US two generations behind Russian fighter jets

Discussion in 'General Science & Technology' started by Billy T, Jan 6, 2008.

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  1. cosmictraveler Be kind to yourself always. Valued Senior Member

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  3. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I will not be making many more (perhaps none) post here as I know little about jet fighters and dog fights. I think all agree that as I said : "dog fight separations (a few kilometer with missles, ..." and as cosmictraveler said: "Fighters don't get within 5 miles of each other any longer so the way a fighter handles isn't really important any longer. ..." that "dog fights" in the modern era are distant engagements where often neither pilot sees the other plane.

    This does not mean that the missle rapidly closing on its target can not be caused to miss by a jet which can rapidly switch* to flying "side ways" to stop in mid air and then drop tail first** in a cloud of chaff and opaque hot smoke it is releasing. The atacking missle can only make relatively slow smoove turns and even if it gets close, still needs some terminal guidance. Thus I question the validity of the last part of Cosmictravler's text quoted above.

    With reguard to the ref on Lawrence L. Labs, unfortunately I do not have it. I have an old Cornell class mate who is very into airplanes, sends photos from air shows etc. He emailed the link, the LLL text and some of his comments, which I quoted. Little of OP is mine.

    I think the term "dog fight" is still useful even if fighters are a few miles apart as not all of the air space is within range of SAMs (and much of want is will be known, except for mobil SAMs, so often the intercept will be (if made) by a relatively short range fighter lunched missle - that is the modern dog fight. Both may get missles off before either missle reaches it target. Thus the "winner" is the plane than can out manuever the attacking missle by things like the SU-30 can do.

    I think especially important may be the ability to hide in "defensive cloud" that the target has just made, as that cloud could easily be made of radar chaff and opaque hot gases.
    -------------------
    *Must play hell with the missel's computer constantly projecting the intercept point to fly to.

    **BTW, some moths do this to avoid being eaten by bats. They detect the bat's dynamically changing "chirp" and from it know they are his intended lunch. A small fraction of a second before being eaten, they fold their wings into body and drop, causing bat to fly over them. Seems likely to me that the SU-30 could do the same, but it would start to make the hot opaque chaff cloud a few seconds prior to missle's fly by miss.
     
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  5. Neildo Gone Registered Senior Member

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    Jumpsweet said it best in the comments section of either that video or another:

    - N
     
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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I do not know but think the F22 must leave much more of a radar signature in its hot exhaust gas alone that the relative mild "clear air turblence" that is commonly avoided by comercial passenger liners.

    I really doubt that stealth planes are as "invisible" as some here are suggesting. Certainly, not very invisible to bi-static radars as they have often been accidently detected by FAA radars. E.g. the Trenton NJ radar beam bounce off one of the flat surfaces, mirror like, makes a short lived (perhaps only a few seconds) blip on JFK air trafic controller's radar screens.

    It is not in the budgetary interest of the USAF to tell how easily they can be detected by bi-static radars, but continuous tracking of them is surely much harder until they are close enough to have accomplished their mission. (Probably not by chance that the stealth bomber came first in the development line.)
     
  8. Harnu Semper Fidelis Registered Senior Member

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    Not as into jets as I once was, but I noticed you all keep mentioning the F22. We've got a new toy coming around aswell, the F-35 II Lightning.

    In any case, if you're curious about any Soviet jet vs American jet, just watch Top Gun

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  9. Challenger78 Valued Senior Member

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    The f-35 is a maintenance hog, and extremely expensive. Much better off with upgrading and maintaining current F-18E/F. (australia only has F/A 18 As and bs

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  10. Buffalo Roam Registered Senior Member

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    Intresting observation, as the Plane isn't on line yet.
     
  11. Challenger78 Valued Senior Member

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    Projections show that it is much easier to upgrade existing airframes than buy and maintain new ones.
     
  12. Buffalo Roam Registered Senior Member

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    But all airframes reach service life limits.

