Lockheed Martin F-22 Raptor

[Steve Pace]

one can do only so much with shape. while i do believe shape was far more important in the past, with f22 and later projects i do suspect materials play an ever increasing role, perhaps even more than half the rcs reduction for certain wavelengths.

The late great Lt. Gen. David J. "Marshall" McCloud - a former F-117 driver who was later on the ATF selection board told me that the success of very low observables aircraft depends on shape (as much as 85%), the remaining percentage on hiding engine(s), heat emission(s), and RAM. -SP

 

[overscan (PaulMM)]

http://www.ijrame.com/vol2issue1/V2i105.pdf

Some interesting observations here. I was always under the presumption that stealth was about shape, shape, shape, and RAM. This article seems to suggest that RAM is responsible for a good part of the F-22's low RCS. That said, the model used in this simulation may have questionable accuracy. Perhaps more knowledgeable people here can chime in?

The 3D models used appear to be far too simplified to give a meaningful result to me.

 

[stealthflanker]

http://www.ijrame.com/vol2issue1/V2i105.pdf

Some interesting observations here. I was always under the presumption that stealth was about shape, shape, shape, and RAM. This article seems to suggest that RAM is responsible for a good part of the F-22's low RCS. That said, the model used in this simulation may have questionable accuracy. Perhaps more knowledgeable people here can chime in?

Saw this paper before.

The computer model is yes inaccurate and might be not to scale.

The main point of the paper though is to demonstrate detection range of radar in different freque ncyagainst F-22's. It has good and simple approximate calculations.

So basically that paper states that.. VHF band will have roughly 8 times detection range of X-band, L-band would be 1.7 times, given same radar and RCS parameter.

 

[overscan (PaulMM)]

Shaping *alone* might give that relationship, assuming that there are no special materials or ECM techniques in play.

 

[bring_it_on]

F-22 Low Speed Wind tunnel Buffet testing

https://www.scribd.com/doc/260439899/F-22-LSWTBT?secret_password=mHbERbaIMVY2I0XqAuMV

 

[fightingirish]

http://news.usni.org/2014/05/16/air-force-evaluating-new-targeting-monocle-f-22-raptor#more-7787
Air Force Evaluating New Targeting Monocle for F-22 Raptor [...]

The U.S. Air Force has started the integration phase of the AIM-9X missile on the F-22. B)

[...]The 411th Flight Test Squadron and F-22 Combined Test Force (CTF) successfully test fired two guided AIM-9X Sidewinder missiles this year as part of the latest phase in getting the Raptor closer to using the missile operationally.[...]
The F-22 CTF has helped develop the modified launch rail as well as the basic software for integration of the AIM-9X into the aircraft avionic system.[...]

Source: edwards.af.mil - Raptor test force enters new phase of AIM-9X testing

 

[bobbymike]

From AFA:

Raptor Keeps Amazing


—John A. Tirpak

6/2/2015

​No Air Force missions into Syria happen without F-22s playing a pivotal role, said Gen. Hawk Carlisle, head of Air Combat Command, on Monday. “What we have learned” about using the F-22 in combat is its "ability … to enhance everybody else," he told the audience at an AFA-sponsored Air Force breakfast event in Arlington, Va. "It’s amazing what that airplane can do,” he said, noting its impressive situational awareness, "its ability to get there, its sensor suite, its ability to pass information,” and, of course, to defend airspace and drop weapons. Carlisle recounted the story of one F-22 pilot who recently conducted an extraordinary mission. “He did a mission, took off at about 6:05 at night and landed about 6:30 the next morning," he explained. The pilot switched to different roles numerous times during the mission. He "went to the tanker about seven times, did strikes, escort…. He did redirect, did [intelligence surveillance, and reconnaissance], and passed data," said Carlisle. Navy F/A-18 pilots, after an early exercise with Raptors in a wargame called Northern Edge, said they would never disparage the F-22 again, because it’s “making everyone all that much more effective,” said Carlisle. It wasn’t possible to tell whether he called the 2010 “decision not to buy any more of the F-22s” a “fateful” one or “fatal.”

