within the next few years.

The Block 1 upgrades rely partly on development work that P&W carried out for a demonstration in autumn 2013 for the navy’s XTE68-LF1 project. This focused on demonstrating a capability for higher operating temperatures in the F135’s turbine and introduced a variety of new technologies into the engine’s high-pressure turbine (HPT) module. These improvements, which Kenyon described as “advanced cooling technologies”, included new casting technologies for metal- alloy parts; new, highly temperature-resistant HPT materials; new thermal barrier coatings for HPT blades and vanes; more temperature- resistant oils for lubricating and cooling; and a new main shaft bearing. He said P&W’s XTE68-LF1 demonstration in autumn 2013 was “tremendously successful” – so successful that it recorded “the hottest-ever temperature in a production engine”.
P&W has parlayed this successful demonstration into another F135 development initiative on which it is working with the US Navy, called the Fuel Burn Reduction (FBR)programme.

FBR has married the HPT technologies from the XTE68-LF1 demonstration with a series of improvements to the F135’s six-stage, all-blisk compressor to produce an engine offering a fuel-burn reduction of “about 5% – and we’ve identified another couple of opportunities to give [another] 1%-2% of fuel-burn improvement”, said Kenyon. However, saying the XTE68-LF1 and FBR technologies would just reduce fuel burn only in production F135s would be inaccurate: the technologies would also offer other improvements. “TheJPO(F-35Joint Programme Office) and navy are both focused on [engine] life-cycle cost and they need to have the technology working reliably,” said Kenyon. An important feature of the XTE68-LF1 and FBR advanced cooling technologies is that “you need less air to do the cooling [in the HPT] and you can use it more to do other things, with the cooling capability already in the engine. We’re using low-lying fruit to get better thermal management,” he said.

“Right now I’m going to insert this nice cooling technology into my turbine because it helps with [life-cycle] cost [by making the engine more durable], but I could use it to generate more thrust” – perhaps up to 10% more, making the F135 capable of meeting any foreseeable F-35 thrust-growth requirement.

There is no doubt about this. During its original ground-testing effort for the F135, P&W ran an unimproved engine at thrust levels of up to 51,000lb in uninstalled configuration (ie without any accessory gearboxes or drives drawing power from the engine). This suggested that, even on an installed basis, the F135 had several thousand pounds of additional thrust available if necessary, if run at high temperatures.

Kenyon pointed out that, although the F-35 airframe has had heat-retention issues, “right now, there are no thermal restrictions with the engine”. In-service F135s are operating within the specifications required by the JPO and presumably could be operated at a higher maximum temperature as long as the F-35 airframe could withstand and dump the additional heat burden.

F135 Block Upgrade
Programme: Block 2


Pratt & Whitney’s proposed Block 2 upgrades for the F135 would be more complex than those in Block 1. The manufacturer can see a potential path by which it could introduce into the F135 engine, for production from the early 2020s, some of the advanced technologies it has developed for the compressor and turbine in its high-pressure AETD core.
The F135 has the same dimensions as the AETD demonstrator upon which P&W is now working. But while that is a three-stream engine, at this juncture P&W does not view redesigning the F135 into a three-stream, adaptive-cycle engine – which may be theoretically possible.


However, Kenyon said there is an “exciting opportunity we’ve identified, which is unique to Pratt & Whitney’s position, to take some of the key technologies of the three-stream AETD architecture into the F135 to get lots of benefits”.
This opportunity could rely on a potential evolution of the company’s engine-control software for its AETD demonstrator.
Kenyon said: “For example, if you can modulate the [existing] bleed air using the three-stream control laws, rather than using an actual third stream of air,” this could produce substantial benefits from an enhanced capability to use cooling air flexibly at different places in the engine’s hot section. “The trade is really around the re-use of current learning,” he said.
In addition to incorporating a series of AETD- derived hardware and software upgrades, as well as other cooling and design technologies,a future Block 2 upgrade of the F135 might also incorporate the improvements already provided under Block 1. P&W isn’t sure yet of the scale of the fuel-burn reduction and thrust increase a Block 2 upgrade would offer, but they would certainly be more substantial than those provided in Block 1. It’s possible Block 2 modifications could produce benefits even greater than the AFRL’s AETD project targets of a 25% fuel-burn improvement and 10% thrust increase over today’s F135 engine.
The future of adaptive-cycle engines for US fighters, and even the future development of the existing F135, relies greatly upon Congress approving President Obama’s AETP budget request. If approval comes at all, it will likely come this year. Pratt & Whitney is now beginning to flesh out a two-pronged strategy to try to retain its dominant position in current- generation US fighters and win a prominent position on US next-generation fighters. It will hope Congressional approval for AETP is prompt and generous – and that the AFRL likes P&W’s AETD design.




