Powering the Lightning II

All about the Pratt & Whitney F135 and the (cancelled) General Electric/Rolls-Royce F136
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popcorn

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Unread post26 Aug 2014, 00:50

spazsinbad wrote:Anyone have any idea what the coooool exhaust gast temperature from the LiftFan will be please? Any guesses will do. Thanks.


From this article, 350 degree exhaust from the lift fan apparently.

http://www.airspacemag.com/military-avi ... 86459/?all


One week later, pilot Paul Stone of Britain’s Royal Navy took O’Donoghue’s place for another test: the X-32B’s first vertical takeoff. The flight plan called for a vertical landing followed immediately by a vertical takeoff. As Stone brought the airplane down gently, with the tires almost touching the runway, it wobbled momentarily, then a bright flash and a loud pop went off underneath the fuselage. Once again, hot exhaust had been sucked into the engine, and this time had caused a split-second engine “pop stall.”

The media were quick to seize on the episode, but O’Donoghue was unruffled. “All of us who worked with Harriers knew what that pop stall was and it was no big deal,” he says. “In fact, our simulations had predicted exactly what happened: If the plane tilted more than four degrees near the ground, the jet screen would no longer protect the engine and a stall would likely follow. We had already fixed the problem in our final design proposal with a bigger jet screen.”

As far as the Boeing team was concerned, the pop stall had been a nonevent, but the members knew it hadn’t looked good. Perception is everything, and the episode was a reminder of other inherent drawbacks that direct lift had and Lockheed’s fan didn’t. As with the Harrier, the 1,350-degree heat of the Boeing airplane’s exhaust gases would pose a threat to the surface of carrier decks, if not to the life and limb of Navy crews (the downdraft from Lockheed’s lift fan was some 1,000 degrees cooler). Since Lockheed’s fan boosted engine thrust, its powerplant could run at lower temperature and with less strain, and these differences would translate into longer life. Most significant, assuming its reliability could be ensured, the lift fan would offer an extra margin of power and safety in a hover. In the end, that ensured Lockheed’s victory
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
CSAF Gen. Mark Welsh
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Unread post26 Aug 2014, 01:17

Wow, what a great article/find! The internet is best when we see such stories/anecdotes instead of the blahblah blah that it 'doesn't do this or that' - YET. Thanks for this gem/info 'popcorn'. :mrgreen:
"...
The Marines stipulated that, unlike the Harrier, their STOVL version of JSF had to be stealthy, supersonic, and able to bring back a 5,000-pound payload at the end of a mission...."
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
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Unread post26 Aug 2014, 02:45

spazsinbad wrote:Wow, what a great article/find! The internet is best when we see such stories/anecdotes instead of the blahblah blah that it 'doesn't do this or that' - YET. Thanks for this gem/info 'popcorn'. :mrgreen:
"...
The Marines stipulated that, unlike the Harrier, their STOVL version of JSF had to be stealthy, supersonic, and able to bring back a 5,000-pound payload at the end of a mission...."

No problemo... never expected the downdraft at that temp but definitely cooler than Boeing‘s exhaust.. great outadabox moment for Bevilaqua.
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
CSAF Gen. Mark Welsh
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Unread post26 Aug 2014, 02:59

Same article mentioned some five years ago by 'Tinito_16' (how many is that in internet forum years?) and as indicated then we take it the X-35B STOVL engine is the same as the F-35B? But still - good to be reminded - I'll wager there are a tonne of details out there - most forgotten in the plethora of press good/bad....

viewtopic.php?f=58&t=12786&p=158640&hilit=Hadingham#p158640
&
viewtopic.php?f=22&t=13223&p=164570&hilit=Hadingham#p164570
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Unread post13 Oct 2014, 15:37

These are quite substantial numbers!!

Picked it up on http://elementsofpower.blogspot.dk/2014 ... eport.html

In July, A Pratt and Whitney official was reported on as saying some very interesting things:

Mr. Croswell said Pratt & Whitney also is starting to explore how to upgrade the F135 powerplant in coming years. "We see real opportunities to continue to improve the F135 over time," he said. Fuel consumption could be cut 7% by around 2020 and a combined 15% to 20% around five years later, he said. The life of the engine could be increased around 50% within the next decade, he said. Those effort could be a key element in the wider push within the F-35 program to cut the long-term costs of the Pentagon's most expensive weapons program. (http://online.wsj.com/articles/pratt-whitney-targets-lower-f-35-engine-cost-1405261733)
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Unread post13 Oct 2014, 21:31

It will be interesting to see GE's competing design which should become available in the same timeframe. Great Engine War part 2..
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
CSAF Gen. Mark Welsh
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Unread post14 Oct 2014, 09:30

Those are very substantial numbers if they are fully realized! That would mean huge improvements in operating costs and range/endurance.
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