US two generations behind Russian fighter jets

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

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

    Yes radar pulses do reflect off solid surfaces, but all EM waves such as light or radar are reflected by any change in the density of the transparent material they are propagating thru, not just solid surfaces.

    For example, almost all larger commercial jets have "clear air turbulence detection radar." The hot gases of the SU- 30's exhaust are in near pressure equilibrium with the surrounding air but much hotter, so their density is about half that of the surrounding. (Hot gases do expand and thus lower their density.) That density discontinuity is much greater (I would guess on the order of 80 times greater) than the clear air turbulence induced density change that is routinely detected by radars of commercial jets. Was that explanation, with illustration, clear enough for you to understand? Please correct your erroneous POV that radar only reflects off solid surfaces.

    Certainly not anything like a simple command to lead the target by a fixed distance. Hell, even duck hunters don’t do that. I have seen simplified summaries of the SM -2 and HARM missile’s terminal guidance. (the full version is highly classified.) HARM’s is relatively simple as most of the time it can just home on the ground fire control radar, but if the enemy has two separately located units alternately operating on the same frequency there is the “centroiding problem.” HARM neatly solves that and some other defense attempts I cannot discuss.

    SM -2’s terminal guidance is much more complex, despite it too is basically homing on the ship’s “illuminator” radar beam’s refection off the approaching threat. I.e. the ship “paints” the target but the target may weave and thus it current trajectory must be computed and projected ahead to mutual intercept point which need not be a perfect hit as you are correct there is a folded hoop of steel which expands and cut thru the target if the physical hit miss distance is not too great.

    For your information, the Applied Physic Lab, where I worked for 30 years, invented all this, beginning in the closing years of WWII with the world’s first “proximity fuse.” That is how APL began now ~70 years of mainly saving the US Navy’s ships and designing the Aegis phased array radar, which scans 360 with no moving parts while simultaneously tracking and illuminating a large but classified number of approaching threats. So yes I know a little about all this, and I probably have forgotten much more than you know about both intercept calculations and warhead firing timing methods, which get to be very critical when ship’s defensive missile is traveling at several times the speed of sound to kill a target which is also approaching super sonically at the SM-2.

    Those number came from my use of the sun to try to explain the concept of opacity to you; but you missed the whole point. If the plum is opaque to the IR wavelengths used by the attacking missile, then it will on receive radiation from then “skin depth” Just as we on Earth only receive radiation from the upper layers of the sun (one skin depth thick only) There are a lot of unknowns here, mainly the IR absorption characteristic of the plume and the wavelength the IR guidance detector is using. All I know for sure, from the OP’s video is that in the visible it was not possible to see thru the plume to the plane. I.e. it disappeared inside its own plume. This may, or may not be true in the IR range used by the detector. The USSR, obviously believed plane was hiding against IR detection also. – They put a lot of time and money into making this “hiding” maneuver possible.

    That is correct. The exhaust leaving a jet engine is a thrust to the rear but even some commercial planes I have been on have what I think are called “claim shells” they can swing into the exhaust and redirect it forward. They are normally used on short runways to break faster than flaps alone can. – I have not seen the SU 30, “up close” but assume it has “claim shells” it can used to quickly stop forward motion ins basically level flight as appeared in the OP’s video. I don’t’ see any other way it could decelerate so quickly.

    I will ignore rest of your posts, except to agree that the FA-22’s radar is probably so much better than the Su-30’s that the FA-22 may have fired a missile at the SU-30 before the SU-30 is even able to “see” the FA-22, but if there is a missile closing on you from several Km away in your SW direction, you know it did not get there by magic. If the “duck in plume until it passes” works and you survive, you know when will arrive and you can come out of the plume to look for a second attacking missile etc.

    Again, I admit that I know little about modern air to air combat, I just know a little physic so I corrected you when you said jets work by pushing on the air or that only solids reflect radar, and here again tried to get you to understand that if a gas cloud is opaque, then you don’t see the hotter interior from the outside of it. I have no evidence that this is the case but the USSR spent a lot of time and effort making a plane capable of at least in the visible disappearing inside its own exhaust plume – It would be very strange that they failed to check the IR characteristic of the plume too. Common smoke is used to hid in by tanks etc.
    Last edited by a moderator: Oct 17, 2010
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  3. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    to Dywyddyr

    I am only quoting the US air force claim of 22 G in a tight turn. The do acknowledge that the pilot will black out and provide him with a "black out button to automatically make this drastic turn and then fly straight an level until the pilot regains consciousness and resumes control.

