YF-22 vs YF-23

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zero-one

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Unread post18 Feb 2020, 09:51

So the way I'm getting it is, both designs were next gen in their own way, Achieving or exceeding the required 35,000 lbs thrust levels.

The YF-120 used a variable bypass method which could increase efficiency in some parts of the envelope.
The YF-119 used a more traditional approach but with more advanced cooling techniques and blisk rotors to reduce compressor stages.

A few questions tho.
1. Did the reduction of compressor stages contribute to the YF-119s efficiency over the YF-120 in other parts of the envelope. But the YF-120 had even less stages, 2 fan and 5 HP stages to the 119's 3 fan and 6 HP stages. :shrug:
So how is Pratt achieving so much efficiency (at some parts of the envelope) with their design, in other words whats their secret sauce?

2. As far as i know the YF-120 chose to go with a Variable cycle design specifically for efficiency on different flight profiles. Did Pratt simply take a different approach to achieve their efficiency targets or was the fact that the YF-119 was more efficient than the YF-120 on some altitudes simply the result of the YF-120 being less mature.

3. Was the Blisk rotors responsible for the reduction of compressor stages, if so, why does the GE-F110 have more than 10, (I think 12) despite using Blisk rotors too and did the YF-120 use them too?
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Corsair1963

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Unread post18 Feb 2020, 09:58

Sounds like a question for TEG... :wink:
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zhangmdev

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Unread post18 Feb 2020, 11:54

YF120 design is unorthodox and risky. F119 is a straightforward design.

Never saw a photo of F119 fan, compressor, turbine, or anything inside for that matter. The compressor is described as "robust, yet compact, features the most advanced airfoil aerodynamics and integrally bladed rotor disks for ensured durability".

I think the old generation F110 design must look primitive comparing to F119

http://webcommunity.ilvolo.it/general-e ... 10737.html

Modern fan blade designs are no longer straight, often in weird shapes because of advanced aerodynamics. Another way to improve compressor efficiency is to let it rotate faster. F119 compressor blades are low aspect-ratio and made of better materials to withstand greater stress.
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disconnectedradical

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Unread post18 Feb 2020, 17:12

zero-one wrote:A few questions tho.
1. Did the reduction of compressor stages contribute to the YF-119s efficiency over the YF-120 in other parts of the envelope. But the YF-120 had even less stages, 2 fan and 5 HP stages to the 119's 3 fan and 6 HP stages. :shrug:
So how is Pratt achieving so much efficiency (at some parts of the envelope) with their design, in other words whats their secret sauce?


Reduced compressor stages is more about better durability and maintenance instead of raw performance. Fewer stages means lower aspect ratio and bigger blade chord which makes it stronger. Advance in aerodynamics made it possible to do more work per stage, so F119 6 stage HP compressor does more work than F100 10 stage HP compressor.

There's not really a "secret", just advances in materials, compressor aerodynamics, cooling technology, etc. The exact details are classified.

zero-one wrote:2. As far as i know the YF-120 chose to go with a Variable cycle design specifically for efficiency on different flight profiles. Did Pratt simply take a different approach to achieve their efficiency targets or was the fact that the YF-119 was more efficient than the YF-120 on some altitudes simply the result of the YF-120 being less mature.


Exact details would require someone with knowledge of both YF119 and YF120, probably someone within program office or some documentation that was archived and maybe will be declassified one day.

zero-one wrote:3. Was the Blisk rotors responsible for the reduction of compressor stages, if so, why does the GE-F110 have more than 10, (I think 12) despite using Blisk rotors too and did the YF-120 use them too?


YF120 uses blisks as well, and upgraded F110s also has blisk fan. F110 is older technology and derived from B-1's F101, which is only a bit newer than F100. YF119 and YF120 are a completely new generation of technology, and some of that eventually got applied to upgraded F100 and F110 models.
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avon1944

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Unread post14 Mar 2020, 08:28

I have read many of the postings on many pages and one thing not discussed is a very large reason the USAF chose the YF-22 over the YF-23 was one big factor. A large part of the decession was based up the fact that Northrop / McDonnell Douglas's YF-23 team was not as far in the design process than the Lockheed / Boeing / General Dynamic's team YF-22 was the Lockeed and partners showed more confidence by flying twenty-four more missions than the Northrop / McDonnell Douglas YF-23 partners did! The Lockeed team flew a total of seventy-four missions while the Northrop team was only able to fly fifty missions. The Lockeed team also fired Sidewinder missiles. The overall acessment was that the Lockeed team appeared to have a greater knowledge on the YF-22 program than the Northrop team. The Lockeed team "appeared" to have a greater knowledge and further along in the design process of their fighter and thus a better chance of controlly the cost. The Northrop team did not demonstrate as much confidence in their design and how they were presenting their fighter.
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smsgtmac

