I totally agree that minimizing the time between fill and fire is a good
idea. If I wait too long, then I either have to vent the tank or refill
it. I'll reserve some time during the hot-fire static tests to do some
LOX-only testing prior to loading to loading the fuel. Thanks!
-Bob
On 09/15/2016 01:22 PM, Ben Brockert wrote:
It's possible that if you open the vent you'll get a big burp of
liquid out, it depends on the geometry of the whole thing and what
exactly is the cause of the short filling you were seeing before.
If you can fill->cram->press->fire in short order that's your best
bet. Small rockets with cryogens inherently have less dwell time
because of the proportionally greater surface area per volume of
propellant. A one liter spherical tank has an area of 485 cm^2 per
liter, a thousand liter spherical tank has an area of 48 cm^2 per
liter.
On Tue, Sep 13, 2016 at 4:39 PM, Robert Watzlavick
<rocket@xxxxxxxxxxxxxx> wrote:
So if I close the vent first after filling to compress the ullage and squeeze
more in but then immediately open it after closing the full valve and before
pressure starts to increase significantly, I would still lose some due to boil
off. But would I end up with more usable liquid than if I had used the normal
fill process (leave the vent open the entire time)?
-Bob
