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Author Topic: P&W confirms stealthy augmentors of F119, F135  (Read 13522 times)

Online flateric

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P&W confirms stealthy augmentors of F119, F135
« on: April 05, 2011, 05:02:34 am »
Sferrin must remember these discussions with insiders at f-16.net...

http://tinyurl.com/3nh2wnu

Screech, the F135 and the JSF Engine War
Posted by Graham Warwick at 3/17/2011 1:33 PM CDT
For those of us who thought screech was the noise made by GE/Rolls and Pratt & Whitney in their war of words over the JSF second engine, here's the background to comments made this week about screech problems with the F-35's F135 engine.

Testifying before the House Armed Services Committee on Tuesday, JSF program executive officer Adm David Venlet said afterburner screech on the F135, which prevents the engine from sustaining full thrust, "caused us to avoid certain portions of the flight envelope." Instead, F-35s have flown to other points in the envelope to keep flight-test going. Kits are being installed to overcome the problem, he said.

So what is screech and what's the fix?

Pratt says screech is a phenomenon caused by pressure pulsations in the afterburner at low altitude and high speed. The problem was discovered during development testing around March 2009, having previously been encountered - and solved - in the F-22's F119 engine, from which the F135 is derived.

Pratt points out that the F119 and F135 are the only production engines with stealthy augmentors. Their design eliminates conventional spray bars and flame holders and integrates multi-zone reheat fuel injection into curved vanes that block the line-of-sight to the turbine.

Building on its experience with the F119, the fix for the F135 includes "minor hardware changes to the fuel system, reduced aerodynamic leakages and upgraded software," says Pratt, adding that the modified engine "now provides full max augmented thrust throughout the flight envelope."

A kit has been developed for flight-test engines, and two have been modified. The production configuration will be validated this year in both the CTOL/CV and STOVL variants of the F135, Pratt says.

I have asked GE/Rolls whether their F136 has a screech-free stealthy augmentor. Watch this space for their answer.

And here it is:

GE/Rolls says the F136 has "no known" screech problem, but acknowledges it is four years behind Pratt in development. An augmented F136 was demonstrated recently to the JPO on its Evendale test stand without experiencing screech, but the engine has not flown yet.

GE/Rolls also points out that afterburner screech was a problem of fighters long before stealth came along...
"There are many disbelievers in
stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

Offline sferrin

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #1 on: April 05, 2011, 07:28:09 am »
"DARPA Hard"  It ain't what it use to be.

Online flateric

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #2 on: April 05, 2011, 08:16:43 am »
oh. damn. rare vizitor there lately
« Last Edit: April 06, 2011, 11:09:58 pm by flateric »
"There are many disbelievers in
stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

Offline sferrin

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #3 on: April 05, 2011, 09:00:58 am »
oh. damn. rare vizitior there lately

I felt like a person who'd seen a flying saucer but I didn't want to scan the shots in Jay Miller's book and show them.  :)
"DARPA Hard"  It ain't what it use to be.

Online flateric

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #4 on: April 05, 2011, 09:35:32 am »
I have this Jay's book of course. What can I say...some guys follow OPSEC rules
"There are many disbelievers in
stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

Offline sferrin

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #5 on: April 05, 2011, 09:59:11 am »
I have this Jay's book of course. What can I say...some guys follow OPSEC rules

Except these don't really qualify as they were mentioned in the press and shown in Jay's book years ago.  ???
"DARPA Hard"  It ain't what it use to be.

Offline SOC

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #6 on: April 05, 2011, 07:26:41 pm »
Except these don't really qualify as they were mentioned in the press and shown in Jay's book years ago.  ???

They sort of qualify.  The shots right up the nozzle of the F119, showing the LO fixtures, are some of what the USAF realized after the fact shouldn't have been published.

Online flateric

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #7 on: April 05, 2011, 11:02:53 pm »
Except these don't really qualify as they were mentioned in the press and shown in Jay's book years ago.  ???
I'm talking of previous discussion at f-16.net of blockers existence and some replies.
"There are many disbelievers in
stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

Offline Spring

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #8 on: April 06, 2011, 10:17:41 pm »
Pratt points out that the F119 and F135 are the only production engines with stealthy augmentors. Their design eliminates conventional spray bars and flame holders and integrates multi-zone reheat fuel injection into curved vanes that block the line-of-sight to the turbine.

Give an engineer paper, not an aviation week article.

Thank you, Next...
Hello!

Online flateric

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #9 on: April 06, 2011, 11:26:47 pm »
if Graham Warwick, directly stating that he's citing P&W representative, is not a credible source for you, find Aronstein and Piccirillo F-22 book where augmentor part on F119 cutaway for some reason filled with black

from P&W site
Quote
The F119 introduces a number of advanced technologies such as integrally-bladed rotors; burn-resistant, lightweight titanium components; integrated steath features; and a pitch-vectoring exhaust-nozzle system that greatly enhances maneuverability.
« Last Edit: April 06, 2011, 11:36:22 pm by flateric »
"There are many disbelievers in
stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

Offline Spring

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #10 on: April 06, 2011, 11:36:20 pm »
Lack of common sense is funny

Why would you want a 'blocker' that looks exacly like a flameholder, covers exacly the same area and geometry.

And no a PW 'represantive' is not a realiable source, at least for a guy that have been 3 years reading industrial technical manuals....

Is my opinion...He that hath ears to hear, let him hear.
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Online flateric

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #11 on: April 06, 2011, 11:47:18 pm »
Why would you want a 'blocker' that looks exacly like a flameholder, covers exacly the same area and geometry.

once more - can you read?
"Their design eliminates conventional spray bars and flame holders and integrates multi-zone reheat fuel injection into curved vanes that block the line-of-sight to the turbine."

radar blocker in F119 is not my idea fixe, it was just an information that appeared long ago and recently got another confirmation

And no a PW 'represantive' is not a realiable source, at least for a guy that have been 3 years reading industrial technical manuals....
so what? that now qualifies as a reason to believe you more than to Warwick?
« Last Edit: April 06, 2011, 11:51:33 pm by flateric »
"There are many disbelievers in
stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

Offline sferrin

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #12 on: April 07, 2011, 03:13:28 am »
Lack of common sense is funny

Why would you want a 'blocker' that looks exacly like a flameholder, covers exacly the same area and geometry.

And no a PW 'represantive' is not a realiable source, at least for a guy that have been 3 years reading industrial technical manuals....

Is my opinion...He that hath ears to hear, let him hear.

Shhh.  Don't listen to them, it's a conspiracy.   ::)
"DARPA Hard"  It ain't what it use to be.

Online flateric

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #13 on: April 07, 2011, 03:25:42 am »
Stephen Morford
Director, Aerodynamics at Pratt & Whitney

Current
  • Director, Aerodynamics at Pratt & Whitney
Past
  • Manager, Acoustics, Inlet & Nacelle Aerodynamics at Pratt & Whitney
    Team Leader, F119 Augmentor at Pratt & Whitney
    Manager, Low Emissions Combustor Technology at Pratt & Whitney
« Last Edit: April 07, 2011, 03:37:23 am by flateric »
"There are many disbelievers in
stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

Offline PaulMM (Overscan)

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Re: P&W confirms stealthy augmentors of F119, F135
« Reply #14 on: April 07, 2011, 03:30:35 am »
Team leader on the F119 augmenter? Pah! What would he know about the F119 aug... oh.....

Spring: apologies are in order I think.
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