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  • Hand-Flying Reentry

    From Scott M. Kozel@21:1/5 to All on Mon Jan 15 20:31:24 2018
    Reading a book about the X-15 program. Says that the pilots
    hand-flew the reentry on the missions to space, the highest
    mission was 67 miles and several minutes outside of the
    atmosphere. Initial planning was for missions as high as
    180 miles; that would obviously have been a much longer and
    higher speed reentry, I wonder if the pilot could hand-fly
    it? Don't think there was any automated way to do it back
    in the 1960s.

    Would it be possible for the pilots to hand-fly a space
    shuttle reentry? Or would an automatic system be required
    given the exacting parameters on a reentry from orbit?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeff Findley@21:1/5 to All on Tue Jan 16 06:32:50 2018
    In article <04b0789c-1d53-468d-aaa3-64281ea8562c@googlegroups.com>, kozelsm@comcast.net says...

    Reading a book about the X-15 program. Says that the pilots
    hand-flew the reentry on the missions to space, the highest
    mission was 67 miles and several minutes outside of the
    atmosphere. Initial planning was for missions as high as
    180 miles; that would obviously have been a much longer and
    higher speed reentry, I wonder if the pilot could hand-fly
    it? Don't think there was any automated way to do it back
    in the 1960s.

    Actually there were electronics to help fly the aircraft. I Believe
    these were all analog (you can actually do a lot with analog control
    systems). But, there was no "modern" digital autopilot that would fly
    the entire reentry for them.

    Cite:

    Experience with the X-15 Adaptive Flight Control System https://www.nasa.gov/centers/dryden/pdf/87785main_H-618.pdf

    Would it be possible for the pilots to hand-fly a space
    shuttle reentry? Or would an automatic system be required
    given the exacting parameters on a reentry from orbit?

    The pilot was trained to fly the shuttle manually during pretty much all
    stages of flight. But you can't fly a space shuttle with zero
    computers. The space shuttle has a digital control system (i.e. fly by
    wire). There were no cables connecting the flight controls directly to
    the control surfaces. Control surfaces were hydraulic and powered by
    the shuttle's APUs.

    That's why the shuttle had 4 redundant computers to control it (in case
    of hardware failure). It also had a fifth computer with completely
    different, but minimal, flight control software in case a software
    failure caused the 4 main computers to fail.

    Jeff
    --
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    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Scott M. Kozel@21:1/5 to Jeff Findley on Thu Jan 18 20:58:14 2018
    On Tuesday, January 16, 2018 at 6:32:51 AM UTC-5, Jeff Findley wrote:
    In article <04b0789c-1d53-468d-aaa3-64281ea8562c@googlegroups.com>, kozelsm@comcast.net says...

    Reading a book about the X-15 program. Says that the pilots
    hand-flew the reentry on the missions to space, the highest
    mission was 67 miles and several minutes outside of the
    atmosphere. Initial planning was for missions as high as
    180 miles; that would obviously have been a much longer and
    higher speed reentry, I wonder if the pilot could hand-fly
    it? Don't think there was any automated way to do it back
    in the 1960s.

    Actually there were electronics to help fly the aircraft. I Believe
    these were all analog (you can actually do a lot with analog control systems). But, there was no "modern" digital autopilot that would fly
    the entire reentry for them.

    Cite:

    Experience with the X-15 Adaptive Flight Control System https://www.nasa.gov/centers/dryden/pdf/87785main_H-618.pdf

    Would it be possible for the pilots to hand-fly a space
    shuttle reentry? Or would an automatic system be required
    given the exacting parameters on a reentry from orbit?

    The pilot was trained to fly the shuttle manually during pretty much all stages of flight. But you can't fly a space shuttle with zero
    computers. The space shuttle has a digital control system (i.e. fly by wire). There were no cables connecting the flight controls directly to
    the control surfaces. Control surfaces were hydraulic and powered by
    the shuttle's APUs.

    That's why the shuttle had 4 redundant computers to control it (in case
    of hardware failure). It also had a fifth computer with completely different, but minimal, flight control software in case a software
    failure caused the 4 main computers to fail.

    One of the books about the X-15 said that reentry had to be flown
    very precisely, as even at the best, it was close to the limits for
    heating on the airframe, g-forces on the airframe, aerodynamic
    forces on the airframe, and g-forces on the pilot. A small amount
    of miscalculation could push one or more of them beyond the danger
    point.

    That is why the limited the altitude flights to around 350,000 feet
    or 67 miles.

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