A STEAM MOTOR BICYCLE.

A NEW AND PRACTICAL DESIGN BY STEAM CAR MANUFACTURERS.

WE have referred previously to the possibilities of the steam motor bicycle, and in 1909 published a description and photographs of a steam sidecar machine, which was actually in use for some little time.

It is now our pleasure to make the announcement that Messrs. Pearson and Cox, Ltd., Shortlands, Kent, who are manufacturers of light steam cars, have been giving considerable attention to the question of propelling a motor bicycle by a steam engine. They have been experimenting for about two years, and have evolved the machine which is the subject of this article.

The illustration of the complete motor bicycle shows it to be fairly neat and by no means displeasing to the eye.

The engine is set in the old Ormonde position behind the saddle tube, and the diamond frame is taken up by the water tank, while fitted transversely across the forward ends above the footboards is the generator or boiler. The engine has a single acting cylinder, and develops 3 h.p., with a bore of 1¾ in. and stroke of 2in.

A single acting engine is the most simple type, and dispenses with the need for glands and packing. There are very few parts, which are as follows: Cylinder, piston, flywheels, connecting rod, crankshaft, two mushroom valves, and a simple type of plunger pump, worked by an eccentric off the crank shaft. The valves are operated by means of cams and rockers, the cams being keyed one to each side of the crankshaft. The valves have a lift of 3-32in. and rarely need attention. The feed water pump is of the vertical plunger type, having double suction and delivery valves. The generator burner is of the horizontal Bunsen type, practically noiseless, and burning paraffin; it is fitted with a hand operated valve for reducing the flame when the machine is at rest.

Starting from Cold.

In the present model the starting is somewhat crude and takes about ten minutes, but in the new type a small spirit lamp will allow the main burner to be within five minutes. The generator consists of horizontal layers of specially drawn weldless steel tube, the various layers forming four sections, which are coupled together by means of unions placed outside the rectangular casing. A section, therefore, can be replaced with ease if one be damaged. It is impossible for the generator to explode, owing to the small quantity of water and steam at any time in the generator and to the extremely strong form of construction afforded by the small bore tubing, which will withstand a pressure of 7,000 lbs. to the square inch, although the actual working pressure varies between 100 lbs. and 500 lbs. to the square inch.

Transmission.

The drive from engine to the back wheel is by a single chain, and the gear ratio is 3½ to 1. The inner flange of the large chain wheel acts as a bearing surface for the internal expanding rear brake.

On the occasion of our visit to Messrs. Pearson and Cox's works we were interested to see the machine started up from cold. In the first place, a small quantity of methylated spirit was poured into a trough running round the burner soaking several wicks and then lighted. After about ten minutes sufficient heat was obtained to allow the paraffin carried in the tank behind the saddle to be turned on, while pressure was obtained by means of a hand pump fitted to the offside of the machine, until the gauge in the pressure tank on the near side showed a pressure of 30 lbs. to the square inch. The paraffin vapour valve was then opened and the burner lighted.

As the engine is of the single-acting type, and depends upon its own pump for delivering water into the generator, it is not self-starting, and, in consequence, the machine must be walked for a yard or two before it will start. On the stand it is only necessary to pull up the back wheel slowly once or twice.

Control and Running. At this stage we must say a few words concerning the control, which is of the simplest possible nature. Adjacent to the offside handle-bar grip is a lever controlling the quantity of water supplied to the generator, and close to the near side handle-bar grip is a Bowden lever, which, when raised, closes the steam release, to which we shall refer later.

To start the engine the feed water control is opened to its full or nearly fullest extent, and after the back wheel has been turned round the engine will start slowly at first and then rapidly accelerate. The water control lever is then adjusted till the machine assumes a speed of twenty-five or thirty miles an hour, and then left in this position. This position of the water lever provides ample reserve for hill-climbing, or for a short burst of speed. To stop the machine it is only necessary to let down the steam release valve lever on the near side, which instantly allows any steam there may be in the generator to pass into the water tank.

We were allowed to take the machine to the nearest hill, and found it very easy to control and start, and capable of extreme flexibility, so much so that it could be turned round in the ordinary suburban road without the rider dismounting and with the engine "firing" at every stroke.

On the hill, which was approached at a particularly slow speed owing to the appalling nature of the surface, as soon as the water control lever was opened the engine took hold and brought us to the top at a very smart pace, easily beating as regards acceleration a well-known machine with 3½ h.p. petrol engine which was following.

Naturally, this brief trial was totally insufficient to give any idea of the capabilities of the machine during an extended run, but we hope to have an opportunity for a longer trial at no very distant date. The machine we tried is absolutely the first of its type, and a few further points concerning it may be of interest.

Exhaust.

The moment the water reaches the generator it is flashed into steam, and passes through the steam pipe (the lagged tube shown in the illustration of the complete machine) to the cylinder. After having done its work the steam enters the exhaust pipe and passes through two tubes on either side of the generator casing, on the lower portion of which holes are bored. The exhaust steam is, therefore, able to get rid of the by-products of the burner by creating a down draught, and it issues from the pipes in an invisible form, owing to its high temperature.

