Darwin Charles Brown

“ The nucleus of the fatigue fracture was centered in a pit in the bore or bearing surface of the master rod, the fracture progressing under the action of fluctuating stresses until all but a small portion of the rod section had been penetrated. ”

“ It was evident that the damage to the engine was the result of the fatigue failure of the master rod. The failure apparently stopped the crankshaft so abruptly that the inertia of the propeller twisted off the nose section. The fuel characteristics were within proper limits and the condition of the sump and oil tank samples was not abnormal.
Disassembly and examination of the propeller by the Bureau of Standards revealed that the propeller was in normal operating condition up to the time of the powerplant failure, all damage to it being incurred by impact with the ground. ”