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Early days both bikes just after Gerry had
acquired them
This arrangement was very successful and no annoyance was
experienced by the rider of the cycle. The steam
whistle—a very effective device—was fitted on the top of
the case.
The steam temperature was
originally controlled by thermostat, but eventually a
small loop of tube was fitted at back of case in a small
box with a Mica window for observation by the rider, which
proved very successful. Steam pressure varied from
200 to 1,000 p.s.i. and a foot pedal was arranged to
operate the safety valve, which otherwise blew off at
1,400 p.s.i.
The burner was a modified Simpson vaporising type,
specially made by the late W.H. Simpson, the oil burner
specialist of Hastings. It was pre-heated by methylated
spirits or acetylene for about three minutes before
switching over to paraffin.
The engine was a special type of single-acting poppet
valve design, using simple expansion. Bore was 45 mm.,
stroke 80 mm. It was built to use hot steam at as much as
1400 p.s.i. and was run at 10,000 r.p.m. on test-although
I do not believe in such high speeds. The poppet steam
admission and exhaust valves were operated by phosphor
bronze tappet guides and cam followers. Variable cut-off,
0.80 deg., was obtained by a sliding camshaft, driven by
two easily accessible bronze gears wheels. The two
cylinders were cast in special hard quality close-grained
cast iron, and splash lubrication from the aluminium
crankcase proved adequate.
This is
the engine from Field #1 but it is almost identical to the
second engine
This engine gave great power for it’s size, much more than
the best petrol motor-cycle engine, and it ran without
viabration. On test it twisted a steel transmission
shalft of about ¾ in. dia. Through a full quarter turn.
Transmission was by chain to counterhaft and thence to the
rear wheel. To the countershaft was fitted a
foot-operated “dog” or “claw” clutch to give a free engine
for warming up and to make wheeling about in garages
relatively easy. This shaft drove the ¾ in. stroke fuel
and water pumps, which were vertical and driven by
eccentrics, all fitted in an aluminium case and splash
lubricated. Pump delivery was controllable and the fuel
was led to the small brass pressure chamber seen at the
rear just above the countershaft
The exhaust steam was led through the 2 in. diameter brass
tube to therear of the machine. This tube was sealed at
the end and contained a number of small diameter copper
tubes in which the feed water flowed before reaching the
condenser, thus forming an effective feed water heater and
assisting the condenser. From the end of this brass tube
a smaller tube conveys the exhaust steam back to the first
part of the condenser, fitted underneath the countershaft
and consisting of a number of thin flattened brass tubes
on edge. Then it is collected into a cross tube which, in
turn, has a number us small diameter tubes rising up in
front of the generator case to the main water tank. No air
or circulating pumps were used, the condensate been forced
up by the pressure of the exhaust steam to the tank.
The fuel pump, with variable delivery, kept the small
pressure chamber supplied—15 p.s.i. being used when
standing and up to 45 p.s.i. when running. The fuel
supply could be further controlled by hand adjustment of a
needle valve on burners supply.
The machine could be ridden away from all cold in a few
moments, the burner requiring about three minutes
pre-heating, as noted previously, then the rider mounted
and as soon as the steam gauge a showed sufficient
pressure, the cut off lever--it looks like a
gear-lever--was moved to “start” position, and away you
went. Should the engine be on dead centre one small push
by foot was sufficient.
The rider had to be careful to remember to always sit on
the saddle before moving the cut-off lever to start
position. The acceleration was so rapid that it was easy
to be left behind. All this was in silence and with
complete freedom from “choked” exhaust fumes, blue smoke,
etc.
Fuel and feed water supply was controlled from the
handle-bars and gave no difficulty.
I had some interesting and sometimes exciting trips with
this machine. I used to turn at six in the morning and
run till 8 a.m. round the district on the country road.
So quite was the machine, the engine being silent and only
the humming of the tyres being audible, that sometimes, as
I came up from behind sleepy cyclists they would awake
with a start and nearly fall off their bikes. The steam
siren, which was fitted to supplement the whistle, also
had an interesting effect. When used in the early morning
near road junctions it would sometimes cause windows to be
hastily thrown up to frame startled faces. Such times
were not suitable for tarrying, and I never waited to
witness the after-effects.
After riding an i.c. engined motor-cycle, I had to be very
careful not to enter corners or approach road junctions
too fast. The silence made speed deceptive, and more than
once I had to keep straight on at a cross-road. It was
usually found, on returning from a trip, that the
speedometer, which registered to 80 M.P.H., was thrown out
of gear!
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