Safety First! A Few Guidelines

A year ago, at our third club meeting ever, I was bracing the potato gun against my side when we fired it. Today at our fourth club meeting of the year, Jason was doing pretty much the same thing. Every other potato gun launch we've ever done has been perfectly fine. But these two times, we got a pair of holes in our shirt. Why? And how can you prevent it? (HINT: it's very easy and totally reliable.)

Potato Gun Safety

1. Never walk in front of the potato gun while it's primed and loaded. Actually, I'd avoid walking in front of it any time it's being used. If you do have to walk in front, be sure the person holding it AND the person holding the ignition switch know you're there.
2. If you're holding the igniter, NEVER go until the chamber lid is firmly on. Wait until after the person who screwed it on takes his or her hand away. Willy got burned once because someone jumped the gun and clicked too soon.
3. And here's the one Jason and I have to pay attention to. Notice where the two wires from the igniter go through the PVC and into the chamber. See the two little holes? Jason and I got burned because we had them facing towards us. Normally its not a problem, because most of our potato guns have those holes epoxied. (Epoxy is that super-strong glue stuff.) If the holes are epoxied, you're perfectly safe. Don't worry at all. We've done this dozens of times, if not hundreds. If you can't tell whether or not there's any epoxy (think glue) around the holes, tell one of the club presidents or a teacher. But as long as you keep the holes facing away from you, you'll be completely fine. It's a very very small flame coming out of there, and it only goes for an instant.

Rockets

1. Don't be near the rocket when it fires. If you're launching it, stand as far back as the wire length will allow. If you're not launching it, stand even farther back.
2. Don't stand behind the rocket, or downwind of it. You'll get a mouthful of yucky yucky smoke. It's not really dangerous, but it's yucky.
3. Never try igniting the engine with anything other than the electronic igniter.

Other than that, don't do anything dumb. When in doubt, ask a teacher. Or me. Or Peter. Or Vivek.

Using the Potato Gun and Launching Rockets: A Few Tips

When you have thirty kids running around begging for pudding, sometimes it can be hard to give them all good instructions. These are a few tips that will help us get the most out of our meetings.

The Potato Gun
Nobody Likes a Misfire

Today at our fourth club meeting we did a ton of potato gun firing. We did have quite a few misfires, though - that is, times when the potato gun just didn't fire. There were also a few misses, although our aim was fairly good. In any case, here are a few tips for being a potato gun expert.

AIMING: If you want...

• Maximum Distance: Hold the potato gun at a 45-degree angle.
• Maximum Height: Hold the potato gun straight up, of course! :)
• To Hit Something: If you're relatively close - say, half the width of the Lower Field - you should pretty much aim straight at the target. Aim a little bit up, but probably not more than 10 or (at most, if you're, say, all the way accross the Lower Field) 15 degrees. This one will just take practice.

POWER: How do I get the most?

• We haven't yet done a lot of testing, but there's a perfect amount of hair spray to spray. We've found that 4 seconds works quite well.
• Also, choose a nice big potato - bigger than the barrel. Use the sharpened edge of the barrel to cut it down to size. Try to avoid ANY air gaps on any side of the potato.

MISFIRES: Why do they happen, and how do you prevent it?

• The potato gun will not fire if you have too little or too much hair spray in the chamber.
• NOTE: More hair spray does NOT always mean it'll go farther! There's an optimal ration of air to fuel. If there's too much fuel and not enough air in the chamber, it won't ignite.
• SO: don't spray too much! (That's a lot more common than spraying too little.) It it won't fire, wait! Air out the chamber.
• Note that sometimes, misfires are out of your control. Sometimes a wire is loose or unplugged or broken or something like that. But 98% of misfires are thanks to having a bad air-to-fuel ratio.

DUDS: Why did the potato just softly plop out of the barrel?

• Again, there is an optimal ratio of air to fuel. If you have just a little too much or too little hair spray, the potato may not go very far.
• Also, the potato needs a good seal in the barrel. That is, it should fit very snugly, and give a good deal of resistance when you shove it down the barrel. Otherwise, all those explosive gasses can just escape out the gaps around the potato instead of launching the potato.
• SO: spray for about four seconds. (It's probably worth experimenting a bit with the exact timing.) Don't have too long a countdown - three seconds will do it.

