RS-68A ?

Damon Hill wrote:
Hopefully they'll
get in a 'fix' for the large hydrogen flare at ignition.


Yes, we probably do want to _do that_, don't we? :-D
But that's more of a pad design problem than something wrong with the
engine itself.
Still, I love the big crimson flames from it.

It would seem that large liquid engines with ablative nozzles don't
quite cut the mustard? SpaceX dropped their design for a regen nozzle,
too.


Oh, that's not half of the story - SpaceX put a ablative inner lining
inside of the _combustion chamber_ of their Merlin engine so they
wouldn't have to cool it at all, and just replace the lining after every
flight.
The lining de-bonded from the walls of the combustion chamber during a
test, plugged the nozzle throat, and caused the whole engine to explode.
Next thing I knew, I was forced to remove all postings discussing that
event from all newsgroups under threat of legal action by SpaceX.
It was that perennial cat-loving *******, Scott Lowther, who led to all
that.
The guy's a national menace... at the moment he's living with feral cats
and taking warped photos on things sparking on grindstones in the middle
of the night: http://up-ship.com/blog/
There, but for the grace of alcohol and a allergy to cats, go I. :-D

Pat

On Nov 22, 4:18*pm, Damon Hill wrote:
Pat Flannery wrote in news:7emdnVfQ-
e:





Damon Hill wrote:
It didn't have a particularly long lifetime in its original form, did
it?

Isn't that a good thing? *I always look forward to design and
performance improvements.

I should of phrased that better... it wasn't meant as a criticism of the
engine, just a historical observation compared to some other rocket
engines... but come to think of it, most of them got improved fairly
soon after entering service in their original form.
It would be fun to look at a original Thor IRBM engine next to the
current engine on the Delta II's first stage.

I believe the RS-27's been around for a good while now; it's very
reliable and I guess "good enough" for the application. *There was a
similar design of 400,000 lbs/thrust that never made it into production.

Looks like the RS-68A won't be much different; I the -B is the one
that'll be fully regen,

Not true. The B model is just a "manrated" version. The regen nozzle
is not in the cards at this time