Q and A

Question 1: Who makes spark friction ignitors for the potato cannon?
Two companies that I know of—Coghlan and Coleman. You should be able to find one or the other in stores that sell lanterns for camping. If you can’t find any local suppliers, you can get one online. Go to a search engine and type in “Coleman spark igniter”, and you’ll find several suppliers.

Question 2: I can’t find any stores that sell Calcium Carbide chips for the Calcium Carbide Cannon. Can I get it mail order?
It’s illegal to transport calcium carbide chips throught the mail. You can, however, legally obtain a powdered calcium carbide product called Bangsite. Order it at 1-800-BANGSITE.

Question 3: Can you tell me the exact proportions of ingredients in ANFO type explosives?
I don’t know, and that’s not what Backyard Ballistics is all about.

Question 4: What kind of hair spray works best in potato cannons?
I’m partial to White Rain, but almost any aerosol spray should work.

Question 5: Can I try starting ether in the spud gun?
No. Don’t make substitutions in propellants. Things like starting ether are untested, too volatile, and probably very dangerous.

Question 6: Do all matches work equally well in match rockets?
It might be obvious, but look for paper matches with the biggest match heads. Also, it seems to me that white match heads seem to work the best, but I can’t back that up with scientific proof.

Question 7: I have some cool ideas for backyard ballistics type projects. Do you want to hear about them?
Sure. Use the email link below. And we’re much obliged for good ideas.

Question 8: I want to modify the big ballistic pendulum project to measure the how fast I can pitch a baseball. Why do we need all the wadded up newspaper inside the Ballistic Pendulum?
Because there must be no bounce or recoil inside the pendulum when the projectile hits. The paper makes a non-bouncing environment. Physicists would term this “an inelastic collision”, and the equations used to determine velocity assume the collision is inelastic.

Question 9: I’m having trouble with the Cincy Fire Kite. Any suggestions?
It is a tricky one, all right. Luckily newspaper is cheap, so keep trying. Remember, cool nights work best. Also, the bigger sheet of newspaper is, the better. Make the folds such that the gaps at the seams are as small as possible. Finally, a physically big paper like the Wall Street Journal works better than smaller-sized newspapers

Question 10: What kind of detergent bottle works best for the Pneumatic missile?
Use as big a HDPE plastic bottle as you can find. Any bottle with a spout that you can fit the plastic tubing over should work fine.

Question 11: What’s with the numbers on your protractor drawing?
They are reversed. Put the 90 where the 0 is and vice versa.

Question 12: How about using gasoline in the potato cannon?
No. This is way too dangerous. Leave flammable liquids alone.

Question 13: What’s the biggest vegetable shooter out there?
Probably the Aludium Q-36 Pumpkin Modulator. Its a big pnuematic cannon that can heave a pumpkin about a mile. A team of people in Illinois made it for the annual pumpkin chunkin festival in Delaware.

Question 14: Will there be a second book of more Backyard Ballistics experiments?
Maybe next year. Send an email to me at williamgurstelle@backyard-ballistics.com and I’ll notify you when it comes out. (I promise not to share the email address with anyone else, ever.)