Help finding lockwood-h jet plans!!!

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Bclark215
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Help finding lockwood-h jet plans!!!

I need help finding some plans for a Lockwood hiller (would consider other styles if they fit the criteria) style pulse jet 40 lbs or above for a jet kart. Before you go and berate me for not looking in the "looking for plans LOOK HERE!!!!" section I've already looked through it and didn't find much of what I was looking for. I've found several pictures of standard Lockwoods with no real thrust rating. I figured I could scale the drawings up, however I don't know whether the original plans work well, much less my scaled up version. This is for a school project, and because of the time limit, and the fact that we will be using tools in working business shops, we really only have one go at this. We either create a working pulse jet and enter it, or we fail and drop out. So what I'm really looking for is plans for a tried and true Lockwood that would make enough thrust to push our kart, with no major modification to the plans. Ive searched the forum and couldn't find much, if I'm overlooking something sorry, but I ask if any of yall could please help us out and drop plans or links here. Thanks in advance!

metiz
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Re: Help finding lockwood-h jet plans!!!

1st page of the looking for plans thread. 55 pounds. have fun download/file.php?id=11410&mode=view
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Bclark215
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Re: Help finding lockwood-h jet plans!!!

Thanks I already had that plan saved I just never knew it was a 55 lb engine. When cutting the pieces to roll you would do pi•d (pi times the given diameter) to get the circumference. Do I need to add the double of the material thickness to the circumference to get the final edge for the piece? The metal will stretch some when rolling too won't it, would this offset the material thickness? I'll be drawing these in a program calley plasma cam(similar to CAD) would I just draw a trapezoid making the height the same as the cone height, and the parallel sides the same as the circumference of the cone opening, or do these sides have a radius?

Also is it better to butt the edges of the cone up directly and weld the butt weld, or to overlap the edges a set amount and weld the lap joint? I'll be using 18 gauge (1.25mm) or 16 gauge (1.651mm) mild steel due to the high cost of ss.
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metiz
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Re: Help finding lockwood-h jet plans!!!

Yeah, you'd do π*(d+(2*material thickness)). Butt the edges of the pieces, don't overlap. Roling the sheet steel into cones will decrease the material thickness some but that's negligible so no need to compensate for that. If you use mild steel, go with the 16 gauge. the cone layouts have a radius, I think, not sue what you mean, see drawing
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Bclark215
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Re: Help finding lockwood-h jet plans!!!

Thanks for all they help guys. We have started building the 55 lb engine recommended earlier. Were ready to cut and roll all of our pieces, but we are stuck on the u bend. In the plans it says the u bend is 3 inch id all the way around, and the exhaust cone minor opening is 3inch Id also. The only mandrel bent 180 I can find is .065 exhaust pipe with a 3 inch outside diameter. Will this still work? If not, where do I get a u bend that fits the plans? Also any advice for rolling the cones in a 3 bar sheet metal roller? Thanks!

metiz
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Re: Help finding lockwood-h jet plans!!!

Bclark215 wrote:Thanks for all they help guys. We have started building the 55 lb engine recommended earlier. Were ready to cut and roll all of our pieces, but we are stuck on the u bend. In the plans it says the u bend is 3 inch id all the way around, and the exhaust cone minor opening is 3inch Id also. The only mandrel bent 180 I can find is .065 exhaust pipe with a 3 inch outside diameter. Will this still work? If not, where do I get a u bend that fits the plans? Also any advice for rolling the cones in a 3 bar sheet metal roller? Thanks!
instead of finding a suitable u pipe, you can also build one with sheet steel, see pic. As far as I know you can't roll cones with a straight 3 roll sheet roller. You can, however, do those by hand. I'd suggest cutting up the cone layout into 2-3 pieces and hand rolling them (try bending and hammering them over a pipe clamped in a beefy vice) and then welding them back together into one big cone.
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30 degree separation between pieces
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Bclark215
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Re: Help finding lockwood-h jet plans!!!

metiz wrote:
Bclark215 wrote:Thanks for all they help guys. We have started building the 55 lb engine recommended earlier. Were ready to cut and roll all of our pieces, but we are stuck on the u bend. In the plans it says the u bend is 3 inch id all the way around, and the exhaust cone minor opening is 3inch Id also. The only mandrel bent 180 I can find is .065 exhaust pipe with a 3 inch outside diameter. Will this still work? If not, where do I get a u bend that fits the plans? Also any advice for rolling the cones in a 3 bar sheet metal roller? Thanks!
instead of finding a suitable u pipe, you can also build one with sheet steel, see pic. As far as I know you can't roll cones with a straight 3 roll sheet roller. You can, however, do those by hand. I'd suggest cutting up the cone layout into 2-3 pieces and hand rolling them (try bending and hammering them over a pipe clamped in a beefy vice) and then welding them back together into one big cone.
I had considered making pie cuts in 3 inch I'd pipe, similar to the sheet metal thing, but just for the sake of simplicity I'd prefer to use a premade u bend if the 1/8 difference wouldn't hurt too much. When you say cutting up the cone layout are you meaning cut it lengthwise or, are you saying make several small cones and weld them to make a large one?

Bclark215
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Re: Help finding lockwood-h jet plans!!!

So the plans I have say +/- 1/16 inch, and everyone talks about how finicky pulse jets are about inside diameter, but then when I read on other parts of the forum about hand forming, everyone says they use the "beat the crap out of it" method until it's roughly a cone. If the inside dimensions were so finicky wouldn't the dents and imperfections in the cones throw the engine off? I'm in the middle of hand formingy pieces now and they are close, but nowhere near perfect so I'm just wondering if this will throw of the final engine? If I have access to a box/pan break would I be better off bending my pieces into 10 sided conical frustrums instead of actual cones?

metiz
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Re: Help finding lockwood-h jet plans!!!

for a large engine like the Lockwood, you can get away with "beating the crap" out of the metal to get the right shape, but don't go overboard. The dimensions are sacred, the shape (e.g., slightly oval, small dents etc) are not. When I say cut up the cone, I mean lenghtwise, yes. hand bending short, large diameter cones is much, much easier than doing the entire thing at once
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metiz
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Re: Help finding lockwood-h jet plans!!!

Sorry, incomplete answer. yes, using the 0.065 U bend is fine.
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Bclark215
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Re: Help finding lockwood-h jet plans!!!

metiz wrote:Sorry, incomplete answer. yes, using the 0.065 U bend is fine.
Thanks to everyone for all of the help. We've got almost all of our cones roughly rolled and I'm going to order the u bend right now. I'll let tall know how it works out.