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It's funny how articles about hypersonic weapons always talk about their speed when the defining property is manoeuvrability; Obviously you can't turn very well

It's funny how articles about hypersonic weapons always talk about their speed when the defining property is manoeuvrability; Obviously you can't turn very well if you go super fast, so the solution is to go slower: hypersonic missiles aren't actually the fastest missiles around.

rbanffy 5y ago
If you know where your target will be, you don’t need to manoeuvre too much. If you are getting there on Mach 9, the target will very much be wherever it was when you launched.
- bernulli 5y ago
  But you also don't want your target to know that it is being attacked to prevent countermeasures.
  - rsfern 5y ago
    The current sort of arms race around hypersonics is precisely because there are no good currently existing countermeasures for a missile traveling at like Mach 10. I’m sure it’s being worked on, but there’s a lot of effort going into the mutually assured destruction short of strategy.
- SiempreViernes 5y ago
  A car going 30 km/h clears the 30m blast radius of a 900kg bomb in about three seconds, and the 340m fragmentation radius in about 40 seconds. This means that to hit a moving target at Mach 9 (or about 3 km/s) you need to launch your 11m long rocket within either 9 or 120 km depending on the desired probability for a kill. As a reference, an aircraft carrier can go over 50 km/h, the Chinese hypersonic weapons go about 1.7 km/s and have a range of at least 1000 km. How does that work out you wonder? Simple, they put nukes on their hypersonic missiles.
  - elric 5y ago
    > an aircraft carrier can go over 50 km/s I'm assuming you mean km/h there? I'd love to see a boat going that fast.
    - SiempreViernes 5y ago
      Yeah, thanks for pointing out the typo. Probably wouldn't have spotted it in time to edit it otherwise.
  - mLuby 5y ago
    As impressive as an aircraft carrier with solar escape velocity would be, I'm betting that's a typo. A 50km/s vessel carrying hypersonic missiles would be like bringing turtles on a transatlantic flight!
sudosysgen 5y ago
Missile maneuvrability is measured in lateral acceleration. Hypersonic missiles pull just as many Gs as any other missile, they are not any less maneuverable.
- SiempreViernes 5y ago
  Hypersonic get their claim for manoeuvrability by comparison with their faster cousins the ballistic missiles, not short range (less than 60 km) air-to-air missiles that have sort bursts of Mach 4.
  - sudosysgen 5y ago
    This is wrong. Hypersonic vehicles are thought to have maneuvering accelerations over 15Gs. That's more than most cruise missiles. Of course they will not be as maneuverable as A2A missiles. But what's the point? If you want to evade A2A missiles already going slower than you you're using energy to your advantage so 10Gs is more than enough. As it stands hypersonic missiles are more maneuverable than all other missiles including cruise missiles short of specialized A2A missiles. So for the purpose of evading interceptors and penetrating defence systems it's more than enough.
    - jhgb 5y ago
      > Hypersonic vehicles are thought to have maneuvering accelerations over 15Gs Considering the mediocre L/D ratio of hypersonic vehicles, this seems extremely optimistic to me.
      - sudosysgen 5y ago
        The X-15 was able to sustain G forces in excess of 15Gs. The limit was that its chassis would break apart. Maneuvrability works very differently for high-trust, vectored, supersonic vehicles. That's why A2A missiles can pull of 50Gs despite very low L/D ratio, speed helps a lot. Hypersonic flight magnifies this even further. I mean, look at the X15, it was able to do more than 15Gs despite having lower relative thrust and non-vectored engines, at higher altitudes!

rbanffy 5y ago

If you know where your target will be, you don’t need to manoeuvre too much. If you are getting there on Mach 9, the target will very much be wherever it was when you launched.

bernulli 5y ago
But you also don't want your target to know that it is being attacked to prevent countermeasures.
- rsfern 5y ago
  The current sort of arms race around hypersonics is precisely because there are no good currently existing countermeasures for a missile traveling at like Mach 10. I’m sure it’s being worked on, but there’s a lot of effort going into the mutually assured destruction short of strategy.
SiempreViernes 5y ago
A car going 30 km/h clears the 30m blast radius of a 900kg bomb in about three seconds, and the 340m fragmentation radius in about 40 seconds. This means that to hit a moving target at Mach 9 (or about 3 km/s) you need to launch your 11m long rocket within either 9 or 120 km depending on the desired probability for a kill. As a reference, an aircraft carrier can go over 50 km/h, the Chinese hypersonic weapons go about 1.7 km/s and have a range of at least 1000 km. How does that work out you wonder? Simple, they put nukes on their hypersonic missiles.
- elric 5y ago
  > an aircraft carrier can go over 50 km/s I'm assuming you mean km/h there? I'd love to see a boat going that fast.
  - SiempreViernes 5y ago
    Yeah, thanks for pointing out the typo. Probably wouldn't have spotted it in time to edit it otherwise.
- mLuby 5y ago
  As impressive as an aircraft carrier with solar escape velocity would be, I'm betting that's a typo. A 50km/s vessel carrying hypersonic missiles would be like bringing turtles on a transatlantic flight!

sudosysgen 5y ago

Missile maneuvrability is measured in lateral acceleration. Hypersonic missiles pull just as many Gs as any other missile, they are not any less maneuverable.

SiempreViernes 5y ago
Hypersonic get their claim for manoeuvrability by comparison with their faster cousins the ballistic missiles, not short range (less than 60 km) air-to-air missiles that have sort bursts of Mach 4.
- sudosysgen 5y ago
  This is wrong. Hypersonic vehicles are thought to have maneuvering accelerations over 15Gs. That's more than most cruise missiles. Of course they will not be as maneuverable as A2A missiles. But what's the point? If you want to evade A2A missiles already going slower than you you're using energy to your advantage so 10Gs is more than enough. As it stands hypersonic missiles are more maneuverable than all other missiles including cruise missiles short of specialized A2A missiles. So for the purpose of evading interceptors and penetrating defence systems it's more than enough.
  - jhgb 5y ago
    > Hypersonic vehicles are thought to have maneuvering accelerations over 15Gs Considering the mediocre L/D ratio of hypersonic vehicles, this seems extremely optimistic to me.
    - sudosysgen 5y ago
      The X-15 was able to sustain G forces in excess of 15Gs. The limit was that its chassis would break apart. Maneuvrability works very differently for high-trust, vectored, supersonic vehicles. That's why A2A missiles can pull of 50Gs despite very low L/D ratio, speed helps a lot. Hypersonic flight magnifies this even further. I mean, look at the X15, it was able to do more than 15Gs despite having lower relative thrust and non-vectored engines, at higher altitudes!