Rockets
Push the button HARD

Rockets are, in some ways, a lot simpler to launch than is a potato gun to shoot. You don't need to optimize this or that. But it is a longer process. Here are the steps:

PREPARE THE ROCKET (note: I won't be too detailed about actually making the rocket.)

• When your rocket body is all assembled, crumple up three or four pieces of fireproof wadding and stuff them down the body tube.
• Attach the parachute, fold it up and put it into the body tube.
• Take the bottom of the rocket off and put in the engine. Put the bottom back on.
• Stick the black end of an igniter (the little metal wires split like a weird V) into the hole in the bottom of the engine. Secure it with one of those little plastic plugs - the things that look like thumb tacks. Bend the wires out to either side.

ON THE LAUNCH PAD

• If there's no wind, keep the launch rod aiming straight up. If there's wind, tilt it slightly into the wind.
• Slide the rocket down the launch rod. Try to suspend it off the metal disc an inch or two, e.g. by wrapping the rod in tape at that point. (The tape part isn't necessary, but helps.)
• To test it, take the the black box (electronic control box thingy) and clip the ends of the wires together. Put the key in the hole and press down hard. If the light lights up, you're good to go. Otherwise, you need new batteries.
• Clip the wires from the control box to the two wires of the igniter on the bottom of the rocket. Keep the clips from touching any other metal.
• Walk as far away as you can with the control box. If the launch pad is tilted in any direction, stand behind it. The wires will come unclipped very easily, so you may want to have someone hold on to the wires by the launch pad so that when you pull it taut, it'll tug on them and not the fragile connection to the rocket.

ACTUALLY LAUNCHING IT

• Start a countdown
• Around 3, put the key in the hole and press down hard.
• Right on one, or even an instant sooner, press down hard on the black square button and hold it. Hold it! It'll take a second for the engine to light.

And that's it! :) Now you're all potato gun/rocket launch experts.

A Guide to the Blog

Welcome to the official Beaver Science and Engineering Club blog! Here you'll find news, videos, pictures, and more. To help you get around, here are a few links to the most important posts and items:

Year One
First Meeting: Planning our first meeting ever, spent doing some simple planning
Second Meeting: Rube Goldberg Machines 9th grade won, 10th grade lost. :(
Third Meeting: Potato Gun I get the burn on my sweatshirt

And then there was a long stretch where we didn't do very much, but worked on rockets with egg payloads for a long time.

?th Meeting: Egg Launch Finale finally! after THREE MONTHS!
?+1th Meeting: Burning Flour the beginning of a new era
?+2th Meeting: More Flour... Waaaaay More we got some BIG flames

We did a bit more before the end of the year, but nothing significant.

Year Two
First Meeting: Potato Gun the year we don't make the mistake of starting out without a bang
Second Meeting: Silly Putty and Basic Rocket Launch fewer bangs, more chemistry
Third Meeting: Van de Graaff Generator and Rocket Dune Buggy less chemistry, more electricity
Fourth Meeting: Potato Gun + Target this time we have something to shoot AT, plus some more ammunition variety
Fifth Meeting dry ice, smashing a monitor, rocket car
Sixth Meeting rocket javelin [with video]
Seventh Meeting dry ice and two rockets, including one that kind of nearly killed us (or at least, nearly hit us) [with video]
Eighth Meeting we fail at making a hydrogen fuel-cell car
Ninth Meeting our rocket does eight flips [with video]
Tenth-Twelfth Meetings Recap the egg launch project puts us in a bit of a lull for the second year in a row

Miscellany
Become a Potato Gun/Rocket Launching Expert a few tips and tricks
Safety Guidelines we try not to be quite as reckless as we look

I will expand this guide as the blog expands.

Third Meeting: Van de Graaff Generator & Rocket Dune Buggy

Last Friday, the 10th of November, we held our third meeting. We started off by playing around with a Van de Graaff generator, which went quite well. I've never seen so many people so eager to hurt themselves. It's a bit disconcerting, actually.

We started off with some, ahem, shocking high-fives. Then it progressed to fist pounds and even a slap or two accross the face. Several people formed a long chain to extend their collective reach.

Then, by special request, we learned a bit about nukes. Unfortunately, the person who requested it was absent that day, so it was totally pointless and I apologize for wasting your precious time.

