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3D Thrust-Vectoring and Supercruise

  1. Jun 14, 2004 #1
    What is 3D thrust-vectoring and Supercruise ? I frequently see this terms in Military Fighter Aircraft data. I know nothing about it. Can you explain me in detail? Any website for it?
     
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  3. Jun 14, 2004 #2

    enigma

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    According to this page, supercruise means the "ability to... fly at supersonic speeds without using afterburners" (2nd paragraph).

    ---

    Thrust vectoring is the use of flaps near the engine outlet to point the flow in a desired direction. This increases the possible turn and roll rates.

    Here's a website with some pictures of 2D thrust vectoring. 3D just has side to side capabilities as well.
     
    Last edited: Jun 14, 2004
  4. Jun 15, 2004 #3
    thrust vectoring can also be used to acheive vertical lift off, but unless it is truly essential to verticaly lift off the loss in efficiency when vectoring that much dose not make it worth the cost in efficiency
     
  5. Jun 20, 2004 #4

    DM

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    To some extent this is right.

    Supersonic cruise requires the help of afterburners, no matter what.
     
  6. Jun 20, 2004 #5

    enigma

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    There are no planes which can fly supersonically at full throttle with just engines alone?

    What mechanism is preventing supersonic flight without afterburners?
     
  7. Jun 20, 2004 #6

    DM

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    Name an aircraft.
     
  8. Jun 20, 2004 #7

    enigma

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    This site says that the Concorde uses afterburners in the transonic regime and then turns them off for supersonic cruising.

    I'm not sure if it's accurate or not.

    It's possible that fighter aircraft are engineered to rely on afterburners for supersonic flight, but I can't think of a reason why they'd be needed.

    Heck, the X-43 doesn't use afterburners either, but it doesn't really apply.
     
  9. Jun 20, 2004 #8
  10. Jun 20, 2004 #9

    DM

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    Enigma, (sorry if this isn't your real name)

    I can see your point of view towards afterburners, I suppose that you, just like I am, are worried about our environment. It's indeed very worrying.

    However it is very hard to reach supersonic speeds without the use or help of afterburners. The reason I say this is because just like the concorde, fighter planes attempt and succeed reaching supersonic speeds as fast as possible.

    If you think about it, a plane reaching supersonic speeds without the use of afterburners takes a long time. This would be extremely concerning towards fighter planes that have the goal of arriving at a place as quick as possible.

    So concluding, the emphasis of using afterburners is in order to reach supersonic speeds as fast as possible. Ever wondered why the concorde used them? the promised 2h15m from EGLL (Heathrow) to JKFK (John Kennedy) would be dragged to at least 6 hours if the integration of afterburners never took place.

    Daniel
     
    Last edited: Jun 20, 2004
  11. Jun 20, 2004 #10

    enigma

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    Well, I'm an engineer. As an engineer, I'm always curious why things work the way they do, particularly aircraft (which isn't my area of expertise) and spacecraft (which isn't either, but I'm working on it...). I had never heard that there weren't any supersonic planes which did not rely on afterburners. Since you mentioned it, I wondered if you knew why there aren't any.

    I'm sure that a bigger reason would be the tremendous increase in aerodynamic drag in the transonic regime. That drag decreases again once you go past Mach 1.3 or so. I still don't see why they'd need afterburners for supersonic flight.
     
    Last edited: Jun 20, 2004
  12. Jun 21, 2004 #11

    russ_watters

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    Supercruise was a critereon for the design of the Advanced Tactical Fighter. I think thats where the term came from. The YF-23 was Northrup's entry into the design contest and Lockheed's was the YF-22. The YF-22 won and is now the F-22. It has supercruise and single axis (pitch) thrust vectoring.
    Like enigma said, drag increases quickly in the transonic reason - this means that acceleration is pretty good right up until you get to mach 1.
    There may be an exit velocity/nozzle shape issue with some engines.
     
    Last edited: Jun 21, 2004
  13. Jun 21, 2004 #12
    Both thrust vectoring and supercruise are features of the Joint Strike Fighter (JSF). Thrust vectoring is what the AV8B uses to enable S/VTOL (as originally developed for the 'Harrier' on this side of the Atlantic). It also enabled the development (during the Falklands War) of a new tactic - 'vectoring in forward flight' (VIFFing) - to climb, brake and force pursuing enemy aircraft to pass on by and come into weapons range.

