Robertson and Gas Turbine Lab manager James Letendre tried cleaning and greasing the mechanism in-situ. Working in the depths of the tunnel during the height of summer was “like working in a pizza oven wearing a toaster-oven hat,” Robertson said. With the sun beating down on the outside of the big steel tube, inside temps can easily exceed 110F. Still, the tunnel refused to operate properly. Consulting with WBWT director Professor Mark Drela, Robertson and Letendre realized there was no other option — the blades would have to come out and the pitch transmission disassembled. Over a period of several days during December 2016, the blades were hoisted through a hatch in the tunnel top and carried into the WBWT control room, where they were cleaned and greased. Under the guidance of technical instructor Todd Billings, who manages AeroAstro’s Gelb Laboratory machine shop, and with the aid of the original blueprints, the gear mechanism was removed, disassembled and inspected. The good news was that after nearly eight decades, the gears themselves were in perfect condition. The problem was the shafts on which the planet gears were mounted. The inner races of bearing sets that were pressed to the shafts had worked loose, wearing down the shafts and allowing the gear sets and shafts to shift laterally.
One down, five to go: space manager Anthony Zolnik steadies a blade from above while (from left) Professor Mark Drela, Jim Letendre, and Dave Robertson prepare to carry it off. (William Litant/MIT photograph)
Pitch fix: Tackling eight decades of Wright Brothers Wind Tunnel hard use
Annual magazine review of MIT Aeronautics and Astronautics Department research and educational initiatives.