Harness the power of precision mixtures of pressurized flammable vapor. Safety first! These are advanced potato guns - not for the beginner.
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D_Hall
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Wed Mar 26, 2008 8:34 am
jimmy101 wrote:Sounds very interesting. Would love to see the performance data and any info they collected on pressure, burn time etc. I wonder if they ever published anything on the gun?
No idea. I suspect the data I'll be getting will be contemporary. I don't know much about it beyond what I've already said. The guy I was talking to at lunch is the program lead, but he's not an engineer so he doesn't worry too much about the nuts and bolts. He gave me the names of the engineers but it will be some time before I have an opportunity to talk to them as right now at the office I'm busier than the proverbial one legged man.
I wonder how many of the features you were considering incorporating (multiple sparks, fan, turbulance inducers ...) were known back then?
Dunno. I do know they're having some problems. I suspect it's poor fuel/air mixing based on what little was said, but I don't KNOW that.
Crap, now I want to see a picture of a big-ass hybrid with a bunch of beatle-haired, bell bottoms wearing engineers standing around it. Half of'm will probably have goaties.


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SpudMonster
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Tue Apr 01, 2008 3:59 am
Wait... We had hybrids in the 1970s?
This is nuts. What sort of chamber pressures were they getting? How many PSI before ignition? We need details man!
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Blitz
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D_Hall
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Tue Apr 01, 2008 9:43 am
SpudMonster wrote:Wait... We had hybrids in the 1970s?
This is nuts. What sort of chamber pressures were they getting? How many PSI before ignition? We need details man!
No idea, but given the muzzle velocities involved it's gonna be a "high mix" hybrid. Chamber walls are apparently on the order of 1" thick.
Still haven't seen the gun and can guarentee I won't for several more weeks (insanely busy myself, can't make it over there!).
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D_Hall
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Tue Apr 22, 2008 8:31 pm
OK, today I dropped by after lunch and saw the gun. No photographs, sorry.
Barrel is 6" bore, 27' long. That much we knew.
Chamber.... I'd call it 36" long and 18" in diameter. Rated to 3,000 psi. Currently they're running it as an 8X mix.
They've zero pressure data and such as of the moment. Right now just muzzle data. So far the hardest they've pushed is 11 lbs to 500 fps.
For burst discs? Three pieces of canvas rubber cemented together. The canvas holds the pressure. The rubber seals it.
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DYI
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Tue Apr 22, 2008 8:58 pm
Sounds like the gun has much higher potential than it's being used at. That's more than 4 times the volume of the hybrid I'm working on, with a barrel twice as long, but with less than a quarter of the muzzle energy.
On the upside, they've got a great safety factor on that thing. Do they know what kind of pressure the disks burst at?
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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D_Hall
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Tue Apr 22, 2008 9:16 pm
They claimed around 100 psi.
'Tis really sad. These guys have one heck of a gun on their hand but they don't really know how to use it. And no, I'm not going to help them as I want the Pipe Dream to kick ass.
Speaking of the Pipe Dream... I'm keeping my fingers crossed, but it looks like actual construction may start in 4-6 weeks.
edit: Wait... No.... They didn't say 100. They're using an 8X mix so it holds at LEAST 100. Didn't say how much more it may or may not hold.
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psycix
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Wed Apr 23, 2008 7:02 am
D_Hall wrote:Speaking of the Pipe Dream... I'm keeping my fingers crossed, but it looks like actual construction may start in 4-6 weeks.

Yeeehaaaa!
You are going to get us some pics are you?
Keep us updated
