XCOR did more piston pumps. Flometrics did pistonless pumps. Armadillo
built a boilerplate one at one point, it worked. My issue with
Flometrics' approach was that while the pump is simpler and harder to
blow up, their baseline expectation was to use pressure fed boiled
liquid helium as the motive power, which makes operating it really
expensive to impossible depending on the state of the helium market at
any given time.
On Thu, Dec 15, 2016 at 8:15 AM, Dave McMillan <skyefire@xxxxxxxxxxxx> wrote:
On 12/15/2016 11:01 AM, Thomas McNeill wrote:
For amateurs a much much lower chamber pressure is more likely. There are
some good graphs online of Isp vs Chamber pressure and at some point the
marginal gains are not worth the engineering time and money spent on a
higher pressure pump.
I have been curious about different pumping mechanisms. Instead of a turbo
pump what about positive displacement pumps, like gear or lobe? Has there
been any attempt at using one of these types of pumps?
I have to admit to being curious why I've never heard of any amateurs
trying a variant on XCOR's piston(less) pumps -- those seem like a much
lower bar to get over than any kind of turbomachinery. Some subtle
difficulty I'm not seeing, there?
