Engine upgrades

The US Navy awarded United Technologies subsidiary Pratt & Whitney an $18.4 million contract modification for additional funding of the F-135. The F-135 is a mixed-flow afterburning turbofan developed specifically for the F-35 Lightning II. The engine’s propulsion system powers all three variants of the fighter aircraft. According to Pratt & Whitney it delivers more than 40.000 Ibs. of thrust. There are three F135 variants: the -100 engine, -400 engine, and the -600 engine. The -400 is similar to the -100, the most important difference being the use of salt-corrosion resistant materials. The initial F-35s went into production with the F135 engines. However, Pratt and Whitney is cooperating with the US Navy on a two-block improvement plan for the F135 engine. The goals of Block 1 are a 10 percent increase in thrust and a 5 percent lower fuel burn. The plans also include better cooling technology for turbine blades. This would increase the longevity of the engine as well as reduce maintenance costs. The goal of Block 2 is to work with the US Air Force's Adaptive Engine Transition Program, intending to introduce technology for an engine rated at 45,000 lb of thrust, to be used in a sixth-generation fighter. Work under the current deal will take place within the US as well as the UK and is scheduled to be finished in March 2022.

Edpop- where is this news article from? Last year they split the AETP, a 45,000lb thrust class engine for possible F-35 propulsion upgrades and a separate engine for whatever platform(s) come out of PCA.

While neither here nor there, Personally I think P&W is pushing growth options 1&2 to avoid possibility of losing a re-engining effort in the 2020’s to GE.

https://www.flightglobal.com/news/artic ... ut-450053/

Those are understated numbers, anyhow. A 10% increase over 43k, is over 47K. The AETP motor is supposed to provide 20 to 25% more thrust (or 51.6K to 53.75K.) They've already run the standard motors to 51K, so those are well within the realm of probability.

Edpop- where is this news article from? Last year they split the AETP, a 45,000lb thrust class engine for possible F-35 propulsion upgrades and a separate engine for whatever platform(s) come out of PCA.

While neither here nor there, Personally I think P&W is pushing growth options 1&2 to avoid possibility of losing a re-engining effort in the 2020’s to GE.

https://www.flightglobal.com/news/artic ... ut-450053/

From Defense Industry Daily...........

I'd like to see B-1B get these new engines on a service life extension program. Instead of retiring B-1B turn it into a rapid forward deployment tanker with a swap-able kit. They need to retain the ability to be maintained as a venue to drop smart ordnance like they've been utilized in Afghanistan.

Lots of engine upgrades thread posts so I'll plonk this here. Why is the F-35 under ranged? Just baffling - because it ain't.

ANALYSIS: F-35's next engine to reach for more range
06 Aug 2019 Garrett Reim

"One criticism – among many – of the Lockheed Martin F-35 Lightning II is that the fighter lacks the range needed to conduct long-range stealth strike missions. While Lockheed Martin has studied adding external fuel tanks to extend the aircraft's range, slinging the bulky hardware under the F-35 would ruin its minimal radar cross section, giving away the stealth fighter's chief advantage.

In place of extra onboard fuel, the US Navy (USN) has boosted the flight endurance of its F-35C variant by using its Boeing F/A-18E/F Super Hornet as a substitute in-flight refuelling tanker. The service is also funding the development of four Boeing MQ-25A Stingray unmanned in-flight refuelling tankers for $805 million....

...The USAF is looking at how the F-35 can do more with its fuel capacity. One important effort is the service's Adaptive Engine Transition Program, which aims to create a novel engine that has not only more power, but also more fuel economy.

Adaptive engines work by varying the volume of air flow that bypasses the turbine core by opening a third stream when flying in cruise mode. This third flow – in addition to core flow and bypass flow – increases the engine's efficiency in producing thrust and also creates a new heat sink within the engine, allowing for further fuel efficiency gains from increased core temperature. The result is an engine that can play the turbofan's efficiency trick of running a large bypass ratio when cruising – while retaining the raw power of a turbojet in other situations....