 

[sferrin]

]It wasn’t possible to tell whether he called the 2010 “decision not to buy any more of the F-22s” a “fateful” one or “fatal.”[/b]

Right up there with MacNamara's Blackbird decision. Gotta love egomaniacs.

 

[bobbymike]

]It wasn’t possible to tell whether he called the 2010 “decision not to buy any more of the F-22s” a “fateful” one or “fatal.”[/b]

Right up there with MacNamara's Blackbird decision. Gotta love egomaniacs.

You know what an incredible conventional deterrent 400-700 Raptors would be?? At 40 to 60 a year since cancellation we'd be approaching the high 300's already. What a waste.

 

[bobbymike]

http://breakingdefense.com/2015/06/secaf-james-russia-is-biggest-threat-f-22s-may-come-soon/

When the F-22 are spread TOO thinly across the globe with 'penny packets' hither and yon will Gates be held to account for his decision?

 

[Bruno Anthony]

]It wasn’t possible to tell whether he called the 2010 “decision not to buy any more of the F-22s” a “fateful” one or “fatal.”[/b]

Right up there with MacNamara's Blackbird decision. Gotta love egomaniacs.

I never got the love affair many conservatives have with Mr. Next-war-itis. Now we have more MRAPs than we can ever use and not enough F-22s. Thanks Bill!

 

[sferrin]

I never got the love affair many conservatives have with Mr. Next-war-itis. Now we have more MRAPs than we can ever use and not enough F-22s. Thanks Bill!

Uhm, wut?

 

[RadicalDisconnect]

I never got the love affair many conservatives have with Mr. Next-war-itis. Now we have more MRAPs than we can ever use and not enough F-22s. Thanks Bill!

Uhm, wut?

I think he's referring to how Gates, a Republican, was so focused on Iraq that he seemed to neglect the ability to counter near-peer adversaries.

On an unrelated note, here's something about the F-22 in the latest Air International I thought was interesting.

"It can cruise at 40,000ft (12,192m) at Mach 1.2 (1,470km/h), with the nose heading 20 degrees off the course of travel to enhance stealth."

So it can supercruise with 20 degrees alpha? ???

 

[bobbymike]

I never got the love affair many conservatives have with Mr. Next-war-itis. Now we have more MRAPs than we can ever use and not enough F-22s. Thanks Bill!

Uhm, wut?

I think he's referring to how Gates, a Republican, was so focused on Iraq that he seemed to neglect the ability to counter near-peer adversaries.

On an unrelated note, here's something about the F-22 in the latest Air International I thought was interesting.

"It can cruise at 40,000ft (12,192m) at Mach 1.2 (1,470km/h), with the nose heading 20 degrees off the course of travel to enhance stealth."

So it can supercruise with 20 degrees alpha? ???

I interpret that as 20 degrees but still in level flight my amateur opinion of course.

 

[TomS]

Agreed; I read that as level flight with 20 degrees yaw to present the best possible alignment to a specific sensor.

 

[LowObservable]

That would be a remarkable feat of aerodynamic and propulsive technology. Consider the fact that you're going M=1.2 with one wing swept 62 deg and the other swept 22 deg. Consider the cross-sectional area that the body presents to the airflow and what the shock off the nose looks like. Consider the side loads on the vertical tails and the fact that one H-tail is now washed by turbulent flow in the wake of the body. Consider the asymmetric conditions at the engine inlets.


I call shenanigans.

 

[bobbymike]

That would be a remarkable feat of aerodynamic and propulsive technology. Consider the fact that you're going M=1.2 with one wing swept 62 deg and the other swept 22 deg. Consider the cross-sectional area that the body presents to the airflow and what the shock off the nose looks like. Consider the side loads on the vertical tails and the fact that one H-tail is now washed by turbulent flow in the wake of the body. Consider the asymmetric conditions at the engine inlets.


I call shenanigans.

Not a perfect comparison as you're turning the whole plane but I think aerodynamically it could be done for short periods of flight for sensor alignment as TomS wrote.

 

[totoro]

its ability to pass information....
and passed data,"

can someone enlighten me here? Pass what sort of info in which way? I was under the impression only way raptor can pass info is A) by voice over radio and B) sending data to another raptor flying close by.

are they talking about something else here? Has a proper datalink terminal and its arrays been installed recently?

