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Note: This is a sub-section of Motor Shows
Held at Olympia
This was the first Motor Show to be held at Olympia and the second organised by the SMMT in 1905.
The policy adopted by the Society of Motor Manufacturers and Traders (SMMT) in holding their fourth Exhibition in November instead of in the spring appears to have been completely justified. The decision was based on the fact that many more cars are now used in these islands than in France, and that London is the chief market of the world. Perhaps the fact that the great Paris show is held in December and has hitherto been the means of luring many agents from the home-manufactured goods has also influenced the change in dates.
Whatever the cause the effect is obvious, and it would appear that the time is not far distant when the Society will have to consider seriously the necessity for holding two distinct shows — one for the pleasure side and the other for the commercial branch of the automobile industries.
Compared with the last display the increase in the number of exhibitors is equivalent to about 20 per cent., there being over 300, as against 250 last February.
The hope that continental firms would find it necessary to show their next season's models in London prior to Paris has also been justified, for among the foreign-made cars represented are such well-known typos as Mercedes, Panhard et Levassor, De Dietrich, Gladiator, Delaunay Belleville, Martini, De Dion-Bouton, Hotchkiss, Charon Girardot et Voigt, Renault, Mors, and Germain. There is a decided increase in the number of makers of heavy vehicles such as omnibuses, and vehicles for the transport of merchandise.
To the engineer the most striking features of the show may be briefly summed up in the following items:— The growing tendency to replace steam engines by internal combustion motors; the expanding use of vertical in lieu of horizontal engines; and the general adoption of multiple cylinders for low as well as high-powered vehicles.
For pleasure cars steam as a motive agent lost its attractiveness some time ago, but most engineers would scarcely have believed that before long the internal combustion motor using petroleum spirit for fuel would also supplant steam for industrial vehicles — as it is doing.
If the present show can be held to adequately represent the industry users of mechanically-propelled vehicles must be prepared to pay more dearly for their use than was considered likely two or three years ago, for the number of cars on view worth under £250 apiece is comparatively small. It is gratifying to note that the Daimler Company - as a pioneer of the industry which has experienced all the vicissitudes of pioneer work — has succeeded in standardising to such an extent that a decided reduction in its prices has been rendered possible, while in no way reducing the quality of workmanship and materials.
It is noteworthy that British manufacturers are still confining themselves chiefly to the higher powered cars for pleasure purposes, from which it would appear that no reduction in the existing limit of speed is anticipated at the end of the present legal term.
Although for small and cheap voiturettes a single-cylinder vertical engine will continue to be largely adopted, it would seem that twin and even three-cylinder engines are destined to be superseded by motors having four smaller cylinders, which not only give a better turning movement and a more silent exhaust, but also an excellent balance of forces and couples. We have already seen, in the case of the Humber Company that an acceptable car, with four cylinders, can be placed on the market for less than £300.
One of the sensations of the Olympia Exhibition is the eight-cylinder Rolls-Royce car, shown by Messrs. C. S. Rolls and Co. The chief object in the adoption of this engine was to produce a petrol-driven landaulette which should combine, as far as possible, the silence and smoothness of motion of the electric carriage with the qualities of the touring car, while retaining the appearance of the former. In order to remove the engine as far as possible from the carriage proper without increasing the length of the vehicle by the use of the usual bonnet, the engine is placed under the driver's footboard. This necessitated the use of a shallow engine. It will be seen from the illustrations how this has been effected. The engine has eight cylinders, arranged four on each side of the vertical centre line, and inclined to this at an angle of 45 deg. This gives one impulse for every quarter of a revolution of the crank shaft and the different functions of the four-cycle engine so overlap each other that an even torque is produced.
Moreover, the crank shaft is fairly simple to make, the cranks being all in one plane. The bore of the cylinders is 3.25in. and stroke the same. Although the cylinders are inclined, the valves remain vertical, and both the induction and exhaust valves are on the same side of the cylinder.
