F-22 supercruise real stealthyness?

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Wildcat

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Unread post10 Dec 2003, 19:25

I recently read on CodeOne website that the Raptor was able to supercruise at Mach 1.5 (i.e. fly without using afterburner). It is said to be a potent tactical advantage for the Raptor. I agree with that, but I wonder if such a high speed would not have a big effect on the external temperature of the plane, making it much easier to detect by Infra-red sensors. If I'm right, it would make the Raptor's stealthyness to radar detection a little pointless :? .
What do you think about it? Do you have some information about that subject?
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Habu

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Unread post10 Dec 2003, 19:28

Mach 1.5 doesn't produce that much of a temperature increase. It increases at a higher rate the faster you go, but at 1.5 Mach, it's not such a marked difference.
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habu2

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Unread post10 Dec 2003, 19:35

I think the real tactical advantage of supercruise is the extended range of the aircraft when compared to another jet having to consume large amounts of fuel to fly similar speeds. If you spend very much time in AB in an F-16 (or any other comparable jet) you are going to bingo and have to leave the fight (or die), in the F-22 you should be using less fuel and increasing time on station (or on CAP). You are not going to be doing a lot of evasive maneuvering at M1.5 anyway except extending to escape the fight and live another day.
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Wildcat

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Unread post10 Dec 2003, 20:26

Supercruise is also a major advantage for missile lauching: a fleeing Raptor will be hard to hit as its speed will greatly reduce the possible range of missiles lauched at it, and any missile launched by a Raptor will benefit from a major boost in range.

Thanks, Habu, for info. I know I ask a lot, but does anybody have some figures (graphics, etc...) about how temperature increases with speed?
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Habu

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Unread post10 Dec 2003, 20:36

I could look at my Blackbird books during lunch, see what I can find...I KNOW they did thorough studies into this phenomena.
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kmceject

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Unread post10 Dec 2003, 20:42

The current issue of National Geographic has an article on future flight and they cover the F/A-22 to some degree. One of the more interesting quotes deals with Paul Metz, Lockheed-Martin test pilot. He states that in one test he went head-on against an F-15 which had been given his position and was scanning for him with radar. He was first picked up by the Eagle pilot visually as his jet overflew the canopy of the Eagle.

Not fair in this instance as the Eagle has no IR scanner, and it doesn't mention if any thermal imager was available on board.

From my knowledge of ejection seats I know that ejecting at high Q does cause an instant temperature pulse such that SR-71 pilots and X-15 pilots need the pressure suit as much for temperature abatement as for the pressure and oxygen. I'll have to check my references and see if there is any formula that would help with this. I know that the X-15 case included a Mach 4 ejection which led to a 600 degree heat pulse. At lower Mach numbers, Mach 2 and below, there is no special requirement in the specs for protecting the pilot from the heat pulse. I also know that CAPT Brian Udell ejected at 780mph and no burns were reported in his list of injuries. (780mph equates roughly to somewhere in the 650 KEAS range. Since we are talking Mach number KEAS is somewhat irrelevant though. The friction of the air is the issue. Udell's ejection would have been somewhat over Mach 1, but in the low numbers. He left the aircraft below 6,000ft.)
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habu2

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Unread post10 Dec 2003, 21:10

Temperature rise due to aerodynamic friction is a function of both speed and shape. Sharp edges get hotter quicker, blunt edges more slowly. Also, the lower air density at altitude is a factor. F-111s had the equivalent of a 'stopwatch' when they would fly high speed at low altitude - it basically told them how long they could fly at speed before the windscreen would start weakening from aerodynamic heating. Afraid I don't know much more detail about the -111 system, I'll have to check my references at home.
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elp

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Unread post10 Dec 2003, 22:07

While no system is perfect. The first indication that there are Raptors around would be noticing jets on your team start falling out of the sky from volleys of AMRAAMs. These are shrude people. They aren't going to play fair. If needed they will launch a volley, break, put on speed to egress a bit, turn around and re-evaluate and see what is left to kill. Not something I would want to fight at night, which by the way is when an oponent will most likey die against this jet as it will be used premptively as part of a major strike on opponents airfields, C3, SEAD/DEAD etc. Either you rise to try and stop these massive strikes or you wont have a useable airfield to do it later. Just a few players on the F-22 team would be:

B2 with the ability to hit 80 different targets in all weather conditions ( 80 JDAMS )
JASSM cruise missile ( now operational )
F117 with Enhanced Paveway
SBDs ( in massive numbers from every platform, including F22)
Massive amounts of decoys,

Again not very fair and not something you are going to put a conventional designed jet in the air against this onslaught and expect anything except to have your face put down in the mud and trampled on.
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habu2

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Unread post10 Dec 2003, 22:42

Fair? War? ;)
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Wildcat

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Unread post10 Dec 2003, 23:10

Sure, war is not supposed to be fair. I remember, two or three years ago, when I learnt what the Raptor could do (only talking about the aircraft , not even about its avionics), I thought a lot about what it actually meant for air combat: I concluded that the words air dominancewere pretty relevant to describe the effectiveness of the Raptor. I only found three ways to detect a Raptor, actually:
1. using long waves radars (like WWII radars or using TV waves) would enable to make the Raptor appear on a radar screen, but it would be so unprecise that you could not use it to guide any weapon onto the Raptor. It would only give you a general idea about where the Raptor stands, which would not be very useful against such an easily fast-moving target
2. just being able to see it, which means a lot of luck, because a AMRAAM-armed Raptor would probably not let its opponent have sufficient time to scan the sky and find it
3. sound detector, like in 30's before the advent of radars. No comment... :wink:
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Habu

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Unread post10 Dec 2003, 23:15

All's fair in love & war! :D
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Lawman

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Unread post11 Dec 2003, 07:38

Hey, they knocked a previously untouchable F-117 out of the air over Kosavo, all it takes is something. And its not like the Chinese, Russians, North Koreans, Iranians....ect ect wouldnt love to figure out a way to see threw the Low Radar observability we have now.

I agree though I cant see the Airforce using its pretty new F/A-22(I dont know who there trying to fool with the A) for anything besides the mission previously flown by the F-15C's Air Superiority. That would be something to see in 10 years, the Strike Viper. Cause nomatter how much they talk up the F-35 that thing is no bomber. Sometimes you need a plane that can carry a large number of conventional weapons.


Little thing about the supercruise element. It requires incredible toleranes to achieve such efficency, that inflexability to problems is a major shortfall when you look at useability. Sure it will eventually be solved, but I wouldnt be suprised if you see the same kind of reliability problems incountered by the Apache the first time it was deployed for actual combat.
Drew
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Wildcat

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Unread post11 Dec 2003, 09:42

The F-117 seems to have been downed because somebody forgot the old hard-learnt lessons: they sent the Nighthawk on the same path to target twice, in daylight :? . The Serbs just proved they were not to be more stupid than anybody else, and they set a missile laucher (likely to be SA-6 but it is not known for sure as far as I know) on the path, acquired the plane visually and fired at it (probably several missiles and AAA rather than one missile only, remember they are not stupid). It is that simple: somebody became too arrogant or too dumb, maybe believing that Nighthawks were a kind of ghost planes and got dramatic consequences :cry: .
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Habu

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Unread post11 Dec 2003, 10:15

It even took 14 SA-2s to knock Franics Gary Powers out of the sky, and not one of those misslies actually struck the aircraft.
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habu2

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Unread post11 Dec 2003, 14:47

F/A-22 (I dont know who there trying to fool with the A)

Congress.
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