Once we were done with that we strapped a rocket engine to Tyler's GI Joe dune buggy. Unfortunately, it was a lot heavier than I had anticipated, so we sent it... uh... flying a whole ten feet. :) Well, to look on the bright side, that's about 8 feet farther than I thought it would go.

Check out the videos:


Video: VanDeGraaf Shocks All


Video: Rocket Car

Second Meeting and Harvest Fest: Success! (ish)

Sorry this update is coming a little late. I've been super-busy. Anyway, without further ado:

Second Meeting

We had our second club meeting last Friday. Vivek started us off by leading us through the steps of making some silly putty as preparation for our Harvest Fest booth. Once everything was up and running smoothly, I (and a small breakaway contingent) began to quickly assemble a camera rocket and prepare it for launch. Yearbook Club had come around toward the beginning of club block to take club photos, but we thought we could do better with an aerial shot.

Unfortunately, we had trouble getting the film to advance and decided to launch the rocket from the Lower Field without enabling the camera. It was a fairly windy day, so we made sure to angle the launch rod away from the school (and into the wind). Countdown and liftoff went smoothly, but the wind had died down slightly - we had overcompensated for it. As the rocket deployed its parachute and ejected several pieces of flame-proof wadding (each a small speck in the sky), we lost track of exactly what was what. It came down somewhere in the vicinity of the graveyard, the next-door neighbor, or Hammond Street.

Twenty or so high schoolers soon flooded the neighbor's property and fanned out to look for our rocket. It must have been a strange sight for the puzzled folks staring out the first-floor window at us. Almost immediately Peter jumped up onto the rock wall the separated the neighbors from the graveyard, and before long a large portion of our group had jumped the wall.

Our search was in vain, however. Despite our considerable manpower we never did find the rocket. Perhaps it was just as well that we never managed to arm the camera.

Harvest Fest

On Saturday was Beaver's annual Harvest Fest. For the first time, the BSEC had a booth (or two) of its own.

Segway

The first things people were likely to notice upon entering the Green Gym were two i-series Segway HTs gliding around a test track. This proved to be quite a popular attraction; the waiting list was full from setup time to shutdown time. At one point the wait was around 45 minutes long, yet still people found the rides worthwhile. The 11th Grade (with whom we shared the Green Gym) accused us of stealing their customers, but in truth I think we only attracted more people to the area. Cross-promotion is a powerful thing!

Many expressed frustration with never having a chance to take a Segway ride, so we'll think about doing this again sometime.

Silly Putty

Hampered somewhat by a lack of club helpers (thank you Emily, David & Co. for keeping it running), the silly putty booth was nevertheless a very enjoyable diversion from long wait times. I was busy the whole time at the Segway and 11th Grade booths, so if anyone has any silly putty tales to tell, please do so in the comments.

Third Meeting Plans

Unfortunately we're not quite sure what we're doing at our next meeting. Our tentative plan is to build potato guns, but there are some liability concerns. (No, a simple waiver wouldn't solve those problems.) But don't worry - we have several backup plans. Whatever we do, it'll be cool. Stay tuned.

Second Meeting is Tomorrow

It's been a long three weeks, but the BSEC's second meeting is finally nearly upon us! Tomorrow in clubs we'll be putting our science/chemistry skills to good use and making silly putty, as well as (probably) shooting off a potato or rocket or something. Fun fun!

We'll also be planning two most important things:

1. Our Harvest Fest booth, which will feature Segway rides and silly-putty-making demonstrations,
2. and our third meeting, when we'll actually get to make our own potato guns!

We'll have a report on how it all went sometime in the next few days.

Potato Gun v. Balloons

Any guesses what'll happen? Mmm? Any?

We tried this in the club Friday, but didn't have time to get it to work. Well, today we did. Enjoy... and start thinking about what we should shoot at our next meeting!


Video: Potato Gun v. Balloons

P.S. Sorry about the totally out-of-sync audio...
EDIT: Fixed audio by using MSN Soapbox instead of YouTube.

Fun Possibilities: Beer Cannon, Flaming Visualizer, & Hovercraft Ideas

Beer Cannon:



More info


Flaming Visualizer




More info

Hovercraft Ideas:
Here