Tuesday, May 26, 2015

Progress on the 4-F Club rack rocket

Well, other than finalizing the streamer composition (length and material) and attaching said streamer, the 4-F Club is complete. I found the long basswood rack was quite floppy with only the rear supports so I added another set somewhere around the loaded CG point. This turned out to be a good place to put a rail button so I added a single support near the top for the 2nd button.

P1320115

The actual, unloaded mass is 3.5 oz and the associated CG is at 18" (from the tip of the cone). This makes the rocket quite overstable with 1 - 4 motors. It should be plenty stable with our club's 10' rails. In low winds, it should do well on much shorter rails but, since the longer ones are there, I should use them.

I ran a bunch of simulations at various wind speeds and it should tickle the one mile mark, depending on the amount of weathercocking. In good conditions, it could go way over that altitude. The long rail will help with that too.

Since I will likely lose it, I won't risk an altimeter and thus the difference between a three motor and four motor flight will only be the number of smoke trails. I might wimp out and only go for three. Either way, I need to acquire the motors.

Oh, since the lower regions will char badly, it is single-use even if recovered. I don't think I'll  going to bother painting it.