How well did F-22 meet the original ATF objectives?

[disconnectedradical]

This is something I’ve been thinking about especially in light of one of the common criticisms of the F-22 not having as much range as the USAF wants, but then again nothing really does for the Pacific because of how large it is. But this then brings me to thinking about the original ATF requirements in the 1980s. Based on the 1984 ATF statement of operational needs, it should have these characteristics:

* 800 mile mission radius
* Mach 1.4-1.5 supercruise
* ability to use 2,000 ft runways

All this is tailored for operating in Europe. Based on these original performance requirements, it seems like where the F-22 falls short on is range, which is only 595 nmi or 684 miles subsonic on internal fuel, and with supercruise that gets cut down to just 460 nmi or 529 miles.

I guess the question is, was the original ATF requirement truly achievable with the technology available at the time? I’m guessing maybe with the F-23 it may have been possible since it sacrificed a bit of maneuverability for more range compared to F-22, but it’s a bit moot because it doesn’t carry that much more fuel so it would still not be enough for the Pacific.

[mixelflick]

The story that I heard was USAF went to Lockheed (or vice versa) and said they needed to compromise on one of the following..

1.) Speed (super-cruise)
2.) Weight (or was it RCS?)
3.) Range

At that point, the decision was made it would be range. So they dropped/removed approximately 2,650lbs of the YF-22A's internal fuel (20,650lbs internal fuel in YF-22A, vs. 18,000 in the F-22A). I also recall hearing mention that the STOL requirement was dropped later in the program, which resulted in the YF-23A design team ditching the engine's thrust reversers. Since both used the same engine, I presume the YF-22A did as well.

So all in all, they wound up meeting USAF's specs (after some were lowered/dropped). I personally think they done good: The F-22A can fly approximately as far as an F-15C with 2 underwing tanks. Obviously, this depends how much super-cruise is used, etc. but still..

A def. step up, vs. the F-15C

[f119doctor]

Both the YF119 engines in the YF-22 and YF-23 had nozzles with thrust reversing architecture, although some of the hardware was removed/simplified when the USAF dropped the requirement. The F119 2D nozzle has no provisions for thrust reversing and is significantly lighter than the Dem-Val nozzles, although heavier than a conventional round nozzle.

[viperzerof-2]

Back when the Cold War ended and the ATF was up in the air they were looking at alternatives. This is part of an article on Falcon 21 and they talk about what they really wanted for ATF. It sounds like the F-22 fits that intent fine.

The Falcon 21 study initially began with configuration work on providing conformal and low-drag weapons carriage— both of air-to-air and air-to-ground
weapons—and incorporation of the new wing design into the aircraft without compromising the weapons capability. General Dynamics officials estimated that an advanced F-16 derivative airframe embodying the avionics packages developed for the ATF could do possibly 85-90% of the ATF’s mission. Basically, the ATF was designed to provide NATO with air superiority for up to 200 mi. behind any front line in Europe. Not only was it designed to attack and destroy such high-value targets as Soviet airborne warning and control aircraft, but also to reach and hit large formations of Soviet tactical aircraft before they could form up into a so-called “gorilla package” and stage a mass attack on NATO forces.

New questions now have affected this concept. One is the possible loss of Soviet air bases within 200 mi. of the current East-West border due to political changes in Eastern Europe. The addition of a large buffer space would reduce the requirement for the type of high-speed intervention and attack capability that has been engineered into the ATF. Another question is whether the Soviets will continue to have the capability to mount the type of attack the ATF was designed to counter. If either of these conditions have changed, the requirements for an ATF type aircraft also could change.

[disconnectedradical]

The story that I heard was USAF went to Lockheed (or vice versa) and said they needed to compromise on one of the following..

1.) Speed (super-cruise)
2.) Weight (or was it RCS?)
3.) Range

I know I heard many people say that Lockheed had to compromise and reduce range, but do we actually have proof or documentation that this happened? Or is this hearsay that was repeated so much that it became fact? I know the F-22's range isn't as much as USAF wanted, although I think I read that's a combination of additional requirements added to the F-22 in the 1990s that added some weight, and also the F119 fuel burn was a bit higher than expected.

https://insidedefense.com/inside-pentag ... onsumption

[f119doctor]

The referenced point paper on the F119 TFSC shortfall was from 1995, and was true at the time.

The single stage HPT and LPT of the F119 are a high reaction, high work design, with the both the static nozzle vanes and the blades having a convergent pathway accelerating the airflow to sonic speeds. They discovered that shockwaves were forming between the HPT blades, causing loss of efficiency and higher blade stresses.

In one of the earliest examples of massive parallel computing, P&W ganged together hundreds of Sun workstations to solve the complex numeric aero equations, running overnight for a few weeks, that resulted in revised airfoil profiles that tamed the shockwaves.

This advance, along with others, resulted in the production F119 meeting the design specifications for TFSC.

