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Thank you.

Dimensions are OD and in millimeters? What is the material thickness?

Warn us when you are going to fire that thing up so that we can don our hearing protection.

> One problem I can see happening is the the fuel exits the holes in a laminar fashion You need to keep the pressure high to avoid that (which in turn means smaller holes). A method used in ag sprayers to obtain a spray of fine droplets is to arrange for the jet exiting a nozzle to immediately strik...

I see no pdf or video. In any case, you probably need to turn the propane tank upside down and feed the engine liquid propane. If you have one of the "new, improved" tanks with the built-in regulator you're out of luck.

Where can I find drawings for the HPX?

My fault here as I was told that the gas expands only 62 times. Big difference to 250 times!!!! Well, it depends on temperature and pressure, of course. 250 (approx.) is going from liquid to atmospheric pressure and room temperature. The pressure inside your tube will be much higher than atmospheri...

When it cut out, the copper lines were covered in ice from the needle valve to the preheating coil around the motor. Sounds like evaporation is occuring at the needle valve rather than in the preheater or at the nozzle. I'm curious as to what the difference in volume is, between vapour and liquid. ...

Could you be more specific about what is freezing when you invert the bottle?

metiz writes: Ok so you say it might work, just not too long before the sutt starts blocking things? How hot is the gasoline going to get? If you get it really, really hot (far above the ignition point) it might decompose and produce carbon deposits but you'll be fine if you just evaporate it. Old-f...

mwriz writes: It wouldn't come near 2 metres, more like 850 - 1000mm Thrust would be in the 15-25 pound range. I've got a copious supply of 35mm pipe plus a long piece of 70mm with a plate already welded on one end. Should go a long way toward approximating Miller's setup [1]. Don't have any 30mm pi...

I see now that Miller's paper has been mentioned in another thread, but the link there did not work for me. Sorry for the duplication, I still think it is interesting work, though.

Just found this: http://cambridge.academia.edu/RobertMiller/Papers/87016/Improving_the_performance_of_a_valveless_pulse_combustor_using_unsteady_fuel_injection Membership required. Haven't read the paper yet: just the abstract which is included below. American Institute of Aeronautics and Astronauti...

metiz writes: Sorry for the hijack :) Not a hijack: the question was general. Thank you for responding. I would suggest a medium sized thermojet, maybe linear for easy modifying. How large is medium? I'd like to keep it under 2m or so for ease of transport. I also have some scrap around that might b...

ace_fedde writes: First of all I have materials like automotive injectors. However I don't have what I would choose for: commom rail diesel injectors, but they are easy to buy on a scrapyard here. The multipulse ones should be fast enough (especially the piezo types) but I don't like the very high p...