Time to get started on this build. Since I'm trying to build this rocket to fly on an F67 I'm going to need to keep the weight down where possible so I can't do my normal process which is to over build everything
Figured a good place to start is with weighing all of the components included in the kit stock and seeing where I can reduce weight.
Nose Cone Complete with all hardware in place. 12.0oz
Body Tube 3.7oz
Fins (all three) 6.3oz
Motor Tube .40oz
Motor Retainer .40oz
Upper Ring 1.0oz
Lower Ring 1.1oz
Eye Bolt .90oz
Rail Buttons .20oz
Total Weight of items included in the kit 26.0oz
I should mention the kit also 6.3oz of Nose Weight. I don't think this will be needed for my build as I plan to stick with relatively small motors but I am glad that it is included for those that want to fly larger motors. Looking at some early SIM's I've run, it looks like I will be able to remove some mass from the nose cone and still be stable but it's too early to talk about that right now.
During this build, please remember that I'm attempting to build this rocket to fly on a relatively small F67 motor so changes in construction will be made accomplish two things. The first is to reduce over all weight and the second will be to move weight forward toward the nose cone in the attempt to avoid or minimize the amount of nose weight required to be stable.
I began the build with the motor mount. The outside layer of the motor tube was removed then lightly sanded to open up the fibers to allow adhesive to bond. The upper centering ring was sanded slightly on the flat surfaces and all of the edges beveled to remove any sharp corners including the hole for the eyebolt. The upper ring was attached 1/16" down from the top of the motor tube. This was first tacked in place with a couple of drop of CA then fillets of BSI 30 min. was applied and let cure.
Next it was time to attach the shock cord. The kit includes an eyebolt for this but to reduce weight I have decided to leave the eyebolt out and attach a LOC 15" Kevlar shock cord around the motor tube under the upper ring. This was looped around the motor mount then pushed through the hole in the upper ring. The weight of the shock cord is .70oz.
Here we see the underside of the upper ring. The shock cord was attached with BSI 30 Min. epoxy.
After letting the epoxy cure. the motor mount was inserted into the body tube. The inside of the tube was marked where the upper ring would sit then lightly sanded to open fibers up. The motor mount was inserted until the rear of the motor tube sat 3/8" up into the body tube. This will hide the motor retainer and move the CG forward. This was attached using more BSI 30 min.
A view down the tube from the top shows a nice fillet around the top of the upper ring. Also note that epoxy was spread around the top 2 inches inside the body tube to add some strength to help prevent zippering.
Today I'm working on the fins and will be attaching them over the next couple of days.