My wife was the last caretaker of the TRW pintle injector (at TRW), and used it
in a variety of engines. The biggest was a 650,000 pound sea-level thrust
LOX/LH2 engine at MSFC. The engine had been developed for EELV, and originally
used LOX/RP-1, but NASA wanted to run it with LOX/LH-2. It ran just fine. You
can’t go wrong with pintle injectors - and they tried.
Sent from my iPhone
On Oct 11, 2021, at 3:20 PM, Doug Jones <rocketplumber@xxxxxxxxx> wrote:
I stand corrected, Tom Mueller and I being the exceptions since 1999.
On Mon, Oct 11, 2021 at 3:11 PM roxanna Mason <rocketmaster.ken@xxxxxxxxx>
wrote:
Conversly why the TRW pintle is so stable, got the US on the moon and SpaceX
flying.
Ken
On Mon, Oct 11, 2021 at 12:04 PM Doug Jones <rocketplumber@xxxxxxxxx> wrote:
NASA SP-194 LIQUID PROPELLANT ROCKET COMBUSTION INSTABILITY, particularly
section 7.2.5. If you populate the entire injector face with elements,
you're gonna have a bad time. But it's what everyone seems to have done
ever since the F-1, and none of them ever read the goddamn book. It's
cringeworthy.
On Mon, Oct 11, 2021 at 11:03 AM Ismail Hozain <ismailhozain@xxxxxxxxx>
wrote:
Doug can you please elaborate on the design rules you applied?
Thanks,
Ismail
On Mon, Oct 11, 2021 at 9:16 AM Doug Jones <rocketplumber@xxxxxxxxx>
wrote:
We never used film cooling at XCOR, and had 97% or more cstar with
LOX-kerosene at 2.6 O:F, no mixture ratio compromises. I've never
understood why everyone else seems to struggle with efficiency vs
stability vs cooling- they all pull together in unison. I just applied
design rules published fifty years ago.
On Mon, Oct 11, 2021, 3:20 AM roxanna Mason <rocketmaster.ken@xxxxxxxxx>
wrote:
No, it's not that difficult to build high reliability long lived
biprops, the trick is to do it with high efficiency, c* that is, not off
ratio and/or lots of film cooling as was done with that Spectre RATO
engine which BTW was derived from an earlier Aerojet RATO rocket system
using nitric acid oxidizer with variations of fuels.
Thanks Henry for mentioning Bruno, I lost all my data earlier this year
to a hard drive crash and Bruno's info was one of the casualties. I had
~ 40 pics of that Spectre system with subassemblIes of the TCA showing
the cooling jacket construction which was simple enough for amature use.
If anybody has that link of Bruno's I'd love to get it back into my
archives.
Thanks,
Ken
On Sun, Oct 10, 2021 at 9:22 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Sun, 10 Oct 2021, roxanna Mason wrote:
you get something as flaky and short-lived as a typical rocket engine
Enter SpaceX, particularly their Raptor which is claiming 100 flights.
SpaceX was by no means the first to build reliable, long-lived rocket
engines; citing this as another Miracle Of St. Elon :-) is silly. See,
for example, the attached (posted by Bruno a few years ago) -- note
position of test crew in relation to 1950s rocket engine. If you want
something more recent, see assorted videos of XCOR tests.
It's not magic, it just requires different design priorities and a
different test program -- much more like those of a normal jet engine,
meant for a manned aircraft.
Henry