The key to building the model was the Napier Lion XIA engine. It was the most complex part of the vehicle and everything would have to be scratch-built. Since 3D printed parts were going to be essential, the starting point was the generation of a set of 1:8 scale CAD drawings.

A copy of a Napier Lion instruction book issued by Napier provided some good drawings, although not in the XIA configuration. A descriptive handbook issued by the UK Air Ministry provided other details. In addition there were some good photographs on the Internet.

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​Although not necessary for a static model, the crankshaft and connected cylinders are designed to rotate. Below are pictures and a video of the working bottom end. More details can be found in the Napier Railton Build Story.

There are two engines under construction, one of which is now finished. Pictures of that finished engine are also below.