https://www.scribd.com/doc/269303020/AIR-US-NG
Offline
User avatar

popcorn

Elite 5K

Elite 5K

  • Posts: 7703
  • Joined: 24 Sep 2008, 08:55

Unread post22 Jun 2015, 03:21

It looks like P&W is going to have a lock on the F-35 engine market going forward if it can achieve the projected roadmap, particularly Block 2. Amazing if they can meet or even exceed the AETD performance goals with a tweaked F135 retaining it's 2-stream archirecture. Speaks to the flexibility and soundness of the engine's design.
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
CSAF Gen. Mark Welsh
Offline

magitsu

Senior member

Senior member

  • Posts: 415
  • Joined: 12 Jun 2015, 22:12

Unread post22 Jun 2015, 14:01

Yep, it should prove a hard sell for any replacement engine hopefuls if the current one can be tweaked so easily.
Offline

bring_it_on

Forum Veteran

Forum Veteran

  • Posts: 929
  • Joined: 30 Apr 2014, 14:32

Unread post22 Jun 2015, 14:30

magitsu wrote:Yep, it should prove a hard sell for any replacement engine hopefuls if the current one can be tweaked so easily.


Depends upon the performance goals. As mentioned in the full article, post SDD phase completion, there wouldnt be an engine program in development in the entire DOD (unless there is a bomber engine being developed in secret i guess) so if they do not nail down on a particular engine class for the future fighters, they could just continue to mature the technology though an F-35 engine program and have a third stream engine be developed for the F-35 for the 2030's. Its one option but I agree unless they really want to push 6th generation fighters in the 2040's, they will continue on the lower-cost F-135 enhancement path and run a full on program for the next generation adaptive engines for future fighters and unmanned aircraft.
Offline

neurotech

Elite 2K

Elite 2K

  • Posts: 2346
  • Joined: 09 May 2012, 21:34

Unread post22 Jun 2015, 19:05

popcorn wrote:It looks like P&W is going to have a lock on the F-35 engine market going forward if it can achieve the projected roadmap, particularly Block 2. Amazing if they can meet or even exceed the AETD performance goals with a tweaked F135 retaining it's 2-stream archirecture. Speaks to the flexibility and soundness of the engine's design.

Despite what some people think, the F135 is basically a reliable engine.The F135 core hasn't actually failed in flight yet. Neither has the F119 engine that its based on.

On the GE side, I think they only had a single F414 core failure that was caused by fuel ingestion.

As I recall, the F135 is FADEC limited, and has plenty of thrust growth potential. What most likely will change is the materials and manufacturing methods to allow for the engine to have a long service life while powering a jet at Mach 1.2+ supercruise.
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23277
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post22 Jun 2015, 23:33

LONG ARTICLE at URL so I have only posted the ENGLISH bits - after that - LOTS of engine tech gobbledegook.... :mrgreen:
ANALYSIS: Adaptive engine technology moves beyond the fan
22 Jun 2015 Stephen Trimble

"A 10- to 15-year look ahead into Pratt & Whitney’s vision for military engine technology reveals a very different kind of propulsion system.

It may not be enough for the motor powering the next fighter, bomber or airlifter to simply generate thrust and electric power for a given weight and fuel burn requirement. The future military turbofan could be a far more complex, adaptable machine.

As a throttle governs the amount of fuel flow in engines today, in future, new software and electronic controls will be able to modulate a motor’s bypass airflow and power off-take. Turbofan engines are adapting, even as combat fighters are evolving from short-range weapons trucks into long-range sensor and attack aircraft with a suite of kinetic and non-kinetic armaments.

If, say, a directed energy weapon is on board, the engine may need a way to modulate the bleed-air now used to pressurise the cockpit. That compressed air flow could instead be diverted momentarily to power a laser or a next-generation jammer.

Or the same engine could be reconfigurable in flight, by opening a third stream of airflow when rapid acceleration is not needed, to save fuel and extend range. That same extra stream of cool bypass air could also pull double-duty as a handy place to dump all the new heat generated by those high-power jammers and laser weapons, rather than allow the exhaust to betray the aircraft’s thermal signature by venting it directly offboard...."

Source: http://www.flightglobal.com/news/articl ... he-412423/
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline
User avatar

popcorn

Elite 5K

Elite 5K

  • Posts: 7703
  • Joined: 24 Sep 2008, 08:55

Unread post23 Jun 2015, 00:18

neurotech wrote:
popcorn wrote:It looks like P&W is going to have a lock on the F-35 engine market going forward if it can achieve the projected roadmap, particularly Block 2. Amazing if they can meet or even exceed the AETD performance goals with a tweaked F135 retaining it's 2-stream archirecture. Speaks to the flexibility and soundness of the engine's design.

