OK - decided to stay cheap
I purchased the Madcow 1.6" Tomach during their BF sale. They are kindly sending me the parts to build it as a minimum diameter - tangless fins and un-slotted body tube.
I am going to build it to accept up to a CTI 6xl case even though at the moment my biggest case is a 6 grain. (Sorry Teddy - I was going to build to support the Loki 38mm-1200 case but it is too long for the tube that comes with the Tomach)
Below is a snapshot of the Madcow generated Rocksim file that I modified. I didn't post the actual file since Madcow has it flagged as copyrighted....
I added some mass for electronics in the nose and of course changed the motor mount. I also moved the fins forward a bit to allow for the laminer flow.
The sim shows I have a stability of 3.1. I understand from other threads that the CP moves forward as you break mach so you need extra margin. Can I get by with as low as a 2.0 stability? I may cut the length down a bit to reduce weight and get a higher speed.
With a 6g J354 Rocksim shows to getting over 12000' and 1500 fps, achieving my goal. Although I do recognize that the sims tend to be optimistic.
So a few more questions - sorry....
At what point do I need to worry about heating from air friction? If I ever go to the 6xl and a j530 imax it shows a speed of 1900fps. Should I be using JB weld since it is rated for 500 degrees?
Since I don't have any of the basic tools for adding fiberglass (resin, peel ply, etc) I would like to avoid adding that. Looking at the Wildman site, even the smallest containers of resin and hardener exceeds the price I paid for the kit! From looking at other threads I don't believe I should use the standard 30 min hobby epoxy for laminating.
Since Aerofin does not appear to be available anymore, is there any other means to determine what my max speed can be with the standard 1/16" fins that the kit comes with before I have an issue with fin flutter? Will I break it if I try the imax???
To minimize drag, I plan to use a fly away guide, minimum diameter retainer, and the cable cutter. My thoughts for using the cable cutter is I can avoid shear pins projecting into the air stream as I only need the rocket to "break" in one place at apogee. Plus I own a set, might as well use it
View attachment 276478