 

[TomS]

The F-22 can pass data via an intermediary system like BACN, which can receive the Intra-Flight Data Link and reformat and retransmit the data via another network like Link 16.

http://www.irconnect.com/noc/press/pages/news_releases.html?d=142636.

 

[AeroFranz]

That would be a remarkable feat of aerodynamic and propulsive technology. Consider the fact that you're going M=1.2 with one wing swept 62 deg and the other swept 22 deg. Consider the cross-sectional area that the body presents to the airflow and what the shock off the nose looks like. Consider the side loads on the vertical tails and the fact that one H-tail is now washed by turbulent flow in the wake of the body. Consider the asymmetric conditions at the engine inlets.


I call shenanigans.

Not a perfect comparison as you're turning the whole plane but I think aerodynamically it could be done for short periods of flight for sensor alignment as TomS wrote.

I appreciate the fact that you mentioned that this may be an imperfect comparison. That being said, i will pitch in my .02.
This is too much of apples and oranges, me thinks. In the case of the AD-1, there is virtually no shift in the center of lift, nothing really to generate yaw moments since the fuselage remains straight and whatever asymmetric yaw the forward swept side vs. the rearward swept side generates is small.
Notice that there are no oblique wings that are not also straight, so planform geometry matters to make it viable.
Also i doubt it ever flew at anything above 200 KTAS.
The closest thing i can think of was F-16 AFTI, but you need some sort of force effector (aerodynamic surface, thrust vectoring) in order to cancel any moments and keep the vehicle aligned in the desired orientation.

 

[Jeb]

The closest thing i can think of was F-16 AFTI, but you need some sort of force effector (aerodynamic surface, thrust vectoring) in order to cancel any moments and keep the vehicle aligned in the desired orientation.

I wonder if computer-controlled differential thrust and drag induction could make that work on a Raptor? Sort of like how the B-2 achieves yaw control, but instead of split ailerons, you've got different surfaces deflecting just enough to put that yaw on. Seems like you could get the FCS to do that on request, even though it wouldn't do your range any favors.

 

[bobbymike]

That would be a remarkable feat of aerodynamic and propulsive technology. Consider the fact that you're going M=1.2 with one wing swept 62 deg and the other swept 22 deg. Consider the cross-sectional area that the body presents to the airflow and what the shock off the nose looks like. Consider the side loads on the vertical tails and the fact that one H-tail is now washed by turbulent flow in the wake of the body. Consider the asymmetric conditions at the engine inlets.


I call shenanigans.

Not a perfect comparison as you're turning the whole plane but I think aerodynamically it could be done for short periods of flight for sensor alignment as TomS wrote.

I appreciate the fact that you mentioned that this may be an imperfect comparison. That being said, i will pitch in my .02.
This is too much of apples and oranges, me thinks. In the case of the AD-1, there is virtually no shift in the center of lift, nothing really to generate yaw moments since the fuselage remains straight and whatever asymmetric yaw the forward swept side vs. the rearward swept side generates is small.
Notice that there are no oblique wings that are not also straight, so planform geometry matters to make it viable.
Also i doubt it ever flew at anything above 200 KTAS.
The closest thing i can think of was F-16 AFTI, but you need some sort of force effector (aerodynamic surface, thrust vectoring) in order to cancel any moments and keep the vehicle aligned in the desired orientation.

I was looking at a top view of an F-22 and turned my laptop screen approximately 20% and the new wing location while the plane was still flying straight ahead reminded me of the pictures I has seen of an oblique wing.

I figured the aerodynamics would be much different with the F-22's swept wing but don't have the knowledge to understand the difference so thanks for your explanation.

 

[Flyaway]

U.S. F-22 Raptor stealth jets provide kinetic situational awareness over Syria

Although they were not conceived to play this kind of role, F-22 Raptors have emerged as some of the U.S.-led Coalition’s most reliable combat assets in supporting coalition planes during air strikes in Syria and Iraq.

