A Republic P-47G Thunderbolt is tested with a large blower on the hangar apron at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory in Cleveland, Ohio. The blower could produce air velocities up to 250 miles per hour. This was strong enough to simulate take-off power and eliminated the need to risk flights with untried engines.
The Republic P-47G was loaned to the laboratory to test NACA modifications to the Wright R-2800 engine’s cooling system at higher altitudes. The ground-based tests, seen here, were used to map the engine’s normal operating parameters. The P-47G then underwent an extensive flight test program to study temperature distribution among the engine’s 18 cylinders and develop methods to improve that distribution.