Forced lubrication by a pump is adopted throughout, and the energy is transmitted to the rear axle by means of a clutch to a gear-box of the sliding spur type and from thence to a live axle and differential gear. Although the ranges of speed are thus provided for, it is claimed, that little changing of gears is necessary owing to the remarkable elasticity of the engine. The high- tension ignition system consists of the usual batteries and trembler coils. The distributor is arranged for a complete system of synchronised ignition for each set of four cylinders. The drive is by means of a sliding shaft and spiral key-way which rotates the stationary part of the distributor. Two coils and tremblers are used in such way as to ensure synchronism, and yet to provide practical independent ignition for each set of four cylinders. We noticed that the engine valves and plugs are made easy of access by the provision of removable panels. The situation of the engine under the foot-board rendered a modification of the usual steering column necessary. A shaft runs backwards at right angles to the latter and is operated by bevel gear wheels.
The Daimler Company's stand contains four vehicles, all fitted with four-cylinder engines, the lowest horsepower being 28. The engine has been little altered since the type was first introduced two years ago. The two later designs, namely, 30-40 horse-power and 35-45 horse-power, involve the same characteristics of design and manufacture as the 28-36 horse-power. All the cylinders are cast in pairs with inlet and exhaust valves on one side, the valves being inclined to shorten time length of inlet and exhaust ports, as well as to decrease the size and weight of the cylinder. The valve gearing is exposed.
The company is fitting this year an extra lay shaft on the opposite side of the engine to the cam shaft for the chief purpose of driving the pump. This lay shaft will, in addition, facilitate the driving of a magneto-ignition system if desired. The high-tension ignition system only, with single trembler coil, is adopted. The carburetter is time same as last year, but the company has so altered the system of coupling the throttle and ignition that the timing of the ignition is correct for all positions of the throttle, or, in other words, for full power at all speeds. Ball bearings are fitted throughout the car.
The Iris motor car, made by Legros and Knowles, Limited, Cumberland Park, Willesden Junction, has many good features, and the designers have paid particular attention to the provision of means whereby access can be gained to the working parts. The live axle is solid from end to end. The wheels revolve on this axle, and are driven by shafts turning within it, which are only subject to torsional stress. Through a removable plate at the rear of the whole of the differential and bevel gears can be removed without dismounting the axle. The transmission to this shaft is through a cardan shaft, having at each end an ingenious form of flexible coupling. It will be observed that this coupling is built of steel plates, rigid for torsional stresses, but flexible in other directions. It has no wearing parts, and consequently needs no lubrication, nor are there any pins to work loose.
The clutch is of the multiple disc type. The engine has four cylinders, with a bore of 5in. and stroke 5.25in., cast in pairs. All inlet valves and exhaust valves are situated on one side of the engine; they are mechanically operated by one cam shaft, and all valves are interchangeable. Extra large bearing surfaces are provided throughout the engine, the crankshaft bearings and connecting-rod bearings being babbitted. The engine develops over 35 horse-power at 750 revolutions per minute, and over 40 horse-power at 1,000 revolutions per minute.
The engine speed can be regulated from 120 revolutions per minute to 1,200 revolutions per minute by the manipulation of the control lever. The engine base chamber is of aluminium, and is provided with two large inspection doors at the sides; the bottom half of the crank case merely forms an oil retaining well, and can be easily removed without disturbing any other part, giving immediate access to all the engine bearings. The can shaft can be dismounted easily without disturbing any other part. The carburetter is designed to give the correct mixture at all loads and speeds of the engine.
The throttle valve is combined with the carburetter, and is operated by a small lever, placed over the steering wheel. The high-tension system of ignition is provided. This system has only one coil and trembler and one low-tension timing brush. Distribution is effected on the high-tension circuit, the distributor being enclosed in a dust-tight and damp-proof glass case. The current is supplied from either of the two accumulators which are fitted in position on the chassis. These accumulators are kept automatically charged by means of a dynamo driven by the engine. The same dynamo and battery also supply current for lighting the lamps of the car.
