PHAK Chapter 7-3 Reciprocating Engine

Chapter 7 Aircraft Systems

Reciprocating Engines (Continued)

Even when the engine is operated at a fairly low speed, the four-stroke cycle takes place several hundred times each minute. 

 

In a four-cylinder engine, each cylinder operates on a different stroke. 

 

Continuous rotation of a crankshaft is maintained by the precise timing of the power strokes in each cylinder. 

 

Continuous operation of the engine depends on the simultaneous function of auxiliary systems, including the induction, ignition, fuel, oil, cooling, and exhaust systems. 

 

The latest advance in aircraft reciprocating engines was pioneered in the mid-1960s by Frank Thielert, who looked to the automotive industry for answers on how to integrate diesel technology into an aircraft engine. 

 

The advantage of a diesel-fueled reciprocating engine lies in the physical similarity of diesel and kerosene. 

 

Aircraft equipped with a diesel piston engine runs on standard aviation fuel kerosene, which provides more independence, higher reliability, lower consumption, and operational cost saving. 

 

In 1999, Thielert formed Thielert Aircraft Engines (TAE) to design, develop, certify, and manufacture a brand-new Jet-A-burning diesel cycle engine (also known as jet-fueled piston engine) for the GA industry. 

 

By March 2001, the first prototype engine became the first certified diesel engine since World War II. 

 

TAE continues to design and develop diesel cycle engines and other engine manufacturers, such as Société de Motorisations Aéronautiques (SMA), now offer jet-fueled piston engines as well. 

 

TAE engines can be found on the Diamond DA40 single and the DA42 Twin Star; the first diesel engine to be part of the type certificate of a new original equipment manufacturer (OEM) aircraft. 

 

These engines have also gained a toehold in the retrofit market with a supplemental type certificate (STC) to reengine the Cessna 172 models and the Piper PA-28 family. 

 

The jet-fueled piston engine’s technology has continued to progress and a full authority digital engine control (FADEC, discussed more fully later in the chapter) is standard on such equipped aircraft, which minimizes complication of engine control. 

 

By 2007, various jet-fueled piston aircraft had logged well over 600,000 hours of service.