SpudFiles

I think, that you would be better off with using flour. It is much finer that sugar, (unless you grind the sugar down of course), and much easier to keep in suspension. I would recommend using a 1/8in or larger chinese (has lots of fire and burns really hot!) cannon fuse available at cannonfuse.com, to ignite it.

You could us an RC car motor and a pc fan blade for forcing in air and stirring up the mix, then you could cap it off, light the fuse,,,, and boom!

Edit: You could use a high voltage something to ignite the fuse inside the chamber, that way, there is no holes in the walls....

EDIT: IS ANYONE GOING TO RESPOND TO MY COMMENT!?!?!

you should look into the LEL (lower explosive limit) and UEL( upper explosive limit) for sugar, limits between these will give you your air to "fuel" ratio. Have fun

I think that sugar may be bad for the gun...

...plus it could give off a lot of smoke.

i got that idea coz its used in prank smoke bombs with saltpeter
The rest of the thing is just fancy crap