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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 miss

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!
    - jhgb 5y ago
      The X-15 to my knowledge was not under thrust when maneuvering in the hypersonic regime, so I don't understand the connection here. And because of being unpowered and hypersonic, it would still be losing speed more rapidly than even an unpowered airplane or missile flying at a lower velocity. > That's why A2A missiles can pull of 50Gs despite very low L/D ratio No, they can do this because they're small, and being small means a low ballistic coefficient because your mass shrinks faster than the aerodynamic-force-generating area. But a 100kg missile is not what you use to strike very remote targets on the ground.

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!
  - jhgb 5y ago
    The X-15 to my knowledge was not under thrust when maneuvering in the hypersonic regime, so I don't understand the connection here. And because of being unpowered and hypersonic, it would still be losing speed more rapidly than even an unpowered airplane or missile flying at a lower velocity. > That's why A2A missiles can pull of 50Gs despite very low L/D ratio No, they can do this because they're small, and being small means a low ballistic coefficient because your mass shrinks faster than the aerodynamic-force-generating area. But a 100kg missile is not what you use to strike very remote targets on the ground.