Made some progress on the build. 8" dia. concrete-forming tubes wrapped with fiberglass cloth & epoxy. Coupler and avionics bay made by cutting down the tube to the appropriate diameter and glassing it with two wraps.
Centering rings, bulkheads & coupler bulkheads freehand-cut from 3/8" Baltic birch plywood with jigsaw & sanded to fit. The four 24" x 10" fins cut with jigsaw as well, with one fin (mis)placed 3" forward on the rocket.
75mm motor tube with fins and centering rings already attached. I bought some 2" wide non-adhesive fiberglass tape to reinforce the fins to the motor tube, and the fins to the outside of the body tube. 1,800 # test kevlar tape epoxied to the motor tube for shock cord attachment to the aft end of the avionic bay & the 24" nomex drogue chute made by Phylachutes (my wonderful mother-in-law).
The main parachute tube is a glassed 3" dia. body tube which will run the full length of the "crooked tubes", which will be about 36" total in length. The crooked tubes will be cut at about 8.5 degrees off a straight cut. I'll create a plywood jig to trace the cut on the body tube. It works out to 1.55" difference from one side of the tube to the opposite side. I'll hand-cut the body tubes, as I don't have a compound miter saw. Centering rings with off-center holes will hold the tubes together & in place, along with structural-weight expanding epoxy foam.
The strangest thing I'm planning to try is to cut a 3" hole through both the forward & the forward coupler bulkheads. The parachute tube will be epoxied into the 3/4" thickness of the two bulkheads & will be flush with the base of the coupler bulkhead. A third bulkhead, 6" in diameter, will contain the two main chute charge wells, and will be secured tightly into place against the coupler bulkhead with wingnuts, via four 1/4" machine screws permanently affixed through the avionics forward bulkhead assembly. Matching holes will be in the 6" dia. bulkhead, and I'll use one or two 4" to 5" automotive O-rings to ensure a gas-tight seal.
If you have any other suggestions as to getting the two main chute charges through the crooked tubes & into the forward end of the avionics bay, I'm all ears. I had an even crazier though of putting a long coupler in the main chute tube, short enough at the forward end to add a nomex drogue chute and piston,. That piston would act as protection for the main chute below in the coupler-sized tube. I would have the connection wires for both the drogue & main charges running through the crooked tubes, and terminating at the centering ring at the forward end of the chute tube. The main charge would run via a long igniter wire down to the aft end of the coupler-diameter body tube, and force the nomex-protected main chute out. This REALLY seemed like a hassle.
Centering rings, bulkheads & coupler bulkheads freehand-cut from 3/8" Baltic birch plywood with jigsaw & sanded to fit. The four 24" x 10" fins cut with jigsaw as well, with one fin (mis)placed 3" forward on the rocket.
75mm motor tube with fins and centering rings already attached. I bought some 2" wide non-adhesive fiberglass tape to reinforce the fins to the motor tube, and the fins to the outside of the body tube. 1,800 # test kevlar tape epoxied to the motor tube for shock cord attachment to the aft end of the avionic bay & the 24" nomex drogue chute made by Phylachutes (my wonderful mother-in-law).
The main parachute tube is a glassed 3" dia. body tube which will run the full length of the "crooked tubes", which will be about 36" total in length. The crooked tubes will be cut at about 8.5 degrees off a straight cut. I'll create a plywood jig to trace the cut on the body tube. It works out to 1.55" difference from one side of the tube to the opposite side. I'll hand-cut the body tubes, as I don't have a compound miter saw. Centering rings with off-center holes will hold the tubes together & in place, along with structural-weight expanding epoxy foam.
The strangest thing I'm planning to try is to cut a 3" hole through both the forward & the forward coupler bulkheads. The parachute tube will be epoxied into the 3/4" thickness of the two bulkheads & will be flush with the base of the coupler bulkhead. A third bulkhead, 6" in diameter, will contain the two main chute charge wells, and will be secured tightly into place against the coupler bulkhead with wingnuts, via four 1/4" machine screws permanently affixed through the avionics forward bulkhead assembly. Matching holes will be in the 6" dia. bulkhead, and I'll use one or two 4" to 5" automotive O-rings to ensure a gas-tight seal.
If you have any other suggestions as to getting the two main chute charges through the crooked tubes & into the forward end of the avionics bay, I'm all ears. I had an even crazier though of putting a long coupler in the main chute tube, short enough at the forward end to add a nomex drogue chute and piston,. That piston would act as protection for the main chute below in the coupler-sized tube. I would have the connection wires for both the drogue & main charges running through the crooked tubes, and terminating at the centering ring at the forward end of the chute tube. The main charge would run via a long igniter wire down to the aft end of the coupler-diameter body tube, and force the nomex-protected main chute out. This REALLY seemed like a hassle.
