Tuesday, 6 May 2014

Yankee Tank progress

HR54 Yankee Tank. Inner side tanks in place.

Progress on my HR Yankee Tank has been less than spectacular, as I mentioned in an earlier post, I'm treating the kit simply as a starting point in my quest for a scale model of a Yankee Tank, so to this end I've re-made some of the parts rather than use those in the kit, which is a time consuming method of progress. My mate Bob Goodyear, in nearby Dumfriesshire, has a lathe; he turned me a set of frame spacers which are designed to temporarily hold the frames in position while nickel silver spacers are soldered permanently in place, these are 25.5mm wide and will result in an overall width of 26.9mm for the frames providing negligible side-play on the driving wheels. The rear axle will be rigid and carry an ABC Mini Gooch gearbox fitted with an M1824 motor mounted upright that should just allow space for a small flywheel. The front driving axle will be sprung and the bogie pivot point will be solid to provide three-point suspension.

Several apparent similarities between the Yankee Tank and the Adams Radial Tank were pointed out to me by Sandy Harper which prompted me to compare drawings of these engines. I found a drawing of the Adams engine in J N Maskelyne's "Locomotives I have Known" and realised while perusing this that the inside valve gear was not only Stephenson's in both cases but also that the works from the Adams engine should fit the Yankee Tank. I promptly ordered a set of Adams valve gear from Martin Finney,who sells this item as a separate kit. The space between the frames beneath the Yankee Tank's boiler is very visible and I think Martin's finely engineered kit of parts should fill it nicely.

The boiler itself is 4' 3" diameter according to my drawing and this is the diameter I made it despite reading in Cormack and Stevenson that the maximum diameter of the boiler was a quarter inch under four foot. I presume this latter misleading measurement to be without the cladding.

I've added window surrounds inside the cab front and rear plates (a necessity rather than a luxury) using Geoff Holt's method, which I derived from his recently published book on locomotive modelling.

My next next task is to get the engine up and running and first of all I need to address the coupling and connecting rods, which need to be re-made...