White Knight: April 2009 Archives

Now we know that Scaled Composite's explanation for the tail strike and port roll during its WhiteKnight Two (WK2) prototype's fourth test flight on 20 April was thrust asymmetry from its Pratt & Whitney Canada 308A engines caused by a miss setting of the idle thrust settings, apparently giving the starboard engines more power than the port engines

Scaled's statement does not specify which set of engines it was but, just as power was being applied following the touch-and-go the aircraft must have yawed left, because the crew countered with right rudder

credit Flight / caption: now we know it was a idle thrust miss setting

Scaled Composites has put a statement on its website about its WhiteKnight Two prototype Virgin Mothership Eve test programme that confirms what Flight has been saying, that the rudder has had to be modified

There are other rather uncharitable comments made by Scaled in the statement but Hyperbola is sure that between the lines of aggressive corporate rhetoric the readers will see that they are getting factually accurate reportage and well informed comment from Flight about this unique aerospace project

Read here Flight's article about the statement and how it fits in with our coverage of the mothership's test programme

credit Flight / caption: WK2 fourth flight indicated further directional stability issues

So now during a straight forward touch and go manoeuvre Virgin Galactic's WhiteKnight Two (WK2) prototype Virgin Mothership Eve struck its tail as the pilot fought to control a roll left due to a 15kt cross wind, which normally should not be a problem

Its further evidence that Scaled Composites, for all its expertise, did not realise the degree that a two fuselage aircraft with a Boeing 757 scale wing would require larger vertical fins

With vortex generators added and a second horn and an increase in the size of those horns the aircraft still appears to be suffering from directional instabilty. The horns, for those of you who don't know, are the tab like squares that appear to extend from the rudder into the fin and are designed to jut out in the direction opposite to the movement of the rudder, inducing forces to stop any natural tendencies for the rudder to swing back to neutral - its normal position

The big question is, can this WK2 prototype carry SpaceShipTwo (SS2)? A provocative question but while landing in a 15kt crosswind presents such a challenge the carriage of SS2 is not going to occur any time soon

See more pictures and read more detail in this story

click through to access a larger version of the photo of the moment of the tail strike

credit Flight / caption: WhiteKnight Two prototype Virgin Mothership Eve makes second flight

OK revelations may be a strong word but some of you may have noticed a series of articles about that start-up spaceline appearing on flightglobal.com/spaceflight. This article about its customers and this one about its prospective spaceports are the first two of six articles making up a six-page feature for Flight International magazine's 14 April edition

The remaining four articles will be published over the next few days on flightglobal.com/spaceflight with the main text of the feature appearing Tuesday (14 April) evening, UK time

That final article, largely an interview with Virgin Galactic president Will Whitehorn, has an exclusive image from the 25 March third flight of WhiteKnight Two prototype Virgin Mothership Eve and a rather special graphic. Podcasts of that interview with Whitehorn can be found here 

For Flight's coverage of the growing personal spaceflight industry go here to the space tourism landing page