I’m still alive! Ok, quick update… I have moved Jujubee back to the top of my priority list. I’ve completely redesigned the entire rocket, sacrificing some strength for accuracy, reliability, and performance. The design is still in progress so it’s bound to get heavier, but currently RockSim is estimating that it will go about twice as high as it estimated for the last Jujubee (it’s currently saying 7200 feet up, and 1020 feet per second, WITHOUT the cannon). Very, very impressive. I’m a bit nervous because RockSim’s model reports that the rocket is stable, but Barrowman says it’s way unstable. Fortunately this rocket is small enough that the ol’ string test is still doable.
Tonight I CNC’d the fins out of copper-clad 1/16″ fiberglass. This CNC mill is kicking butt for this type of work, and it’s fantastic for slotting the airframe accurately as well. I plan to fiberglass all the fin roots together so this thing will be just about bulletproof. Not as tough as the last rocket, but it will be much easier to set up and it’ll have much less chance of cracking upon launch. One interesting thing about the fins is that I designed them myself more or less through trial and error in RockSim. I don’t know if this is some artifact of its simulation mechanism that is incorrect, but it claims that this particular fin design is extremely efficient — very very short and stubby, all the way at the back of the rocket, but there are several of them (5, currently). I hope RockSim isn’t lying.
This rocket (and the entire system) is going to be pretty hardcore. I’ve got a radio link so I can arm the rocket remotely (after it’s been loaded into the cannon) as well as to help me find it again… I’ve got an awesome switch cover for the “Arm” button on the wireless arming circuit… a keypad for entering in the “launch codes”… It’s going to be great if I can pull it all off. Currently, the launch date is scheduled for Sunday the 27th of August. Gotta be ready!!!
