Combustion Gasses

[ZealousAlcoholic]

Well this is my first thread so here we go!

My friends and I have built a combustion launcher, out of pvc, and a gril igniter. We started off using metered propane, and hairspray(only because my dumbass friend thought it worked better). Then we move up to mapp gass, which seemed to produce better results, louder, and somewhat of a distance increase.

I know acetylene is a no no, but what else is there? What does everyone use? Just looking for new ideas!

Thanks in advance,
William

[frogy]

Propane properly measured to about %4.2 propane to %95.8 air mixture will give great results for fuel....

MAPP properly measured to about %4.6 propane to %95.4 air mixture will give the best results out of any fuel....

Check http://www.burntlatke.com/ for some fuels \ mixture tables.

A chamber fan would greatly increase distance also.... Proper venting, proper mixture

http://www.burntlatke.com/lpmapprussets.html

[plumpthumb]

Amen frogy to the chamber fan! I installed one in my propane cannon and it increased my power greatly. If I would reccomend one upgrade it would be this. Add to that a spark strip and you have an unbeatable combination.
As an aside use a stun gun ignition for a hot spark.

[rl93]

that was funny why did you delete it

[boilingleadbath]

The properties you want in a fuel:
High energy content/volume
High carbon:hydrogen ratio
Reasonably fast flame propagation speed

Now, cyclopropane seems to fulfill all those attributes, but it'll be a pain to get.
And I would (at least initialy) only use it in ABS cannons, which have been shown to be safe (if short product lifetime) to operate, even with acetalene-O2. The stressed bonds make it an unstable molecule, which promotes detonation.