The Pond Racer - An Exercise in the Control of Heat Transfer in a Tight Composite Compartment

The POND RACER is an all-Composite, twin boom airplane Figure 1,(1), (2), (3), fitted with two, dual turbocharged automotive engines. The exhaust system, Figure 2, for this six cylinder power plant occupies the rear portion of a compact engine compartment. Initially, no provision was made for moving cooling air through this densely-packed engine compartment. Portions of the exhaust system passed within less than 2.5 cm (1 in.) of the composite cowl enclosing the engine compartment. The temperatures developed could result in failure of the computer,which controls the engine, other components, and the composite cowl in a matter of minutes. Currently-used insulation designs did not appear to provide enough capability to work for this application. A Thermal Protection System was developed, installed, and proven out during test flights. Analysis of the flight data, measured by thermocouples linked into the flight recorder, verified the adequacy of the Thermal Protection System. These results showed that an insulation design can provide acceptable performance by carefully integrating the thermal requirements into the interface created by the structure and its power-plant.