Issue link: https://www.e-digitaleditions.com/i/1197609
One end is glued into a 1.875" long foam ejection plug that acts as the nose cone shoulder and ejection piston. The ejection plugs are cut out of sheet foam using a plug "cutting" tool. You will need to make this tool by wrapping heavy, epoxy saturated fiberglass cloth around your 40 mm mandrel, similar to the way you make an FAI body. An article on mak- ing plugs may be found on the NAR web- site's Spacemodeling page. EPS (expanded polystyrene) foam works perfect for making plugs. It is white, somewhat spongy, bead foam that weighs a mere 1/2 gram. Center the carbon rod through the plug, extending about 1/4" and through a small plywood plate. Wrap SPORT ROCKETRY JANUARY/FEBRUARY 2020 23 rubber bands will be wrapped around it and not be placed around the shim. Be- low the hub's aluminum spindle tube add another 1/2" long piece of aluminum tube and tape it to the carbon rod to hold the free-wheeling hub assembly in position. At the bottom end of the carbon rod attach a piece of 75 lb. braided Kevlar line about 43" long as the shock cord. Photos 7 and 8 show the completed rotor core. Tuning the Rotor Unit Once you have assembled the rotor unit and it is on the central shaft assembly with the rubber bands hooked up, you will need to tune the balance, pitch, and dihe- dral. Dihedral, or the angle that the de- ployed blades are at in relation to the cen- tral shaft, is the least critical of the three. No Yolking! Our Eggstravagnza Egglofting Kits are back! www.asp-rocketry.com Aerospace Speciality Products Scale, Educational And Competition Model Rocket Kits, Components and Supplies Photo 7. Completed rotor core. Photo 8. Underside of completed rotor core with blades deployed. this protruding end of the rod with thread and glue to secure the plate on the end of the rod. Glue the nose cone on the top of the plug with foam safe glue. Below the foam plug, friction fit another small ply- wood plate onto the rod, and push it up against the underneath side of the plug. Slide a 1/8" long piece of 3/32" OD alu- minum tube over the carbon rod and up against the plywood plate, then slide the rotor unit on. The 1/8" tube will shim the deployed blades of the rotor unit away from the foam plug when deployed, and act as a bushing for the free-wheeling hub to ride against. Note that the upper portion of the aluminum spindle tube of the hub needs to be long enough so that all three