Forum: F-22A Raptor

1) Now that we have the F-22A, when can we expect to see other variants in production like an F-22B, F-22C, EF-22, FB-22, etc.? What would the differences be when compared to the F-22A? Upgrades in electronics, weapons, engines, etc.?

2) Has anything akin to a "Streak Raptor" been produced yet (like the Streak Eagle)? You know, an F-22A with the paint and excess electronics removed for minimum weight and maximum performance? If not, are there any plans for it? Do any of you have any pictures of a Raptor minus the paint that you can show us?

3) How did the YF120 engine differ from the YF119? What, if any, were the changes made to the YF119 when it led over to the production model F119? Were there any particular short-comings or problems associated with the development of the YF119/F119?

4) Are various internal structures and equipment (like the wing supporting ribs and fuel tanks) planform-aligned like the outside of the aircraft is? Or are you not allowed to say?

5) Based on the current world situation, which aircraft do you predict will be the F-22A's first real kill (not DACT)? Will it be something primitive like a MiG-21? Or perhaps even an AWACS or tanker aircraft? Will it ever take on any of the Flanker variants (maybe the Su-30MKK from China)? Is it just too early to say?

6) Are there any plans for conformal fuel tanks on the Raptor? If so, what type of arrangement would they have? Perhaps a pair of tanks along the sides of the fuselage like those on the F-15E? Or a pair of back-tanks like on the F-16 Block 60? Or even a single, dorsal spine-type tank? Which type would you prefer?

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1) We probably won't see them. Congress and the President are about to cap production at 187 jets.

2) I don't think a streak raptor has flown and it probably won't fly. Here are pics of the plane before the final coating(s) are applied, though:

Wow, thanks Tin!

What's up with those different colors? Is the Raptor in those pictures in various stages of being coated? If so, which one is the most "raw" Raptor in these pictures? If not, is there some kind of iridescence that makes it look like different colors from different angles?

If I'm not mistaken the one's that are completely brown are the rawest. Also, I think the second to last pic was of a different primer. I'm not sure tho...

I've been thinking about the conformal fuel tank thing again, and I realized that F-15E-style CFTs would probably overlap the Sidewinder bays and the landing gear doors on an F-22. Utilizing that method would therefore require alot of redesigning.

A back CFT might be best, then. Then I was thinking that maybe that back CFT could be modified ala the F-15SE to contain an extra AMRAAM or two in sacrifice of some extra fuel space. My idea is that, in BVR, the Raptor would roll over onto its back in flight to launch the missile from the CFT and then roll back upright. Firing that missile while upright might not be a good idea (unless you had some powerful ejector rack to propel it well away from the Raptor).

I think you covered every hypothetical ever asked since the YF-22 was chosen over the YF-23. Laughing

Kryptid wrote:

3) How did the YF120 engine differ from the YF119? What, if any, were the changes made to the YF119 when it led over to the production model F119? Were there any particular short-comings or problems associated with the development of the YF119/F119?

The YF120 was more advanced than the YF119 in many respects. It has a "variable bypass" core that could shift from a turbofan mode, to a turbojet mode as the aircraft's flight required. It was said to make more power and get slightly better fuel burn; but all of this was at a price. The YF120 was complicated, and expensive. The technologies weren't considered by the USAF to be "mature" and thus they were considered "high-risk"

The YF119 was a much simpler design, with more proven theory and technologies. It was a lower risk and lower cost engine and it was assumed that the life-cycle cost of the YF119 would be lower than that of the more complicated YF120. In the end the 'simple' / 'less risky' engine won the contract over the more complicated one.

I don't think there were any major changes made between the YF119 and the production F119. Most were minor production details when the engine had to be mass produced on an assembly line, and then maintained by the users in the field.

No specific problems with the YF/F119's development or early production come to mind; after all, it was the engine chosen by both the X-32, and X-35 teams for installation into their proposed fighters for the JSF! Cool

At least that's my take on the situation... Two Cents

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TEG

Kryptkid = Skyhigh?? I hear some similarities in the imaginative technical suggestions and the somewhat casual comments about kills.

Quote:

The YF120 was more advanced than the YF119 in many respects. It has a "variable bypass" core that could shift from a turbofan mode, to a turbojet mode as the aircraft's flight required. It was said to make more power and get slightly better fuel burn; but all of this was at a price. The YF120 was complicated, and expensive. The technologies weren't considered by the USAF to be "mature" and thus they were considered "high-risk"

That variable-bypass feature sounds really cool. Have any other engines used it before or since?

Quote:

Kryptkid = Skyhigh?? I hear some similarities in the imaginative technical suggestions and the somewhat casual comments about kills.

