Comments on: Virgin Galactic changes fuels as it prepares for its next round of test flights

By: Gary Warburton

Gary Warburton — Tue, 27 May 2014 17:44:13 +0000

So there is something going on. It sounds like what Neil said, they`re going to have to switch to liquid fuel if they want to get flying this year. At least they`d know what they need to do. Didn`t Aries 1 have a vibration problem? When you have the oxidizer separate from the fuel it`s only going to exaggerate the problem. The oxidizer can`t get to the fuel evenly with solid fuels.

By: Neil

Neil — Mon, 26 May 2014 01:23:23 +0000

I just watched the video above and this burn doesn’t look very consistent. The diamonds come and go throughout the burn and this seems a sure sign that it’s not particularly stable. It does seem to need a bit of work.
This might be a case of being wedded to an idea and continuing on longer than was supported by the evidence. They really should have ditched this hybrid motor much earlier and contracted or built a lox one instead. They’ve paid for this by the extended development time. Must have cost them heaps in terms of resources. RB was either not being properly informed or simply going for the publicity.
Cheers.

By: D. Messier

D. Messier — Sun, 25 May 2014 06:30:47 +0000

They only fired the rubber engine in flight for 20 seconds. If they had doubled that burn time, the oscillations and vibrations would have torn the ship apart. There was no way they could have gotten to space with it. Richard Branson’s claims of flying to space by Christmas 2013 were completely disconnected from reality.

They tested the rubber engine with helium, which is what we saw in the “full length” engine burn video they released in December. That might have done the trick in damping the oscillations, but it added weight to the ship. The weight would have largely canceled out the extra performance on the burn.

It sounds like they won’t start flying SS2 under power until August, which matched the estimates that I previously wrote about. My sources had not expected tests to begin any earlier than June and as late as August.

The cracks in WK2 were discovered accidentally. And they’re far more serious than the “adhesive imperfections” that Whitesides claims them to be.

By: antares

antares — Sun, 25 May 2014 03:39:24 +0000

â€œWe still expect it to be in the summer,â€ he said of the timing of those flights, perhaps towards the latter part of the summer.

It is always summer in the Mojave.

By: Jim Katzaman

Jim Katzaman — Sat, 24 May 2014 15:30:58 +0000

Fuel change, interior work, setting up a flight simulator — that sounds like a lot of work still to do. 2014 is almost half over. I’d be surprised to see an actual Virgin commercial flight until at least a year from now. Then again, hasn’t it always seemed to be at least a year away?