A new 15 horse-power car, built by the Wolseley Company, Limited, to Mr. Siddeley's designs, is shown. As will be observed, the motive mechanism of this vehicle is a distinct departure from the Wolseley Company's former practice. The engine, is vertical, and has four cylinders, 4in. by 4in. stroke, giving about 18 brake horsepower at 1,000 revolutions per minute. The cylinder jackets are of aluminium, cast in one piece with the crank chamber. The cylinders are composed of cast iron liners and fitted with separate heads. The crank shaft is of Vickers’ crank shaft steel and carried in three phosphor bronze bearings. The induction valves are arranged above the exhaust valves on the same side of the motor, and in independent boxes. They are fitted with a variable lift operated from the control column, the lift being so arranged that it does not interfere with accessibility of the valves. The cam shaft has its cams turned from the solid, and is driven from the crank shaft by a fibre gear wheel. The push rods for the valves are operated by tongue levers fitted with rollers.
The ignition is duplicated and arranged on a new principle. The chief system is the high-tension Simms-Bosch magneto, having a separate distributor, which is arranged as part of the motor mechanism, and the contact breaker is enclosed with the magneto. In this manner it is claimed what has hitherto been a trouble with the high-tension magneto system is avoided, while at the same time the advantages gained are perfect synchronisation and a hotter spark, which ensures complete combustion of the explosive charge.
A reserve system is also fitted and connected up so that by means of a switch it can be utilised with the same contact breaker and distributor in connection with an accumulator and trembler coil. The speed of the engine is controlled by a low-speed centrifugal governor operating a throttle valve in the mixture pipe, and an accelerator pedal is provided for cutting the governor out of action when desired. The clutch is of the cone pattern with leather face. The gears give three speeds forward and one reverse, the normal forward speeds being 9, 20, and 32 miles per hour, with the engine running at 1,000 revolutions. The top speed furnishes a direct drive. All changes of speed are operated by one lever, in a gate giving a separate movement for each speed. The engine is mounted in the frame on three points, and the drive to the gearbox is through a universally jointed shaft. The gearbox is also mounted on three points, and the "live" axle is driven through a universally-jointed propeller shaft. The weight of the chassis is 14 cwt.
Fig. 9 represents the new 14 horse-power Thornycroft petrol car which, with the important exception of the engine and a few other details, is similar in design to the now well-known 20 horse-power car. Special attention has been devoted to making the parts accessible. The engine has four cylinders, the bore and stroke of which are each 3.75in. The valves, which are mechanically operated, are inverted, and open direct into the top of the combustion chamber, each valve being operated by means of a separate rocking lover. These levers are actuated by means of tappet rods worked directly from the cams, the cam shaft being enclosed in a casing bolted to the cylinders at the top. By taking off the end cover of this casing the whole cam shaft, together with its bearings, can be pulled out and inspected.
Lubrication is forced to the whole of the moving parts by means of a gear driven pump in the base of the crank chamber. The water circulating pump and magneto machine, which are fitted on either side of the vertical spindle, are driven from it by means of a bevel wheel, the gearing being enclosed within the crank case, while the couplings for pump and magneto are immediately outside the casing, and can, therefore, be easily disconnected.
The governor is of the spring loaded cross-linked type; it acts on the throttle valve, which is hand controlled, and it can be set to govern at any speed. The crank shaft, which is cut out of a solid billet of best mild steel, has five bearings, the fly-wheel being secured to a flange on the shaft by means of bolts. The ignition is of the low-tension type with "make-and-break" in the cylinder. The rocking levers actuating the ignition gear can readily be inspected by removing the side covers of the cam casings carrying the "make-and-break" gear.
High tension ignition, by means of accumulators and coils, can be fitted in place of, or in addition to, the magneto "make-and-break" gear if desired; provision is made at the back end of the cam casing to permit of a high-tension distributor being fitted and driven from the cam shaft by means of a pair of bevel wheels. The carburetter is of the float feed type, having a spring regulated automatic air control; it is fixed in an accessible position, being bolted to one of the supporting arms of the crank case.