    Now post the projections, citation would be appreciated.
     
  13. Nasor Valued Senior Member

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    Stop from what initial speed? The SU-30 has a top speed of around 375 m/sec near sea level. If by "seconds" you mean 5 seconds then the plane would be subjecting itself to about 75 Gs of acceleration - which would surely be enough to break the plane into small pieces. Heck, even if the plane could take it I suspect that would be enough to kill the pilot.

    You'll note that the people at Livermore Labs said that it out-performs our aircraft in near combat situations. As has already been pointed out, dog fights are very rare; modern air-to-air combat involves missiles fired from very long rages, and an aircraft's top speed and rate of climb are generally far more important than maneuverability.
     
    Last edited: Jan 8, 2008
  14. Enmos Valued Senior Member

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  15. Echo3Romeo One man wolfpack Registered Senior Member

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    In fact, yes, stealth craft are not completely invisible to all radars. Their composition and design is such that their radar cross section is significantly reduced to something much less than it otherwise would be (for example the B-2 is said to have an RCS the size of a bumblebee wrapped in aluminum foil) and that reduces the detection radius of the aircraft enough to allow them to pass through gaps in an enemy's air defense radar picket line. Due to other design features, the stealth technology doesn't do the whole stealth thing to as great a degree when being pinged with a low-frequency (UHF) radar beam. Fortunately, low-frequency radars are generally not too big a deal for the following reasons:

    1) They require a positively obscene amount of amplification to work. This means that you are losing a ton of accuracy. The instant someone makes a completely lossless amplifier they will have solved the detection of stealth problem. They will have also violated every law of physics out there. This means that the radars are inherently lossy and cannot provide a high-resolution track. You may get lucky with a sidelobe paint, which will tell you that something is in your resolution cell, but your resolution cell at those frequencies is huge so it is not useful for developing telemetry for things like SAMs, AAA, etc. Best case, you could get a general area to vector some fighter cover to promptly get shot out of the sky.

    2) Due to the whole radar equation thingy (decent link for those interested here) in order to get usable returns without having absurd amplification requirements, you have to maximize the surface area of the radar. This means a bigass array of parasitic antennas, which also means that radar is going to either be on a bigass ship or a stationary building. This leads to "cruise missile up the ass" syndrome because these targets are just begging for it.

    Now, a few of my thoughts about other detection capabilities that could be used:

    Optical/laser search will detect a stealth aircraft, yes. Problems with this: if the craft is BVR, you're screwed; if the weather is shitty, you're screwed; if its range is pretty limited, you're screwed. I'm pretty sure the best-day range of a laser system is pretty awful (based purely on my own experience directing airstrikes with a GLD in different environments) and the figures I've seen on existing systems bear that out.

    Current radars detect stealth aircraft, absolutely. Stealth aircraft aren't completely invisible, the difference is that their sigma (reflectivity) is significantly less than a comparably-sized aircraft. Go up to that neat link I have earlier, read the equations, and you'll immediately note that stealth aircraft have a finite maximum detection distance. You will also note that it is much less than a conventional aircraft, and that the detection distance is well within the standoff range of almost every air to surface missile in service, to include the AGM-88 HARM. Pulsing radar into the sky is like walking through the woods at night with a giant flashlight: you probably won't see shit with your flashlight, but I can guarantee you that everyone in that wood knows exactly where you are and can dispatch you on their terms.

    As for a heavily distributed, low power detection network (e.g. cell phone arrays and other multistatic radars), I have heard more than enough anecdotes but haven't seen a white paper about it yet, and it is not for lack of searching. In the off chance that it has been researched and I just can't find the paper in the IEEE, I'll point out a few problems this would have. They still aren't at all designed for target track, they operate at high frequencies (and therefore have a tiny range of detection, although this is offset by the sheer number of them in an industrialized country), and will really give you no better idea than that low-frequency radar when it comes to "where the fuck is this thing coming in supersonic about to bomb us?" Furthermore, low power distributed network radars have been around for ages, and haven't put a huge dent in stealth aircraft so far. Cell phone towers just happen to already be in place, which would make them convenient radiation sources if the technology worked better.

