The LR-101 Vernier engine ran off ratio,i.e. 1.8 so aluminum worked but at
2.3 it would be under significantly higher heat flux,
Ken
On Mon, Oct 11, 2021 at 1:56 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Tue, 12 Oct 2021, Jonathan Adams wrote:
The engine I'm working on now runs Jet-A and LOX at 350 psi and r = 2.3
(when operating at its limit). For reasons relating to cost I've so far
been looking at 6061-T6 aluminum, but I'm now wondering whether that's
the right choice... Can aluminum get the job done?
Yes, but. It's certainly been done; it's seen significant use -- mostly
with slightly cooler-burning propellant combinations, but if I recall
correctly, the LR-101 (Atlas vernier) injector is aluminum. The downside:
it's unforgiving -- the cooling must be just right -- because it loses
strength so rapidly with even mild heating. With an aggressive oxidizer
like LOX, it can even ignite. Most likely not a good choice for early
experimental work.
Is there a grade of copper that is preferable for something like this?
C145, aka half-hard tellurium copper, seems to be what people like --
properties much the same as pure copper but a lot easier to machine.
Henry