Quote:
Originally Posted by vicky_molokh
No TAVs are built in the hope of having an air speed that high. The whole point of a TAV is that you don't need either of the two.
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Yes you do. I don't have the stats for the TAVs in front of me, but all the ones I remember have >1G.
Basically, orbit is about moving around a planet fast enough that falling and the curvature of the planet keep up with one another. If you're moving below orbital velocity, you fall faster than that, and so you have to do something so you don't hit the ground. Your choices on that are 'downwards rocket thrust matching gravity', 'aerodynamic lift', and 'get a temporary large upwards velocity, and accelerate while you're in free-fall'. The third option allows you to have short periods where acceleration is less than 1G, but your average still has to be pretty high -- for example, if we figure a velocity of 6,000 mph at a 45 degree angle near the top of the atmosphere, velocity is 1,900 m/s vertical, 1,900 m/s horizontal. It will take us 190s to stop moving vertically, 380s to hit the atmosphere again. If we can accelerate to 7,900 m/s before that happens, we achieve orbit. That requires 1.5G of acceleration...
Quote:
Originally Posted by vicky_molokh
Uh, no. You never try to exceed high machs like those. You reach your stall speed, lift off the runway, attain your cruise speed (or maybe top speed), and then you gain altitude gradually, which reduces atmospheric density (well, you fly to where it's lower), increases both your top speed and your stall speed at the same time.
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What you're missing is that your mach number continues to climb, because speed of sound does not increase at high altitude, and the result is that the stagnation temperature of air at your leading edge also goes up. At mach 25, stagnation temperature of air is on the order of 30,000K.
Quote:
Originally Posted by vicky_molokh
(Also, where's what's the page for the 1/(L/D) rule? I can't find it)
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It comes from Real Physics, not GURPS. Basically, if GURPS is letting you do this, GURPS is wrong.