Advance combustion doesnt work??

Boom! The classic potato gun harnesses the combustion of flammable vapor.
cwazy1
Specialist 3
Specialist 3
Posts: 305
Joined: Mon Sep 10, 2007 8:31 pm

So i built my second advanced combustion for a friend and im debugging right now and it seems like its not lighting the propane mixture??

my chamber is 188cu-in including the elbows its a short stubby chamber.. i went on burntlatke and i used the fueltool and calculated for my 7" long 1/2" sch40pvc meter according to my chamber volume at a 4.03% ratio and it said 52psi in my meter...well now i have 2 questions, is the 1/2" specification on the calculator the same as the 1/2" on my sch40 pvc pipe?? and yeah i dont understand why its not working?? its like 43 degrees here right now and i am using a bbq lighter with a spark gap thats a little longer than 1/8"
User avatar
octane89
Specialist 2
Specialist 2
Posts: 257
Joined: Tue Sep 11, 2007 1:20 pm

The cold weather may not let enough propane thru to build enough psi. So you may not be getting enough of a mix.
"Only after disaster can we be resurrected."
Go Listen to My Friends...The Devil Wears Prada
bluerussetboy
Specialist 2
Specialist 2
Posts: 265
Joined: Fri Nov 02, 2007 12:25 pm

Pete Zaria posted this link on a thread of mine.

http://www.engineeringtoolbox.com/propa ... _1020.html

you might try 2 shots of 27 psi instead of 1 shot of 52 psi or try to keep your propane bottle warmer.
cwazy1
Specialist 3
Specialist 3
Posts: 305
Joined: Mon Sep 10, 2007 8:31 pm

hmm yes but my other advance combustion works fine right now with the standard psi gived on burntklatke. its just this new one that doesnt work.
User avatar
BigGrib
Corporal 2
Corporal 2
Posts: 652
Joined: Mon Oct 01, 2007 11:43 pm
Location: TriCities, WA
Contact:

where is your sparkgap located in the chamber please post pictures so i can get a good visual. are you using a chamber fan ...specs please
Yea, that's definitely going to get you at least a tazer.
<a href="">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
facebook.com/biggrib
sjog
Specialist 4
Specialist 4
Posts: 440
Joined: Sun Oct 15, 2006 9:43 pm
Location: Marthas Vineyard

FAN? dumb question on my part...
cwazy1
Specialist 3
Specialist 3
Posts: 305
Joined: Mon Sep 10, 2007 8:31 pm

yeah well its an under over type and theres a cleanout on the other side. i have my propane injection there and my spark gap is also there. i have no fan. i cant get a fan because im out of money. and im not going to spend of my money onto this project.
User avatar
octane89
Specialist 2
Specialist 2
Posts: 257
Joined: Tue Sep 11, 2007 1:20 pm

Your spark working fine?
"Only after disaster can we be resurrected."
Go Listen to My Friends...The Devil Wears Prada
cwazy1
Specialist 3
Specialist 3
Posts: 305
Joined: Mon Sep 10, 2007 8:31 pm

yup its a very fat spark
User avatar
gwoloshyn
Specialist
Specialist
Posts: 116
Joined: Thu Jul 05, 2007 2:06 pm

Fans make a huge difference especially if your not igniting. Maybe a fan could help mix the air around after charging it with propane?
cwazy1
Specialist 3
Specialist 3
Posts: 305
Joined: Mon Sep 10, 2007 8:31 pm

ehh but with my other cannon, the chamber is 3x longer and even if i dont mix it with a fan, it still lights.
User avatar
octane89
Specialist 2
Specialist 2
Posts: 257
Joined: Tue Sep 11, 2007 1:20 pm

If everything is working fine, and you have no fan I would assume there may be a rich propane mix and can't ignite. Try a fan, its the only other option I can think of.

edit-Seen your previous post. But I think its either to rich or to lean.
"Only after disaster can we be resurrected."
Go Listen to My Friends...The Devil Wears Prada
cwazy1
Specialist 3
Specialist 3
Posts: 305
Joined: Mon Sep 10, 2007 8:31 pm

hehe read the above^^..lol
sjog
Specialist 4
Specialist 4
Posts: 440
Joined: Sun Oct 15, 2006 9:43 pm
Location: Marthas Vineyard

Not very advanced w/o fan :D
User avatar
BigGrib
Corporal 2
Corporal 2
Posts: 652
Joined: Mon Oct 01, 2007 11:43 pm
Location: TriCities, WA
Contact:

Definitely not what I'd call an advanced combustion, basic bbq igniter and no chamber fan all you have is just a step above spray and pray. A chamber fan is 10 bucks at office depot and get a couple connectors for 9v batteries from radio shack and maybe a little switch bingo now you're on your way to an advanced combustion. i would definitely try to use a leaner mix. over fueling is the main cause of a combustion not igniting. the second would be your spark gap but since you said it is 1/8" nice and fat i would like to see a little longer i know with those piezo igniters you can get a really nice 1/4" gap as well. other than that try a fan to mix the fuel, you will definitely see an increase in power with a nice and blended fuel mix. I know with my advanced (and it is fully advanced with metered propane, chamber fan and a 12kV ignition system with dual spark gaps) I can shoot a golf ball rough guess of 1/2 mile. All i know is that when it shoots you can't see it leave the barrel or in flight, and that I have never recovered a golf ball shot for distance.

~BigGrib
Yea, that's definitely going to get you at least a tazer.
<a href="">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
facebook.com/biggrib
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

  • Similar Topics
    Replies
    Views
    Last post