The clutch is of the "friction disc" type, which is now coming into vogue. The gear box is made of aluminium, and is provided with a large flat top cover to facilitate examination immediately under the foot-boards. In the design special attention has been given to reducing the lengths of the gear wheel shafts, and thus to prevent the "springing", which is such a fruitful source of trouble where long shafts are employed. Three speeds forward and a reverse are provided for, the drive on the top speed being direct, no gear wheels being employed for the transmission of power.
The back axle, to which the drive is transmitted by means of a cardan shaft, is of a special design, the differential being of the spur type, while the main drive is by means of a bevel wheel and pinion. It is wholly encased, and runs in oil. The tendency of the axle casing to run round the axle is taken up by a triangle, of which the axle casing forms the base. The apex of this triangle is a ball, which fits in a circular easing containing two stiff coil springs of a square section. The springs casing is fixed to the frame cross member, in which the under-frame terminates. By this arrangement all shocks arising from starting, stopping, reversing, and braking are carried by the direct triangle and taken up by the coil springs.
The chassis shown by the Hotchkiss Ordnance Company, Limited, Victoria-street, London, S.W., shows workmanship of the highest quality. The engine having a bore of 115mm with a stroke of 120 mm., and turning at a normal speed of 1,200 revolutions per minute, gives 85 horse-power on the brake. The crank shaft, which is of special construction, is illustrated in Fig. 11. All the valves are interchangeable and mechanically operated, the exhaust being placed on the left-hand side, and the inlet on the right. Either high or low tension magneto ignition can be fitted. For the latter the Hotchkiss Company has invented a breaking device which is worked by a system of balls, and is practically without wear. Special attention has been paid to the carburetter, which is automatic, the supply of air and gas being regulated by the speed of the motor, thus giving at all times a proper mixture. The water circulation is maintained by a centrifugal pump, and the cooling is effected by means of a honeycomb radiator.
From the motor the power is transmitted to the gear box by a leather faced cone clutch, which is fitted with a universal joint so that any distortions in the frame may not affect the shafts. The clutch leather is fitted with small springs which take up the drive gradually. The gear-box has four speeds and a reverse actuated by three sliding sleeves, a disposition which enables the length of the gear-box to be considerably decreased, with the result that the shafts being short are not liable to spring, and the objectionable chattering gears with the consequent noise are eliminated.
The change-speed sector is of the gate type, and the lever of simple type, being fitted with neither button, nor catch, nor spring. The correct changes of gear can scarcely be missed, and the first or fourth can be taken without passing through the intermediate ones by the ingenious arrangement of cam. A small pedal worked by the heel of the driver prevents any risk of danger caused by taking the reverse gear unawares. From the gear-box to the back axle the motion is transmitted by a propeller shaft fitted with two universal joints, to the lubrication of which much care has been given.
The back axle is of the usual Hotchkiss type with the joint in the case placed horizontally instead of vertically, as is the practice generally. This disposition enables one to inspect the differential gear without taking the axle down. The wheels are mounted on axle tubes so that the shaft is submitted to a twisting strain only. Very powerful internal hand brakes are fitted to the back wheels, and controlled by a hand lever; a pedal applies also a brake on the back of time gear-box. The car is fitted with ball bearings throughout, including the engine crank shaft. The 18 horse-power type of Hotchkiss car, fitted with Limousine, is shown in Fig. 10.
From Aberdeen comes the Harper motor car, an attempt to provide "a proper and complete carriage" of the landaulet pattern at a moderate price. Motive power is supplied by a Cadillac single-cylinder engine which has a bore and stroke of 5in., and is said to be capable of giving 10 brake horse-power. This is stowed away under the footboard and drives the rear axle by means of epicyclic gearing and a single chain. There are two speeds forward and a reverse speed, all of which, besides a brake, are operated by push pedals arranged in a row in front of the driver.
