GE Aviation’s future fighter engine TECHNOLOGY XA100

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

f119doctor

Active Member

Active Member

  • Posts: 113
  • Joined: 13 Mar 2019, 00:07

Unread post25 Feb 2021, 21:41

Variable cycle engines have a major challenge

For a supercruise engine, you want a high pressure ratio fan, and a large moderate pressure ratio core with temperature and rotor speed margins sufficient to maintain airflow and engine pressure ratio at supercruise inlet conditions (approximately 100F inlet temperature at 40K, 1.5Mn).

For a cruise engine, you want a low pressure ratio fan, and a small, high pressure, hard working core module. You can lower the pressure ratio of the fan by opening up the exhaust nozzle, but this lowers the inlet pressure to the core and reduces the power required from the core module. You can rematch and reduce the airflow to the core for this higher bypass condition, but you end up with a low pressure ratio, lazy core. What you gain in propulsive efficiency with the higher bypass, low pressure ratio fan is offset by the reduced thermodynamic efficiency of the core.

While the YF120 engine demonstrated tons of supercruise thrust during the ATF Dem-Val, it was not as fuel efficient as the YF119 engine at either supercruise or subsonic conditions, indicating that GE had not solved that dilemma.

The challenge for the XA100 / XA101 is to raise (or at least maintain) the pressure ratio of the core module at the same time that you are reducing core airflow. I believe that this is going to require variable geometry in the turbine to reduce the flow area, re-matching the core to a higher pressure ratio, lower flow condition for subsonic cruise. Variable geometry in the hot section is major design challenge, to say the least.
P&W FSR (retired) - TF30 / F100 /F119 /F135
Offline

madrat

Elite 3K

Elite 3K

  • Posts: 3034
  • Joined: 03 Mar 2010, 03:12

Unread post25 Feb 2021, 23:11

Why variable geometry of fan blades when changing the angle of the fan to the flow should reach a similar result?
Offline

f119doctor

Active Member

Active Member

  • Posts: 113
  • Joined: 13 Mar 2019, 00:07

Unread post26 Feb 2021, 01:33

madrat wrote:Why variable geometry of fan blades when changing the angle of the fan to the flow should reach a similar result?

Variable geometry in jet engines means variable stators (with the exception of the PW V2500 Superfan demonstrator, which did have variable fan blades). Variable inlet guide vanes are common in Fans, and several stages of variable stator vanes are common in high pressure compressors. Moving these vanes more cambered reduces the angle of attack of the fan / compressor blades, reducing airflow at a specific rotor speed and increasing stall margin at that rotor speed.

When you reduce airflow thru the core with a fixed geometry turbine, the pressure ratio of the engine goes down, reducing the thermodynamic efficiency. With a fan that was is fixed in size, the only way to increase the bypass ratio is to make the core airflow smaller. A variable turbine stator can increase the back pressure with that reduced airflow,so you could maintain pressure ratio with less airflow.

Note that the F135-600 engine system in the F-35B is variable bypass engine. Instead of making the core smaller, they make the fan larger by adding the lift fan. The increased total airflow enables the engine to increase low speed lift thrust up to 40k from the normal 28k Mil Power
P&W FSR (retired) - TF30 / F100 /F119 /F135
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 25912
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post30 Mar 2021, 23:13

TOWARDS TOMORROW GE Aviation's US Fighter Engine [6 page PDF attached NOTE DATE 2015]
Jul 2015 Chris Kjelgaard

"In the second of two articles on the engines to power the US fighters of tomorrow, Chris Kjelgaard finds out about GE Aviation’s views and work on adaptive-cycle engines...

...GE Aviation and FLADEs
Neither GE nor Pratt & Whitney will actually build a full-size AETD engine, but under the research programme both contractors must produce designs for one. (In the absence of specific engine dimension requirements from AFRL, both companies sized their AETD designs so they would fit into exactly the same space the F135 engine takes up in the F-35 airframe.)

AFRL closely guards the engine architecture details of the two companies’ AETD designs. But the fact both have adaptive-cycle fans and third airstreams that are complementary to their core and bypass airstreams means they require variablegeometry features. These are needed to produce the third stream of air and direct it to different locations within the engine, as variably required.

McCormick confirmed GE Aviation’s AETD design uses variable-geometry mechanisms, which the company calls ‘FLADE’ features. The term ‘FLADE’ stands for ‘fan-on-blades’, ‘blades-on-blades’ or even ‘fan-blades-on-fan-blades’....

