Model Rocket Motor Plugs

To check a model rocket for stability one of the easiest things to do is a swing test. To do this you put a motor in the rocket, tie a string at the point where it balances level, and swing it around (the string should be 10' or so long for this). If the rocket flies straight, it's stable. Or so the theory goes.

But I don't always have motors available for this so I did some research and some math and determined that an Estes D sized motor is almost the same weight as 18 pennies, as long as those pennies were minted after 1982 (pennies were heavier before then). An E sized motor weighs the same as 22 pennies, approximately.

So I put 18 pennies in my rocket and proceeded to fling them all over the yard. No, not really. I did tape them together and shove them in for the first few tests, however, and then I thought there has to be a better way!

That's how I came up with these motor plugs. The D sized plug is sized like a D motor and has a void inside that holds 18 pennies