Thornycroft J Class Anti-Aircraft Lorry

History

Thornycroft manufactured 183 of this J class variant between 1915 and 1916. Each carried a 13 pound anti-aircraft gun. This one (below) had an interesting history, which you can read at The Great War forum here.



Briefly, it was acquired by Thornycroft in the 1920s for their own factory museum but during WW2 it was placed on the road embankment between the factory Chassis Store and Deep Lane to ward off German fighter planes! There it languished, rotting away until given away for free to an enthusiast in the 1960s. You can see the state it was in at this time on The Great War forum here.

This movie shows the gun in action. It actually shows two different gun emplacements. Look for the one mounted on the lorry, which is the Thornycroft. Note the number of Tommys operating it and their deployment of the lorry stabilisers.



A super detailed 1:32 kit is available from Tommys War.

Our 1:148 N Gauge Model 

Regular Blog followers will know that we previously made a J class general purpose War Department lorry out of FIMO clay. 

Now we have a 3D printer the J Class Anti-Aircraft Lorry was designed in 3D CAD and 3D printed in plastic as a kit of parts. This facilitates a much greater level of accuracy and detail than using clay. The model is our most detailed  to date, much of which is not seen in the photo. Did you notice that I fitted the gun barrel upside down? It has since been corrected. I'm not showing a larger photo because there are blemishes in the parts, due to the technology of this process, that are barely noticeable at normal viewing distances in this scale.

The trouble with 3D printing is that the plastic is extruded like string and laid down in rows, which are visible. It can also get a bit blobby for very small parts. In fact the wheels did print as blobs. The machine could not cope with the 8 x half millimetre round vents in the wheels! Much filing and drilling was required to get some resemblance of the cast wheels with solid tyres.

Below is the lorry alongside the chassis store in 1939.

david