YF-22 vs YF-23

[zero-one]

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.
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?

[Corsair1963]

Sounds like a question for TEG...

[zhangmdev]

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.

[disconnectedradical]

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.
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.

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.

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.

[avon1944]

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.

[smsgtmac]

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.

[disconnectedradical]

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.

[energo]

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.

[disconnectedradical]

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.

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

[smsgtmac]

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.
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'.

[mixelflick]

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...

[zero-one]

I don't know how to post videos anymore but this is a very good interview with USAF Engineer Rick Abel.
https://www.youtube.com/watch?v=_MUK241uZHM&t=3780s

With regards to the YF-22/YF-23 he says a few interesting things

1. Northrop is primarily an engineering company that hired program managers while Lockheed is a managing company that hired engineers. Both are very capable in delivering what they promised, but they do it in different ways

2. I couldn't care less who won, the Airforce will get a fantastic aircraft that did what they wanted. (he also said it wasn't like the TFX program where there was a clearly superior aircraft)

3. The YF-23 had it's share of strengths and weaknesses and the YF-22 had its share of strengths and weaknesses.

4. Both aircraft met their requirements. However no test point was identical so it was very difficult to make an apples to apples comparison.

[Corsair1963]

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...

I didn't know they selected GE as the winner for the F-15EX??? I thought it was still very much up in the air???

[quicksilver]

“I don't know how to post videos anymore but this is a very good interview with USAF Engineer Rick Abel.”

https://www.youtube.com/watch?v=_MUK241uZHM&t=3780s

Thx for posting. Terrific btdt insights.

[disconnectedradical]

Even though both airplanes are very good, I still think the decision was down to political factors, i.e. not giving Northrop a monopoly on stealth aircraft, and also Northrop's delays with the B-2, and still wanting to preserve the industry base.

The sad part is, only 2 years later, DoD decided that it was impossible to sustain so many different contractors with the end of Cold War, so they basically ordered a merge, which kinda made some of the political factors that went into selecting the ATF winner pointless. So now you end up with Northrop merging with Grumman to become Northrop Grumman, Lockheed buying General Dynamics' aircraft division and merging with Martin Marietta to become Lockheed Martin, Boeing merging with McDonnell Douglas (IMO it ended up being a bad deal for Boeing), etc.