    I apologize for the rather disjointed nature of this post, and I realize that it contains well more than what you were discussing, but since I was on the subject I figured I would add what I could and ramble a bit.
     
  16. spidergoat pubic diorama Valued Senior Member

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    It doesn't matter. The cold war is over, we aren't going to fight the Russians.
     
  17. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    This "bumble bee" radar cross section statement is non-sense for a plane with many flat surfaces. The radar cross section is a strong function of aspect angle, even for ordingary objects like cars and airliners. Surely for the F22 it varies by at least a factor of 100 as the aspect angle changes. The "bumble bee" radar cross section I strongly suspect it the nose on radar cross section, which by design is the smallest value in the 4 pi ster-radians. If the any of the F22's large flat surfaces is perpendicular to the radar beam, even a conventional (not bi-static) radar will detect it at significant range compared to a bumble bee's detection range.
     
  18. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Even the very high flying, Mach 3+, U2 was shot down (with Gary Powers captured alive) several decades ago by USSR's SAM.

    I think the part of your text I made bold is false for long range missle engagement. No plane can out run a modern SAM or air lauched rocket. The only way to make is miss is to either decoy it (flairs if it is heat seeking or chaff if radar guided) or to "duck" it at the last second (Be much more maneuverable than the SAM, Which is no problem for the SU-30 and possibly not for the F22 also, but I have not seen what it can do)

    Again I am impressed by the SU-30's ability to hid in hot, opaque, chaff cloud it has just made, as we saw in the video of the OP. The fact that it can "dance around" in the air must strongly stress the missel's intercept computers, perhaps even the missle's ability to track it. - Normally, to avoid cloud returns etc, there is a Doppler filter that is a "window bracket" on the target's speed. The SU-30 may be able to achieve same velocity as the near-by cloud. - i.e. "escape out of the Doppler window" used by the missle causing the attacking missle not only to miss, but even to lose track.
     
    Last edited by a moderator: Jan 8, 2008
  19. kevinalm Registered Senior Member

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    The U2 was (very) subsonic. Basically an overgrown sailplane with a jet engine, that we thought mistakenly flew to high to be reached by a SAM. We were wrong.

    The Blackbird flew high _and_ fast (M3+) and was never shot down, afaik.
     
  20. Buffalo Roam Registered Senior Member

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    Maximum speed: 434 knots (500 mph, 805 km/h)
    Cruise speed: 373 kt (429 mph, 690 km/h) a long way from Mach 3+


    [edit] Specifications (U-2S)
    Data from International Directory,[14] Global Security,[15] USAF Fact Sheet,[16]

    General characteristics
    Crew: One
    Length: 63 ft (19.2 m)
    Wingspan: 103 ft (31.4 m)
    Height: 16 ft (4.88 m)
    Wing area: 1,000 ft² (92.9 m²)
    Empty weight: 14,300 lb (6,760 kg)
    Max takeoff weight: 40,000 lb (18,100 kg)
    Powerplant: 1× General Electric F118-101 turbojet, 19,000 lbf (84.5 kN)
    Performance
    Maximum speed: 434 knots (500 mph, 805 km/h)
    Cruise speed: 373 kt (429 mph, 690 km/h)
    Range: 5,566 nmi (6,405 mi, 10,300 km)
    Service ceiling 85,000+ ft (25,900 m)
    Flight endurance: 12 hours
     
  21. Echo3Romeo One man wolfpack Registered Senior Member

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    We never fought the Russians during the Cold War, either, but we seemed to find ourselves toed up against their export hardware an awful lot.

    Yes, RCS varies infinitely with aspect angle from the transmitter.
     
  22. Gustav Banned Banned

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    that vid overwhelmed

    /overwhelmed
     
  23. Gustav Banned Banned

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    /speechless
     
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