my first hybrid

[maggotman]

well ive just wacked together a hybrid of sorts and ive tried using it but i cant get it to fire i think its a metering problem or the spark not in the middle
all ive got from it was a small pop and a hissing sound i thik it fired but was a crap mixture and dident work





this is what ime using as my sparck source its an old bike coil and a small mosot and some homemade points it makes about a 10mm cotinus spark

i have tried it at 200psi and with 9psi map gass befor filling an no go i have read thro hybrid fueling 101 and dont fully under stand it

[ALIHISGREAT]

what kind of metering are you doing and what are you metering through?

[maggotman]

i have been filling the gun with map to a calculated pressue then adding air to a calculated pressure

i have tried it a 13.7 mix no go
i filled the gun to 9.1psi mapp then top it of with 200psi air it is sparking at 200psi because my burs disk are clear and i could see the spark

[ALIHISGREAT]

i have been filling the gun with map to a calculated pressue then adding air to a calculated pressure

i have tried it a 13.7 mix no go
i filled the gun to 9.1psi mapp then top it of with 200psi air it is sparking at 200psi because my burs disk are clear and i could see the spark

you mean to say that you looked down the barrel of a gun pressurized to 200psi

anyway... moving on from that, try a lower down mix... or re-do the calculations?

[maggotman]

i hav tried all sorts of mixes and gone over the calculations bit it wont fire ?
well annoying is

[ALIHISGREAT]

ok... i'm sorry i have to ask but....

you are sure you are pressurizing with air? (justification: it could be coming from a bottle or something)

are you filling through schraders or something that would screw around with the mix because of the crack pressure?

and you should check the calcs again (just to be extra sure)

[maggotman]

ime filling it with ball valves

this is what i did

fill it up with 9psi then fill it with 200psi air then closed the valve directleay on the chamber to stop high pressure fucking the gage the turn on the sparky thing and nothing its propa annoying ime using the sided of a 2 liter coke bottle as a burst disk

[ALIHISGREAT]

have you got any normal propane lying around you could fill with?

because then i could tell you to fill to 4.2psi x mix number (i think) then add (mix number -1)Bar of air.

[maggotman]

no i haven't i might try an get some
i hav also tried spraying deoderent in the sparking it and no flame ? i can see the spark and hear it but no flame or bang ?

[Sticky_Tape]

Wow somebody needs to look at cannoncreators thread. Not olny did you look down the barrel of a YOU LOOKED DOWN THE BARREL OF A CANNON FILLED WITH A X13.7 MIX. Got that out of me now maybe the spark needs to be smaller or you need more power for the spark don't know I am inept with electronics the way that most people are inept with spudguns.

[maggotman]

it was filled with just air and it was just the chamber no barrel and i was some distance away will this low mixture light with a form of glow plug ?

[starman]

Start out with a much smaller mix, even 1x and move up. I know that sounds boring. If you can't get a 1 or 2X mix to fire then you have no hope as you go higher. You'll need a regulator on that propane and a meter pipe.

Continue with that spark gap, glow plugs aren't your answer. Nice work so far.

[POLAND_SPUD]

did you fill the chamber with water to measure its volume ?

[maggotman]

i cant aforrd a regulator all the parts ive used on my guns have been given to me or ive found
would the bottle being upside own down affect it ?

[ALIHISGREAT]

Calculations:

Propane pressure:
To get the right amount of propane for your mix you calculate that like this:
For a 1x mix you will inject 0.045BAR of propane, the good thing is that you simply multiplies that number with the mix you want. So lets say you are going for a 5x mix. You multiplies 0.045 with 5 (0.045*5) then you get 0.225 and there you have the pressure of propane needed for a 5x.
Lets take one more example, a 17x mix, that would be 0.045*17. then your propane pressure will be 0.765 BAR, inject that and your fueling of the propane part is done for the 17x.

Air pressure:

This is even more simple. If you use a 3x mix you will use 2BAR of air, for a 6x you need 5BAR and off that goes. Just one bar less than the mix number..


The acctual fueling.

Propane:
You open the protecting valve (on the chamber) then you open the valve that is connected to the propane bottle untill you get the pressure needed on the 0-15psi gauge. Look above. After you have reached that pressure you quickly shut the valve on the propane bottle (not the one on the chamber). After that is shut and you can see that the gauge is still reading correct pressure you close the other valve. The fueling meter for the propane is no protected from the peak pressure.


Air: you does just the same as the propane just to another pressure of air. That would as said be one bar under the mix number.


To get PSI out of bar:
If you are the psi guy you simply find the pressures in bar first and multiplies them with 14.5 to get psi.

thats how to do manometric metering.... written by Spudfarm... but thats the calculations for propane.