“We are operating regularly in Iraq and Syria. The F-22’s advanced sensors and low-observable characteristics enable us to operate much closer to non-coalition surface-to-air missiles and fighter aircraft with little risk of detection,” said Lt. Col. J. (name withheld for security reasons) in a recent 380th Air Expeditionary Wing release. “We provide increased situational awareness for other coalition aircraft while simultaneously delivering precision air-to-ground weapons. This allows us to reduce the risk to our forces while mitigating the risk to civilian casualties, one of our highest priorities in this conflict. It is a true multirole aircraft.”

http://theaviationist.com/2015/08/15/f-22-kinetic-situational-awareness/

 

[bobbymike]

U.S. F-22 Raptor stealth jets provide kinetic situational awareness over Syria

Although they were not conceived to play this kind of role, F-22 Raptors have emerged as some of the U.S.-led Coalition’s most reliable combat assets in supporting coalition planes during air strikes in Syria and Iraq.

“We are operating regularly in Iraq and Syria. The F-22’s advanced sensors and low-observable characteristics enable us to operate much closer to non-coalition surface-to-air missiles and fighter aircraft with little risk of detection,” said Lt. Col. J. (name withheld for security reasons) in a recent 380th Air Expeditionary Wing release. “We provide increased situational awareness for other coalition aircraft while simultaneously delivering precision air-to-ground weapons. This allows us to reduce the risk to our forces while mitigating the risk to civilian casualties, one of our highest priorities in this conflict. It is a true multirole aircraft.”

http://theaviationist.com/2015/08/15/f-22-kinetic-situational-awareness/

At the risk of being admonished by the Mods for repeat posts - I really wish we had more of these, just think if you had a Raptor 2-ship for every 4-ship F-35 package (or the original 750) If the line stayed open we would be approaching 350 aircraft by now. Will go down, IMHO, as one of the biggest mistakes in aviation history.

 

[Sundog]

At the risk of being admonished by the Mods for repeat posts - I really wish we had more of these, just think if you had a Raptor 2-ship for every 4-ship F-35 package (or the original 750) If the line stayed open we would be approaching 350 aircraft by now. Will go down, IMHO, as one of the biggest mistakes in aviation history.

I'll actually disagree with that, and it's simply because we're never going to need all 183 Raptors at once. It's funny how people always tie systems to airframes. I would argue that the F-22 is overkill for that role. In fact, it would seem to me that that is the role more suited for the F-35C, at least that's how the Navy is planning on using it's F-35s. So, while I'm not a fan of the F-35 for various reasons, I would argue that the Pentagon made the right choice in shutting down the Raptor line, if that's the rationale for keeping it open.

 

[sublight_]

At the risk of being admonished by the Mods for repeat posts - I really wish we had more of these, just think if you had a Raptor 2-ship for every 4-ship F-35 package (or the original 750) If the line stayed open we would be approaching 350 aircraft by now. Will go down, IMHO, as one of the biggest mistakes in aviation history.

I'll actually disagree with that, and it's simply because we're never going to need all 183 Raptors at once. It's funny how people always tie systems to airframes. I would argue that the F-22 is overkill for that role. In fact, it would seem to me that that is the role more suited for the F-35C, at least that's how the Navy is planning on using it's F-35s. So, while I'm not a fan of the F-35 for various reasons, I would argue that the Pentagon made the right choice in shutting down the Raptor line, if that's the rationale for keeping it open.

But given the current miniscule price differential between F-35 and F-22, we certainly could have used another 100 Raptors. Maybe not against every ISIS-come-lately, but if another super power decides to get super stupid.....

 

[Triton]

At the risk of being admonished by the Mods for repeat posts - I really wish we had more of these, just think if you had a Raptor 2-ship for every 4-ship F-35 package (or the original 750) If the line stayed open we would be approaching 350 aircraft by now. Will go down, IMHO, as one of the biggest mistakes in aviation history.

A United States Air Force study released in September 2002 set the requirement at 381 aircraft. 240 primary aircraft and an additional 141 aircraft for training, attrition, and to allow for periodic depot maintenance. The 240 primary aircraft would be distributed to the then ten active Air Expeditionary Wings/Groups to form ten squadrons of 24 F-22A aircraft each.

Source:
http://www.globalsecurity.org/military/systems/aircraft/f-22-production.htm

In 2008, then Air Force Chief of Staff General Norton Schwartz reduced the number to 243 aircraft.