...For its part, GE Aviation announced the successful completion of the XA100 detailed design process in February 2019. The company believes the engine could result in a 35% increase in range and a 50% improvement in loiter time. That range improvement applied to the F-35C would add 420nm – taking range for the USN's variant to 1,620nm.

"In the Pacific theatre of operations this is significant, allowing either operations from greater distances or more time to operate at the combat edge," says USAF Major General Larry Stutzriem (retired), now director of research with the Mitchell Institute for Aerospace Studies. "This improvement could also allow F-35s to drop from their tanker support earlier, keeping those extremely vulnerable aircraft further away from adversary defences."..."

Source: https://www.flightglobal.com/news/artic ... ge-459856/

The engines of innovation thread did cover the AETP upgrades.

1620 nm combat radius is insane, holy sh...t

1620 nm combat radius is insane, holy sh...t

Range...not radius, to wit — “That range improvement applied to the F-35C would add 420nm – taking range for the USN's variant to 1,620nm.”

Those are understated numbers, anyhow. A 10% increase over 43k, is over 47K. The AETP motor is supposed to provide 20 to 25% more thrust (or 51.6K to 53.75K.) They've already run the standard motors to 51K, so those are well within the realm of probability.

Yes and many sources give the range of the F-35A/C at ~ 1,200 miles. When in fact we know it to be more in the real world....


So, in all honesty an F-35 equipped with an ACE Engine (XA-100 or XA-101) may actually have a range in the 1,800 -1,900 miles! (i.e. internal fuel only)

1620 nm combat radius is insane, holy sh...t

Range...not radius, to wit — “That range improvement applied to the F-35C would add 420nm – taking range for the USN's variant to 1,620nm.”

Now that's an "Air-Dominance" fighter!

Those are understated numbers, anyhow. A 10% increase over 43k, is over 47K. The AETP motor is supposed to provide 20 to 25% more thrust (or 51.6K to 53.75K.) They've already run the standard motors to 51K, so those are well within the realm of probability.

The question of the day is, ‘how much more thrust can be produced without changing the inlet geometry?’

Say you ''loiter' it out at 438KTAS = M0.75 @ FL320 to a tanker, maximize range extension from there, release weapon, fly back to a tanker then RTB. That's so much range you'd start to encounter pilot fatigue, 'solved' via super-cruising with a higher thrust allowance (and at higher altitude for less drag).

Say you ''loiter' it out at 438KTAS = M0.75 @ FL320 to a tanker, maximize range extension from there, release weapon, fly back to a tanker then RTB. That's so much range you'd start to encounter pilot fatigue, 'solved' via super-cruising with a higher thrust allowance (and at higher altitude for less drag).

Pilots flying in the ME for the last 17+ years have been routinely flying very, very long sorties. Would fatigue be a factor? Yes, but not sure how much different it would be from what they’ve done for a very long time already. My sense is that sortie duration would remain similar but it would cut down (not eliminate) on tanker demands.

I would also offer that loiter speeds (max endurance) are used when you have arrived where you wanna be; max range (which would be somewhat faster and at somewhat higher fuel flow) gets one the most distance for the least amount of fuel. What we don’t know is where in the performance envelope (speed/fuel flow) those quoted improvements reside.

Say you ''loiter' it out at 438KTAS = M0.75 @ FL320 to a tanker,

... I would also offer that loiter speeds (max endurance) are used when you have arrived where you wanna be; max range (which would be somewhat faster and at somewhat higher fuel flow) gets one the most distance for the least amount of fuel. What we don’t know is where in the performance envelope (speed/fuel flow) those quoted improvements reside.

Sure, just using that speed as a lower threshold to get some feel for endurance time, speed and range before it's throttled-up. I suspect loiter, max-endurance (not necessarily the same V) and max-range cruise speed are all going to be quite close to each other at mid to upper jetstream altitude range.