SpaceShipTwo engine tests?

If you got Issue 12 of Virgin Galactic’s email newsletter earlier this week, you might have seen this tidbit subtly included in the text: “Excitement was running high for the high speed taxi runs in December and a succession of rocket motor fires”. (The online version of the newsletter has a slightly different wording: “but nothing could compare to the anticipation of the Rocket Motor Fires which brought the project one step closer to Richard Branson’s and Burt Rutan’s dream of making space more accessible to everyone.”) Still, it appears to indicate that the SpaceShipTwo team finally started test-firing rocket motors.

Flight International confirms that milestone with Virgin Galactic president Will Whitehorn. The “Rocket Motor Two” (RM2) program, in Whitehorn’s words, is working “to mirror rapid progress on the [WK2] flying programme and SS2 final construction, but we are saying no more than that,” including no information on the duration of the tests, the propellants used, or even where the tests took place. “We don’t give out details like this for potential competitors beyond what is said on the newsletter website,” he explained. Other companies in the field, by comparison, tend to see the first hot-firings of rocket engines as a newsworthy milestone, but, of course, the Scaled team tends to be a bit more secretive than others.

4 comments to SpaceShipTwo engine tests?

  • Ben Brockert

    These firings are being done at SpaceDev’s facilities down near San Diego. Those of us stuck in Mojave haven’t gotten to see them go.

  • Peter

    At first I didn’t think that SpaceDev had the facilities to fire the full scale SS2 motor but according to their website they have a rocket firing facility in Capistrano (which according to google earth is in Irvine, CA). But I still wonder if they’re really firing the actual SS2 motor or a subscale motor so as to test out differant fuel and/or oxidizer combinations at a more cost effective level. I’m just speculating but it seems like it would be possible to use the original SS1 tank and motor to test out the various fuels while Scaled continued to troubleshoot the SS2 motor accident.

    If they are testing the full scale SS2 motor I hope they release video or photos soon anyhow.

    As for the construction of SS2 we all saw that video they released of it being 40% done back when they unveiled the design of WK2 and SS2. Then reading the press release Scaled made about the accident they indicated that they’d be moving from a plastic liner (on their oxidizer tank) to a metal one (given that certain plastics burn quite well in an oxidizer rich environment). So I’m guessing that they had to disassemble SS2 to remove that tank (and I’m not sure that they designed it to be removed). The SS1 tank was bonded to the inside of the fuselage, all the way around, with an elastomeric compound so it wasn’t a permanent epoxy bond but still??? Just curious if they had to do some serious hacking to remove the tank or even start from scratch if it’s not removable.

  • [...] I talked to him briefly afterwards and asked him about the status, including any engine tests, which the company had hinted at in recent weeks. “There have been, but not the full scale,” he said. “Subscale models?” I [...]

  • Peter O'Driscoll

    About 2 years ago I wrote to Burt Rutan including:

    ” I have recently worked on what I thought was a novel design for a hybrid engine, and obtained a provisional patent for the concept. Unfortunately, others had had the same idea earlier, so with or without patent, it is not novel.

    The concept may be of interest to you, if you have not already investigated it. Basically, it is designed to increase the power of a hybrid rocket engine. The regression rate of a hybrid is usually limited by the rate of mixing the liquid oxidizer and solid fuel. My provisional patent described a method of increasing the oxidizer/fuel mix rate.

    The concept is augmentation of the solid fuel, typically HTPB, with a crystalline oxidizer, ammonium perchlorate for example. Typical ratios would be 75% HTPB to 25% perchlorate. Ferric oxide or other additives might also be included in the formulation. This ratio would not burn without the added flow of liquid oxidizer, and would be extinguished by termination of the liquid flow. Burn rate could be over 300% over that for a 100% HTPB fuel grain.

    Thus, for a very small increase in risk during manufacturing and handling, a significant increase in burn rate could be achieved. Reduction of oxidizer flow rate is also a possibility.”

    The idea was originally investigated, as far as I know, by engineers at Thiokol, Huntsville.

    I wonder if this option has been explored.

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