A 2010 RAND report looked at re-starting the F-22A production line to produce an additional 75 aircraft bringing the number to 262 aircraft.

I wonder what the military requirement for the F-22A would be today given what has happened since 2009.

If Robert Gates and the Obama Administration had known what was going to happen since 2009, would they have ended F-22A production at 187 aircraft in 2009?

 

[Dragon029]

But given the current miniscule price differential between F-35 and F-22, we certainly could have used another 100 Raptors. Maybe not against every ISIS-come-lately, but if another super power decides to get super stupid.....

Assuming the FRP price is met (a big assumption, but one which I think is fairly reasonable, considering the efforts and emphasis that have been put in by the services and LM / contractors), you're looking at an F-35A that's almost exactly half the price of the last F-22s off the production line; not exactly a minuscule price differential.

 

[bring_it_on]

If Robert Gates and the Obama Administration had known what was going to happen since 2009, would they have ended F-22A production at 187 aircraft in 2009?

There would have been plenty of reasons to buy some more if someone had the foresight but at the end of the day they are investing some money into next generation prototyping so they will have plenty of options a decade from now if they need to make changes to the inventory.

 

[totoro]

Maybe it's worth mentioning that f-15 production, back in the cold war, gave usaf some 870 aircraft up to 1986. with attrition, perhaps 800-ish throughout 1980s? That's at a time of perception of much, much greater danger and at a time when su-27, mig-29 and mig-31 were entering service from 1981 to 1985. and yet, the decision was made to terminate fighter variant of f15 for usaf with last planes being made just as su-27 achieved initial service.

Compared to that, stopping f-22 production at 180ish planes when perceived enemies have both far less planes which are less advanced seems quite normal.

 

[sferrin]

Maybe it's worth mentioning that f-15 production, back in the cold war, gave usaf some 870 aircraft up to 1986. with attrition, perhaps 800-ish throughout 1980s? That's at a time of perception of much, much greater danger and at a time when su-27, mig-29 and mig-31 were entering service from 1981 to 1985. and yet, the decision was made to terminate fighter variant of f15 for usaf with last planes being made just as su-27 achieved initial service.

Compared to that, stopping f-22 production at 180ish planes when perceived enemies have both far less planes which are less advanced seems quite normal.

Except the plan was to have the F-22 in service in the early 90s when they ended F-15C production. Bit of a difference.

 

[totoro]

ATF's timeline clearly shows the demo prototypes couldn't have been made ready earlier than they were. after all, it was still cold war then and development went as fast as it could. so decision on the winning team was made in 1991. and that's when things slowed down, not earlier than that.

f-15 design was selected in 1969, flew in 1972, then took until 1976 to enter service.
yf17 was selected for usn in 1975, f18 flew in 1978 and entered service in 1983.

since every new generation took longer and longer to develop, f-22 would have took longer than these two examples, even with continuation of cold war and full funding and support. Basically, expecting final f-22 prototype to fly before 1994/1995 would be impossible. And then at least another 5-6 years until service entry. 1999-2001 is earliest possible timeframe f-22 could have entered service even if cold war went on and even if full funding went on.

 

[bobbymike]

http://www.weeklystandard.com/blogs/fleeting-raptor_1023492.html

Too few Raptors?

 

[sferrin]

ATF's timeline clearly shows the demo prototypes couldn't have been made ready earlier than they were.

Yeah, hindsight is 20/20 that way. That was not the original plan though.

 

[bobbymike]

The Indispensable Raptor

—John A. Tirpak 9/17/2015

​The F-22—in combat operations for less than a year—is proving “even better than we thought,” Air Combat Command chief Gen. Hawk Carlisle told reporters at ASC15. “We won’t send airplanes into certain areas” of the Syria/Iraq battlezone “unless they have F-22s with them,” Carlisle said, praising the situational awareness of the jets, their precision attack ability and capacity to serve as the quarterback of any air operation. Moreover, the F-22s are turning in mission capable rates of 75-80 percent, and “even better in the field,” he noted, and are proving “far more” maintainable than originally expected. “So far in the Middle East, they’ve flown thousands of hours and flown hundreds of sorties and dropped hundreds of bombs with incredible accuracy.” During the recent deployment of F-22s to Europe, the jets “flew 100 percent” of the scheduled sorties. The deployment “went exceedingly well,” he said, and the rapid deployment was a great messaging vehicle. “When American airpower shows up in a place people don’t expect...it sends a pretty big message. (It) assures our allies, friends, and partners, and also sends a distinct message to potential adversaries out there that we can be where we need to be when we need to be there.” Carlisle acknowledged that the number of F-22s is far too small, and when asked if USAF should buy more, said, “I dream about it every night.” Practically, though, he said the budget may just be too tight to permit such a thing, although the tooling was retained when the production line closed. Carlisle called the F-22 “extraordinary” and “really reaching its stride.”

