4 ms·

Why would a propulsion system like this not be put on missiles first? Seems like there are many more tactical applications.

ceejayoz 9y ago
Some missiles already travel at these sorts of speeds.
csours 9y ago
Turn it around: Why would a propulsion system like this be put on a missile? Missiles are generally powered by rocket motors - they don't need air intake. Missiles are also generally one-time-use - you send it somewhere and don't expect to reuse it (also it usually explodes) I suppose it might be possible to increase payload per fuel efficiency, but the only reason the military would probably care about that is cost, and the rocket engineering is already paid for and proven.
- Xylakant 9y ago
  The first missiles (V1) were basically ramjet engines, so it’s not exactly unheard off. The advantage of such an engine is that it doesn’t need to bring its oxidizer along like a rocket engine would need to, so depending on how the engines weight compares to a rocket engine, it would allow for more payload at the same total weight which might be interesting in various places.
  - mulmen 9y ago
    The second and essentially all subsequent missiles were rockets though.
    - Xylakant 9y ago
      Yes, since ramjets with performance such as this one were outside our engineering capabilities. As the article states, even this one was not possible a few years ago. It’s also not entirely true, tomahawk cruise missiles for example use turbofan engines with a solid state booster.
    - eesmith 9y ago
      Perhaps you are thinking specifically of ICBMs? There are other types of missiles, not all of which are rocket powered. https://en.wikipedia.org/wiki/AGM-86_ALCM https://en.wikipedia.org/wiki/AGM-86_ALCM - "All variants of the AGM-86 missile are powered by a Williams F107 turbofan jet engine" https://en.wikipedia.org/wiki/Tomahawk_(missile) https://en.wikipedia.org/wiki/Tomahawk_(missile) - "After achieving flight, the missile's wings are unfolded for lift, the airscoop is exposed and the turbofan engine is employed for cruise flight." https://en.wikipedia.org/wiki/Harpoon_(missile) https://en.wikipedia.org/wiki/Harpoon_(missile) - "Power plant: Teledyne CAE J402 turbojet, 660 lb (300 kg)-force (2.9 kN) thrust, and a solid-propellant booster for surface and submarine launches" https://en.wikipedia.org/wiki/Kh-55 https://en.wikipedia.org/wiki/Kh-55 - "It is powered by a single 400 kgf Ukrainian-made, Motor Sich JSC R95-300 turbofan engine, with pop-out wings for cruising efficiency." The hypersonic missiles use a rocket to get up to speed, like: https://en.wikipedia.org/wiki/Zircon_(missile) https://en.wikipedia.org/wiki/Zircon_(missile) - "A booster stage with solid-fuel engines accelerates it to supersonic speeds, after which a scramjet motor in the second stage accelerates it to hypersonic speeds."
  - perilunar 9y ago
    The V1 use a pulsejet engine (Argus As 014), not a ramjet.
    - Xylakant 9y ago
      The difference between a pulse jet and a ramjet is quite small if you compare it with a rocket or a turbofan: Basically they're both air-breathing without a compressor or fan to compress the intake air, so I'd stand by "basically a ramjet".

ceejayoz 9y ago

Some missiles already travel at these sorts of speeds.

csours 9y ago

Turn it around: Why would a propulsion system like this be put on a missile? Missiles are generally powered by rocket motors - they don't need air intake. Missiles are also generally one-time-use - you send it somewhere and don't expect to reuse it (also it usually explodes) I suppose it might be possible to increase payload per fuel efficiency, but the only reason the military would probably care about that is cost, and the rocket engineering is already paid for and proven.

Xylakant 9y ago
The first missiles (V1) were basically ramjet engines, so it’s not exactly unheard off. The advantage of such an engine is that it doesn’t need to bring its oxidizer along like a rocket engine would need to, so depending on how the engines weight compares to a rocket engine, it would allow for more payload at the same total weight which might be interesting in various places.
- mulmen 9y ago
  The second and essentially all subsequent missiles were rockets though.
  - Xylakant 9y ago
    Yes, since ramjets with performance such as this one were outside our engineering capabilities. As the article states, even this one was not possible a few years ago. It’s also not entirely true, tomahawk cruise missiles for example use turbofan engines with a solid state booster.
  - eesmith 9y ago
    Perhaps you are thinking specifically of ICBMs? There are other types of missiles, not all of which are rocket powered. https://en.wikipedia.org/wiki/AGM-86_ALCM https://en.wikipedia.org/wiki/AGM-86_ALCM - "All variants of the AGM-86 missile are powered by a Williams F107 turbofan jet engine" https://en.wikipedia.org/wiki/Tomahawk_(missile) https://en.wikipedia.org/wiki/Tomahawk_(missile) - "After achieving flight, the missile's wings are unfolded for lift, the airscoop is exposed and the turbofan engine is employed for cruise flight." https://en.wikipedia.org/wiki/Harpoon_(missile) https://en.wikipedia.org/wiki/Harpoon_(missile) - "Power plant: Teledyne CAE J402 turbojet, 660 lb (300 kg)-force (2.9 kN) thrust, and a solid-propellant booster for surface and submarine launches" https://en.wikipedia.org/wiki/Kh-55 https://en.wikipedia.org/wiki/Kh-55 - "It is powered by a single 400 kgf Ukrainian-made, Motor Sich JSC R95-300 turbofan engine, with pop-out wings for cruising efficiency." The hypersonic missiles use a rocket to get up to speed, like: https://en.wikipedia.org/wiki/Zircon_(missile) https://en.wikipedia.org/wiki/Zircon_(missile) - "A booster stage with solid-fuel engines accelerates it to supersonic speeds, after which a scramjet motor in the second stage accelerates it to hypersonic speeds."
- perilunar 9y ago
  The V1 use a pulsejet engine (Argus As 014), not a ramjet.
  - Xylakant 9y ago
    The difference between a pulse jet and a ramjet is quite small if you compare it with a rocket or a turbofan: Basically they're both air-breathing without a compressor or fan to compress the intake air, so I'd stand by "basically a ramjet".