my first hybrid

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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starman
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Sat Jan 17, 2009 3:44 pm

maggotman wrote:i cant aforrd a regulator
Well you're gonna need one. Try some propane while you're testing, it's cheaper. This is the propane table...

Nx - Propane - Air -- Total
1 - 0.616psi 14.7psi 0.616psig
2 - 1.23psi 29.4psi 15.93psig
3 - 1.85psi 44.1psi 31.25psig
4 - 2.46psi 58.8psi 46.56psig
5 - 3.08psi 73.5psi 61.88psig
6 - 3.69psi 88.2psi 77.19psig
7 - 4.31psi 102.9psi 92.51psig
8 - 4.93psi 117.6psi 107.83psig
9 - 5.54psi 132.3psi 123.14psig
10 - 6.16psi 147.0psi 138.46psig
11 - 6.77psi 161.7psi 153.77psig
12 - 7.39psi 176.4psi 169.09psig
13 - 8.00psi 191.1psi 184.4psig
14 - 8.62psi 205.8psi 199.72psig
15 - 9.24psi 220.5psi 215.04psig
16 - 9.85psi 235.2psi 230.35psig
17 - 10.47psi 249.9psi 245.67psig
18 - 11.08psi 264.6psi 260.98psig
19 - 11.70psi 279.3psi 276.3psig
20 - 12.31psi 294.0psi 291.61psig
maggotman
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Sat Jan 17, 2009 3:56 pm

thats what ive used but with mapp it i think it is down to the spark ime going to try it with some steel wool in the chamber as thats the easiest to do at the moment

propain is a bit inconvenient because i have got a box of them disposal map canisters i want to use up is i cant get it to work how accurate do the numbers have to be ?
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starman
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Sat Jan 17, 2009 4:26 pm

That table is a little confusing so just so you know, the first and last number are the relevant ones when using your gauge. Inject the propane first, then fill the chamber with air up to the pressure in that last column, the total number. That number includes propane and air pressure.
maggotman
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Sat Jan 17, 2009 5:46 pm

what is the best way to get electric into a mettle chamber ?
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ALIHISGREAT
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Sat Jan 17, 2009 6:21 pm

have an insulated input through a spark plug (homemade or off the shelf) then have it jump to the chamber wall.
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Sun Jan 18, 2009 6:52 am

okay ive made a new spark i can get a goot spark at 200psi to jump a 3mm gap no matter what a go it wont fire if a put some gas in and leave spark on and slowleay ad air it should fire when it reaches the right mix ?
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ALIHISGREAT
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Sun Jan 18, 2009 6:58 am

yes but then your air filling set-up will be venerable to the blast....
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Sun Jan 18, 2009 7:37 am

arr this is head doing ive tried every method i can think of light even with my spray an pray if i got the mixture wrong i would still get a flame ?
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ALIHISGREAT
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Sun Jan 18, 2009 7:57 am

maggotman wrote:arr this is head doing ive tried every method i can think of light even with my spray an pray if i got the mixture wrong i would still get a flame ?
yeah i think so... unless you are spraying like a whole can in.... try just a small burst then if that doesn't ignite add more.... and more...
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Sun Jan 18, 2009 8:05 am

yeh ive tried i think i will get some propane or give up
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ALIHISGREAT
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Sun Jan 18, 2009 8:13 am

What are you using for ignition?
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john bunsenburner
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Sun Jan 18, 2009 8:28 am

Why not take off the barrel and bust disc and just try making a flame, every time it doesnt work put a match in to see if your mix is wrong of if it is your ignition, and do that 3 or 4 times atleast one of them with a optimal mix (i know MAPP will escape, and i know its only a combustion becaus it is at amospheric pressure but maybe there is just a problem with your ignition nothing else...)
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maggotman
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Sun Jan 18, 2009 1:18 pm

i cant get the map to light with out the chamber if a spray some deodorant down i get a flame ive just got some propain so will try that when i get back from collage ime using a motor cycle ignition coil (same as a car just smaller)
connected to a motorized set of contacts to produce a constant spark
how good are disposable cameras for sparks ?
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Sun Jan 18, 2009 1:38 pm

I know I've already written it but how did you measure chamber volume ?? if you use a lot of metal fittings it is might be difficult to measure volume properly... i suggest filling the chamber with water (or some non corosive liquid)
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maggotman
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Sun Jan 18, 2009 1:49 pm

i tried using manometrik filling also when im trying to get it to fire ime out side and its kinda cold

all the fittings are brass or s steel ime going to mesur the chamber volume and try and make a propain meter
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