Despite what some people think, the F135 is basically a reliable engine.The F135 core hasn't actually failed in flight yet. Neither has the F119 engine that its based on.

On the GE side, I think they only had a single F414 core failure that was caused by fuel ingestion.

As I recall, the F135 is FADEC limited, and has plenty of thrust growth potential. What most likely will change is the materials and manufacturing methods to allow for the engine to have a long service life while powering a jet at Mach 1.2+ supercruise.

Just demonstrates that one builds on previous successes. No shortcuts and magic bullets can substiture for the institutional expertise and knowledge developed over decades
As for the F135 tweaks that would boost thrust, it will be interesting to see how they address the thermal management issue which is reported to constrain F-35 operations at lower altitudes.
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
CSAF Gen. Mark Welsh
Offline
User avatar

popcorn

Elite 5K

Elite 5K

  • Posts: 7703
  • Joined: 24 Sep 2008, 08:55

Unread post27 Jun 2015, 03:15

More stuff on AETD. This is going to be a fascinating competition to follow.
http://www.flightglobal.com/news/articl ... he-412423/
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
CSAF Gen. Mark Welsh
Offline

bring_it_on

Forum Veteran

Forum Veteran

  • Posts: 929
  • Joined: 30 Apr 2014, 14:32

Unread post08 Jul 2015, 14:45

Does anyone have an idea on the F135 and F136 Thrust to weight ratio? According to Sweetman the F-135 has by far the smallest T2W ratio of the current group of fighters (4th and 5th generation)..Any particular reason for so??

download/file.php?id=10587&t=1
Offline

stobiewan

Senior member

Senior member

  • Posts: 311
  • Joined: 14 Jan 2010, 12:34
  • Location: UK

Unread post08 Jul 2015, 15:05

bring_it_on wrote:Does anyone have an idea on the F135 and F136 Thrust to weight ratio? According to Sweetman the F-135 has by far the smallest T2W ratio of the current group of fighters (4th and 5th generation)..Any particular reason for so??

download/file.php?id=10587&t=1


F35 has a vast internal fuel capacity - 18K lbs in the A model. If you compare an F35 fully fuelled with a similar jet with a full fuel load, the F35 is heavier, much heavier.

Put the same amount of fuel in the form of external tanks onto the jet you're comparing with and the numbers look closer, put it that way.
Offline

bring_it_on

Forum Veteran

Forum Veteran

  • Posts: 929
  • Joined: 30 Apr 2014, 14:32

Unread post08 Jul 2015, 15:42

I was referring to the engine T2W ratio and not that of the aircraft.
Offline

optimist

Forum Veteran

Forum Veteran

  • Posts: 983
  • Joined: 20 Nov 2014, 03:34
  • Location: australia

Unread post08 Jul 2015, 16:05

AFAIK the not to exceed 6k for a/b and 10k lb for c weight are for the total system including intakes, fan, ducts etc. Some are measured engine only and I've seen the f135 engine only (dry weight) weight to be "Dry weight: 3,750"

https://www.google.com.au/#q=f135+%22dry+weight%22
Aussie fanboy
Offline

bring_it_on

Forum Veteran

Forum Veteran

  • Posts: 929
  • Joined: 30 Apr 2014, 14:32

Unread post08 Jul 2015, 16:10

optimist wrote:AFAIK the not to exceed 6k for a/b and 10k lb for c weight are for the total system including intakes, fan, ducts etc. Some are measured engine only and I've seen the f135 engine only (dry weight) weight to be "Dry weight: 3,750"

https://www.google.com.au/#q=f135+%22dry+weight%22



See this discussion -

http://aviationweek.com/defense/f-35-fi ... h-solution

I hope TEG or someone more informed than myself on these matters can shed some more light.
Offline

optimist

Forum Veteran

Forum Veteran

  • Posts: 983
  • Joined: 20 Nov 2014, 03:34
  • Location: australia

Unread post08 Jul 2015, 16:46

Back in 2008 there was a post here viewtopic.php?f=56&t=11547
Aussie fanboy
Offline

bring_it_on

Forum Veteran

Forum Veteran

  • Posts: 929
  • Joined: 30 Apr 2014, 14:32

Unread post08 Jul 2015, 17:00

optimist wrote:Back in 2008 there was a post here viewtopic.php?f=56&t=11547


Ah, Thanks. Interesting contribution to the discussion. I don't think Sweetman ever went on record in an article to claim that to be the weight of the F135 but he does sound pretty confident.
Next

Return to F-35 Engine

Who is online

Users browsing this forum: No registered users and 2 guests