Friday, September 18, 2009

Rocket birdhouse building frenzy

Well, not exactly a frenzy but compared to the last month or so the Dungeon is buzzing. I surveyed the rocket birdhouses, began gathering parts I had lying around and listing what I need to acquire.

Raygun Gothic Birdhouse

I first cut, sawed, and pried the top off.  I found that, with a little grinding on the side of the body opening, a 2.5" tube fits snugly.  So I slid a tube in, marked the needed length and cut the tube to fit.  I'll use one 24mm-2.5" cardboard ring and will drill a 24mm+ hole in the base.  Motor retention will be provided via a bolt inserted from the inside of the body.

I need to make a shoulder for the cone and drill a port to add nose weight.  Fins are still the big issue.  To use the stock fins or not, that is the question. I may just want to add clear fin extensions to these and save the swept back fins in my concept design for another build.

Raygun Gothic HoJo

The fins are attached with both glue and wire brads and  were easy to remove.  My quick and dirty measurement was right -  a 3" tube matches the base perfectly.  I'll make a shoulder with coupler tubing and a couple of bulkheads. I have the rings and tubing for a 29mm motor mount but am contemplating a 24mm cluster.

I fiddled with body tube lengths and fin sizes.  I started with the numbers from a RockSim for the Madcow 2.6"  HoJo, which I scaled to 3.125".  I rounded the fin dimensions up and think I'll use 1/8" plywood. 

I also played with the body tube until it looked right. If I used the correct length body tube, it looked funny because the birdhouse cone is so much shorter than the scale one.  It looked even worse when I used a tube that would keep the entire rocket the correct scale length.  The actual tube will be in between. I know, it will look kinda funny in any event :)