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One difference is that huge strides have been made in materials research. Boom advertises extensive use of carbon fiber, which was not available when the X-3 wa

One difference is that huge strides have been made in materials research. Boom advertises extensive use of carbon fiber, which was not available when the X-3 was designed/built.

ChuckMcM 6y ago
Agreed, and it will be super helpful to see how carbon fiber deals with supersonic shock waves compared to steel. Like I said, it makes a lot of sense to build a platform that can prove that your tooling gets you to a working aircraft. And once you can do that, you can then iterate using the platform to inform your engineering choices. SpaceX has done this brilliantly and is the current poster child AFAICT. So I'm looking forward to the test program to see how it does, but was chuckling at the over the top marketing speak with which they "rolled out" this revolution. Step 1: Build a plane (check!) Step 2: Fly the plane (next on the list)
- tobinfricke 6y ago
  I'd guess carbon fiber is replacing aluminum. I'm not a materials guy but it's hard to imagine replacing titanium with carbon fiber. I don't think steel is used much in aircraft. > So I'm looking forward to the test program to see how it does, but was chuckling at the over the top marketing speak with which they "rolled out" this revolution. Same! :-) I'm even more skeptical of their use of the word "sustainable," although I commend them on making that a goal.
  - deleted 6y ago
    [deleted]
  - vkou 6y ago
    > I don't think steel is used much in aircraft. It's not, but there's a very conspicuous counter-example - developed in the USSR. https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25 https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25 - with only 9% titanium content, compared to 26% of the F-15. For a number of economic and engineering reasons, instead of making jets out of titanium, the USSR, for the most part, preferred to export it to the US, in exchange for dollars.
    - tim333 6y ago
      The MiG-25 was unusual in that it was designed to go mach 2.8+ which overheats normal materials. Boom said they were limiting their design to mach 2.2 so as to be able to stick to normal safety approved stuff. It's interesting to see the Mig-25 steel design come back pretty much in SpaceX's starship.

One difference is that huge strides have been made in materials research. Boom advertises extensive use of carbon fiber, which was not available when the X-3 was designed/built.

ChuckMcM 6y ago

Agreed, and it will be super helpful to see how carbon fiber deals with supersonic shock waves compared to steel. Like I said, it makes a lot of sense to build a platform that can prove that your tooling gets you to a working aircraft. And once you can do that, you can then iterate using the platform to inform your engineering choices. SpaceX has done this brilliantly and is the current poster child AFAICT. So I'm looking forward to the test program to see how it does, but was chuckling at the over the top marketing speak with which they "rolled out" this revolution. Step 1: Build a plane (check!) Step 2: Fly the plane (next on the list)

tobinfricke 6y ago
I'd guess carbon fiber is replacing aluminum. I'm not a materials guy but it's hard to imagine replacing titanium with carbon fiber. I don't think steel is used much in aircraft. > So I'm looking forward to the test program to see how it does, but was chuckling at the over the top marketing speak with which they "rolled out" this revolution. Same! :-) I'm even more skeptical of their use of the word "sustainable," although I commend them on making that a goal.
- deleted 6y ago
  [deleted]
- vkou 6y ago
  > I don't think steel is used much in aircraft. It's not, but there's a very conspicuous counter-example - developed in the USSR. https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25 https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25 - with only 9% titanium content, compared to 26% of the F-15. For a number of economic and engineering reasons, instead of making jets out of titanium, the USSR, for the most part, preferred to export it to the US, in exchange for dollars.
  - tim333 6y ago
    The MiG-25 was unusual in that it was designed to go mach 2.8+ which overheats normal materials. Boom said they were limiting their design to mach 2.2 so as to be able to stick to normal safety approved stuff. It's interesting to see the Mig-25 steel design come back pretty much in SpaceX's starship.