Innovation Cubed

Photo by Alan Estenson

-- Alan Estenson, MASA president
upon seeing this creation [1/27/2001]

Construction

After a long and exhaustive search for exactly the right parts, I settled on these precision rocket components:

1. one large plastic cup from Arby's
2. two Medium paper cups from Subway
3. one Medium paper Coke cup from, I believe, Leann Chin
4. one Medium paper cup from Burger King
5. one Dannon french vanilla with raspberries yogurt cup
6. one Land O Lakes raspberry yogurt cup
7. a straw
8. a paper cone from a Chippewa Springs water cooler
9. a paper towel roll core
10. 3" worth of .75" tube
11. 1/4" of an expended 18mm motor casing
12. cardboard stock
13. Free ISP CDs from America Off-line, Earthunlink, and Juno
14. One homemade 18" parachute

I started by cutting holes for the paper towel tube in the bottoms of the Arby's, Coke and one Subway cup. To help make round circles, I used a compass holding an exacto blade instead of a pencil (a slot is cut in a dowel and the blade is taped in place). The cut-outs are saved for later use as centering rings. After cutting a rear centering ring from some scrap cardboard, I glued the paper towel tube down the center. A shock cord goes through two holes in the sides of the Arby's cup (under the Subway cup) and up next to the tube.

I needed a coupler of some sort to hold the nose cone on, but allow it to separate at the proper time. I decided to use two stacked cups as a coupler, and to separate mid-body. Thus, a second Subway cup is placed inside the Coke cup and allows the rocket to (intentionally) break in two at ejection.

The biggest challenge of the project was constructing the launch lug standoff. This required use of a straight-edge and a ruler to measure the shape created by the two cups. A piece of cardboard was cut and a straw was glued to it, with paper glued over the straw to give it some strength.

The final challenge was selecting which CDs to use as fins. Four CDs were precision-cut 1" in from the outside edge by scoring and breaking. They were then glued to the plastic Arby's cup with plastic model cement. These joints did not seem particularly strong, so I reinforced them with the cut-off scraps.

Photo by Steve Robb

Photo by Alan Estenson

The Future

This rocket really needed a 24mm motor mount. It doesn't go very high on a C5-3.

I didn't get cups from Taco Bell, McDonalds, Blimpie, etc.

Flights

1/27/2001,White Bear Lake, MN:
Lift-off was a bit slow and the rocket arced into the wind and over the crowd. Apogee was only a couple hundred feet up, with ejection occurring a tense moment after apogee.