Thursday 13 March 2014

A steam lorry made in Greenwich

In the early 20th century the great Penn works on Blackheath Hill was taken over by Thames Ironworks - the shipbuilders based on Bow Creek, who built the Warrior and many other important ships.  They used the Penn site to build steam motor vehicles. The following piece describes one of these.
Please note - this piece has been scanned from a photocopy handed to us, the source of which is not known and which has no identifying features.  If it is your copyright - or you know whose copyright it is - please let us know.  If it is, it can be removed from this site at once or a credit given.   Even better would be more information and maybe the picture which clearly once accompanied this.
"This is a five ton design of wagon designe'To comply fully with the requirements of the Heavy Motor Car Order.' Unlike many designers of the period the Thames wagon had the undertype compound engine with cylinders 3.7/8" & 6 ½ " x 6" set across the frame and with the two crankshaft pinions engageable with the spur ring on a counter- shaft. This countershaft was extended outside the oil-tight casing to the bevel driven differential gear on the back axle, the bevels giving a reduction of 1 :4·6. At 450 r. p m the engine developed 30 b. h. p. Both cylinders had normal slide valves and the crankshaft was 2 1/4" diameter.

"Steam was generated in a locomotive type boiler containing 32 tubes 1 3/4" dia. the heating surface totalling 50 sq. ft with a grate area of 3 sq. ft.   The exhaust steam was passed through the ash pan to deposit any moisture in suspension and then through a heating coil in the smoke box. This was to render the exhaust practically invisible".

"Standard channels 6" x 2 ½”  were used for the chassis framing and cross braced. Rear main springs were 'four feet long with secondary springs above them two feet long permitting a large movement but well damped. The fore-carriage mounting the front axle was in effect a rectangular frame pivoted at its centre thus providing three- point suspension. Steel wheels 3' 2" dia x 9 1/2" tread were used for the rear and 2' 911 dia. x 5 1/2" tread for the front on a wheelbase of 10' 3". "

"Other main features were an external contracting brake on the spur ring on the countershaft, wood block brakes on the rear wheels and a water tank holding 120 gallons mounted beneath the rear end of the framing. The unladen weight of the five-tonner was 4 T 10 cwt and four to five hundredweights of fuel were carried. If desired an extra two or three tons could be taken on a trailer."


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