KJ 66 Gas turbine

After spending many years building locomotives I wanted a change in direction with my model engineering so I decided to have a go at a gas turbine. For many years the concensus of opinion amongst model engineers was that it was not possible to build such a small engine.... Untill Kurt Shreckling wrote his illuminating book describing the building and running of his design for the FD3-64 which not only ran well but powered one of his model aircraft. The KJ 66 was the next generation of minature gas turbine which Kurt designed in conjunction with Jesus Arteus and is illustrated in he photos below.

Compressor end

The final assembly fo the engine just berore its first run

Turbine end

With the tail pipe removed the turbine wheel can be seen clearly.

Jet engine compressor

The above photo shows the engine with the front cover removed, showing how the compressor wheel fits in the diffuser.

Shaft, tunnel and compressor wheel

The rotor unit is shown above. The compressor wheel is a commercially made kkk type and is mounted on its shaft and fitted into the bearing tunnel.

Outer casing

The embryo outer wrapper is on the right. Made from 1mm thick 310 grade stainless steel. The domed end was spun on my Boxford Lathe and has been fitted to a rolled up tube and then TIG welded

Compressor diffuser

The diffuser ring is made from a single piece of aluminium and was manufactured without the aid of CNC , on a small milling machine using a rotary table and dividing head.

Combustion chamber

The assembled combustion chamber

Combustion chamber

The combustion chamber was made in a similar fasion to the outer casing. The tubes on the ring to the left are where the fuel is vaporised before entering the chamber and burning

Tailpipe components

A completed tailpipe is on the right, an embryo one is on the left and to the centre is a steel spinning former.

Part made turbine wheel

The turbine wheel is made from a single piece of Inconel, a typeof hard stainless steel that withstands high stress levels at very high temperature. The disc was turned on a lathe and then had the blades formed by slicing into it with an abrasive cutting disc mounted in the milling machine. The final shaping of the blades was done by hand using needle files.

Jet engine running

The KJ 66 in action. Fitted to its test bed the engine is running here at about 70,000 rpm. An orange glow within the tailpipe can just be seen. The engine has now done many hours of reliable running and was a most sucessful project. Often taken to Taunton Model Engineer events and demonstrated at their exhibitions it never fails to draw a crowd of amazed spectators.

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