My hyrbid will NOT fire

[steven_main]

Im absolutelly 100% positive Im fueling this thing correctly. I built a VERY large PVC hybrid.
I have a slightly odd shaped chamber (lots of steps) so I filled the cannon chamber with water all the way to the burst disk and it came out to be 408 cubic inches (6700CC/ML) I built a volumetric propane log with a matching pressure gauge to the one on the launcher. It happened to be 3.57 Cubic inch (58cc) from the first cutoff valve to the male air fitting. 100/95.8=1.0438 or 4.38 CC fuel per 100 CC chamber im told is optimal or stoich for propane. 67 (100)cc is my chamber so I need 67(4.38cc) fuel or 293.46 cc. Since my fuel meter came out to 58 CC I need 293.48/58=5.05 bar of propane in my meter. 5.05 * 14.7 = 74.235 PSI absolute or -14.7 to read ~ 60 psi on my gauge....

I finished these calculations, screwed the cap on my chamber, installed a burst disk of Nashua aluminum Foil Insulation tape. Put 60psi in my fuel meter and filled the cannon with the 1x charge... Boom ... 4 times with 100% reliability... Next I pressurized my log to 60 PSI fueled the cannon, repeated again for 2x. Charged the Cannon to 1 bar on the same brand/type of gauge I used on the meter.... Nothing. no light no anything. I tried pumping more air in up to 30 PSI with the same fuel and it still wouldnt light. I started letting air out and held down the trigger while doing so and One time as a fluke in lit, it was so spectacular to launch a 3 oz slug of potato at 500 Miles per hour into a tree! I didnt know a potato could cut wood like an axe!... However, the celebration didnt last... after a dozen attempts I can not get this thing to light. any ideas folks?

[Zeus]

Narrow your spark gap, as pressure increases, the distance a fixed voltage can arc drecreases. I'd use a 2-3mm gap.

[steven_main]

oh, makes sense, you do the same thing when you supercharge a car (I have a 1200 horsepower trans am drag car) Ill try it out thanks!

[Zeus]

No worries mate. Good to see someone else who doesn't think turbos are the be all of performance addons.

[jackssmirkingrevenge]

I built a VERY large PVC hybrid.

What is the smallest pressure rating on your parts? On large diameter fittings I would not go beyond 2-3x.

[Crna Legija]

No worries mate. Good to see someone else who doesn't think turbos are the be all of performance addons.

Turbos are for toddlers, bottles for babys, real men get BLOWN!

[pneumaticcannons]

You aren't by any chance this guy, are you?

[jrrdw]

You aren't by any chance this guy, are you?

No Trans Am or Hybrid so I doubt it...

Remember the smaller the gap the hotter the spark.

Is your electrodes on a strip on the chamber wall or centered in the chamber?

Did you think about using multiple spark gaps?

[steven_main]

Actually I was just being vague didnt realize so many auto enthusiasts were here. From an Engineering standpoint my race car is what an engineer would refer to as Turbo-Supercharged. From an automotive standpoint its Just turbocharged baby.

402 LQ9 (LS type motor but an Iron block from a truck) LS3 Corvette heads flowing 330 CFM per port with 2.165" intake valves Precision Turbo 101 MM Turbocharger and Air to water intercooler. Its a beast, and now its for sale I cant afford to run it no more.
http://www.cardomain.com/id/z28boysteve

http://www.racingjunk.com/Outlaw-10-5/2 ... ns-am.html

[jrrdw]

didn't realize so many auto enthusiasts were here.

We have everything from mechanics to rocket scientist here.....well...close to it, a rocket engine tester for sure. L0L

[steven_main]

OUCHHHHH It was spark gap, ... without a barrel or projectile it fired perfectly, I thought it was so loud like a .45 going off next to my ear... Until I tried to shoot it at 1bar indicated (2x)...... Pics to follow... PVC hybrid bad idea even at 2x.. I can't believe im alive but my arm feels broken.... CURSE WORDS !#(#*!*!)!#(#!)(#!)(!#)#!(