Eggtimer Rocketry Eggtimer User Manual page 43

For example, a small 5" payload bay 1.5" inches in diameter (inside of a BT-60 coupler...)
1) Length of Payload Bay in inches: 5
2) Diameter of body tube:
3) Square of #2
4) Multiply #1 and #3
5) Divide by 1500
6) Take the square root:
We'll multiply this by 32 to get the size of the drill in 1/32nds, it's 2.77/32" so we should be fine
with a 3/32 drill bit. Make sure that you use a good sharp drill bit, you do not want any burrs on
the outside of the tube disturbing the airflow. You may want to sand the area around the holes
with some #400 extra-fine sandpaper to smooth out any burrs or flash, and possibly harden it
slightly with some thin CA glue too.
1.5
2.25
11.25
.0075
.0866
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