my valveless will run but wont throttle up

[rtemple989]

ive had my valveless pulsejet for nearly a month now and can only get it to run idle. i cannot throttle it up to get any power out of it at all. when i turn the canister upside down it sputters and shuts off any help is appreciated because now im beginning to get frustrated

[Mike Everman]

Welcome. Tell us about your fuel setup and the size of your motor.

[rtemple989]

thank you
ok heres my pulsejet running idle

http://www.youtube.com/watch?v=EukjppzghXQ

im using a small 16.4 oz propane grill cylinder

my problem is only when i switch from gas to liquid. my pulsejet just sputters and flames out without putting out any power.
its actually quite annoying.

im using a ball valve for the whole thing. ive had people tell me to use a needle valve with the ball valve. is it important to have one? and also is there any specific way to configure the fuel jets? i mean since it sputters and spits out liquid fuel instead of a nice clean stream. my fuel jets are two small metal tubes with tiny holes punched into the tips of them. is there a more efficient way to do this?

[metiz]

get rid of any restrictor. this engine will easily flame out on vapour propane, no liquid required. what size gas tank are you using? if its on of those small burner tanks, get a bigger bbq size tank and use that one.

also, just get some straight tubes without any mods. it will work just fine with smaller engines

[HPSCL]

rtemple989,

I had the same problem (with the same engine) of no-start / flame-out. The injector setup with this engine (if it is the Model J3-200; purchased off of ebay) appeared to be a well thought-out setup. But the fittings just would not seal against the flare, no matter how tight they were.

With a flared fitting, you should only tighten it so that it's barely snug. Overtightening will crush the flare and/or distort it, so it will not seal properly. I took the fuel set-up apart again, blew out the injector lines (opposite of flow) to dislodge any debris from drilling... (I did this, because I noticed that only one of the injectors was constantly burning).

I applied 2-3 tight wraps of Teflon taped to each of the male threads, even though this should not be needed... After many flame-outs through the intakes, the fittings would catch fire around the threaded portions.

Installing a Campbell-Hausfield air pressure regulator:



--- inline between the propane tank and the injectors, allowed me to have a finer adjustment for the throttle control.

The adapter I used on the propane bottle, allows high-flow from the bottle, with no other modifications:



Last and most importantly: The 16.4 oz. propane bottle was immersed in warm (NOT HOT) water. I used a large pot, and strapped the bottle down, against the side of the pot in an upright position. This was accomplished "ghetto-style", with a couple of zip-ties and some string. - Ha!

The warm water keeps ice from forming on the outside of the bottle, thus raising the internal pressure and keeping your fuel-line flowing at a steady pressure. As per the included instructions, the engine was given a few minutes to warm-up, and then the pressure was slowly increased from 5psig, to (approx.) 20-25psig...

The engine went from a loud/grumbling idle to a high-cycling/self-sustaining roar, with no need of help from compressed air.
I have had no problem since... Cold weather / small bottle is not a good mix.

Better late than never? I hope this helps, if you're still having problems.
~Dave.