Airplane Piston Engine Dynamics as an Aeronca E-113 Case Study

Kinematic equations were developed to describe the dynamic motions of the aircraft piston engine components in terms of time dependent position, velocity, and acceleration relationships. Using the Aeronca E-113 engine as a case study, the brake mean effective pressure (BMEP) rating was used to model the cylinder gas pressure profile. The moments of inertia of the dynamic components including connecting rod, crankshaft, and propeller were measured using a pendulum swing method. Representative values were obtained for inertial and gas pressure forces acting on crankshaft journals, connecting rods, and cylinder walls. The resulting model can help in the design of crankshafts and other dynamically loaded parts to resist failure due to fatigue.