Not as cool as Ben's idea but a while back, I was considering something
similar to this:
http://www.mtssensors.com/about-mts/temposonics-technology/index.html
http://www.mtssensors.com/fileadmin/media/pdfs/551019.pdf
I've used the Temposonics before for displacement measurements and they
work as advertised. I assume as long as the buoyancy of the floating
donut was greater than the mass x acceleration during flight, it would
get you the level pretty close. I don't have a requirement (yet) to
know the propellant level during flight but I would really like to know
the LOX level before launch since I intend to short load the tanks for
the first unguided flight.
On the Optocoupler idea - I assume you would directly immerse the
devices in the liquid? Would you just string them from top to bottom
maybe tied to a PTFE rod? How would you keep the plastic packages from
cracking?
-Bob
On 09/14/2015 04:14 PM, Ben Brockert wrote:
One of the few disadvantages liquids have over solids is propellant depletion. A solid burns nearly all its propellant, though some of it tends to be at lower than nominal pressures during the tail off. For a liquid stage to get maximum impulse it is imperative that it deplete both propellants simultaneously. The last kilogram of propellant is the most important it. A real world example of this is that Stiga flew to ~90km but had 30lb of fuel remaining after it burned out the LOX; with equal depletion it would have reached roughly 120km.
Ben
