The Lieutenant Johnson 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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bigbob12345
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Sun May 04, 2008 12:12 am

Well this is my first submition to the hybrid cannon showcase.
I am having problems fueling it but Ill get to that later. i have gotten a couple shots off, and it is very loud especially at higher mixes.
I Name it Lieutenent Johnson :lol: No idea why, it was just the first thing that popped into my messy brain.

Here is an intro pic for ya guys
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Well I better give some specs so...

Chamber:8in of 1.25in black iron pipe
Barrel:6ft of 3/4in black iron pipe
Valve:Just a good ol' union(3/4in)
Ignition:Electric BBQ ignitor(makes a sizable rapid firing spark)
Fuel:Propane
Air source:Bike pump
Velocity:Insanely fast
Noise output:ALOT



Well this gun wins the award of most expensive gun I have made yet at a whopping $70 :shock: Probably seems cheap to you but to me thats 5 weeks worth of money gone :(
I also wasted some money but that was not included in the total cost. I broke a $9 gauge and bought a $13 air reg that didn't work and I cant return it because I was running propane through it :cry:

As said above i am having trouble fueling this thing and have done all the calculations in hybrid fueling 101 many times and keep on getting the same answer, to pressurize the meter to 7.3psi to get a 1x mix. I don't know if this is right or wrong but it doesn't work when I pressurize it to that. The times I have gotten it to work have been sheer luck.
So I would love it if someone could calculate the pressure I need to pressurize my fuel meter to to get a 1x mix and see if they get the same answer.
BTW meter is 1.221ci and chamber is about 14ci

I promise Ill get you a good res vid if I can get it working consistently.

A collection of pics


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Tell me what you think

Edit VID
Alot of effrt went into getting you this vid
I know I didnt do some of the shots that I said I would do becasue it got dark.
Anyway enjoy
[youtube][/youtube]
Last edited by bigbob12345 on Wed May 07, 2008 6:44 pm, edited 8 times in total.
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hi
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Sun May 04, 2008 1:09 am

pretty sweet. looks like you really cranked in that plug...
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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bigbob12345
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Sun May 04, 2008 8:28 am

Thanks
And that plug actually wasnt cranked that much, it just slid in there with ease(well I guess ease isnt the word for cranking it in with a pipe wrench as hard as possible).

Edit:Not to many responces :(
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SpudFarm
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Sun May 04, 2008 8:41 am

hey congratts on your first hybrid! welcome on the team!

what did you shoot with and what did you shoot at?
how high was your mix?


just try until you get the mix right.. anf the mistake can be that the meter is to big for your chamber so the gauge is not accurate at 7PSI..


nice first hybrid you got there..
"Made in France"
- A spud gun insurance.
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bigbob12345
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Sun May 04, 2008 8:51 am

Thanks
It now has a name, as seen above

And when I shot it once it was 1x, another time it was 3x, and the last time was 4x(LOUD).

Maybe Ill just pressurize the meter to the amount needed for the mix.
example:2x=14.7psi, 3x=22.2psi and so on
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SpudFarm
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Sun May 04, 2008 8:56 am

that will solve your prob..
and remember to use a strong burst disk that don't burst if you use it at a mix lower than the mix it was made for.

try to wad up a marble and put it through a two by four.. go to 6x today and get some damage shots
"Made in France"
- A spud gun insurance.
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bigbob12345
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Sun May 04, 2008 9:01 am

I tested the my burst disks up to their burst pressure with my hp pump to make sure they burst at the peak of the shot.

And I have some heavier ammo than marbles that should be a little more fun.
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SpudFarm
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Sun May 04, 2008 9:11 am

ok then cast some lead :D

try some bolts at steel plate to!

and last do some buck shot with lead pellets.. that is the most over whelming shot i had since it had more power than a 12gauge on 30 feet.
"Made in France"
- A spud gun insurance.
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bigbob12345
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Sun May 04, 2008 9:16 am

Yes that is what I was getting at
Lead+The luitendent johnson+6x=Fun, yaaay
:lol:

I currently dont have any sheet metal tho shoot the bolts at so ill just shoot them at an old liscence plate.

I dont have any lead pellets but i have thousands of copper bbs which I will shoot at a 2 by 4 and try to replicate your very impressive result.
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JDP12
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Sun May 04, 2008 9:23 am

hmm looks like a nice gun bigbob
"Some say his pet elephant is pink, and that he has no understanding of "PG rated forum". All we know is, he's called JSR. "
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bigbob12345
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Sun May 04, 2008 9:24 am

Thanks
stupid message is too short thing
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SpudFarm
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Sun May 04, 2008 10:37 am

bigbob12345 wrote: I dont have any lead pellets but i have thousands of copper bbs which I will shoot at a 2 by 4 and try to replicate your very impressive result.
eyy thanks!!
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"Made in France"
- A spud gun insurance.
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bigbob12345
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Sun May 04, 2008 10:41 am

I never cease to be impressed by that picture.
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STHORNE
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Sun May 04, 2008 10:43 am

very nice hybrid bigbob...

and about the "message too short thing". all you have to do is hold the space bar for a couple seconds after typing a short message and hit post...
Forum Rules - follow them or else!
“Happiness is the meaning and the purpose of life, the whole aim and end of human existence”
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bigbob12345
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Sun May 04, 2008 10:46 am

Thanks


Edit:spacebar thing works, cool
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