    Also in one of my earlier post I explained the most radars must have a Doppler lock out band to avoid be responsive to ground clutter, slow flying birds, or local rain clouds, etc.
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  5. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    I have no idea what "classified" information you've seen on HARM, but it should have noted that HARM does NOT (ever, in any way) lead the target. HARM is designed for (and used) against fixed radar installations (or, at "best", relatively slow-moving warship radars). The name is a clue - High-speed Anti-Radiation Missile.

    "Obviously"? Or do you mean that's just your opinion? Source for the claim that the USSR spent time and money on this please, everything I've seen from the Russians indicates that it is, apart from a nifty air show manoeuvre, only useful in (as previously stated) breaking a doppler radar lock.

    That would be CLAM shells, not claim.

    I have, and it doesn't.

    No they didn't.
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  7. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Source please. I doubt very much this "quote" was anything but a bullshit claim by someone shooting a line.

    Again, balls. There is NO WAY the structure is stressed for 22G. That would make the airframe itself prohibitively heavy.

    Doppler ignores anything that is "stationary". I.e. what is moving toward the aircraft at the aircraft's own speed is considered to be fixed (as if it were ground, houses, etc) and any aircraft that is going up (or down) vertically has zero relative movement laterally compared to the ground. And is consequently also filtered out.
    Last edited: Oct 17, 2010
  8. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    It is quite heavy - more than the F-15.

    Maj. Gen. Rick Lewis said: "The Raptor Operated Against All Adversaries with Virtual Impunity; … They're the first military aircraft ever built that is equipped with a "black-out button". What that means is this ... The best conditioned fighter pilots are capable of maintaining consciousness up to in the vicinity of 15+ G. The Raptor is capable of making 22+ G. turns.

    “The Raptor is capable of making 22+ G turns. If someday an adversary builds a missile that is capable of catching* up to one of these airplanes and a Raptor pilot sees that a strike is imminent, he hits the 'b.o.b.' and the airplane makes a virtual U-turn, leaving the missile to pass right on by. “

    From: which claims to be the “Military Blog – A Soldier's Perspective”

    “The F-22 is a great plane, but don't oversell it either. It is a heavy fighter larger and heavier than an F-15, it is NOT the most agile, the SU-30 with moveable forward canards and thrust vectoring engines beats it easily.” –A comment explaining why the SU-30 is more agile at:

    From your link at:
    Some performance data is given:

    Max Level Speed at altitude: 1,355 mph (2,180 km/h) at 30,000 ft (9,150 m), Mach 2 [afterburner]
    1,070 mph (1,725 km/h) at 30,000 ft (9,150 m), Mach 1.6 [supercruise]
    at sea level: 920 mph (1,480 km/h), Mach 1.2
    Service Ceiling 50,000 ft (15,240 m)
    Range typical: 2,000 nm (3,700 km)
    ferry: unknown
    Endurance unknown
    g-Limits +9.0 / -3.0

    I am not an expert but all this seems to be very conservative. For example only Mach 1.2 with afterburner operating. It is also in direct conflict with many other sources, including a quote from Maj. Gen. Rick Lewis, first given above. If it could only do 9 G, there would be no need of the “black out button” which is a automatic turn described more fully in post 126, another reference claiming G =22 also.

    I mentioned this many posts back when explaining why an SU-30 falling vertically tail first with less than 1 G downward acceleration cannot be seen by the FA-22’s radar, even if the plume is transparent to its radar beam.

    Probably ground returns could often be discriminated against by angle, but cloud reflections would need to be dropped in the Doppler filter. Range gate as an alterantive, would often fail filter when the returned energy is from a compact target like a tight flock of birds. As I recall, the Aegis radar can see birds 100 miles away, but they must be at altitude as that is far beyond the sea level horizon.

    * I don't know much about air to air missile, but the Ship launched SM-2s are much faster than the 1.2Mach reported in your reference for the FA-22's top sea level speed. I thought most of the air to air missiles could easily over take a 1.2 Mach plane if that is really all the FA-22 can do.
    Last edited by a moderator: Oct 17, 2010
  9. adoucette Caca Occurs Valued Senior Member

    That's at Sea Level.
    Which is actually quite impressive.

    It will do Mach 2 at altitude, but more importantly, it will do Mach 1.6 WITHOUT afterburner.

    Now THAT's impressive.

