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Model Rocketry
The 6 foot beer can special
Hi,
So you are interested in model rocketry....well this page describes a model rocket that I built from scratch; and flew a few times. It also has a few pictures to stimulate your own creativity. Please also see Antoine Lefebvres page: http://pages.infinit.net/linux/rocket/index.html for interesting motor information. This is what the rocket looks like:
This rocket is made of pop cans
glued end to end or my preferred material, beer cans (why not
have some fun building it). Its about 6.5 feet high. Now, you are
not supposed to make rockets out of metal, but.........
The nose cone is made from a craft store styrofoam cone. I could have covered it with a smooth material and it probably would have less drag, but hey, I just wanted to fly the darn thing.
The fuselage is made of pop cans, they are ideal since they are very light and structurally strong for this application. I removed the center of the top and bottom of the cans. I left the top and bottom "rings" since they added strength. I glued them together using epoxy glue (you can use a hot glue gun as well--its faster) and laid them on an aluminum angle to ensure they were straight. 14 to 15 cans are required. I covered the joints with 1 inch wide electrical tape.
The rocket separates 2 "cans" above the fin canister. Basically, I made a coupling ring from one can that slipped over the top section and is glued in place. The other side of the ring slips over the bottom section.
I made the fins from glass epoxy printed circuit board material, but this is too heavy--it is what I had around. I would use 1/8 th inch thick acrylic sheet instead. The fin cannister is made by cutting two rings out of acrylic the same size as the inside diameter of a pop can. The ring should have a 1.5 inch hole in the center to allow the gases of the separation charge to pass through. Three 1/8th inch wide equi-distant notches are made on the outside edge of both rings. The fins are inserted into the notches of the rings and glued. Then the fin assembly is inserted into a pop can. Cut 1/8th wide slots equidistant in a can and insert the fin assembly. Glue everything in place. I will make a sketch to show this more clearly.
The motor canister is made in a
similar way. You can fit 3 motors inside a regular size pop can.
You will need a larger diameter can to fit additional motors.
First, make the motor mounts buy rolling pop can material around
the motors you will use, and taping them so they don't unravel.
Next, glue in a stopper in the top end of the motor mount. Use
spent motor casings for this, since they already have a hole in
the middle. Make a template and locate the center of each motor.
Cut 2 rings the inside diameter of the motor canister can. Cut
round holes for motor mounts--there is no center hole. NOTE: I
used wire to secure the motor canister to the top fuselage and
parachute, since the ejection gasses are very hot. Position the
motor mounts in the rings and glue securely. Cut slots in the
motor canister can and insert the motor mount assembly, glue in
place.
I used 5 parallel "D" size motors, since they were the highest power I could get in Canada. Now I believe we can get "E" size.
The launch rod guide rings are made of spent small motor casings. The parachute is made of nylon and packed in the bottom section of fuselage. Always use wadding, I used aluminum foil since it is not flammable.
The launch pad is simple, a board with a rod. I have since made a more elaborate version. Also, I will post the plans for the ignition system shortly.
Simultaneously igniting 5 motors is a challenge. Planning is required here. I used the standard Estes ignitors and added glue in between the leads to make them more rugged. Using the motor canister as a guide, I soldered each ignitor to a wire ring. One for positive and one for negative.
You will notice that most of my launches are done in the winter. I just happens to be the time of year that I was able to do this. NOTE: Rocket motors must be kept warm until just before launch. Otherwise, they will freeze and the propellant will separate from the casing and explode on ignition.
© Tony Ratajczak 2002,2003