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This is a popular engine by Allied Signal called a JFS 100. It is the starter engine for a larger aircraft engine. It is a twin shaft or free turbine engine meaning that the power turbine is not directly connected to the engine turbine. It would be similar to a torque converter in an automobile, as the powerful gases produced by the engine drives the power turbine and through a gear reduction, on this particular engine, will produce about 90 horse- power. It has a centrifugal compressor and an axial flow turbine. It also has it's own starter/fuel control system, and will start at the simple flip of a switch. |
| I chose this engine because it is completely self contained, easy to operate and is simple to convert to a thrust jet engine. By comparing the picture on the right with the one above, you can see that all you have to do is remove all the power turbine and it's gear reduction sytem and add an appropriate exhaust nozzle. With the exhasut nozzle, you can expect around 85 pounds of thrust. The completed engine will weigh about 50 pounds. |
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The starter and fuel system requires 24 volts to operate, so I have two lawn mower batteries to the right of the engine. The exhaust nozzle with an inner cone is easily visible plus the ignitor at the upper right can be seen. Having the fuel tank above a hot engine doesn't seem the best location, but it was there or in my lap. I chose there. |
| View of the completed Kart. I have not decided on a throttle yet. There are two ways it can be done. You can modify the governor as I did on my GTP30, or just bleed off some of the fuel going to the fuel injectors (five of them). The engine was never designed for long runs so has a limited amount of oil reserve. Coolers can be added to extend running time. At present, with no throttle, I have a switch located on the steering wheel. When I am ready to go, I flip the switch and away you go. To stop, just flip the switch off and hit the brakes. |
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Here is a view of the left side of the engine.
Some of the solenoid fuel valves are visible in the center of the engine. The starter and governor are mounted below the main housing. |
| Here is a video capture of my first test run. The view is of the engine as it fires off. When it gains full rpm's, flames are not visible. Acceleration is slow but continuous. Jet power is not like a wheel powered vehicle. There are no "lower" gears for getting started so it's like taking off in 12th gear. But, a jet keeps pushing you at the same rate as your speed picks up. I certainly had a limited area to test the Kart, but once I find a safe and legal place to run it, I will add more operation data. |
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