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

    Previously I have only corrected your errors of physics, my field, (three different corrections in post 141) but from DyWyddry’s link in post 144 I read for FA-22:
    Length 62.08 ft (18.92 m)
    Wingspan 44.50 ft (13.56 m)
    Height 16.42 ft (5.00 m)
    Wing Area 838 ft² (78.0 m²)
    Canard Area not applicable

    I.e. not only are the no controllable Canards as in the SU-30, which make it very agile,* there are no fixed canards either.
    *Probably unstably so, but some computer is dynamically stabilizing it.
    Last edited by a moderator: Oct 17, 2010
  11. fedr808 1100101 Valued Senior Member

    The F-22 can do a 22-g turn. But the pilot basically has to disable a few safeties and a lot of other stuff not normally tinkered with. Imagine the F-22 turning with literally it's thrust vectoring pointed as far as it can go, it's control surfaces also pointed as far as it can go, that would be a tight turn. I'd imagine the only reason to ever do this is if you are out of flares/chaff and it is the last chance to break a lock. You gotta admit, that tight of a turn would probably break most locks.
  12. fedr808 1100101 Valued Senior Member

    I said the F-22 had canards? My mistake, I never thought it did, I was probably trying to say the F-22 also has thrust vectoring but I was thinking faster than I was typing and I put in canards as a mistake. I apologize
  13. fedr808 1100101 Valued Senior Member

    I'm sorry billyt, it does not matter how maneuverable the SU-30 is, so long as the Sidewinder-X is more maneuverable it will get nailed ever time.

    Also, look up "thermal imaging" it allows you to make a physical image based off of IR, not only that but it can also see past hot gases like smoke and what not to other IR sources. Firefighters use it to find trapped people in a hot burning building.

    The Sidewinder-X uses it.
  14. fedr808 1100101 Valued Senior Member


    Are you implying that the SU-30 can decelerate at the touch of a button (how many g's will that pilot experiance going from close to mach 1 to 0 mph in a second or two?), than hover in this gas plume as LONG AS IT LIKES until the missile passes?

    And no offense, how big is this plume exactly?

    Also, ask yourself this, if plumes actually do reflect radar signals, than why exactly has no radar guided missile EVER, EVER, EVER gone after the plume created by the jet it is homing on?

    Moreso, how is the F-22 nearly undetectable at modest ranges if it's plume as you claim is able to reflect radar signals which would surely give it away?!?

    Plumes do not reflect radar signals, and if they do it is near insignificant, it is infinitely more likely they merely slow down the signal or even warp it's trajectory by a degree or two than to outright reflect it.

    And you seem to be implying that the Su-30 can defy physics and just stay still in one place for as long as it likes with no motion.
  15. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Not physically possible.
    Billy T's quotes are NOT official (or sourced) figures, just fan boy bollocks.

    And somewhat dishonest of Billy with this:
    Re-read it: the ACTUAL quote from the Maj. gen did NOT reference 22 G. And FYI pilots can black out at far less than 22G.

    So what? The BAC (English Electric) Lightning could too. 40 years ago.
  16. adoucette Caca Occurs Valued Senior Member

    You have a reference showing it could do Mach 1.6 without Afterburner?

  17. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    No exact figure:
    Concorde supercruised at ~Mach 2. Every single day.
  18. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    With reference to this mythical "black out button": what's the point of engaging some supposed "defensive tactic" which will leave the pilot helplessly unconscious and the aircraft automatically flying straight and level after a missile attack? Or did the originator of this ridiculous story never think that the F-22 would face more than one enemy at a time? Or an enemy with more than two missiles?
    Oh yeah... the F-22 dodged that missile. And that one. And now the pilot is asleep while the flight system has the F-22 going in a straight line until he wakes up...
    Can you say "sitting duck"?

    I love hearing ignorant fan boy myths, they're so funny.
  19. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Quite a few, but I’m too lazy to calculate an answer for a 1.5 second stop from Mach 1 speed as that would depend up the altitude as the speed of sound is a function of altitude.

    Anyway, I think the plane may be limiting the possible deceleration, not the pilot, as when it uses its canards to flip 90 degree up it is still moving forward on its prior momentum, so the wings are now broad side into the wind and are under great stress. Also pilots do not black out instantaneously and may keep conscious for a second or two under many Gs. (It takes a few seconds to drain the blood from the brain.)

    I never suggested that the SU-30 could sit in its exhaust plume “as long as it likes.” Remaining there 1 second in a just established plume should be long enough, unless more than one missile is attacking it. Its computers know the distance and approach speed of the attacking missile quite accurately. If the stop and start to slowly fall tail first inside the plume takes 1.5 second, then starting that maneuver 2 seconds second before the missile will arrive would be adequate and spending no more than a second hiding in the plume would be OK.

    Because when the jet is fleeing there is nothing that could be called plume. There is at most a “condensation trail.” The diameter of that depends mainly on the exhaust mass flow coming out of the tail pipe and its average temperature mainly, but for the SU-30, it will have increasing diameter for slower rates of fall.