[disconnectedradical]

Good to know that the F119 does meet the TSFC spec. I really wonder then what caused the weight increase of the F-22, since it's supposed to be 60,000 lbs at takeoff, but now it's at about 65,000 lbs. Just using the basic Breguet range equation, with the same amount of fuel of 18,000 lbs, if the airplane was 5,000 lbs lighter, then range would have improved by almost 10%, which means a 654 nmi or 753 mile subsonic combat radius, which still doesn't quite reach 800+ miles in the original ATF requirements, and especially not with supercruise.

I wonder if the range requirement especially when combined with supercruise was really achievable in an aircraft the size of an F-22 using only internal fuel. Even with the F-23, I read that it allegedly has about 3,000 lbs more fuel capacity than the F-22, but that was also a dimensionally bigger aircraft with more volume and probably would have been heavier, so even then I'm not sure if it could have met the range requirement. Again using the range equation, even optimistically assuming the F-23 has same empty weight and weapons load, as a rough assumption with all else being equal, 3,000 lbs more fuel will get 14% more range, bringing subsonic combat radius to 678 nmi or 780 miles, so closer but still not at the original 800+ mile requirement, and any supercruise would just reduce this further. Again I think the F-23 would probably be heavier in terms of empty weight than the F-22 since it’s a slightly bigger airplane with more volume.

[milosh]

Northrop planned to use lot of composites (tech from B-2) to make F23EMD as light as possible goal was similar empty weight as YF23. On other hand it would lose big nacelles and reverse thrust mechanism of YF23 so it isn't too unrealistic F23EMD to have similar weight as YF23 even though it was longer for aim9 weapon bay.

I think F23EMD would carry more fuel then YF23 too.

YF23 test pilot couple years ago couldn't talk about range but he mentioned YF23 was able to do same test sortie as YF22 but flying supersonic! This shows YF23 was fantastic design from supercruise POV.

[mixelflick]

Northrop planned to use lot of composites (tech from B-2) to make F23EMD as light as possible goal was similar empty weight as YF23. On other hand it would lose big nacelles and reverse thrust mechanism of YF23 so it isn't too unrealistic F23EMD to have similar weight as YF23 even though it was longer for aim9 weapon bay.

I think F23EMD would carry more fuel then YF23 too.

YF23 test pilot couple years ago couldn't talk about range but he mentioned YF23 was able to do same test sortie as YF22 but flying supersonic! This shows YF23 was fantastic design from super-cruise POV.

Yes, some test pilots comments sure raised eyebrows. That airframe was so capable (especially for its time!), I have to believe some of the tech/data points would be a great "base" to start NGAD. When you think about it, many of the NGAD requirements could likely be met by a "scaled up" YF-23A:

- Extreme range
- Greater internal weapons carriage
- Super-cruise
- Better sensors/sensor fusion
- Extreme stealth
- Ability to fly with/direct multiple CCA

The extreme range will be a combination of much bigger airframe, low drag and new, less thirsty variable cycle engines. A scaled up YF-23 with new motors would probably meet that range requirement, likely one of the lower risk technologies they'll have to deal with. More internal weapons goes hand in glove with the much bigger airframe. AIM-260 will be prioritized, but air to ground weapons should be planned from the start. 2,000lb class weapons and perhaps even greater (thinking of hypersonic strike weapons). Better sensors? That tech is advancing rapidly, could probably port a lot of it over from F-35 Block 4.

I've heard of Super-Cruise being "optional" or lower priority in the NGAD specs. I respectfully disagree. Covering vast distances quickly may be the difference between winning and losing. It would get higher and faster, imparting more range/energy to its AIM-260's Even if not always used, the ability to get someplace fast should be a hard and fast requirement IMO. A subsonic only NGAD would need to be based much closer to the front lines (relatively speaking). Consequently, you'd need more of them and they'd be more vulnerable to being lost on the ground.

The ability to control/manage multiple CCA's, now that would be entirely new. I don't know enough about it to say it warrants 2 seats, additional avionics etc.. Personally, I think this is going to be the biggest "guess" when deciding what's needed. It's so new, I'm not sure USAF (or the Chinese, for that matter) fully understand what's needed. That, balanced with the cost for that capability will have to be carefully weighed.

[wrightwing]

Northrop planned to use lot of composites (tech from B-2) to make F23EMD as light as possible goal was similar empty weight as YF23. On other hand it would lose big nacelles and reverse thrust mechanism of YF23 so it isn't too unrealistic F23EMD to have similar weight as YF23 even though it was longer for aim9 weapon bay.

I think F23EMD would carry more fuel then YF23 too.

YF23 test pilot couple years ago couldn't talk about range but he mentioned YF23 was able to do same test sortie as YF22 but flying supersonic! This shows YF23 was fantastic design from supercruise POV.

Considering that none of the 4 teams knew any of the flight test results from the other teams, it's doubtful that any YF-23 pilot could compare the aircraft.

[disconnectedradical]

Northrop planned to use lot of composites (tech from B-2) to make F23EMD as light as possible goal was similar empty weight as YF23. On other hand it would lose big nacelles and reverse thrust mechanism of YF23 so it isn't too unrealistic F23EMD to have similar weight as YF23 even though it was longer for aim9 weapon bay.