On the steering column below the wheel are two levers for controlling the supply of mixture to the engine and for the regulation of the electric spark. The body of the carriage is designed for all weathers, having a folding top like a landau. The Harper Motor Company, Aberdeen, are the makers.
Amongst the firms who remain content with horizontal petrol engines is that of Messrs. James and Browne, Limited, 395, Oxford-street, W. A motor omnibus, made by Messrs. James and Browne, is fitted with a four-cylinder 25-30 horse power engine, with four speeds forward and reverse. The transmission is by chain driven from a sprocket on a special reducing-box, which contains an internally cut wheel driven by a pinion on the gear shaft. The countershaft brakes are carried on a sprocket shaft, and are arranged so that the brake drum covers the reducing gear and thus economises space. The brake shoes are fixed over this, and are replaceable from the outside of the car without any need to get under the car or to dismantle the body in any way. There is a metal-to-metal clutch with a special arrangement of levers, which makes it easy to operate. Cars with two and four- cylinder horizontal engines are also exhibited.
There is an extensive display of heavy commercial vehicles and motor omnibuses. Perhaps the most remarkable of the steam wagons is that shown by the Hay Motor Company, Limited, South John-street, Liverpool. An illustration of this vehicle is given in Fig. 13. It is intended to carry six tons, and the tare is said to be under five tons. The motive mechanism consists of a single-cylinder double-acting engine, 10in. diameter by 12in. stroke, arranged on the centre line of the vehicle. The driving gear consists of two connecting-rods, two ratchet wheels on the roar axle, and four clutches fitted with pawls - two for the outward and two for the inward strokes of the piston. As the piston reciprocates the connecting-rods follow the same motion. On the backward stroke the under rod, by the aid of the pawls, pushes the ratchet wheels upwards and forwards, the pawls of the upper connecting-rod slipping meanwhile; on the forward stroke the pawls of the upper rod engage and pull the ratchet wheels downwards and forwards. For reversing the vehicle the forward pawls are held out of action, and the reverse pawls are brought into use, the pawls of the upper rod pushing the ratchet wheels backwards and downwards, whilst the under pawls pull the ratchet wheels also backwards. No differential gear is necessary on the vehicle, as when turning corners the outer road and ratchet wheels are allowed to travel faster than the inner road and ratchet wheels by the slipping of the outer ratchet wheel past its pawls.
It will be seen that the train of gear wheels and chains usually employed for transmitting motion from the engine to the road wheels is dispensed with. Nor is there any differential gear. The engine runs at an average speed of 80 strokes per minute to give a road speed of five miles per hour. The cylinders, trunk, and connecting-rods of the motor are at the forward end hung by a universally jointed rod from the transverse member of the frame, and at the rear end are similarly supported with the assistance of the two radial stays. The boiler is of a well-known fire-tube pattern, and requires no description, but the road wheels are of an unusual type, being shod with deep wood blocks with the grain end on. The steering is on the Ackermann principle, with the steering centre inside the wheels. The length of the wagon overall is 23ft. 6in., the platform area 132 square feet, and the wheel base 11ft. 6in. by 6ft. 3in.
Other exhibitors in the "heavy" section include the Straker Steam Vehicle Company, with a five-ton steam wagon and petrol lorry; Thames Engineering Works, Greenwich, a steam wagon previously described in The Engineer, a petrol delivery van and omnibus chassis; John L. Thornycroft and Co., Limited, with petrol engined omnibuses and lorries and vans; Wallis and Steevens, Limited, with a light steam tractor; Foden, Limited, Coulthard and Co. Limited, and Jesse Ellis and Co., Limited, steam wagons; all of which are of standard types.
Messrs. Clarkson, Limited, Chelmsford, show their latest pattern of steam chassis for double-deck omnibuses fitted with new automatic semi-flash boiler.
The marine section contains craft of various types, and operated chiefly by petrol engines from 60 horse-power downwards.
