In article ,
says...

In sci.space.history Robert Clark wrote:

So Sir Richard: How?s the Engine Coming?
Postedby Doug Messieron May 23, 2011, at 7:07 pmin News.
http://www.parabolicarc.com/2011/05/...engine-coming/

Fascinating:

The stories have persisted and, if anything, have grown
stronger. The latest one circulating in Mojave is that the test in
March didn?t go well, and that the propulsion team has decided to
abandon the hybrid rocket for a liquid system. There is also a
confirmed report that Virgin Galactic has formed its own
propulsion team and hired the former director of SpaceX?s Texas
engine testing facility ? and an expert in liquid propulsion ? as
a member of it.

So How?s The Engine Coming?
http://www.transterrestrial.com/?p=34067

Remember that Barber Nichols Inc (BNI) has already produced a
34,000-lb thrust peroxide and kerosine engine for an unknown
customer (probably Blue Origin) and BNI also built the SpaceX
Merlin engine turbo pumps
(http://www.barber-nichols.com/produc...e_turbopumps/).

I thought that SpaceX bragged about the engines being all their own?

Switching to all liquids is a good thing anyway. Hybrids just seem to
have most of the downsides of solids and all of the headaches of
liquids. Might as well ditch the solid part and switch to all liquids.

In the long run, all liquids have a better shot at "gas and go"
operations than hybrids do. Sure you can switch out the fuel/combustion
chamber on every flight for one with a full load of fuel (and fill the
oxidizer tank), but that seems to be quite a bit more work that just
filling tanks with fuel and oxidizer.

Jeff
--
" Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry
Spencer 1/28/2011