    Off hand I would guess with an SU-30 in 0.5G acceleration down, then at the end of a second the plane has fallen 16 feet and the plume surrounding it is at least 100 feet in diameter with the hottest part of the plume visible to an IR detector more than 25 feet below the tip of the exhaust pipe. (The exhaust has a lot of momentum and goes well be below the slowing falling plane before coming to rest with respect to the air.) While the just leaving tail pipe exhaust is hotter, the radiation from it traveling horizontally must pass thru the colder radiation absorbing exhaust gas that was released earlier. I don’t know how deep into that earlier exhaust an IR photon escape from, without re-absorption, is possible. Directly below the tail, but on the surface of the plume, is where the hottest gas is exposed on the surface of the plume. Quite possibly the simple IR guided missile will fly thur that point. It could have more complex guidance which recognizes that the “ball of plume” with hottest spot on the bottom, is being made by an SU-30 and ignore the hottest visible spot to pass closer to the SU-30.

    As far as why sidewinders etc have little trouble flying even up the tail pipe of a plane they are chasing that is because they fly into the plane’s exhaust and constantly “see” , immediately in front of themselves, an exhaust that is both growing hotter and has ever smaller diameter, eventually only as large as the tail pipe diameter.

    This “tail pipe kill” is sort of a high speed version of what happens when a wake-homing torpedo is chasing a capital ship. The USSR has some huge (as large as some submarines) torpedoes which could out run even US subs and certainly any displacement type ship.). I.e. when they first crossed into the ships wake, it might be a few miles wide, due to turbulent mixing, but as it got closer to the ship, the wake became stronger and only a little larger than the ship's propeller diameter. If they were smaller torpedoes, they would need to settle for propeller damage, but these big mothers would dive about 100 feet below the middle ship and explode. This makes a brief but huge bubble under the middle of the ship so the ship has water support only at the front and rear. That “breaks the ship back” as the middle sections falls into the gas bubble. It is the only way even a big torpedo can sink an aircraft carrier. The carrier could hear the wake-homer coming, but not localize it with its sonar as the turbulence messed up the sonar echos. In some sense, the USSR’s torpedo was hiding in the wake as it closed on the ship, somewhat like the SU-30 hidding in its own exhaust long enough for the attacking missile to pass by.
    Last edited by a moderator: Oct 17, 2010
  20. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    I tend to agree, and think I noted that the FA-22 was an easy kill with pilot unconscious in prior post. As I said, I was only quoting some of the many sources telling of the BoB.

    Almost the same as if I said there are many reports of reports of alligators in the sewers of NYC but a BoB existing is at least possible and might even be useful as escape from immediate death. It is conceivable that the computer/radar system would detect a second missile's approach while pilot is unconscious and do one or even two more 22G U turns as there is little risk of brain damage even if pilot is blacked out for five minutes.
  21. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    A superb way of ripping off the canards. There will be a limiting deflection angle based on current speed. All control surfaces on modern aircraft feature this limit so as not to over stress the airframe or the actuators (or the surfaces themselves - it's, to say the least, potentially embarrassing to tear off your control surfaces while trying to manoeuvre).

    One more time: IR missiles do not look at the plume, they see heated portions of the airframe as well, and are programmed to go for the cockpit.

    The "tail pipe kill" hasn't really been a feature of air combat since the 70s. At which time missiles were designed to look at the entire target and go for, have you heard this?, the cockpit.
  22. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Any reliable sources for this BoB?

    You mean the radar that looks forwards, that's located in the extreme nose of the aircraft?

    Number of 22G turns possible by F-22: zero.
    It's a myth. And a badly thought out one at that.
  23. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Yes, just as I said, the plane, not the pilot will limit the max deceleration.
    Also agreed, IF the attacking missile has “optically thin” air between it and it target. But not if the target is behind or in “optically thick” gas.

    It is sort of like a “white out” condition in an arctic snow storm* – no objects can be seen as the photons that left the surfaces of objects are absorbed when they travel a distance which depends up the molecules in the gas and the wavelength used by the IR system.

    Also I think, hitting the cockpit may be quite hard if the missile is chasing at M=2 a plane fleeing at M=1.5 which has 5 Km head start on the missile, just from considerations of geometry.

    *Once, while in high school, I was driving my girl friend home in a valley where the fog was so dense that I had to get out and walk a head of the car only about 15 feet as she inched it forward as that was as far thru the fog she could see me (or anything). We had to keep the headlight off as with them on it was just a white screen in front of the car.

    I am going to drop out of further discussion as all I can add is some physics. Everything else, including the reality of the BoB & 22G U turn is just repeating things one can read on the internet, but there is no “truth filter” operational for it, yet.
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