SUBJECT: ROCKET STABILITY
MATERIALS: glue/string/typing paper/scissors/3/8" dowel rod/
3"x5" index card/sinker/fin alignment sheet/compass/
protractor
Directions: 1. Fold the typing paper in half so it measures 4 1/2" x 11". Cut the paper at the fold.
2. Wrap 1/2 of the sheet lengthwise around the dowel rod and glue it in place. Once the glue has dried; remove the dowel from the cylinder.
3. Lay out a 3" circle on the index card and cut it out. Cut a slit equal to the radius of the circle. Fold the two edges over each other to form a cone with a point on one end and a 3/8" opening on the other-or slightly larger.
4. Glue the cone onto one end of the cylinder and check for leaks.
5. Select a fin style from the fin and alignment sheet and cut it out for a template. Trace three fins on the index card and cut them out. Where the fin attaches to the rocket cut several 1/4" deep slits and then fold them in alternate directions to form tabs. These tabs make gluing easier.
6. Using the fin alignment sheet locate the position of the fins on the open end of the cylinder. Extend the marks up the cylinder vertically using the door post of the classroom. Glue the fins onto the cylinder about 1/2" from the bottom.
7. To check the rockets center of gravity lay it at a 90 degree angle across your index finger. The rocket must balance in the center. To change the center of gravity, weight must be added to the top or bottom area.
8. To test the rocket's stability, tie a string in the center and swing the rocket around you. If the rocket is stable, it will continue to point in the direction of rotation.
9. When launching the rocket, be sure to select a safe direction away from buildings, people and other obsticles.
10. You can construct rockets with no fins in order to see the affect fins have on the vehicle.
1. Required length 11" (1 point subtracted per 1/8" short)
2. Check nose cone for leaks (10-no leaks; 5 some leaks; 0 nose falls off)
3. Requires at least 3 fins (3 points off per missing fin)
4. Check for fin location using alignment sheet (3 points per not aligned)
5. Check fin location above body bottom-1/2" (2 points per 1/8" off)
6. Check fins are perpendicular to the bottom of the rocket (3 points per)
7. Tie a string around the rocket to check that the center of gravity is in the middle (2 points per each 1/8" off)
8. Swing the rocket in a circle to test stability-if it points off to either side the fins are usually not glued on straight (1 try 10 points, 3 off per extra try)
9. Safety (3 points off per safety violation-safety glasses, scissors, testing)
10. A successful flight (3 points off for each part lost in flight)
Feel free to develop additional areas of evaluation or to modify these.
Robert Goddard