Exclusive Pictures: SpaceShipTwo Engine Test Firing in Mojave

January 16, 2014 Doug Messier News 10 Comments

Nitrous nylon engine test on Jan. 16, 2014. (Credit: Ken Brown)

Ken Brown captured these spectacular photos of a hybrid engine test at the Mojave Air and Space Port on Thursday afternoon. Scaled Composites conducted the hot fire of the nylon-nitrous oxide engine, which is being tested as an alternative to the rubber-nitrous oxide that Virgin Galactic’s SpaceShipTwo has used for three test flights, sources say.

Scaled is developing SpaceShipTwo and WhiteKnightTwo for Sir Richard Branson’s spaceline, which is supposed to begin commercial operations from Spaceport America in New Mexico by the end of the year.

The test today lasted longer than 30 seconds. View a video that captured most of the hot fire.

Scaled has been conducting tests on the nylon-nitrous engine since at least last May, according to sources.

Steven Hunt
It certainly appears to burn cleaner than their current engine, although Wikipedia says burning nylon produces hydrogen cyanide…
windbourne
Why the move to nylon? Ease of making the motor? Higher ISP?
Carolynne Campbell
Yes it does look a lot cleaner doesn’t it? Nylon is harder to get lit than HTPB, but it’s harder so less chunks and bits ejected. Can’t see it having much impact in ISP. N2O with any hydrocarbon will be about the same. Judging by the size of the fuel-grain fire after the burn, there’s a lot of ‘additives’ in that grain. If it’s AP (Perchlorate) there’ll be lots of nasty combustion bi-products. So much for “Non Toxic”.
jb
Come on Virgin..bite the bullet. Stop going hybrid .go liquid..:)
Richard
Quick question Doug, how do you know this one was Nylon, from your secret squirrel ‘sources’ that have been pretty reliable so far?
Douglas Messier
Moose and squirrel on the case here in Mojave.
Douglas Messier
The nylon engine has been contemplated for some time. I remember
Branson’s PR guy, Will Whitehorn, mentioning it at the runway dedication
at Spaceport America few years ago. This was right after stepped aside
for Whitesides. He actually came out of the audience to answer a question that had been posed, if I recall right.
They’ve been having a lot of trouble with getting the rubber engine to burn cleanly and efficiently and dealing with oscillation and vibration problems. That’s what my sources tell me. That thing just doesn’t scale up very well and it looks like a flying tire fire (which can’t be good for Branson’s image).
If you look at the FAA’s final environmental assessment report for the launch and re-entry permit, which was pushed in May 2012, you see that the agency looked at emissions for nitrous-rubber and nitrous-nylon, so Virgin was contemplating switching engines for a while now.
http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20120502_Mojave_SS2_Final_EAandFONSI.pdf
At the bottom of page 30 (page 44 in the PDF), you see the estimated
total emissions from the space plane, WK2 and the chase aircraft. In terms of CO2, there’s virtually no difference because most of the emissions are from WK2.
Nitrous-rubber — 59,941 lb
Nitrous-nylon — 58,978 lb
The nylon engine would look a lot better, and it might burn a lot smoother, but the carbon footprint would be virtually the same.
Douglas Messier
Moose and Squirrel, your source for Mojave space news!
therealdmt
Which one are you — Moose, or Squirrel?
windbourne
thanx for the info.