Source: AIR International Magazine July 2015 Vol.89 No.1
Attachments
GE Adaptive Engine Air International Jul 2015 pp6.pdf
(981.11 KiB) Downloaded 60 times
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline

Corsair1963

Elite 5K

Elite 5K

  • Posts: 7551
  • Joined: 19 Dec 2005, 04:14

Unread post31 Mar 2021, 02:54

Do we have anything more recent on the New Adaptive Cycle Engines from GE and/or P&W??? (XA100 - XA101)


:|
Offline

Corsair1963

Elite 5K

Elite 5K

  • Posts: 7551
  • Joined: 19 Dec 2005, 04:14

Unread post18 May 2021, 01:26

General Electric’s “Transformational” Adaptive Cycle Jet Engine Completes Testing

By Albert L in Air Force, Aviation, Daily News, Technology, USA May 17, 2021

General Electric has announced the successful completion of testing on its first XA100 adaptive cycle engine. The 14 May announcement comes just over five months from the start of testing at GE’s Evendale, Ohio, altitude test facility on 22 December, 2020.


The company says that the XA100’s performance and mechanical behavior during the test were consistent with pre-test predictions, and “fully aligned” with the objectives of the U.S. Air Force’s Adaptive Engine Transition Program (AETP). According to GE, this validates the XA100’s ability to “deliver transformational propulsion capability”.


“We were exceptionally pleased with how the engine performed throughout the test,” said David Tweedie, GE Edison Works’ General Manager for Advanced Combat Engines, he continued:


“Bringing a new centerline fighter engine to test for the first time is a challenging endeavor, and this success is a testament to the great team that worked so hard to get us here. We’re looking forward to working with the Air Force and other stakeholders to identify the next steps toward bringing this revolutionary capability out of the test cell and into the hands of the warfighter.”


According to GE, there are three key innovations at the heart of the XA100’s “generational” leap in performance:

•An adaptive engine cycle that provides both a high-thrust mode for maximum power and a high-efficiency mode for optimum fuel savings and loiter time
•A third-stream architecture that provides a step-change in thermal management capability, enabling future mission systems for increased combat effectiveness
•Extensive use of advanced component technologies, including ceramic matrix composites (CMC), polymer matrix composites (PMC), and additive manufacturing

These innovations allow for a 10% increase in thrust alongside a 25% increase in fuel efficiency, coupled with “significantly more” aircraft heat dissipation capacity. All of this is “within the same physical envelope” as current aircraft engines.


The successful engine test of the XA100 is the culmination of GE’s multi-year collaboration with the US Air Force to develop adaptive cycle engines for USAF aircraft. Research on adaptive cycle engines began in 2007 with the Adaptive Versatile Engine Technology (ADVENT) program, followed by the Adaptive Engine Technology Development (AETD) program in 2012, and then the launch of AETP in 2016. GE is now assembling a second XA100 engine, with testing of it expected to begin later this year. The completion of testing on the second engine will conclude the major deliverables of AETP.

The description of the XA100 being dimensionally compatible with current aircraft engines is no coincidence. In 2018, GE confirmed previous speculation that AETP would eventually result in a replacement for the F-35’s Pratt & Whitney-made F135 engine. Additionally, the USAF considers adaptive cycle technology to be the future of combat aircraft jet propulsion, with an adaptive cycle-engined F-35 leading the way for future aircraft – Next Generation Air Dominance included – all equipped with adaptive cycle engines.

https://youtu.be/T3eudKVbdG0

https://www.overtdefense.com/2021/05/17 ... s-testing/
Offline

hornetfinn

Elite 3K

Elite 3K

  • Posts: 3564
  • Joined: 13 Mar 2013, 08:31
  • Location: Finland

Unread post18 May 2021, 07:04

Corsair1963 wrote:These innovations allow for a 10% increase in thrust alongside a 25% increase in fuel efficiency, coupled with “significantly more” aircraft heat dissipation capacity. All of this is “within the same physical envelope” as current aircraft engines.


That sounds like a absolutely massive increase in capability for a jet engine. Especially so if (I think they are) those stated improvements are in comparison to F135 which is definitely currently the most advanced jet engine around. The improved heat dissipation capacity will definitely become handy with high-power lasers and ever more powerful avionics systems requiring a lot of that. Of course everybody would love higher thrust and increased fuel efficiency.
Online
User avatar

steve2267

Elite 2K

Elite 2K

  • Posts: 2793
  • Joined: 12 Jun 2016, 17:36

Unread post18 May 2021, 07:30

Does the F135 produce 40,000lb thrust in full reheat, or 43,000lb?

