3 ms·

I do wonder how much modern design can overcome, in materials, engines, aerodynamics, and flight controls. Less drag at higher altitudes, easier to travel furth

I do wonder how much modern design can overcome, in materials, engines, aerodynamics, and flight controls. Less drag at higher altitudes, easier to travel further, cover more distance in less time. Should be able to eliminate refueling stops at the very least. One of the problems of fast high altitude flights is preventing stalls. Maybe computer aids and thrust vectoring would help prevent or mitigate such events.

powderpig 4y ago
Worth noting the use of titanium at Mach 3, Mach 3.5, is really at its limit. Any faster and you'll start to see serious problems with thermal management. This pushes you into using super nickel alloys or even ceramic matrix composites, which would be necessary for use cases at Mach 5+ for sustained flight. Acknowledging planes in the last have gone faster like the X-15 but this such plane's architecture wouldn't stop for longhaul flight distances. CMCs and super nickel alloys will be very very expensive.
- stametseater 4y ago
  The version of the X-15 that got the most impressive speed records was coated in an ablative paint designed to burn away while in flight to protect the plane. With a rocket engine, reaction control system and ablative coating, the X-15 almost had more in common with a space ship than an airplane.
  - zbrozek 4y ago
    Have we gotten good enough at jet engines to be able to generate enough thrust in the upper atmosphere to turn planes into ICBMs for an ex-atmospheric inertial jaunt?
    - stametseater 4y ago
      With ramjets/scramjets maybe, but developing the inverse of what you suggest is where the money is being spent. Missiles on ballistic trajectories are easier to see on radar and have less ability to maneuver, so they're easier to intercept. So instead of starting out breathing air and then pulling into a ballistic climb at the end, the idea is to start out with a rocket powered ballistic flight, reenter the atmosphere, and then glide/fly through the atmosphere, possibly with a ram/scramjet, to the target. This way the missile is much harder to detect and intercept. Like this image depicts: https://en.wikipedia.org/wiki/Qian_Xuesen#/media/File:Tsien_Hsue-shen.jpg https://en.wikipedia.org/wiki/Qian_Xuesen#/media/File:Tsien_... (This sort of missile flight is sometimes called a Qian Xuesen trajectory, after the man who first came up with the idea.)
      - zbrozek 4y ago
        Shame; those dollars aren't going to improve my lifestyle the way that faster passenger flight would.
V_Terranova_Jr 4y ago
> I do wonder how much modern design can overcome, in materials, engines, aerodynamics, and flight controls. The basic physics are arrayed against you. Higher speed cruise flight already means you already fly at higher altitudes or the thermal and structural loads would be intolerable. Stall departure resistance isn't the issue. Get high enough, and you're no longer talking about cruising flight, you're talking about hypersonic glide that has been accelerated to hypervelocity by rockets (this is called point-to-point boost-glide). It has been looked at, and people are continuing to look at it. There is a whole loose industry coalition in the U.S. called "FastForward" that is interested in this topic.

powderpig 4y ago

Worth noting the use of titanium at Mach 3, Mach 3.5, is really at its limit. Any faster and you'll start to see serious problems with thermal management. This pushes you into using super nickel alloys or even ceramic matrix composites, which would be necessary for use cases at Mach 5+ for sustained flight. Acknowledging planes in the last have gone faster like the X-15 but this such plane's architecture wouldn't stop for longhaul flight distances. CMCs and super nickel alloys will be very very expensive.

stametseater 4y ago
The version of the X-15 that got the most impressive speed records was coated in an ablative paint designed to burn away while in flight to protect the plane. With a rocket engine, reaction control system and ablative coating, the X-15 almost had more in common with a space ship than an airplane.
- zbrozek 4y ago
  Have we gotten good enough at jet engines to be able to generate enough thrust in the upper atmosphere to turn planes into ICBMs for an ex-atmospheric inertial jaunt?
  - stametseater 4y ago
    With ramjets/scramjets maybe, but developing the inverse of what you suggest is where the money is being spent. Missiles on ballistic trajectories are easier to see on radar and have less ability to maneuver, so they're easier to intercept. So instead of starting out breathing air and then pulling into a ballistic climb at the end, the idea is to start out with a rocket powered ballistic flight, reenter the atmosphere, and then glide/fly through the atmosphere, possibly with a ram/scramjet, to the target. This way the missile is much harder to detect and intercept. Like this image depicts: https://en.wikipedia.org/wiki/Qian_Xuesen#/media/File:Tsien_Hsue-shen.jpg https://en.wikipedia.org/wiki/Qian_Xuesen#/media/File:Tsien_... (This sort of missile flight is sometimes called a Qian Xuesen trajectory, after the man who first came up with the idea.)
    - zbrozek 4y ago
      Shame; those dollars aren't going to improve my lifestyle the way that faster passenger flight would.

V_Terranova_Jr 4y ago

> I do wonder how much modern design can overcome, in materials, engines, aerodynamics, and flight controls. The basic physics are arrayed against you. Higher speed cruise flight already means you already fly at higher altitudes or the thermal and structural loads would be intolerable. Stall departure resistance isn't the issue. Get high enough, and you're no longer talking about cruising flight, you're talking about hypersonic glide that has been accelerated to hypervelocity by rockets (this is called point-to-point boost-glide). It has been looked at, and people are continuing to look at it. There is a whole loose industry coalition in the U.S. called "FastForward" that is interested in this topic.