Infinite Control: Bear-Loc® in Boeing’s Wind Tunnel

A 35-foot Bear-Loc raises then locks into position a helicopter undergoing critical performance tests in the Boeing Vertical/Short Takeoff and Landing Wind Tunnel (BVWT), located window tunnelnear Philadelphia. In that facility, aerodynamic vehicles—from aircraft to NASCAR racers–undergo force, pressure, flight control, vibratory, and dynamic tests. These tests are meaningless if the lock cannot stay put.

helicopter blade testsWhy a Bear-Loc?

Boeing Wind Tunnel lead engineer Erik Hoet explains: “When the wind tunnel was built, check valves were used for the hydraulic locking at first. But like trying to close off a water hose by squeezing it, water eventually leaks out and things start moving. We needed the Bear-Loc’s positive locking ability—it locks when the hydraulic pressure is off—and we needed its capacity to lock in any position.”

Boeing also loved the value: from its first installation in 1968, this Bear-Loc did not require an overhaul until 2015. The refurbished Bear Loc boasts 120,000 pounds of locking power and resides below the test floor.