help i need help

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lucky rookie
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help i need help

Post by lucky rookie » Wed Sep 27, 2006 7:47 am

engine=short lady fwe
fuel=propane butane mix
i have a good spark and do have ignition the enginebut it starts with a pop and blue flame but it wont run on itself i am using compressed air at very low psi
with air on at inlet it will run making a quiet almost rumbling sound but it will not make the crossover to running by itself with that pulsejet sound

please can someone help
my wife maybe right
Last edited by lucky rookie on Wed Sep 27, 2006 7:34 pm, edited 1 time in total.
i WILL get this pulsjet running even if my wife says i wont

Jonny69
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re: the difficulty im having

Post by Jonny69 » Wed Sep 27, 2006 9:20 am

Sounds like it needs a lot more fuel. What regulator are you using?

lucky rookie
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re: the difficulty im having

Post by lucky rookie » Wed Sep 27, 2006 7:31 pm

heres a small vid of me trying to start my fwe short lady can anyone have a look to give me some clues
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[The extension wmv has been deactivated and can no longer be displayed.]

i WILL get this pulsjet running even if my wife says i wont

larry cottrill
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re: help i need help

Post by larry cottrill » Wed Sep 27, 2006 8:31 pm

Can't see much, but the sound is a lot more important. To me it just seems like (a) too much air, most of the time; and (b) not enough fuel, all the time.

Any other opinions?

L Cottrill

Mike Everman
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re: help i need help

Post by Mike Everman » Thu Sep 28, 2006 12:32 am

Yeah, you can't possibly have a hand free like that! Fuel setting and air amount and angle get varied in a dizzyingly random fashion until you see results. From little to lots of both and every combination in between. I hope you've not got a 4psi regulator on the tank, and it's a big (bbq size) tank.

good luck!
Mike
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Dave_G
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re: help i need help

Post by Dave_G » Thu Sep 28, 2006 2:57 am

Hi Lucky (Got a real name?):

Definitely not enough fuel, and not injected with high enough pressure. For your very first experiments try a single injection orifice about 0.5mm diameter.

Use a pressure gage on your fuel line and make sure you can get 20 to 100 psi forepressure to your injector. This type of intake is sensitive to injector location and will require you to experiment a bit. You can also look up Rosscojectors (sic?) on this website and try one of those. They're probably your best bet for 'field expedient' success.

For your next video, could you shoot it looking into the tailpipe or intake? [Helps to see what's going on inside the motor at this stage...]

Since your ignitor is "manually-operated", you need three hands to start this motor -- not good. Either use a switch on your ignition circuit so you can vary / move the air with one hand and the fuel with the other, OR rigidly attach your starting air line so it can run hands free. Get your motor running first and then you can worry about turning off the starting air to verify that it self-aspirates.

Also, your compressed air source needs to inject with enough force to induce some turbulence, or you'll need a serious supply of air like that from the outlet of a dust collector or leaf blower. Try 90 psi from a compressor (with tank!) through a 1mm orifice for the starting air. Yes, some motors start very easy with very little air, but you're not quite there yet. Get yours running first and then you can try to finesse things a bit.

Lastly, if you want to stay lucky, Rookie, watch out for fireballs and flame-outs while you're experimenting. If you start to flow sufficient fuel you'll probably decide (rather quickly!) that hand-held fuel injectors aren't much fun. Instead, hard-mount it and use a 1/4-turn ball valve in-line with your fuel injector so you can shut off flow instantly if needed.

Take it easy,
Dave

Dave_G
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re: help i need help

Post by Dave_G » Thu Sep 28, 2006 3:40 am

Hi Again, Lucky,

I just watched your video again and the most valuable advice I can give you, bar none, is WEAR GLOVES when you do that!!

Seriously, never let any exposed skin to be in front of the intake or exhaust, or even close enough to the engine that an enveloping fireball can contact it.

You can be seriously burned in a fraction of a second -- far quicker than you can move out of the way! It may take several minutes for the blistering to occur, but the damage will have already been done and once that happens there's nothing you can do about it. Ice may relieve the pain but it's not gonna change the basic facts when you give yourself a second degree burn across your hands, arms or worse yet, your face.

Have fun / Play safe.

Dave

larry cottrill
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re: help i need help

Post by larry cottrill » Thu Sep 28, 2006 1:15 pm

rookie -

Your wife will be more positively impressed if you can get your engine running without suffering permanent disfigurement ;-)

Here is a VERY simple arrangement that should work nicely to free up a hand or two. The drawing can be considered purely schematic; you can extend the pipes as far from the engine as you like, and at any convenient angle. I like them branching off to the left side out in front a few inches.

The spacing from the starting air tube to the intake flare is not critical; it can be half an inch or more. This will allow you working room to completely remove and replace the little copper fuel tube, if desired, to try different fuel tube configurations. The ALIGNMENT of the starting air tube IS fairly critical - it should shoot right down the center of the intake tube. As little as 30 PSI from a small compressor applied to the front end of this tube will give you sure starts.

Be sure to run the rough weld line shown, on one or both sides of the engine. This will keep your tubing from slipping around on the engine after you wind it on. In my opinion, you might as well tack weld the starting air tube on; you won't need to vary it once it's in place and properly aligned.

Try it - you'll like it!

L Cottrill
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FWE_simple_fuel_air_setup.jpg
Very simple, sure-fire setup for fuel vapor and starting air tubes usable for any style of FWE engine. Drawing Copyright 2006 Larry Cottrill
FWE_simple_fuel_air_setup.jpg (87.16 KiB) Viewed 4429 times

Jonny69
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re: help i need help

Post by Jonny69 » Thu Sep 28, 2006 3:35 pm

"Oh bollocks!" :D

Yeah definitely looks like not enough fuel. Get yourself a 4kg propane bottle and a variable regulator for 0-4 bar. That will allow you to feed in a lot more gas and play with the quantity.

If you can make a sparking circuit that makes multiple sparks it also makes starting a lot easier.

lucky rookie
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re: help i need help

Post by lucky rookie » Thu Sep 28, 2006 6:11 pm

thankseveryone for your help and safety tips i shall have another attempt on sat night


i will keep you posted with results
i WILL get this pulsjet running even if my wife says i wont

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