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From my point of view, when the SpaceShipOne and Two get released from their carrier planes (WhiteKnight and WhiteKnightTwo) they are in free fall, therefore the pilots should become weightless inside them. They even push the yoke so that the nose doesn't go up when jacking out of the carrier plane. If so, how long does the weightlessness last in glide flights (in powered flights obviously until the engine is launched)?

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The vehicle leaves its parent, according to Wikipedia at about $15\,\mathrm{km}$ up: well inside the atmosphere. If it doesn't light its engine it will be in free-fall, in some sense, for no time at all, at there will always be some drag from the atmosphere on it. In practice it will be for a few seconds until the atmospheric drag builds up.

The expression for drag is

$$D = c A \frac{\rho v^2}{2}$$

The acceleration due to the drag is then

$$a = c A \frac{\rho v^2}{2M}$$

where $c$ is some drag coefficient depending on the shape of the thing, $A$ is the effective area, $M$ is the mass of the object, $\rho$ is density and $v$ is velocity. $\rho$ is something over a tenth of atmospheric pressure at that altitude I think.

So drag goes like $v^2$, and in the absence of drag, $v = gt$: without knowing the various parameters it's hard to give an exact answer unfortunately. But seconds at the outside.

Note that for the first few seconds there will of course be drag from the forward velocity of the thing: whether this is significant enough to feel I don't know: my guess is yes, it is, at that low altitude.

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Spaceship two has wings so in general will be producing lift and not be in true free fall. It would be possible for a winged craft to fly a negative angle of attack to achieve zero G but this will produce an ever increasing dive if starting from level flight. More likely it is a low but not zero G release with spaceship two moving away from whiteknight because it is producing less lift (small wings) than it weighs (full of fuel) at the release speed rather than a true fall.

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  • $\begingroup$ Your answer is good too. I've accepted tfb's one because it goes more into detail and states that there's indeed some microgravity until air drag builds up. $\endgroup$ – LoveForChrist Jul 1 '20 at 12:53

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