mungo
Part of things
Posts: 318
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Oct 15, 2012 12:21:00 GMT
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Right , I was getting board with grinding rust and mending cars so tried something a bit different . I had a sheet of steel lying about so got some plans off the net and did a bit of my best maths to re-scale it so I could use the bends from the mondeo exhaust that was kicking about . Then get going on the welder:   It ended up looking like this :  The plan was to use a spark plug to light it but that failed ...So we ended up lighting a bit of rag soaked in thinners poked down the end before the gas was turned on  This was the result: It wasn't really very successful...it seemed to run but only when I was firing air into it , it should carry on running when I stop the air. I guess my measurements were'nt quite accurate enough ?? Has anyone made one  Any ideas?? The gas is going in via bit of copper brake pipe and a 2.5mm hole . The thought that should be enough gas Don't know ... |
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56' bug 2332 +ida's
56' lowlight ghia
72' bus 1600 devon
67' type 3 square - gone
83' gti - gone
90' gti 16v - gone
82' chevette - gone
70' GP1 Beach buggy -gone
78' lightweight landrover 3L v6 -gone
89' gti - gone
83' gti - gone
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Oct 15, 2012 14:35:26 GMT
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Jonny69 in this section has made a few.
PM him for more advice.
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Oct 15, 2012 14:39:07 GMT
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sparkyt
Posted a lot
selling stuff
Posts: 1,767
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Oct 15, 2012 16:28:10 GMT
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It got to be a tuned length . So a few mm will make a difference both in the pipe size and length ..
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mungo
Part of things
Posts: 318
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Oct 17, 2012 12:34:52 GMT
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Yeah, I know the length has to be right. I tried to make it as accurate
to my scaled dimensions as possible but maybe it's still not good enough.....it's close close though!
It's a job to know weather to lengthen it take a bit off.
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56' bug 2332 +ida's
56' lowlight ghia
72' bus 1600 devon
67' type 3 square - gone
83' gti - gone
90' gti 16v - gone
82' chevette - gone
70' GP1 Beach buggy -gone
78' lightweight landrover 3L v6 -gone
89' gti - gone
83' gti - gone
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Oct 17, 2012 15:35:16 GMT
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AFAIK, you can't scale up (or down) things like this - they have to be calculated for each size. Also, using slightly rusty pipe will have higher internal friction, slowing each pulse.
Using that logic - I'd say the resonator would have to move further towards the bends to compensate. But that's purely an educated guess!
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You're like a crazy backyard genius! |
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Oct 17, 2012 20:15:22 GMT
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So when you made it what does it do ?
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OVY871
Part of things
Owner of Austin A35 Saloon
Posts: 321
Club RR Member Number: 66
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I want to see that working and put into something like this  |
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Oct 22, 2012 17:13:20 GMT
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I need to keep a closer eye on this part of the forum ;D Yeah, I've made a few. There are a few rules you need to stick to so you might want to take a step back and make another simpler one because you can't scale the Lockwood design up and down like that. The simplest valveless pulsejets are just normal valved pulsejet dimensions with a tuned valveless intake. From memory (so it might be wrong!), the intake needs to be 2/3 the cross sectional area of the exhaust and the length is about 4 times that equivalent diameter. My big one is a 2" diameter exhaust and about 32" long. The intake is whatever diameter 2/3 the area of a 2" circle is and about 120mm long. From those dimensions, just by my eye I think yours is too long and the intake diameter too big. From the video I think you need to give it more gas (2.5mm jet should be fine but 1.5mm might be better), but I think the intake is too big and the tail too long, even with the flare. It should fire up like this and be a LOT louder than yours has been. Check out how my camera man jumps when he hears the bang when it fires into life, to give you an idea: Here's the same jet with a valveless intake: I've simply remade that jet with a U shaped exhaust and a single intake:  |
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Last Edit: Oct 22, 2012 17:14:45 GMT by Deleted
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mungo
Part of things
Posts: 318
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Oct 24, 2012 12:35:59 GMT
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Cheers johnny
If you have a minute could you scribble some dimensions on your picture for me.
So , The long tube is 2" diameter and 32 " long , the combustion chamber looks about 4/5" diameter and 7 long ?? , the intake is 41mm diameter and 5" long ??
I'm desperate to get one going now !! ;D
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Last Edit: Oct 24, 2012 14:39:27 GMT by mungo
56' bug 2332 +ida's
56' lowlight ghia
72' bus 1600 devon
67' type 3 square - gone
83' gti - gone
90' gti 16v - gone
82' chevette - gone
70' GP1 Beach buggy -gone
78' lightweight landrover 3L v6 -gone
89' gti - gone
83' gti - gone
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mungo
Part of things
Posts: 318
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Ok, took jonnys advise and back tracked a bit...... Got some 2" tube and did a bit more grinding and welding ,which resulted in this ,    success super loud,super hot ......not a vast amount of thrust though ..... |
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56' bug 2332 +ida's
56' lowlight ghia
72' bus 1600 devon
67' type 3 square - gone
83' gti - gone
90' gti 16v - gone
82' chevette - gone
70' GP1 Beach buggy -gone
78' lightweight landrover 3L v6 -gone
89' gti - gone
83' gti - gone
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Superb! Love that it appears to be glowing purple there too.
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Any ideas??
