Pack your bags, boys and girls. Virgin Galactic is going to display their SpaceShipTwo at the upcoming AirVenture show in Oshkosh.  For 200 k$ you can strap a reusable rocket plane to your backside and take a suborbital flight. The AirVenture website has an animated video of a flight that is worth seeing. (The animators left out the floating vomitus that is sure to be a part of the experience.)

The designer and builder is none other than Burt Rutan’s Scaled Composites. This second generation suborbital vehicle uses the same reentry stabilization scheme that the first vehicle used. The lifting craft has 4 engines- two outboard of each of the twin fuselage sections. It has 4 engines instead of two to protect against the undesirable situation of loss of thrust from one side of the plane. With the engines so far from the centerline, the asymmmetric thrust that would result would make the plane difficult to fly.

The space vehicle is carried to a suitably high altitude (ca 50,000 ft) for release followed by an 80 second boost from the rocket motor. The boost phase sends the craft into a suborbital arc carrying the craft to a projected 361,000 ft peak altitude.  The passengers are treated to a period of weightlessness between the moment the rocket motor quits and when the reentry phase begins to encounter significant atmospheric drag.

At some point after the boost is complete, the tail booms pitch into an elevated position quite far from the centerline of the craft. The craft has reaction motors that stabilize the flight attitude during the phase in which the aerodynamic control surfaces are ineffective.

The reentry attitude is one in which the underbody of the craft faces in the direction of motion so as to provide maximum drag. The elevated, or “feathered” tail elements serve to stabilize the motion of the craft as it accelerates belly first into the ever thickening atmosphere.  The stabilization that the feathered empannage provides is much like the stabilization afforded a shuttlecock.

The feathering configuration helps the crew manage the kinetic energy developed during reentry to the atmosphere. The scheme includes a deadstick landing, so energy management is quite important.  Eventually, the tail booms retract to the in-line position and the craft transitions to a gliding condition with conventional flight control surfaces.

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