Source: Courtesy of NASA. http://www.nasa.gov/centers/glenn/about/fs01grc.html
The selection of an appropriate engine is critical to the performance of an aircraft or any other vehicle. However, aircraft have tighter constraints. Thus, an appropriate engine that best suits the given mission requirements must be selected. Constraints on engine selection often include size, weight, power, and specific fuel consumption. For general aviation (GA) aircraft flying at low altitudes and at low Mach numbers, reciprocating engines have proved to be the best propulsion options. Of course, electric engines are also making significant progress in small aircraft and Uninhabited Aerial Vehicle (UAV) applications. For airplanes flying at speeds up to about 500 knots and a service ceiling of about 40, 000 feet, turboprops serve the best. Beyond these limits, turbojets and turbofans are the most appropriate power plants.
The piston engine is an integral part of the general aviation aircraft design. The importance of the piston engine in aviation can been seen by looking at all of the small civilian aircraft that are completely reliant on piston engines as their means of propulsion. The majority of small UAVs and radio-controlled aircraft are also piston engine powered.
In this chapter; we briefly ...