"THE only motor car in which machinery and carriage body do not quarrel" is claimed to be that built by the New Engine Company, of Acton Hill Works, Acton. This car certainly embodies several original features.
A horizontal four cylinder balanced engine with cylinders 4.5in. by 4.5in., is built in transversely under the front seat of the carriage. Practically no portion of the motive mechanism is visible owing to the main frame and body being hung low. The frame is suspended from the axles by plate springs fitted to each corner, the front springs being secured on top and the rear springs beneath the axle.
Behind the engine is the fly-wheel, and behind this again an epicycle change-speed gear, giving two forward and one reverse speeds. The gearing and the motor are secured to an independent framework. From the change-speed gear the motion is transmitted to a "live" rear axle by a central propeller shaft with universal joints and worm gearing. The engine develops about 30 brake horse-power at its normal speed of 1,250 revolutions per minute, and the car is either geared to run at 27 or 35 miles per hour, according to requirements.
Each piston is fed with oil direct from a large lubricator on the dashboard, but the other moving parts are lubricated through the hollow four-throw crank shaft by means of a pump.
The Napier cars shown by Messrs. S. F. Edge, Limited, have vertical six-cylinder petrol motors of 40 horse-power. The cylinders are cast in pairs and bolted to an aluminium crank case. The inlet and exhaust valves are all operated from one cam shaft, the former by tappet rods and levers and the exhaust valves by plungers. The carburettor combined with the Napier hydraulic air regulator is provided with a cylindrical throttle valve actuated by the governor. The governor is attached to an extension of the water circulating pump spindle. This pump is driven by a chain from the crank shaft. To ensure synchronous firing of the charge in all the cylinders a special distributor coil, together with high and low-tension circuit distributor, are provided. These distributors are driven from a vertical spindle, taking its motion from the engine cam shaft. The advantage claimed for this system is that in only having one coil all errors that would occur in firing by employing multiple coils or tappet rods and springs are eliminated, and the distributors being mechanically driven, the firing must be, and is, absolutely correct, at no matter what speed the engine runs.
Whether there is a sufficient demand for cars fitted with six-cylinder engines it is not for us to inquire, but the advantages claimed for motors with so many units, compared with four-cylinder engines, are scarcely sufficient to justify their use; while the disadvantages in the extra length of wheel-base involved, and the cost of fuel, are considerable.
While retaining the leading features of last year's cars, with which our readers are familiar, the Brotherhood-Crocker Motor Company has introduced one or two improvements in details in the 1906 car which are worth mention. Hoffman ball bearings, hitherto used on the road wheels, are now fitted in the gear-box and cross-shaft. A new type of radius rod working truly round the centres of the sprocket shaft and rear axle respectively, always keeps the chain centres equidistant. This is also arranged to carry the bands for the rear brakes, always assuring the brake bands being true to the brake drums under all conditions. The brake drums on the rear wheels are now fitted between the sprocket ring and the spokes, being made in one with a steel driving ring, built up in the road wheel, making this part more compact, lighter, and stronger. A pawl and rack arrangement is provided on the near side road wheel to prevent the car running backwards downhill. The pawl is carried on a bracket from the axle, and engages in teeth solid with and inside the brake drum. The pawl is either dropped or raised by a small lever on the change-speed lever quadrant, and the latter is so arranged that when the change-speed lever is in the reverse position the pawl is automatically held free from this rack, so that it is impossible to drive the car on the reverse gear when the pawl is locking the road wheel.
On a new 40 horse-power chassis made by this firm, the general features of the 20 horse-power car are retained, but a departure has been made in the clutch. This is of the disc pattern, somewhat on the lines of that designed by Professor Hele-Shaw.
There of the most prominent British firms who have become converts, partially or altogether, from the horizontal to the vertical type of petrol engine, are the Arrol-Johnston Company, of Paisley; the Lanchester Company, Birmingham; and the Wolseley Company, Birmingham.