No, I am not skyhigh. I believe that I joined up here before he did (I'm not sure, though. I haven't checked the dates). If you don't believe me, I'm sure the moderators could clear this up.

Yes, I do try to come up with imaginative technical ideas. It's something of a hobby. What comes of technological progress without innovation? I <i>do</i> realize that some of my ideas don't work so well. But you often get more things wrong than you get right when you're imagining new technologies. Anyway, what's wrong with a CFT on the Raptor? I know that it would increase drag, but that's a penalty that has been accepted on numerous other aircraft. It's also better for stealth than wing-mounted tanks would be.

Or perhaps the suggestion for carrying AMRAAMs in the CFT was too much for you? I'm not a pilot nor a military technician, so I can't really tell you if rolling over on your back to launch a BVR shot is feasible or not. It's just my conjecture. It seems to me like it shouldn't be all that difficult if you're flying straight and level. Afterall, what's the FLCS for?

What exactly do you mean by "somewhat casual comments about kills"? I never made any claims that a BVR launch from a CFT would have a superior or inferior chance of impacting a target versus a standard launch.

The thing is, you can't just put CFT's on stealth a/c without having to extensively redesign the outside to compensate. If the changes aren't so big (like between the F-35 variants) it won't affect stealth so much. But when you start putting bulges on a/c the stealth is going to suffer unless you redesign.

Putting ordenance on top of a/c is possible, the SEPECAT Jaguar was one such plane: http://en.wikipedia.org/wiki/SEPECAT_Ja ... ing_pylons

However I can imagine it is easier to put ordenance on top of wings than on top of the body.

Another item to consider is the placement of all the sensors like MLD/DAS, EW, etc that will be blocked.

If you look at the way the wings/body of the F-22 and F-35 are blended together, it implies that the 'conformal' tanks are built right into the design of the aircraft as a whole. Note there aren't 'sides' to the engine bays/inlets like on the F-15/F-16. Not only does it add internal volume for fuel, but reduces RCS by reducing the angles at which parts of the airframe meet.

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TEG

Quote:

The thing is, you can't just put CFT's on stealth a/c without having to extensively redesign the outside to compensate. If the changes aren't so big (like between the F-35 variants) it won't affect stealth so much. But when you start putting bulges on a/c the stealth is going to suffer unless you redesign.

I'm glad you brought that up. I've noticed that the CFTs on the F-15E have a well-defined edge that delineates them from the aircraft itself. I suppose that CFTs on the Raptor would have to be smoothly blended into the fuselage without hard edges. If you build them into the fuselage like that, I guess they wouldn't really be CFTs anymore, but rather a part of the aircraft itself.

So no CFTs for the F-22, I guess.

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Another item to consider is the placement of all the sensors like MLD/DAS, EW, etc that will be blocked.

Oops, I didn't know about that. Heh.

Kryptid wrote:

That variable-bypass feature sounds really cool. Have any other engines used it before or since?

Briefly the SR-71's PW J58 engine used a "variable bleed" system on the compressor that could change flow. Not exactly "variable cycle" but the first use of the idea.

PW and GE have both worked on/with the variable by-pass or cycle technology.

See this thread, near the bottom:
http://www.f-16.net/f-16_forum_viewtopi ... rt-30.html

I have found more on the YF119/F119 differences; the F119 has a slightly larger fan for increased thrust.

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Compared with the YF119, the F119 produces 10-15% more thrust and has a 10-15% lower specific fuel-consumption

Below is a 'retouched' photo of the YF120 engine for the ATF competition.

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TEG

Sorry for the necro, but I thought it might be better to revive this thread rather than to make a new one.

1) I've seen a photograph of the F-22 from the rear aspect and I noticed that the turbines were visible. We know that the engine faces are hidden by s-ducts because they would otherwise represent good radar reflectors. It seems like this should be true of turbines as well. However, hiding the turbines using s-ducting behind the engines would be impractical due to the added weight, heating problems, and thrust reduction. Did the turbines represent a problem for engineers when considering rear-aspect RCS? I do suppose that the nozzles could help cover them somewhat, but I don't think they can hide them completely. As far as I know, the hot gases exiting the engine might act as a radar absorber/deflector in itself.

2) I read on some website that the Russians had experimented with flat nozzles of their own, but that the nozzle resulted in a thrust reduction of about 15% when compared to an axisymmetric nozzle (IIRC). Does the F119 suffer from similar thrust-reduction problems? Or did the Russians simply design their nozzles "wrong"? From the photograph I saw, the nacelle (on an Su-27, I think) was greatly extended beyond the airframe in order for the flat nozzle to be integrated. It seems like that would have added to weight and reduce efficiency.

Forum: F-22A Raptor

Some F-22 questions, ya'll!