I think F23EMD would carry more fuel then YF23 too.

YF23 test pilot couple years ago couldn't talk about range but he mentioned YF23 was able to do same test sortie as YF22 but flying supersonic! This shows YF23 was fantastic design from super-cruise POV.

Yes, some test pilots comments sure raised eyebrows. That airframe was so capable (especially for its time!), I have to believe some of the tech/data points would be a great "base" to start NGAD. When you think about it, many of the NGAD requirements could likely be met by a "scaled up" YF-23A:

- Extreme range
- Greater internal weapons carriage
- Super-cruise
- Better sensors/sensor fusion
- Extreme stealth
- Ability to fly with/direct multiple CCA

I'm somewhat skeptical about this for several reasons. If you look at the dimensions and also the volume, the F-23 is a bigger aircraft than the F-22, and even if Northrop planned on using more composites than Lockheed, that's no guarantee of lighter weight and composites technology was still not as mature. Remember F-22 ended up using less composites than planned so what's to say that won't affect the F-23 too? Both the YF-22 and YF-23 are light because they don't carry all of the avionics for a production F-22 or F-23.

I've never seen a reliable source on the fuel load of the YF-22 or YF-23 technology demonstrator prototypes, but based on what some people were able to analyze from the F-23 EMD drawings, fuel load would have been higher than F-22, but not dramatically, and as I showed using the range equation above, the improvement is definitely sizable but still not enough for what USAF wants out of NGAD for the Pacific. FYI, I think the original ATF requirement was for 800 miles, not nautical miles.

Based on 1998 report, it seems like the range problems with the F-22 is both because it's a bit overweight and the TSFC of the F119 was still a bit higher than required. However it does still meet the combat radius requirement, although I don't know if that's still the same value as in the original 1984 ATF requirement. Doubtful, since F-22 subsonic combat radius is now 595 nmi or 684 miles, short of the originally required 800 miles.

https://www.govinfo.gov/content/pkg/GAO ... -98-67.htm

With NGAD, I think USAF wants a design with no tails. The F-23 likely had better stealth from the sides because it only has 2 tails while F-22 has 4 tails, but USAF wants something even stealthier with a tailless supersonic aircraft. As cool as the YF-23 and F-23 is, and even though I think it's a better fit for how USAF uses the F-22, I don't think it was a dramatic difference between the two.

[milosh]

Considering that none of the 4 teams knew any of the flight test results from the other teams, it's doubtful that any YF-23 pilot could compare the aircraft.

If I remember it was something like this (what test pilot said)

YF22/119 was able to do required sortie, YF23/119 was able too but in our case whole sortie was done on super cruise. He was quite clear about noticeable better suoer cruise capability for example range compare to YF22.

And we need to remember some test crew which worked for NG team after yf22 selection start working for LM team.

[charlielima223]

Considering that none of the 4 teams knew any of the flight test results from the other teams, it's doubtful that any YF-23 pilot could compare the aircraft.

If I remember it was something like this (what test pilot said)

YF22/119 was able to do required sortie, YF23/119 was able too but in our case whole sortie was done on super cruise. He was quite clear about noticeable better suoer cruise capability for example range compare to YF22.

And we need to remember some test crew which worked for NG team after yf22 selection start working for LM team.

Quite possibly but doubt it. As wrightwing and so many others involved in the program stated, the two teams didn't know each other's flight test results for the sake of unbiased outcomes and eventual selection. They did communicate with each other for the sake of safety but beyond that... nadda.

Even Paul Metz who flew the YF-23 and eventually the EMD F-22 doesn't compare the YF-22 and YF-23, nor does he compare the F-22. He did however during a presentation clear clear up some common misconceptions such as high AoA flight test. The YF-23 was able to meet the desired requirements however Lockheeds team was able to showcase there YF-22 better.

But getting back to the subject...

One thing to remember is that initial requirements are often very lofty and demanding. When the rubber meets the road things start to come into perspective better. Look at the initial requirements/wish list for early JSF... even those were curtailed to be more realistic/attainable.

[disconnectedradical]

There seems to be some confusion on what the original 1984 ATF requirements were for range. I’ve seen some articles here and there reference 800 miles combat radius but there’s some back and forth on whether it’s statute miles or nautical miles, and also if it includes supercruise.

So I went through the ATF to F-22 book by Aronstein, Hirschberg, and Piccirillo, and while it didn’t say what the range numbers were in the 1984 requirements, in page 207 when talking about range goals when developing the engines, it mentions 500 miles combat radius with supercruise, and 800 miles subsonic. Based on these numbers, the F-22 seems to be close to the supercruise combat radius but not the subsonic one, assuming the book is using nmi which is standard in aviation.

[charlielima223]

With Raptor drivers I have gotten a chance to speak to and ask questions to during airshow I remember one saying that it can fly a "bit further than what the book says".