This point has been discussed in the past, but I'm unsure a consensus was reached, or the question definitively answered.

The Air Force and its pilots (e.g. recent video by Capt Beo Wolfe) all seem to say 40,000lb. If it was 40,500lb or 41,000lb, ok, I could see "rounding it off" to 40,000. But IMO, 43,000lb is significantly different than 40,000.

Why am I harping on this point? AETP is supposed to net +10% thrust. So is the JPO / USAF / USMC / USN going to come out and say "we need this new AETP motor to get +10% thrust -- 44,000 lb is what we really need." Or is F135 already putting out 43,000 and +10% gets the jet to over 47,000lb?
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
Offline

Corsair1963

Elite 5K

Elite 5K

  • Posts: 7551
  • Joined: 19 Dec 2005, 04:14

Unread post18 May 2021, 07:51

steve2267 wrote:Does the F135 produce 40,000lb thrust in full reheat, or 43,000lb?

This point has been discussed in the past, but I'm unsure a consensus was reached, or the question definitively answered.

The Air Force and its pilots (e.g. recent video by Capt Beo Wolfe) all seem to say 40,000lb. If it was 40,500lb or 41,000lb, ok, I could see "rounding it off" to 40,000. But IMO, 43,000lb is significantly different than 40,000.

Why am I harping on this point? AETP is supposed to net +10% thrust. So is the JPO / USAF / USMC / USN going to come out and say "we need this new AETP motor to get +10% thrust -- 44,000 lb is what we really need." Or is F135 already putting out 43,000 and +10% gets the jet to over 47,000lb?



Sources vary between 41,000 - 43,000 lbs. Of course how they measure it is likely the difference? (Static Thrust, Sea Level, etc.)


Nonetheless, I think the 10%+ number is on the low side. As most sources I've seen believe the Adaptive Cycle Engines (ACE) will make in the high 40,000 lbs or even low 50,000 lbs range.

Speaking of 10% P&W has upgraded versions of the F135 that offer similar performance improvements. So, clearly the ACE Engines would have to improve on that. Otherwise, what is the point....

For example....



Pratt & Whitney Validates Growth Option for F135 Engine

Engine improvements demonstrated under DoD technology maturation programs could benefit global fleet of F-35s



News provided by
Pratt & Whitney

May 31, 2017, 12:00 ET
Share this article

WEST PALM BEACH, Fla., May 31, 2017 /PRNewswire/ -- Pratt & Whitney, a division of United Technologies Corp. (NYSE: UTX), today announced the successful completion of performance testing of its Fuel Burn Reduction Demonstrator Engine. Based on this success, Pratt & Whitney can now offer a Growth Option 1.0 upgrade configuration for the F135 engine, which powers the fifth generation F-35 Lightning II fighter aircraft. The engine testing, conducted at Pratt & Whitney's West Palm Beach, FL, facility, verified this upgrade can provide a 5 to 6 percent fuel burn improvement and a 6 to10 percent thrust increase across the F-35 flight envelope...........

https://www.prnewswire.com/news-release ... 66212.html
Offline

hornetfinn

Elite 3K

Elite 3K

  • Posts: 3564
  • Joined: 13 Mar 2013, 08:31
  • Location: Finland

Unread post18 May 2021, 09:35

Corsair1963 wrote:Nonetheless, I think the 10%+ number is on the low side. As most sources I've seen believe the Adaptive Cycle Engines (ACE) will make in the high 40,000 lbs or even low 50,000 lbs range.


It might be that they have to balance between thrust, efficiency and heat dissipation capacity. I'd say that even 10% increase in thrust is pretty significant as F-35 is already very powerful. IMO, improving efficiency and heat dissipation capacity are much more important improvements. Those have significant effect on range/endurance, stealth (lower thermal signature) and also allow more capacity for avionics upgrades. 25% increase in fuel efficiency is like getting weighless and dragless VLO EFTs and CFTs. Of course there is never too much thrust, but I'd rather have 10% increase in thrust and 25% improvement in fuel efficiency than vice versa.
Offline

madrat

Elite 3K

Elite 3K

  • Posts: 3034
  • Joined: 03 Mar 2010, 03:12

Unread post18 May 2021, 12:14

I don't think this engine is a simple F135 drop in replacement. The F135 was supposed to be a conservative 35,000 pound class but it's likely much better than that. F-35A doesn't suffer from a range problem. NGAD will need a high performance engine in the vein of this program. It would be a monster aircraft with a pair of F135 derivatives. But to hamstring NGAD with an F-35 engine would mean defining it's limits to just a bigger F-35. I doubt this is the goal.
Offline

