smpip

When the combustion chamber momentarily ceases to function (due to fuel starvation and pressure drop) the valves are then released from the closed position, the fuels are able to flow again, combustion occurs the valves seal against the expansion of gases, etc etc etc, the faster the unit the greater the "G" force acting on the fuel, ergo it would/could function in a vacuum, I would say that without actual models to assume that (at onset) a low pressure unit would remain so during any firing period, is a bit premature, and also who's to say this would be a low pressure system?
I grant you (at onset) only the fuel delivery is low pressure.
Do you have any relevent fuel reaction info so that we could at least come up with a few mathematical models.

I've put this web address in, if your not familiar with the lockwood / hiller "pulsejet", you might get some mileage out of it, click on the Hiller 5.25 link,the information on the web link is all worth reading, 150lbs thrust from a 15lb unit!! (fuel weight not included)
But first check out the site before going to the link, it has a few interesting photo's

http://blastwavejet.com/

Von Braun used Hydrogen peroxide with Naptha disolved in Ether, these combust upon contact with each other and it was used in a demonstration unit, that was simply two fuel chambers and a combustion chamber with strategically placed one way valves, gravity fed, How, could this work,I hear you ask!!!!
Well even pulse jet engines need fuel and they have strategically placed valves, and which ever direction they were traveling in, they created their own "gravity".

"Right" said Simon "now we have a new shiney table , we won't be needing this one" and with those word he proceded to drag it out the door, Adam put his palm against Simon's chest to stop him, and asks "what are you going to do with that?"
"Make charcoal of course!" retorts Simon, and continues with his efforts, Adam turns and looks at Richard, Who returns the look with a shrug of his shoulders as a sign of resignation to the events unfolding before all to see.

For example you can chemically test your dextrin to test for the presence of starch. A brown colour change from purple is what you are after.

Although the colour does give a loose indication that the dextrin is nearly ready.

Could the Honcho and Mr G colaborate and agree on this topic because there seems to be an amount of conflicting info, only a tad though

Oh yeah, welcome back Chris, has it been two weeks already

What about gravity fed fuels, like a rather famous (or should I say infamous Von-brawn or was it brown?) his first demonstration model was just two tanks (made to exacting standards I am sure) with one way valves (very well machined) and used two spontaneously combusting products that did their stuff once introduced into the combustion chamber below?

"It is exactly 75 years since Dr Robert H. Goddard successfully launched the first liquid-fueled rocket on 16 March 1926."
I just got this from a web page, so it was not Von-oogeemaflip that did it all first