The Arrol-Johnston Company, like the last-named firm, is keeping to the horizontal motor for the low-powered cars, but in the higher-powered vehicles and omnibuses a four-cylinder vertical engine, capable of developing 24-30 horse-power, is fitted. The cylinders are 4.25in. by 5in., and two types of ignition apparatus are provided, low tension magneto and batteries. The gearbox gives four speeds, and the power is transmitted to the differential gear on the live rear axle by means of a cardan shaft. When applied to omnibuses, however, the differential shaft is distinct from the back axle. It forms a countershaft from which motion is transmitted to the road wheels by side chains.
The Lanchester Company is giving up the horizontal engine altogether; the 20 horsepower vertical engine, now fitted has cylinders 4in. diameter by 3in. stroke, and projects up through the footboard. It is encased by a bonnet, by removing which the valves can be reached. The exhaust and induction valves are fitted on either side of the engine and operated mechanically from cam shafts. The engine is governed on the throttle, acting separately on each cylinder. The cooling system acts upon the thermo-syphon principle. The familiar wick carburetter has been retained. The transmission gives a direct drive on the high gear, through a metal-to-metal lubricated clutch. The well known epicyclic gear and worm drive are still features of the Lanchester car.
Apropos of clutches, the Sparks-Boothby Hydraulic Clutch Company, Limited, 88, Parliament-street, Westminster, exhibited an ingenious device in which a quantity of oil is enclosed between the driving and the driven members, and is the only medium through which the power is transmitted. The slip of the clutch is dependent on the resistance offered to the circulation of oil, and not on contact friction. It consists of two chief parts, A C. There is an annular chamber formed at the rim of fly-wheel A, which is the driving member, and the pallets E which fit the annular chamber act as pistons. A stop D forms a partition in the annulus, and a valve Z is constructed to allow the oil to circulate round this stop. This valve is controlled by the movement of the clutch pedal. The whole of the fly-wheel casing is filled with oil, including the annulus. Upon the driving member A being rotated, the driven member C must, then, also rotate, because the oil which fills the annulus cannot pass either the pallet E or the stop D until the valve Z is opened by depressing the foot pedals. When this valve is opened the oil is allowed to circulate freely, and no power is transmitted. As the pallets E approach the stop D they are automatically and alternatively removed by the cam J from the circular path of the annulus, thus avoiding collision with the stop D. The chief objection to this ingenious clutch appears to be the difficulty of keeping it perfectly oil tight.
The marine section of the Exhibition was fairly representative of the motor boat industry, but features of novelty were few. John I. Thornycroft and Co., Limited, however, showed a two-cylinder marine engine designed for suction producer gas.
The Parsons Motor Company Limited, Southampton, exhibited an internal combustion engine for marine work, which is designed to work with either petrol or paraffin — or, perhaps, it is more correct to say that the engine works on both. That is, petrol need be used for starting only. For paraffin no external vaporiser is needed, and the carburetter is of any ordinary pattern used for spirit. The paraffin is vaporised in the engine valve chamber in a novel manner. The valves are combined, and the exhaust valve is seated upon the hollow tubular inlet valve. The exhaust passing through the latter heats it up, and emerges through ports at the bottom of the valve. The incoming charge impinges upon this hot valve and is vaporised. We are informed that this arrangement acts equally well with either fuel. In the matter of boat propulsion the Parsons Company use a clutch and a feathering or reversible blade propeller, which gives the advantage of variable pitch, and by releasing the clutch, obviates undue stress on the parts when reversing under power. In all models of the Parsons engine, a universal joint is provided for the connection to the propeller shaft, thus allowing a vertical engine with a raking shaft. The engines are made with one, two, or four cylinders, and the workmanship leaves nothing to be desired.
The Exhibition closed last Saturday night, and has been remarkably successful from all points of view. The visitors numbered over 155,500, and the estimates of the value of cars sold is beyond the most sanguine anticipations.
The illustrations published with this article are on the relevant company pages