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Unread post17 Mar 2020, 01:28

avon1944 wrote:I have read many of the postings on many pages and one thing not discussed is a very large reason the USAF chose the YF-22 over the YF-23 was one big factor. A large part of the decession was based up the fact that Northrop / McDonnell Douglas's YF-23 team was not as far in the design process than the Lockheed / Boeing / General Dynamic's team YF-22 was the Lockeed and partners showed more confidence by flying twenty-four more missions than the Northrop / McDonnell Douglas YF-23 partners did! The Lockeed team flew a total of seventy-four missions while the Northrop team was only able to fly fifty missions. The Lockeed team also fired Sidewinder missiles. The overall acessment was that the Lockeed team appeared to have a greater knowledge on the YF-22 program than the Northrop team. The Lockeed team "appeared" to have a greater knowledge and further along in the design process of their fighter and thus a better chance of controlly the cost. The Northrop team did not demonstrate as much confidence in their design and how they were presenting their fighter.

No.
I was active duty at the time, and was part of the AFFTC. I have stood within ear-protection-required distance of both prototypes while their engines were running during ground tests. They were both awesome at the time, as were the engines.
The reason the YF-22 was selected was that the AF 'perceived' (remember that word) that the design of YF-22 as it existed (and the P&W engine too BTW) as being more 'producible'. This was publically stated at source selection and this was an era of maximum cost and risk avoidance: Everyone on the left was talking about 'peace dividend' and Aspin (spit) was rampant on defense spending in the House and the press, and was soon to be SecDef.
I was still active duty and a participant in 'Stealth Week' (https://www.latimes.com/archives/la-xpm ... story.html) and Lockheed had to perform major surgery on the YF-22 to ship it there and to restore it. Northrop reps commented at the time that all they had to do was undo some bolts and disconnect connectors to ship the YF-23 anywhere. So much for production ready. The evolution from the YF-22 to the F-22 is evidence of just how much work was needed to produce the F-22, and we'll never know how much the YF-23 would have needed. Northrop-ters to this day (Full disclosure, I retired from NGC in January having worked for them since 1993) still believe they had the better design. It was certainly stealthier. What Locheed did was to go above and beyond the specs to give the AF some 'wants and wishes' in the form of thrust vectoring. Firing an AIM-9L was also brilliant marketing but not required, and fortunately for LM everybody heard about the launch but not about the FOD damage it caused.
--The ultimate weapon is the mind of man.
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disconnectedradical

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Unread post17 Mar 2020, 02:01

Aspin wasn’t secretary of defense until 1993 over a year after ATF selection. But it’s true peace dividend started in HW Bush administration.
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energo

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Unread post17 Mar 2020, 23:45

smsgtmac wrote:
avon1944 wrote:The evolution from the YF-22 to the F-22 is evidence of just how much work was needed to produce the F-22, and we'll never know how much the YF-23 would have needed.


I wonder what radar they planned to fit into that nose. :mrgreen:
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disconnectedradical

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Unread post18 Mar 2020, 02:16

energo wrote:
smsgtmac wrote:
avon1944 wrote:The evolution from the YF-22 to the F-22 is evidence of just how much work was needed to produce the F-22, and we'll never know how much the YF-23 would have needed.


I wonder what radar they planned to fit into that nose. :mrgreen:


Same radar as F-22, AN/APG-77. The F-23 EMD nose is larger then YF-23 because of the radar.

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smsgtmac

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Unread post18 Mar 2020, 05:25

disconnectedradical wrote:Aspin wasn’t secretary of defense until 1993 over a year after ATF selection. But it’s true peace dividend started in HW Bush administration.


Yes, 1993 was 'soon' after 1991. :D
IMHO the 'era' in...
"an era of maximum cost and risk avoidance: Everyone on the left was talking about 'peace dividend' and Aspin (spit) was rampant on defense spending in the House and the press, and was soon to be SecDef"

began when it was getting apparent the Soviets were folding their hand in the mid-late 80's, when Aspin was a total *** about defense in general and classified programs in particular. It lasted not much longer than when Aspin (spit) resigned from SecDef (after getting the job for being that total ***) for health reasons. Unfortunately, he was able to pull off his "Bottom Up Review" debacle'charade/scam before he left the SecDef job. After Aspin's exit, the Faux Military Reform crowd pretty much lost their seats at the big people policy table, having lost their credibility in most people's eyes after Desert Storm, and so the draconian cuts in the defense establishment were the de facto 'Peace Dividend'.
--The ultimate weapon is the mind of man.
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Unread post18 Mar 2020, 12:57

We got a great fighter out of it, the best in the world (by far). I loved the YF-23A, but it was not to be. Perhaps PCA will give us a 2nd glance/2nd coming.

I hope GE gets back in the game on PCA. Nothing against Pratt, but they always seem to win and GE gets sloppy seconds. They'll be powering the new F-15EX though, and it'll be no small increase in thrust. An additional 10,000lbs over the F-15C! Let's just hope it's weight doesn't grow too much, and we're at least at 1:1 insofar as thrust to weight ratio is concerned...
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