Starting as a propane burning engine, the Turbitrac was added with a diesel after burner which makes the engine to run also in diesel. By supplying propane direct from the battle without a regulator, the engine still starts on propane. Through the evaporator system, the gas enters the Combustion Chamber (CC). From an open pipe, the gas enters and mixes with the air stream to the evaporator. As shown below, ducted around to the end of the CC is a portion of air being supplied from the compressor.

The inverted cup has a back plate that will be heated by the burning gas once it is ignited and this is where the gas enters and is taken by the air flow through a set of 6 swirl vanes and into the evaporator cup. The cup is sealed to the end cap except for a series of small holes around its outer sides as shown below. A loud pop can be heard when the gas exits the small cap holes and ignited by a spark. A spinning compressor supplies the air that is mixed with gas to make way through the evaporator system.

The back plate of the evaporator cup is heated by the burning gas as it expands the air in the CC by heating it. The turbine spins faster due to the hot expanded air. Because of the common shaft, the turbine picks up speed as well as the compressor wheel. More air and fuel means more heat and more RPM on the common shaft as the compressor wheel gets driven faster and more air is compressed into the CC. the evaporator cup back plate will be glowing after running for just a few minutes since the idle speed on the Turbitrac is about 30,000 RPM.

Just in front of the 6 swirl vanes, fuel is delivered through a stainless steel thin wall pipe which is mixed with the turbulent air exiting. By squashing the end of the pipe in a drill so it ends up with 3 flat segments as shown below, the volume of fuel being delivered is controlled. For the fuel delivery to be in the region of 5 gallons per hour, the jet is further fine tuned.

Until it all hits the hot glowing back plate, the crude spray pattern allows partial mixing of the fuel with the air. The fuel is evaporated and exits the air through the small holes in the cup at this point.

An increase in the speed of the turbine can be noticed as the evaporated fuel is ignited by the burning gas. The engine RPM can be kept stable until the gas is turned off by careful control, reducing the gas, and increasing the fuel. As the speed of the engine changes, the temp of the gas exiting the turbine changes. As shown below, the slower speed hotter gas exiting the turbine ignites the AB fuel with a real big bang but may have to be repeated a couple of times until the AB is hot enough to sustain the flame.

The engine fuel tank has a submersible high pressure pump and the AB tank has two external high pressure pumps. Some images of the finished Turbitrac are shown below.