The Chapelle Two-Speed Motor-Bicycle.

The Two-Speed Gear Machine.

The Direct Geared No. 2 Machine.

The frame has been very carefully studied and designed, being made up with the best weldless steel tubing, specially strengthened throughout to support the weight of the motor and its accessories, as well as the virtual "dead" weight of the rider. It is also very strongly stayed with an extra horizontal tube running from crown to diagonal tube.

The front forks have been made so that steel tubular stays can be attached in front, thus avoiding any likelihood of breakage. These forks have not been designed upon ordinary cycle lines, but specially for the motor-bicycle.

DESCRIPTION OF THE MOTOR.

The 1¾ h.p. motor is fitted vertically, in what is considered the best possible manner, being placed in the axis of the frame, where it can in no way trouble the rider's movements, whilst the exhaust and the heat is altogether out of the rider's way.

The motor is of the usual 4-cycle type, and runs at a speed of 1,400 to 2,000 revolutions per minute. The cooling is obtained by radiating gills forming part of the cylinder, which is made in cast iron instead of steel. The latter metal is much lighter, it is true, but it lends more easily to gripping or tearing up the metal, which promptly puts the engine out of service. Cast iron, by the action of the heat, and the contact of petrol, forms in the interior a surface which gives remarkable results as a bearing, owing to its polished and unctuous contact with the piston and its rings. All is very solid, and the working parts are entirely closed in an aluminium case—consequently there is very little wear.

CENTRE OF GRAVITY.

The centre of gravity is placed as low as possible. It is a well-known fact that when the centre of gravity can be placed below any point in contact with the ground, such a system is of perfect stability; but such is impossible in practice, as far as the motor-bicycle or such vehicles are concerned. Corners may be taken at a fair speed, and there is little fear of side slips, even less than with an ordinary safety bicycle, as the rider's weight is to a certain extent balanced by the motor.

SPEED CHANGING GEAR.

The speed changing device has been patented in all countries where a bicycle can be ridden.

With the speed changing gear the rider can obtain three distinct advantages, as follows :—

1.- The motor may be thrown entirely out of gear by means of a small lever placed in a suitable position upon the top tube

below the handle bar, and easily accessible, when the machine may be pedalled exactly like an ordinary bicycle, without the rider being obliged to dismount to take off the belt in order not to " drag " the motor resistance ; also without having to use a valve lifter, open a compression cock, or other such devices, to free the motor.

2.- By using a speed changing gear, in conjunction with a petrol motor, it has the important advantage of increasing the power of the engine, as the following well-known mechanical principle teaches. " What is lost in speed is gained in power."

3- When the slow speed gear is thrown in, the hill-climbing capability of the machine is remarkable, and this will be naturally greatly appreciated over "switchback" roads. On the low gear, gradients from 8 to 10 per cent, can be easily climbed without pedalling, on an average of between 8 to 12 miles an hour, whilst up abnormal gradients the machine will at least take itself up.

4- On the high gear a speed of from 30 to 35 miles an hour can be obtained over good level surfaced roads.

5.- Pedalling is almost entirely unnecessary with the machine fitted with a two-speed gear.

6.- Being able to throw the motor entirely out of gear, is an important, not to say a necessary, factor in the traffic of large towns, as the machine can be pedalled by the driving belt with perfect ease, and there is an entire absence of vibration.

DESCRIPTION OF THE CHAPELLE TWO-SPEED CHANGING GEAR.

The speed changing gear is explained in Figs. 1 and 2.

On the motor axle "B" is fixed a pinion which is always in gear with a similar pinion "D." (Fig. 1.)

The pinion " D " runs loose upon another axle, which axle is fixed to the outside of the gear-case.

The two pinions "L" and "B" are fixed between the two gear wheels "G" and "H" and these form part of the driving pulley "A."

The position of the crank bracket can be seen in Fig. 2. The cranks "F.F." are fixed to the axle "A" which assures the propulsion of the machine by the rider. The speed changing gear is manipulated by means of a rod or lever, which passes in the tube of the frame, and this lever works a sleeve "C" so as to throw in gear either the pinion " D " with the gear wheel " G " or the pinion "B" with the gear wheel "H." By this means two speeds are obtained and communicated to the driving pulley "A." The cranks "F.F." are thrown out of gear by the driving pulley, which permits the rider to rest in a stationary position. The right lever on the top tube of the machine serves to throw the motor out of gear by loosening the belt and actuates at the same time a band brake. The left- hand lever throws the speed gear in and out along a notched plate, which plate is adjustable. The forward notch is the high speed, centre neutral, and back, low speed.

Source: Motor Cycling Magazine, Sept 10th 1902.