Second launch of Spaceship 1

Watching the second launch of Spaceship 1 and thinking on the
roll couple that begins as the rocket is fully started and
seems to get a step increase crossing the sound barrier. Ideas
range from mass swirling through the nozzle to various
interactions between aerodynamic elements. The continued rolling
would seem more an artifact due to rolling while exiting the
effective atmosphere.

Ideas?

I am hoping that after the 3rd flight further studies will be
made to better understand exactly what's going on rather than
simply adding a correcting force and ignoring the effect.
Virgin Airlines has announced plans to license the design to
evolve into a slightly larger version.
--
Anvil*

I posted on this last night, but it hasn't showed up back at my
newsreader yet. Basically, it looks to me like a rotating hybrid engine
will carve spiral grooves on its fuel grain as the oxidizer flows past
it. And those will impart a swirl to the gas. The faster the ship
rolls, the stronger the carving effect. The grooves form in the
direction that tends to increase the rotation, which increases the
spiral cutting: vicious circle.

And of course this can only be seen outside the atmosphere, not on a
test stand or preliminary flights.

This implies that the roll starts more or less randomly, and gets worse
rapidly. Will they get lucky this time? If not, have they figured out
that it's important to cancel the roll ASAP and maybe even to reverse
the roll to cut counteracting grooves?

Chris

Anvil wrote:

Watching the second launch of Spaceship 1 and thinking on the
roll couple that begins as the rocket is fully started and
seems to get a step increase crossing the sound barrier. Ideas
range from mass swirling through the nozzle to various
interactions between aerodynamic elements. The continued rolling
would seem more an artifact due to rolling while exiting the
effective atmosphere.

Ideas?

I am hoping that after the 3rd flight further studies will be
made to better understand exactly what's going on rather than
simply adding a correcting force and ignoring the effect.
Virgin Airlines has announced plans to license the design to
evolve into a slightly larger version.


--
Chris Phoenix
Director of Research
Center for Responsible Nanotechnology http://CRNano.org