Although only of the single-acting type, the engine has a considerable advantage over the four-cycle petrol motor, as the piston receives an impulse every down stroke. As the hand control is entirely on the quantity of steam the boiler is allowed to generate, it will be seen that, by turning on the full supply of water, the steam pressure is immediately raised, and the engine will develop its full power on a steep hill, even travelling very slowly; in consequence no change speed gear is necessary.

Owing to the fact, however, that the engine is not self-starting, a plate clutch in the hub would, perhaps, be desirable, or self-starting could be obtained by the use of a hand pump to inject water into the generator tubes.

The advantages claimed by its makers are silence, smoothness of running, great flexibility, and wonderful hill-climbing power.

Modifications on the New Model.

The present type carries sufficient petrol and water for about forty miles, but the new model will have a stroke of 2 ½in in place of 2in, a new type of generator (the burner of which an be started in about five minutes) and larger water and paraffin tanks.

The line elevation on previous page shows how the latest model will look when finished, and we certainly think readers will agree that the design is very neat and symmetrical. On the new model the water and fuel capacity will be sufficient for seventy miles, and the fuel will cost about 4d. a gallon. Whereas the experimental machine weighs 145 lbs., the new one will weigh 150 lbs. Engine lubrication is by crank case splash, a hand pump being situated on the forward part of the tank, from which a charge of air-cooled or special steam oil must be injected every nine miles. The maximum speed on the road is between forty and forty-five miles an hours - surely sufficient for reasonably-minded tourists.

The Motor Cycle December 26th, 1912.

Pearson & Cox Steam Motorcycle

Some experiments were tried in this country to apply steam power to motorcycles, but none of these ever proceeded far beyond the experimental stage. In England, however, there is a steam-propelled motorcycle that is not radical in appearance and which must be a commercial success because it is said that it has been on the market for three years.

The drawing at Fig. 14 shows the general appearance of this machine which is known as the "Pearson and Cox," presumably because it is made by this firm in Shortlands. Despite the unconventional means of propulsion, this motorcycle is not so much different than those we are accustomed to that it would attract attention except of those well versed in motorcycle construction.

The power is supplied by a single cylinder, single-acting steam engine with a bore of 1¾ inches and a stroke of 2½ inches. This is mounted in the frame back of the seat-post tube and immediately in front of the rear wheel. The power plant is supported by the rear forks. The engine is given a nominal rating of 3 horse-power, but it is said that the boiler has capacity enough to furnish steam pressure sufficiently high so the engine will generate 6.50 horse-power. The power is delivered to the rear wheel through the medium of a single roller chain which connects sprockets mounted on the engine crankshaft and on the rear wheel hub. Owing to the fact that the steam power is always in reserve and that the steam engine may be put in motion by simply opening a throttle valve, it will be evident that no clutch or variable speed gear is necessary. When climbing hills, one merely admits more steam to the engine cylinder and its power is increased proportionately as the steam pressure is augmented.

The water is converted into steam in a flash boiler which is a coil composed of about 65 feet of pipe heated by the burner flame. The boiler is called a "flash generator" because as soon as water is pumped into the coil by the plunger pump driven from the engine for that purpose, it is converted instantaneously into steam having the high pressure of 1,000 pounds per square inch, and a temperature of 800 deg. Fahr. As the pump that supplies the water to the flash coil is driven directly from the engine, the amount of water supplied and consequently the steam generated is proportional to the demands of the engine. At very low speeds, when the steam consumption is small, a by-pass valve opens so some of the steam passes back into the water tank and is condensed into water. This valve is controlled from one of the grips on the handle-bar. The boiler, or rather, steam generator is located directly under the front diagonal frame tube and is protected from dirt by a liberal sized mud-guard on the front wheel. The whole of the diamond of the usual type camel-back frame is filled by the water and fuel container. In order to prevent waste of water which would make frequent refilling of the tank necessary, the exhaust steam is condensed by a suitable device and is pumped back into the water tank where it is used over again.

The heat to flash the water into steam is produced by a burner that utilizes crude oil, the cheapest form of oil fuel. Even though about twice as much of the cheap fuel is needed, as the amount of gasoline consumed by a gas motor of similar capacity, it is claimed that the fuel cost per mile is less than on the internal combustion engine propelled forms. The operation of starting the generator is not unlike that of starting the familiar gasoline torch. A certain amount of the oil is allowed to drip into a suitable shallow pan, and this puddle is ignited and heats the oil contained in the vaporizing coil that forms part of the burner to a high enough point to generate gas, at which time the main fire may be lighted.

After the burner fire has been started, a small amount of water is injected into the hot flash coil by an auxiliary hand water pump, and the requisite steam pressure is obtained for starting the engine. Of course, after the vehicle is once set in motion the generation of steam is automatic. The speed and power of the engine may be controlled by a simple throttle valve in the steam line between the generator J and engine cylinder which may be operated very easily from one of the grips. While this machine has had some sale in England, it is doubtful if the ease of control and smooth operation permitted by steam power offers enough advantages over the gasoline motor to make steam power a factor in motorcycle design. There is an added disadvantage in connection with steam power that the average rider will not take kindly to, and that is the possibility of a disastrous fire occurring, should the fuel tank spring a leak and allow the liquid fuel or fumes due to its evaporation to come in contact with the naked flame at the generator.

Motorcycles Sidecars and Cyclecars, 1914, by Victor Page. Page 44