Re: SpaceShipOne News Coverage just a little rough on the edges

From: Peter Stickney (peter_at_Mineshaft.local)
Date: 10/25/04 

Date: Mon, 25 Oct 2004 16:42:28 -0400

In article <28326d49.0410251017.2600d44@posting.google.com>,
        d_schneider@emulex.com (dave schneider) writes:
> Pat Flannery <flanner@daktel.com> wrote:
> [...]
>>
>> They already know that it has control problems due to its excessive
>> dihedral; frankly it's an historic aircraft and shouldn't be risked-
>> it's time to move on to an improved version.
>
> I've heard that a change approved by their aerodynamicist was
> effective in dealing with the control issue on the 2nd prize flight.
> I still haven't found out what that change was, although some coverage
> has appearently said it was in the afterbody.

It was more of a trajectory change. The initial flight profile of SS1
was pretty simple - light the rocket, and point it straight up.
That's all well and good, but it seems that SS1 isn't particualrly
stable in roll at Cl (Lift coefficient) = 0.0, and it doesn't have a
whole lot of roll control auhority at Cl = 0, either.
So, the big change was to not pitch up fully vertical, and mantina a
touch of lift on the wings as long as possible. That would cut the
apogee down a bit, 'cause the vertical velocity vector would be a
fraction of the total velocity vector, instead of the whole thing, but
they had more than enough rocket burn to make up for the difference.
Another Rutan Solution - a simple fix to a point problem, and very
clever. 

-- 
Pete Stickney
 A strong conviction that something must be done is the parent of many
 bad measures.  -- Daniel Webster

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