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Will F-35 Get New AETD Engine?

red admiral

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Question 1 is whether this would only be an engine upgrade for F-35A and C, given the much larger technical challenge and performance degradation that'll come from it being able to integrate with the lift system.
 

sferrin

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"ADVENT - Variable cycle - optimized for multiple design points - 20k lb thrust class - thought to be for NGB
specifically..."

Except that doesn't really line up with a 45,000lb+ 3-stream fighter engine. ???



(Too many acronyms. IHPTET, VAATE, ADVENT, AETD, AETP. . .)
 

NeilChapman

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sferrin said:
"ADVENT - Variable cycle - optimized for multiple design points - 20k lb thrust class - thought to be for NGB
specifically..."

Except that doesn't really line up with a 45,000lb+ 3-stream fighter engine. ???



(Too many acronyms. IHPTET, VAATE, ADVENT, AETD, AETP. . .)
ADVENT started in 2007. Follow-on programs modified requirements. That's what I wanted to elucidate.
 

sferrin

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NeilChapman said:
sferrin said:
"ADVENT - Variable cycle - optimized for multiple design points - 20k lb thrust class - thought to be for NGB
specifically..."

Except that doesn't really line up with a 45,000lb+ 3-stream fighter engine. ???



(Too many acronyms. IHPTET, VAATE, ADVENT, AETD, AETP. . .)
ADVENT started in 2007. Follow-on programs modified requirements. That's what I wanted to elucidate.
Thanks. Much appreciated.
 

marauder2048

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sferrin said:
NeilChapman said:
sferrin said:
"ADVENT - Variable cycle - optimized for multiple design points - 20k lb thrust class - thought to be for NGB
specifically..."

Except that doesn't really line up with a 45,000lb+ 3-stream fighter engine. ???



(Too many acronyms. IHPTET, VAATE, ADVENT, AETD, AETP. . .)
ADVENT started in 2007. Follow-on programs modified requirements. That's what I wanted to elucidate.
Thanks. Much appreciated.
I find some of the remarks about AETP and F-35 compatibility curious since the design target vehicle for AETP is explicitly the F-35A. Possibly the OEMs are being coy because of Congressional language
that prohibits a second engine for F-35.
 

sferrin

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Who knows? I'll track down the specific quote later when I get a minute. In the meantime this completely contradicts that statement and says both GE and P&W are sizing 3-stream engines for the F-35:

http://aviationweek.com/defense/three-stream-engine-moves-new-phase
 

CammNut

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The GE and P&W engines will be sized to fit in the F-35. The two $1 billion contracts just awarded for the AETP transition program to follow on from the AETD technology demonstration cover ground-test engines, but include options for ground and flight test in the F-35.
 

NeilChapman

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marauder2048 said:
sferrin said:
NeilChapman said:
sferrin said:
"ADVENT - Variable cycle - optimized for multiple design points - 20k lb thrust class - thought to be for NGB
specifically..."

Except that doesn't really line up with a 45,000lb+ 3-stream fighter engine. ???



(Too many acronyms. IHPTET, VAATE, ADVENT, AETD, AETP. . .)
ADVENT started in 2007. Follow-on programs modified requirements. That's what I wanted to elucidate.
Thanks. Much appreciated.
I find some of the remarks about AETP and F-35 compatibility curious since the design target vehicle for AETP is explicitly the F-35A. Possibly the OEMs are being coy because of Congressional language
that prohibits a second engine for F-35.

My understanding is that AETP is to build multiple adaptive engines in the 45k lb thrust class leading to an "EMD" downselect when the program has completed. This started out as a technology risk reduction program. Once AoA for whatever airframe is required has been completed then EMD phase would commence to build adaptive engines for that particular airframe, e.g. will it one or two engines? will it need to run wet? will it need to be bigger? will it need to be smaller? Basically they want a core design that can scale.

I haven't understood the "design target vehicle" for AETP to be "explicitly" the F-35A as far as DoD is concerned. Perhaps if I were GE that would be my target since the government is footing the bill - they've even said as much. But without airframe modifications to the F-35 it would be tricky to include the 3rd stream. That doesn't bode well for a simple engine upgrade. Perhaps a F-35 variant? Or perhaps they'll engineer a solution that fits? Or maybe DoD will accept an 80% solution?

But that doesn't mean that both vendors aren't working to integrate what they've learned into the existing F135 footprint.
 

NeilChapman

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riggerrob said:
With all that talk about fuel-cooling, how much of an advantage would it be to re-fuel the airplane with chilled go-juice just before take-off?
How much more of a hassle is it for ground crew to use two fuel trucks? The first truck off-loads ambient temperature fuel while the second truck delivers cooled fuel?
How many more calories in cool fuel because it has higher density?
How many more calories available to fuel-cool accessories?

