January 28, 2009
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The motor extension tube from the kit was a bit long and not needed for my purposes (it was added to the kit to accommodate the long hybrid motors). Although I originally decided to remove only 2” from its length I decided I would rather have the additional room in the airframe for the drouge chute and harness and so 4” was removed and a solid bulkhead added to the top.
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The Kevlar shock cords were attached to the U-bolts on both sides of the lower motor tube centering rings using an Anchor knot and the 6” of remaining cord was firmly held together with electrical tape.
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The completed motor tube assembly is shown here ready to be mounted into the tailcone.
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A small bulkhead with U-bolt was mounted into the nose cone. The bulkhead was sanded to a contour that will mate flush against the inside of the nosecone. The bulkhead was then glued inside the nose with Epoxo-88 paste in order to get a good fit and to seal the spaces between the bulkhead and the irregular surface of the fiberglass nosecone. A good amount of West Systems epoxy was then poured in to make the bulkhead attachment as strong as possible (don’t want the nosecone flying off on its own!).
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January 23-24, 2009
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Epoxy fillets were generously applied to all ring/tube joints.
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After reviewing the instructions and test fitting the placement of the coupler (between the tailcone and the booster airframe) it was necessary to cut 1/4” x 9/8” slots in the coupler to allow the forward fins to clear the coupler. I also decided to shorten the motor extension by 2” to provide more room in the booster airframe for the drouge chute and kevlar cords. The photo shows the coupler extending past the fin slots. It was this piece that was cut out to allow the coupler to extend the full 7 1/2” into the airframe.
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January 17-19, 2009
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A 1/4” hole was drilled through the airframe and the space between the airframe and the eBay was filled with approximately 3.5 ozs. of expanding foam. After the foam cured the hole was drilled into the eBay and a section of brass tubing was epoxied in to provide the static port for the altimeters.
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After reviewing the maximum thrust of the Loki M1882 and discussing motor selections via emails with Kent Burnett of Giant Leap (the designer of the Talon-6) it was determined that the M1882 would provide a bit too much punch for the Talon. With this in mind I decided to use the Aerotech M1315 reload instead. Since it is well known that Aerotech hardware will work with the Slimline retainer I decided to stay with Slimline motor retainer as supplied with the Talon-6 kit. The retainer was attached to the motor tube with J-B Weld.
I wanted the aft section of the motor tube to have a little more support so I added a centering ring about 6 inches from the motor retainer. The edges of the ring were sanded to a taper that would fit the curve of the tailcone.
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A critical part of the Talon is the forward motor tube ring assembly that supports the motor tube at its center point and also provides the anchor points for the tubular kevlar cords that hold the aft section to the mid section. It is this part that will take the force during separation at apogee. Since the original set of rings (cut to the ID of the tailcone) would not pass through the neck of the tailcone (the fiber-glassing on the inside where the tailcone and the coupler are attached) a new set of rings were supplied by the vendor. The shims were mounted to the inside of the tailcone where the new rings will be ultimately be epoxied when the motor tube assembly is attached inside the tailcone.
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Here is a view of the shims with one of the two centering rings placed to support the shims while the epoxy cures.
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The two new rings were glued together and then sanded to fit the shims. Once the fit was verified U-hooks were added to the rings and they were glued to the proper location on the motor tube. Epoxy fillets were applied to all mounting points where the rings meet the motor tube.
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January 11, 2009
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Completed eBay and collar assembly is expoxied into the upper airframe. Epoxy will be poured into the seam between the tube wall and the exterior rings to form fillets.
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The coupler harness and bulkhead is completed.
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January 3, 2009
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Initial construction has started. The Electronics Bay (e-bay) and collar assemblies are shown to the right. Although the assembly of the e-bay and collar assemblies are essentially per the instructions, I need enough room in the e-bay to hold two altimeters and batteries. The original separation of the threaded rods (as per the provided Giant Leap Rocketry 3.9" Av Bay) needed to be increased to 2.5”.
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The original holes in the e-bay bulkheads were filled with cotton soaked in epoxy and new holes drilled to accommodate the 2.5” spacing of the threaded rods. The supplied external endcaps were scraped and new ones made.
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Here is the completed e-bay assembly.
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Lesson Learned: Using the Talon-6 e-bay assembly on my “Helios” uncovered a bit of a problem. Since the kevlar harness could not be removed from the collar it was VERY difficult to maneuver the endcaps into place from within the airframe. The modification here was to add 1/4” Quik Links that will allow the attachment of the harness after the e-bay endcaps are in place.
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