 

[bobbymike]

http://foxtrotalpha.jalopnik.com/everyone-who-wanted-more-f-22s-is-being-proven-right-1732105884

 

[Sundog]

That would be a remarkable feat of aerodynamic and propulsive technology. Consider the fact that you're going M=1.2 with one wing swept 62 deg and the other swept 22 deg. Consider the cross-sectional area that the body presents to the airflow and what the shock off the nose looks like. Consider the side loads on the vertical tails and the fact that one H-tail is now washed by turbulent flow in the wake of the body. Consider the asymmetric conditions at the engine inlets.


I call shenanigans.

Not a perfect comparison as you're turning the whole plane but I think aerodynamically it could be done for short periods of flight for sensor alignment as TomS wrote.

I appreciate the fact that you mentioned that this may be an imperfect comparison. That being said, i will pitch in my .02.
This is too much of apples and oranges, me thinks. In the case of the AD-1, there is virtually no shift in the center of lift, nothing really to generate yaw moments since the fuselage remains straight and whatever asymmetric yaw the forward swept side vs. the rearward swept side generates is small.
Notice that there are no oblique wings that are not also straight, so planform geometry matters to make it viable.
Also i doubt it ever flew at anything above 200 KTAS.
The closest thing i can think of was F-16 AFTI, but you need some sort of force effector (aerodynamic surface, thrust vectoring) in order to cancel any moments and keep the vehicle aligned in the desired orientation.

I was looking at a top view of an F-22 and turned my laptop screen approximately 20% and the new wing location while the plane was still flying straight ahead reminded me of the pictures I has seen of an oblique wing.

I figured the aerodynamics would be much different with the F-22's swept wing but don't have the knowledge to understand the difference so thanks for your explanation.

While the oblique was an interesting idea, aerodynamically speaking, structurally speaking, it had a lot of problems at high speeds. They simply couldn't get the aeroelastic modes down to where it wouldn't rip itself apart without being too heavy. That may have changed now, with the ability to use active flight controls to control loading and flutter, but back then it certainly wasn't a viable solution.

 

[bobbymike]

http://www.wired.com/2015/10/brilliant-screens-make-f-22-sim-realistic-ever/

 

[bobbymike]

http://nationalinterest.org/blog/the-buzz/how-americas-lethal-f-22-stealth-fighter-could-dominate-the-14294

 

[bobbymike]

Book one of many to come, I'm guessing, on the worst decision, IMHO, in recent aerospace history

http://www.realcleardefense.com/articles/2015/11/27/reviewing_air_power_abandoned_longing_for_more_raptors_108730.html

Central to Dorr’s premise is that the number of F-22s procured is insufficient to meet the national defense needs of the United States. He therefore spends significant time determining what the appropriate number of F-22 deliveries should have been and why that number of F-22s was eventually capped at 187. In 1991 the Air Force selected the Lockheed F-22 Raptor as the winner of the Advanced Tactical Fighter competition over the Northrop/McDonnell F-23, and planned for the production of 749 aircraft to replace the F-15C Eagle. In 1997 Congress halved the Raptor buy, limiting production to 339 aircraft, a number that was revised upward to 381 in 2003. Cost overruns and production delays made the F-22 a political target, however, and political and military leaders continued to spar over the final size of the F-22 fleet. Then, in 2009, Secretary Gates ended the debate, if not the conversation, by directing the closing of the F-22 line. Dorr argues passionately that this decision prevented the effective recapitalization of the Air Force fighter force, and ultimately threatens the ability of the US to fight and win air wars in the 21st Century.