To avoid over-loading the logistics train, let's limit the conversation to only cooled versions of jet fuel that are already in inventory (e.g. Jet A or JP4).
Might be tough if your landing planes on highways in the PI or Estonia and your feeding jets from what you can bring in on C-130's. Not suggesting this is the norm but it would bite if your aircraft can only complete the sortie rate required from a fully functioning airfield.
 

sferrin

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NeilChapman said:
But that doesn't mean that both vendors aren't working to integrate what they've learned into the existing F135 footprint.
The article I posted a link to above (Post #45) seems to indicate this is the case. I haven't been able to locate the GE quote regarding their 3-stream engine not fitting in the F-35 without losing it's 3rd stream. Was one line in an AvWeek article sometime in the last year. Maddening.
 

CammNut

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Check out Guy Norris's latest story on GE's AETP test plans at Aviation Week (it was posted digitally on July 11 for subscribers). It says GE has developed a configuration that Lockheed has verified fits in the F-35 (which needs the third stream for cooling), but that it presented a "significant challenge".
 

NeilChapman

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sferrin said:
NeilChapman said:
But that doesn't mean that both vendors aren't working to integrate what they've learned into the existing F135 footprint.
The article I posted a link to above (Post #45) seems to indicate this is the case. I haven't been able to locate the GE quote regarding their 3-stream engine not fitting in the F-35 without losing it's 3rd stream. Was one line in an AvWeek article sometime in the last year. Maddening.
Not sure about GE stating that. They've been hot on the F135/F136 size for some time. I seem to recall P&W hedging about the 3rd stream "fitting" the F135 size. But someone has stated that "Block Upgrades" to jets can include significant structural changes. Perhaps that will be an option.

Sounds like the US has got a great deal of engine tech to protect. There are countries that are working diligently to reduce their own development investment by stealing it from others. This is years of work and billions of dollars in transformational technology advances. I would be concerned that large portions of this technology will be used in commercial applications and reverse engineered.
 

NeilChapman

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marauder2048 said:
NeilChapman said:
I haven't understood the "design target vehicle" for AETP to be "explicitly" the F-35A as far as DoD is concerned.
From AETP's Second Industry Day Q&A

Good old fbo.gov!!!

Thanks M!
 

dark sidius

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The F-35 will have surely better performance with aetp engine, may be better high speed for air/air fighting.
 

RadicalDisconnect

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According to AFM.

http://www.airforcemag.com/DRArchive/Pages/2016/July%202016/July%2012%202016/Engine-Up-the-F-35.aspx​

Farnborough, UK—Last week's matching $1 billion contracts to Pratt & Whitney and General Electric for the Advanced Engine Technology Program could produce a powerplant delivering 20 percent better fuel efficiency—hence much better range—for the F-35, Pratt's Bennett Croswell, president of Pratt military engines, told Air Force Magazine Monday. The first block of the program could be designed by 2019 and in production in 2024, he said, delivering seven-10 percent better efficiency. Block 2 would follow five years later, with a likely 15-20 percent improvement over today's F135 engine. However, Croswell said the F-35 would probably need to be modified to accept a new engine. The airframe is "basically wrapped around it," and the fit is snug. While he said the intakes wouldn't have to be altered, "the back end" would need to grow, "and if you do that, the exhaust nozzle" would probably have to be re-engineered as well. Croswell declined to speculate about whether the AETP program is meant to give GE—and competitive engine buys—another chance. The alternative F136 engine, developed by GE, was killed by Defense Secretary Robert Gates, who insisted it was unnecessary and wasteful.
 

phil gollin

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.

My memory might be wrong, but weren't there severe problems with the gearbox's ability to transmit the power to the fan ?

Will it need a new gear box ?
 

Dragon029

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phil gollin said:
My memory might be wrong, but weren't there severe problems with the gearbox's ability to transmit the power to the fan ?

Will it need a new gear box ?
I could be wrong, but while there were certainly challenges in designing it, I don't think there were any real problems or deficiencies in the gearbox; I think there was an issue at one point with the drive shaft though (it just didn't quite have a sufficient diameter to combat oscillation or something).

There was a recent article about the P&W-proposed Block 1 (non-AETP) upgrade for the F135 where they or the JPO did explicitly mention that changes would be needed to the lift fan (likely in the gearbox and driveshaft) if they want the extra 5-7% thrust to be carried over to vertical thrust.
 

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