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Aerospace Requirements for Supercruise?

  1. Apr 15, 2017 #1
    What does an aircraft require for supercruise flight? Is it difficult to make an aircraft supercruise, or is it more that by the time it became possible militaries were moving away from high speed/high altitude flight and the capability wasn't as important?
     
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  3. Apr 15, 2017 #2

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    Supercruise requires very strong engines not using afterburner and very low aerodynamic drag of the airplane. It is not easy and is really restricts the airplane design. The first supercruise plane was the F-22 fighter designed in the late '80s. A few others can now do it. I think they are all fighters. It would probably be considered standard now for a modern fighter.
     
  4. Apr 15, 2017 #3

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    What do you mean? There are a number of former and current planes that can supercruise. Most modern air superiority fighters have some sort of supercruise ability (F-22, Eurofighter Typhoon, Dassault Rafale, etc.). Of course the SR-71 could supercruise, and any supersonic transport (e.g. the Concorde) will supercruise. The bottom line is that by the time it was feasibly, it was no longer economical on long range bombers since ICBMs had replaced them, and with interceptors, it's more useful to have better high-subsonic performance and maneuverability. Therefore, you really only see it on transports, air superiority fighters, and reconnaissance aircraft.

    Really what you need are engines that can operate efficiently at supersonic speeds (with or without afterburners) and you need a fuselage and set of wings designed to operate efficiently at supersonic speeds. Some might argue that it can't include afterburners, but most people would just define it as being sustained supersonic flight without frequent refueling, so the SR-71, with its afterburners that were designed to operate more efficiently and for a sustained duration, counts in my book.
     
  5. Apr 15, 2017 #4

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    It is considered somewhat standard since the F-22. The supercruise capability of the F-22 was considered one of the advantages it had over other fighters of the time.
    SR-71 used afterburners. You are right about the Concord. That was a very special plane.
    I disagree. Afterburners use fuel so fast that it is not considered supercruise.
     
  6. Apr 15, 2017 #5

    boneh3ad

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    And yet it could fly thousands of miles on afterburners. Generally, afterburners are very inefficient, but there are some that are designed specifically for long-duration use that are much more efficient, like the SR-71. So, I suppose I'd argue that, in general, afterburners do not enable supercruise, but some very specifically-designed afterburners can. But again, I also suppose that depends on the precise definition of supercruise being used, and there is no set definition. If you just want sustained (i.e. efficient) supersonic flight, then afterburners can work. If you want afterburner-free supersonic flight, then they can't by definition, even if they can approximate it.
     
  7. Apr 16, 2017 #6
    @ Delta Force, For an aircraft to cruise from subsonic to supersonic speeds it requires both streamlining and engine design changes. I mean we need to workout hard on the both above said. Streamlining involves reducing the drag on the air craft(includes fuselage,wing,tail,nose, ailerons,flips....each and every part of the aircraft those are exposed to the external climate) and it requires a good knowledge in fluid mechanics and flight dynamics. Having knowledge on CFD is an added benefit to know about the drag and extra thrust requirement for supercruising. And coming for the engine requirement to supercruise is high thrust engines during the mid flight. In general, modern aircrafts uses jetengines of the type turbofan with afterburner. These are generally of low bypass ratio engines. They utilise the max. portion of the available air in the combustion chamber. This is upto what a turbofan engine is. Now coming for the afterburner.....it is nothing but another, extra,added combustion chamber after the turbine. That's how it got the name AFTER BURNER. It gives the extra thrust required for early take-offs and supercruising of the aircraft but at the expense of fuel economy. There are some more engines for the supercruising,like Ramjet engine, Scramjet engine. These 2 engines don't have any rotating or reciprocating parts. These are aero thermodynamic ducts. Simply aethodyds. Also called as flying stoves. Because they are only interested to burn the fuel with out using any rotating or reciprocating compressor and turbine to derive the thrust. These are the ducts shaped in such a way that, air entering the engine is initially compressed from supersonic speeds to sub sonic speeds in case of the Ramjet engine and fuel is the added for the compressed air in the combustion chamber (c.c.) followed by flow of very hot gases through the nozzle, results in very high thrusts at supersonic speeds. Scramjet compresses the air at supersonic speeds and rest of the working procedure is as same as that of Ramjet does. Aethodyds are very effective,effecient and economic at supersonic speeds and can even achieve hypersonic speeds. There is another technique to achieve the super sonic speeds, i.e. use of supersonic bloom. Aircrafts developed in the recent past utilised this technique. It involves usage of supersonic bloom of the steam around the aircraft that pushes the aircraft. But significant modifications in the streamlining of the aircraft should be done irrespective of the engine to break the sound barrier. FOR GIVE ME IF I HAD COMMITTED FOR DELIVERING OF ANY WRONG CONCEPT. Thank you.
     
  8. Apr 18, 2017 #7
    There was a lot of interest in supersonic flight during the 1950s and 1960s and many aircraft were designed with clean aerodynamics, such as the A-5, B-58, and F-106. Could they have been able to supercruise if they had better engines?
     
  9. Apr 18, 2017 #8

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    I think that is probably right, but I am not an expert. The planes that can do practical supercruise (long enough, fast enough, with enough stores to make a military difference) need engines that are designed for sustained supercruise. The ability to keep stores internally in a weapons bay is probably important for being aerodynamically clean enough.
     
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