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Here's one way how to think about this missile. You start from the report to Congress [1]. On page 8: In FY2022, the Air Force launched the Hypersonic Attac

Here's one way how to think about this missile. You start from the report to Congress [1]. On page 8: In FY2022, the Air Force launched the Hypersonic Attack Cruise Missile (HACM) program to develop a hypersonic cruise missile that integrates Air Force and DARPA technologies. Some reports indicate that HACM is intended to be launched from both bombers and fighter aircraft, with a senior Air Force official noting that a B-52 could potentially carry 20 HACMs or more. B-52 can carry 32 tons of munitions. So 20 of these missiles "or more" may mean that each missile is about 1500 kg. That's in line with the current AGM-86 long range air launched cruise missile [2], [3]. Of course, AGM-86 is subsonic, while HACM will be supersonic. AGM-86 has a range, depending on configuration, between 950 km and 2500 km (maybe even more, this is the non-classified range). I guess HACM will have a similar range. Being hypersonic means it's easier to carry out a saturation attack (you send more missiles than the enemy can defend against simultaneously). That means, the US Air Force will be able to carry deterrence patrols with their B-52s in order to prevent China from sending a naval landing force to Taiwan. Without this weapon, the main deterrence was supposed to be provided by the US Navy and their carrier strike groups. With this weapon, the US Air Force may be able to provide a cost effective alternative. [1] https://news.usni.org/2022/07/22/report-to-congress-on-hypersonic-weapons-7 https://news.usni.org/2022/07/22/report-to-congress-on-hyper... [2] https://en.wikipedia.org/wiki/AGM-86_ALCM https://en.wikipedia.org/wiki/AGM-86_ALCM [3] https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104612/agm-86bcd-missiles/ https://www.af.mil/About-Us/Fact-Sheets/Display/Article/1046...

sofixa 4y ago
> B-52 can carry 32 tons of munitions. So 20 of these missiles "or more" may mean that each missile is about 1500 kg Not necessarily. US bombers, especially old ones such as the B-52 were designed for bomb loads stored inside and dropped when the doors open. Carrying missiles was added later on, and since those have to be outside, usually on the wings, the main limitations is space, not weight. If it cannot fit more than 20 missiles due to only 10 launchers with 2 missiles each (for instance) being able to physically fit on the aircraft's fuselage/wings, it doesn't matter how many more it could carry inside. Also, has tech advanced so much to have a similarly weighing scramjet hypersonic missile have a similar range to a supposedly more optimal subsonic one?
- credit_guy 4y ago
  > Also, has tech advanced so much to have a similarly weighing scramjet hypersonic missile have a similar range to a supposedly more optimal subsonic one? According to wikipedia [1], the Russian Kinzhal has a mass of about 2000 kg and a range of 3000 km if launched from a strategic bomber. Of course, wikipedia just repeats the Russian claims, we can't know for sure if these numbers are accurate, but if they are off, they are not off by a factor of 10. Can the US make something similar? It's quite possible, the US military budget is more than 10 times higher. Separately, hypersonic missiles are thought to travel at an altitude of 100km, where the air density is about one million times lower than at ground level [2]. Even if the air friction is ten 1000 times higher than for a subsonic missile (if drag is proportional to v^3 and v goes up by a factor of 10), in the end the total drag could be lower. I personally expect hypersonic missiles like this one come with increased range rather than decreased range compared to their subsonic cousins. [1] https://en.wikipedia.org/wiki/Kh-47M2_Kinzhal https://en.wikipedia.org/wiki/Kh-47M2_Kinzhal [2] http://www.braeunig.us/space/atmos.htm http://www.braeunig.us/space/atmos.htm
  - frostburg 4y ago
    The Kinzhal is basically an air-launched Iskander, a ballistic rocket, not a cruise air-breathing missile.
    - credit_guy 4y ago
      But the scramjet should increase, not decrease the range, no?
      - gffrd 4y ago
        I've been pondering about the range thing, because my immediate kneejerk was "two balls rolling, one's 2x faster than the other, that one will go further" … but I had that "trick question" flag go off as soon as I thought that. Things I don't know: - It's faster … possibly huge fuel consumption to get to operating speed over comparable subsonic missile? (even if sips fuel once at operating speed/altitude) - Will fly at higher altitude … which means lower friction (enough to counter what's added by higher speed) … but also to hit the same target, more distance must be covered (climb/descent to operating altitude + greater orbiting circumference) - Limited "package" size … do scramjet surfaces/elements reduce the amount of space available for fuel? - How much distance is a factor.

sofixa 4y ago

> B-52 can carry 32 tons of munitions. So 20 of these missiles "or more" may mean that each missile is about 1500 kg Not necessarily. US bombers, especially old ones such as the B-52 were designed for bomb loads stored inside and dropped when the doors open. Carrying missiles was added later on, and since those have to be outside, usually on the wings, the main limitations is space, not weight. If it cannot fit more than 20 missiles due to only 10 launchers with 2 missiles each (for instance) being able to physically fit on the aircraft's fuselage/wings, it doesn't matter how many more it could carry inside. Also, has tech advanced so much to have a similarly weighing scramjet hypersonic missile have a similar range to a supposedly more optimal subsonic one?

credit_guy 4y ago
> Also, has tech advanced so much to have a similarly weighing scramjet hypersonic missile have a similar range to a supposedly more optimal subsonic one? According to wikipedia [1], the Russian Kinzhal has a mass of about 2000 kg and a range of 3000 km if launched from a strategic bomber. Of course, wikipedia just repeats the Russian claims, we can't know for sure if these numbers are accurate, but if they are off, they are not off by a factor of 10. Can the US make something similar? It's quite possible, the US military budget is more than 10 times higher. Separately, hypersonic missiles are thought to travel at an altitude of 100km, where the air density is about one million times lower than at ground level [2]. Even if the air friction is ten 1000 times higher than for a subsonic missile (if drag is proportional to v^3 and v goes up by a factor of 10), in the end the total drag could be lower. I personally expect hypersonic missiles like this one come with increased range rather than decreased range compared to their subsonic cousins. [1] https://en.wikipedia.org/wiki/Kh-47M2_Kinzhal https://en.wikipedia.org/wiki/Kh-47M2_Kinzhal [2] http://www.braeunig.us/space/atmos.htm http://www.braeunig.us/space/atmos.htm
- frostburg 4y ago
  The Kinzhal is basically an air-launched Iskander, a ballistic rocket, not a cruise air-breathing missile.
  - credit_guy 4y ago
    But the scramjet should increase, not decrease the range, no?
    - gffrd 4y ago
      I've been pondering about the range thing, because my immediate kneejerk was "two balls rolling, one's 2x faster than the other, that one will go further" … but I had that "trick question" flag go off as soon as I thought that. Things I don't know: - It's faster … possibly huge fuel consumption to get to operating speed over comparable subsonic missile? (even if sips fuel once at operating speed/altitude) - Will fly at higher altitude … which means lower friction (enough to counter what's added by higher speed) … but also to hit the same target, more distance must be covered (climb/descent to operating altitude + greater orbiting circumference) - Limited "package" size … do scramjet surfaces/elements reduce the amount of space available for fuel? - How much distance is a factor.