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Old 08-15-2013, 05:22 PM   #14
MatthewVilter
 
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Join Date: Jan 2010
Location: Los Angeles County
Default Re: EuroSpace E950 Minerva Executive Transatmospheric Vehicle

Quote:
Originally Posted by vicky_molokh View Post
Well, yes and no. You can still go round and round at a suborbital velocity while attaining orbital velocity.
Only by continuously expending energy to maintain altitude.

Quote:
Originally Posted by vicky_molokh View Post
No you're not. Notice that the aAccel is the aAccel the craft maintains in addition to maintaining its current speed.
That is only true in "space" (whatever that means). If you out of the atmosphere but not yet in orbit (or passed escape velocity) then you are on a suborbital trajectory. If you are trying to go up with 0.05 G of thrust and being pulled down at ~0.8 G you are going to fall. One way to get around this is to "jump" out of the atmosphere (using, for example a combination of rockets and air breathers) and then accelerate to orbital velocity before you fall back into the atmosphere. That is not going to work if the accelerate-to-orbital-velocity part takes 6 hours. Well, I guess it all depends on how high you jump...but yeah I really don't think that would work. :/

Quote:
Originally Posted by vicky_molokh View Post
What is a proper free falling speed? If you're talking about terminal velocity for a free fall, then I'm not sure how it's relevant: the craft is not being in a free fall unless you failed to reach stall velocity at the runway (in which case you've got a totally different problem on your hands).
No sorry my bad, I just meant "orbital velocity".

Quote:
Originally Posted by vicky_molokh View Post
Why? Even the silly TL6 aerodynamic knowledge is enough to keep stall speed at 40mph. With a TL10 design that is optimised for a low-thrust launch, this shouldn't be a problem at all. Well yeah, you need a 400m runway to lift off the ground with that sort of thrust. Big deal.
And here I'm talking about keeping your self out of the atmosphere while you accelerate to orbital velocity.
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