    Supercruise is indeed the ability to sustain supersonic speeds without re-heat ('afterburners' on that side of the Atlantic). Do a google on 'JSF' for more information than you require.
     
  14. Jun 21, 2004 #13

    DM

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    That's where afterburners increase from MACH 1.00 to 2.00.

    And Enigma... there are planes in which do not use afterburners to reach supersonic cruise however these fighter planes are rather new.

    I think I explained why afterburners exist for supersonic flight. I'm sorry if you can't understand it.
     
  15. Jun 21, 2004 #14

    russ_watters

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    Cool it, DM. We're all here to learn - even you.
     
  16. Jul 1, 2004 #15
    The airfore recently messed up the definition of what supercruise meant to cover up the failures of the F-22

    The real definition should be "the ability to cruise(cover distance economically) at supersonic speeds."
    Not "supersonic flight without afterburners"

    A real supercruiser in existance today would be the Mig-31.

    Notice the fuel fraction of the Mig-31 compared to other fighters.

    So pretty much discard the current USAF pushed definition of supercruise, it was done to coverup the failures of the ATF/JSF projects.

    For a good overview of the F-22:
    http://www.pogo.org/p/defense/do-000608-f22.htm
     
  17. Jul 26, 2004 #16
    First for an unbiased description (not read the other posts)..

    Supercruise - Is the ability to accelerate pastand maintain trans and supersonic speeds without the use of afterburners

    3D-Thrust Vectoring - It is the ability to rotate the Engine outlets amonst a 360* axis which allows for greater turn Radii and improve strike and life capabilities such as on the ATF F-22 raptor JSF (usa).

    NOw to READ the posts...

    but not 3D thrust vectorin.. and it doesnt require the use of flaps to direct
    the air a direction.. it has adjustable nozzles on the side.. such as on the Harrier Jump-Jet (britain)

    Prove this.... I have been taught and read that this is NOT true.... link it plz... if you COULD disprove it wiht a credible source.. please do, Becuz i have heard from an Air-Force Cheif (my Uncle) that this is NOT the case.. supercruise does NOT! require the use of afterburners

    The use of Afterburners is NOT primarily to reach supersonic spees AFAP.. but yet to Break supersonic speeds efficiently (well more so than conventional jets). Afterburn'ing' is a method of injecting fuel into the exhaust to create more thrust which is needed to aquire trans-sonic speeds (above mach 1.5), in level flight. the Concorde did not use its after burners until mach .8 (atleast) or it would have been unreliable and inefficient. And yes the concorde did turn off its afterburners after supersonic flight, however this is because they did not need to maintain those speeds any longer, in fact they had to Deccelerate to sub-sonic speeds before entering into US air-space (which i belive is 150 NM off the coast). technoicaly you COLD cruise for awhile at super-sonic speeds afterturning off afterburners, howevere you CANNOT maintain those speeds.......
    done... finally... for now atleast
     
  18. Jul 27, 2004 #17

    enigma

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    Trans-sonic is not above M#1.5. Trans-sonic is what happens near M#1 when portions of the airflow over the top of the wing reach supersonic speeds and form small oblique shock waves there. This increases drag immensely.
     
  19. Jul 27, 2004 #18
    o sorry.. musta been thinking of somethin else.. ill look into it for what i meant..
     
  20. Jul 27, 2004 #19

    enigma

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    Maybe you were thinking of hypersonic (M#>5)?

    Welcome to the forums, BTW...

    Always good to have another aero-head here! :biggrin:
     
  21. Jul 27, 2004 #20
    Thx, no thats not what i was thinking of, but i cant find it anywhere.. im sure it'll hit me. My uncle told me once and i looked it up somewhere, cant find it. I'll have to sak him next time i get around to it. Im 16 now and know way too much for my own good.. and ive wanted to fly and know why things fly for as ling as i can remember.. but thats the only thing wrong that i mentioned, because if im wrong please do correct me, once again , im only 16 but i still know alot, however im sure i dont know as much as alot of you guys, so im here to help AND learn
     
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