Hybrid WIP.
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SpeedyFerrite
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I'm building a hybrid that's 35 mm in diameter with 5 mm thick walls, The thing is aluminium, what will be the highest mix I could use safely?
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bigbob12345
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Ill say 12-13x but dont quote me on that
5mm is quite thick, even for aluminum.
I mean look at copper, thats probably not even 1mm thick. Aluminum is a little bit softer than copper but a 5mm wall of aluminum will hold at least three times as much pressure safely.
5mm is quite thick, even for aluminum.
I mean look at copper, thats probably not even 1mm thick. Aluminum is a little bit softer than copper but a 5mm wall of aluminum will hold at least three times as much pressure safely.
1" copper pipe with walls about 1mm thick is rated for ~1 000 psi. This will be able to take higher mixes than a conventional air compressor will be able to fuel it to. I'm assuming you're machining it out of bar stock?
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
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SpeedyFerrite
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No, it's piping, but i did machine the fittings.DYI wrote:1" copper pipe with walls about 1mm thick is rated for ~1 000 psi. This will be able to take higher mixes than a conventional air compressor will be able to fuel it to. I'm assuming you're machining it out of bar stock?
I'll have to install the spark plug tomorow and it'll be good to go.
*edit* what about DDT?
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Lentamentalisk
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your pipe is almost never what you have to worry about pressure wise. The fittings are always much weaker than the pipe. For example, threaded unions at the 2" size can generally only take around 200psi, while their corresponding pipe can take well into the thousands.
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SpeedyFerrite
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I machined the fittings from solid aluminium.Lentamentalisk wrote:your pipe is almost never what you have to worry about pressure wise. The fittings are always much weaker than the pipe. For example, threaded unions at the 2" size can generally only take around 200psi, while their corresponding pipe can take well into the thousands.
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Lentamentalisk
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you should be very well covered on that account...
Cant wait to see it.
Cant wait to see it.
Do not look back, and grieve over the past, for it is gone;
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
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SpeedyFerrite
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Picture of it right now.
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bigbob12345
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oh its low diameter
that makes things even better, i was assuming thjat it was 2in or something.
Im going to stick with my previous opinion of 12-13x maximum although it could probably even take DDT a couple times
that makes things even better, i was assuming thjat it was 2in or something.
Im going to stick with my previous opinion of 12-13x maximum although it could probably even take DDT a couple times
Low diameter actually shortens the DDT runup distance, making it more dangerous. It should be able to survive a DDT, but I wouldn't be too confident in its safety afterward. And the ball valve would obviously need to be replaced if a DDT did occur.
Where did you get that figure from? How many tests were done in the study that came to this conclusion? If that number's right, I either have an extraordinarily strong union, or a metric assload of good luck, because I use them at 450psi regularly on the SCTBDC.
@SpeedyFerrite: If you can find the fatigue yield strength of your aluminum alloy, you can use Barlow's formula to get an approximate static burst pressure (shock would lower that number).
For example, threaded unions at the 2" size can generally only take around 200psi
Where did you get that figure from? How many tests were done in the study that came to this conclusion? If that number's right, I either have an extraordinarily strong union, or a metric assload of good luck, because I use them at 450psi regularly on the SCTBDC.
@SpeedyFerrite: If you can find the fatigue yield strength of your aluminum alloy, you can use Barlow's formula to get an approximate static burst pressure (shock would lower that number).
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
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bigbob12345
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yes I realise that but this isnt nearly long enough for there to be any real danger of 12-13x mixes. If it was twice as long i would say otherwiseDYI wrote:Low diameter actually shortens the DDT runup distance, making it more dangerous.
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sniperjosh
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Looks awesome, what FPS does it pump out? I think your barrel should be a lot longer for that chamber setup.