Machining new shafts required equipment not available in the AeroAstro shop, so Billings had them produced in MIT’s Central Machine Shop. As the orientation of the gears is critical, when the new shafts arrived, the transmission had to be temporarily reassembled and mounted in the tunnel. Robertson and Billings designed and built a jig that marked where securing keyways should be machined. Once again, working in the dark, cramped confines of the tunnel, the team disassembled the transmission, sent it back for final machining, and then put it all back together and refitted the blades. Finally, the blades had to be synced so all six would be in the same position as the pitch is varied. Robertson made a tool that greatly simplified and expedited what would have been a laborious task.
Technical instructor Todd Billings presses the three planet gear shafts into their housing. Specifications for the new shafts were taken from the original 1930s blueprints. (William Litant/MIT photograph)
While this was going on, Robertson sent the 250-volt pitch control motor out for rebuilding. “I told the rebuilder that we have all the original part numbers for the motor, but he told me the maker changed the numbers — in 1952,” Robertson laughed.
Annual magazine review of MIT Aeronautics and Astronautics Department research and educational initiatives.