160 horsepower free shaft turbine engine  

I recently purchased a Boeing 502-6 from Eric Sheldahl on Ebay. (A decent source for turbine engines and parts!) It should make a nice addition to our collection of gas turbines. The engine is in running condition although it needs a few components before it can run.

To learn a little about the 502-6, click here.

The engine was shipped out from Iowa to Vito's house, who held onto it until I could make space in my garage. Now the engine is sitting in my garage, which should be its final resting place, at least for a while.

Here are some pictures of the engine.

The first thing we will try to do is get it running. The engine cannot run without a load on the output shaft, so we may have to remove the power turbine and output reduction gearbox from the engine before we can get it running. Then we have to decide what we are going to put it in, and whether we should use it as a shaft engine or convert it over into a turbojet.

Update- In the last few weeks or so, I have been working on getting the Boeing 502-6 running. I spent some time with the manual and the engine to understand the schematics for the oil, fuel, and electrical system. The thing that struck me the most is that the engine is so simply laid out, and is very easy to work with.

Once I had a firm understanding of all the operations of the engine, I had the hoses that I will need made up, and I started to make up a wiring harness and a crude instrument panel to run the engine. The wiring is pretty much complete, and I expect to do a test firing of the engine next weekend.

The above pictures show, from left to right, the dual element oil pump, the oil manifold, the igniter box with igniter plug, the electric starter, the fuel pump and governor assembly, the fuel cutoff solenoid, the rear of my switch panel, the n1 tachometer, and the completed instrument panel.

I should have the engine up and running next week, and video will follow shortly thereafter.

1/25/03- Today I started up the Boeing 502 for the first time. To my surprise, it lit off on the first attempt, after coughing up some smoke and emitting an orange flame. I ran it a few times without any problems. The 502 is a great engine for a turbine hobbyist because they are relatively inexpensive and so easy to get running. With a minimum of instrumentation and wiring, it will run. It sounds great too!

I used the following starting procedure.

Switch on the electric fuel boost pump to supply fuel to the engine fuel pump inlet

Arm the igniters by moving the ignition switch to on.

Press and hold the start button to energize the starter relay, which in turn energizes the electric starter, the ignition exciters, and the start fuel bypass valve

When the starter peaks, move the fuel switch to on, energizing the main fuel valve. Continue to hold the starter button.

When engine reaches idle speed, (stops accelerating at around 45% N1) release starter button to de-energize starter, igniter, and starting fuel bypass valve.


I started the engine with no load on the output shaft. I guessed that considering the engine's low idle speed and the wastegate bypass duct in front of the power turbine, that the power turbine would not overspeed. Apparently I was correct.

To see a video of the engine starting up and shutting down, click here.

We intend to put the 502-6 into a small 2 seat roadster that we will build of chromoly steel tubing. We will be using the shaft drive to maximize performance. Stay tuned for updates...


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