Last week, my neighbor (a single Mom of a 6 yr old boy) asked me if I would help her son build a Space Derby rocket. She wanted the boy to have a good first experience with Scouts and the boy's Dad refused to buy the kid a $4.95 kit and help him build the rocket. Upon hearing this, I immediately agreed to help the boy. This would be my first Space Derby (they did'nt have this event when my brothers and I were in Scouts) so I went to the local Scout store to get the kit and ask some questions. At the Scout store I saw Dad's buying stacks of scout books, uniforms, kits, etc for the kid's that they lead. Two boys saw me in the Space Derby section and asked me if I was building a rocket. "Yes, " I said. "Do you have any tips?" They boys and I talked for about ten minutes about how to build and race a rocket. Their Dad came over and we talked Space Derby for about 30 mins. This is what it's all about: boy's talking to men and learning how to be men by the example set by their Dads. I salute all of you who take care of business as Fathers to Scouts. So, I bought a couple of kits (one for the boy's Dad just to give him a chance), extra rubber bands and a hangar for test flights. We built the rocket. The boy's Dad called Mom at 6pm the night of the race and said, "This thing requires tools and glue. I can't build it." The boy took our rocket to the race and smoked everyone! The boy's Mom told the Scoutmaster (Navy officer and great guy) the situation before the race and the Scoutmaster stepped in an helped the boy with racing the rocket. The boy's rocket consistantly flew off the end of the string. total success!
I flew fighter jets for the Marine Corps for 25 years. During that time I was involved in various developmental test and operational test and evaluation programs. I want to make the millions of dollars worth of aerodynamic and design information the US Government taught me available to you for your rocket construction. I'll also include photos when I get them from the boy's Mom. Here are the tips I'll expand on in another post.
1. You are not building a flying machine. You are building the most efficient vehicle that rides on a string.
2. Think "bomb". Iron bombs are designed to free fall in a stable, ballistic path. This is a good shape for the rocket.
3. Get rid of weight
4. Balance the rocket
5 Balance the prop
6. Lube the prop
7. Test fly to validate performance
9. Test fly