Aviation Week & Space Technology
10/27/2003, page 14


Scaled Composites' SpaceShipOne is flying again after testing was
halted to address a pitch hangup that occurred on a Sept. 23 flight
(AW&ST Oct. 6, p. 43). The company conducted a full-scale wind tunnel
test of the winged spacecraft's tailboom and tail surfaces, identified
the source of the pitchup, developed a fix and flew it on SpaceShipOne
on Oct. 17.
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Partial reprint of 10/06 article...

Aviation Week & Space Technology
10/06/2003, page 43

Michael A. Dornheim
Los Angeles

Pitch hangup will result in delay and changes to design

SpaceShip1 Hiccups...

The glider was dropped from the White Knight carrier at 46,600 ft. and
115 kt., and Melvill spent 5-10 sec. trimming it in roll. He then
began the stall entry that led to the pitchup. The recovery placed the
aircraft inverted, and after airspeed had built, a 2g pullout put
SpaceShipOne in a secondary departure to the left. Rudder and stick
weren't stopping the departure, so Melvill added right roll trim. That
halted the departure, but caused further oscillations until the roll
trim was removed.

"I had several iterations of overcontrol," Melvill said. "There is no
feel on the stick at high altitude. Things happen slowly, but there's
not much control with the stick alone. The trim has a huge amount of
control, intended for supersonic flight." The departure occurred above
40,000 ft., where there is less damping of body rates than at low
altitude. "Eighty-five knots in denser air could have been OK,"
Melvill said.

The aft operational CG had not been flown before and was achieved by
bolting about 170 lb. of steel plates by the dummy nozzle at the
fuselage end. They were not jettisonable. There was a tank of liquid
ballast in the tail that could be dumped, but it was empty. The rocket
engine's nitrous oxide oxidizer and rubber fuel are placed fore and
aft of the CG, respectively, so there is little change in balance
during the engine firing, which is nominally at a mid-CG.