wrightwing

Elite 3K

Elite 3K

  • Posts: 3784
  • Joined: 23 Oct 2008, 15:22

Unread post18 May 2021, 13:50

madrat wrote:I don't think this engine is a simple F135 drop in replacement. The F135 was supposed to be a conservative 35,000 pound class but it's likely much better than that. F-35A doesn't suffer from a range problem. NGAD will need a high performance engine in the vein of this program. It would be a monster aircraft with a pair of F135 derivatives. But to hamstring NGAD with an F-35 engine would mean defining it's limits to just a bigger F-35. I doubt this is the goal.

The F-119 is the conservatively rated 35k lb class motor. The F-135 is rated at 43k lbs. While the F-35 doesn't "suffer" from range compared to the jets it's replacing, it still doesn't have as much range as the services would like , in the Pacific theater. These upgraded motors will help offset the need for EFT/CFTs, as well as providing more power for systems on the jet, and better thermal management. They definitely were designed to be drop in replacements, for later Block jets.
Offline

alloycowboy

Forum Veteran

Forum Veteran

  • Posts: 864
  • Joined: 26 Oct 2010, 08:28
  • Location: Canada

Unread post18 May 2021, 20:28

madrat wrote:I don't think this engine is a simple F135 drop in replacement. The F135 was supposed to be a conservative 35,000 pound class but it's likely much better than that. F-35A doesn't suffer from a range problem. NGAD will need a high performance engine in the vein of this program. It would be a monster aircraft with a pair of F135 derivatives. But to hamstring NGAD with an F-35 engine would mean defining it's limits to just a bigger F-35. I doubt this is the goal.


@madrat... Aircraft manufacters always choose a reliable engine for the inital introduction of a new airframe in order to reduce the number of unknowns. When the airframe is mature at mid life they will bring in a new engine with an avionics upgrade.
Offline

madrat

Elite 3K

Elite 3K

  • Posts: 3034
  • Joined: 03 Mar 2010, 03:12

Unread post18 May 2021, 22:55

alloycowboy wrote:
madrat wrote:I don't think this engine is a simple F135 drop in replacement. The F135 was supposed to be a conservative 35,000 pound class but it's likely much better than that. F-35A doesn't suffer from a range problem. NGAD will need a high performance engine in the vein of this program. It would be a monster aircraft with a pair of F135 derivatives. But to hamstring NGAD with an F-35 engine would mean defining it's limits to just a bigger F-35. I doubt this is the goal.


@madrat... Aircraft manufacters always choose a reliable engine for the inital introduction of a new airframe in order to reduce the number of unknowns. When the airframe is mature at mid life they will bring in a new engine with an avionics upgrade.


JSF began with F119 then moved to F135 with production. F135 hasn't even really had a chance to mature and it's hardly an interim choice of engines. I think the premise that ADVENT is for F-35 is just premature.
Offline

alloycowboy

Forum Veteran

Forum Veteran

  • Posts: 864
  • Joined: 26 Oct 2010, 08:28
  • Location: Canada

Unread post18 May 2021, 23:32

madrat wrote:
alloycowboy wrote:
madrat wrote:I don't think this engine is a simple F135 drop in replacement. The F135 was supposed to be a conservative 35,000 pound class but it's likely much better than that. F-35A doesn't suffer from a range problem. NGAD will need a high performance engine in the vein of this program. It would be a monster aircraft with a pair of F135 derivatives. But to hamstring NGAD with an F-35 engine would mean defining it's limits to just a bigger F-35. I doubt this is the goal.


@madrat... Aircraft manufacters always choose a reliable engine for the inital introduction of a new airframe in order to reduce the number of unknowns. When the airframe is mature at mid life they will bring in a new engine with an avionics upgrade.


JSF began with F119 then moved to F135 with production. F135 hasn't even really had a chance to mature and it's hardly an interim choice of engines. I think the premise that ADVENT is for F-35 is just premature.


Don't forget that the P&W F-135 engine is basically an F-119 engine core with new components. This is why Pratt and Whitney are already working on the XA101 three-stream adaptive cycle engine.
PreviousNext

Return to F-35 Engine

Who is online

Users browsing this forum: No registered users and 8 guests