The Brennan Mono-Track Vehicle.
Page 5
Page 6
If you've noticed an error in this article please click here to report it so we can fix it.
Demonstrations near Chatham with a Machine Weighing 22 Tons, and Capable of Taking 70 Passengers or 15 Tons of Goods.
Just, as e e were going to press with our last week's issue, we received an urgent invitation, from Mr. Louis Brennan. of torpedo and gyroscope fame, to pay a visit to Gillingham (New Brompton Station), near Chatham, where, on enclosed Government land, he intended to make a demonstration with his full-sized mono-track vehicle, We first drew our readers' attention to Mr. Brennan's researches with the use of a gyroscope, or gyrostat, for securing the stability of vehicles or structures, in our issue of the 9th May, 1907, when we also reproduced some snapshots that were taken during the trials of his oneeighth-size-scale model. Since that, time, considerable progress has been made, and, by constant application to the work, and with the assistance which he has received from the War Department, the India Office and the Durbar of Kashmir—assistance which he gratefully acknowledged when speaking recently to some members of the Press—Mr. Brennan has now completed a machine which is about 40 ft. long, 10 ft. wide, and 13 ft. high ; when empty, it weighs 22 tons. It is capable of taking a load of from 10 to 15 tons on its own platform, and, with that load, of ascending gradients of 1 in 13.
The invitation was sent by telegram, because news had just reached England that Herr August Schell had announced his intention to make a public
thmonstration in the Zoological Gardens at Berlin, with a " gyro-ear" which he claimed to have invented. The German-built machine measures some 17 ft. long, and can carry a matter of half-a-dozen passengers, but, in comparison with the latest English car, Herr Scheil's is but a toy. Mr. Brennan, the inventor of the first really-practicable scheme for
the gyroscopic control of a mono-track vehicle, did not wish it to be said : " Yes, you were the first with the scheme and a working model, but you left it to German engineers to build the first practical machine." Hence, Mr. Brennan's hasty decision to let the public know at once what progress he had made.
A representative of Tun COMMERCIAL. Mount took train to New 13rompton the following morning, and travelled down in company with Major A. C. Joly de Lotbincere, who informed our representative that the State of Kashmir, the Durbar of which he represents in England, is ripe for the introduction of the mono-track car, and that the Durbar will make purchases as soon as Mr. Brennan is ready to put his invention on the market.
The new machine, as may be judged from the views which we reproduce, is by no means a scientific toy. It is workmanlike in design, and the principle on which it is constructed has now been abundantly proved. Several itnehine-tools, operated by workmen, were mounted on an unstable platform in the factory at Gillingham, and, by the aid of gyrostats, the platform has been kept in a state of perfect equilibrium for the past 18 months, during which time the men have gone about their work as freely as in any other part of the factory.
When the design of the full-sized machine was commenced, electrical
engineers would not guarantee a higher speed than 3,000 r.p.m. for electric motors; since that time, however, the inter-polar method of dynamo and motor building has been evolved, and higher speeds are now possible. It is expected, thereeore, that in future mono-track cars the gyroetate may be made smaller in diameter and of less weight. Those on the vehicle recently tested in Kent weighed 15 cwt. each, and were 42 in, in diameter. If made smaller, they could easily be stowed away under the Hoar of the car, thus leaving more space available for the accommodation of passengers or goods. In the netdiine our representative examined, and on which he travelled round. the test track, each gyriestat, with its shunt-wound driving motor, is enclosed by a sheet-steel casing, and from these cases the air is exhaustea down to a pressure of only in. to a in. of mercury. Each case is provided with trunnions, arranged vertically in relation to the carrying platform, and the two cases are carried by a heavy bridge-casting which is securely bolted to the main frame if the vehicle; the cases containing the gyroetats are free to turn about their vertical axes in the bridge-casting, and their resistance to sideways rotation is transmitted through the bridgecasting to the car-frame. The two gyrostats rotate in opposite directions. and the vertical axes of their containing cases are at all times parallel to each other, but the axes of the gyrestets and motors, whilst always set at an angle of 90 degrees to their reepective trunnions, may take up an infinitely-variable angular relation to each other ; or, in other words, the gyrostats may be precessed. The preeeesion is effected through a doublefaced reek, which engages with two quadrants on the gyroetat cases. The double rack is actuated by means of a pneumatically-controlled hal:teeing device, about the details of which Mr. Brernan rightly refuses to speak. The
current fer the gyrostat motors is supplied by by a Siemens dynamo, which is driven by a four-cylinder 20 he). Wolseley petrol engine, and, although intended only for that purpose, this electrical equipment. is sufficient also to propel the ear, with a full load, at
slow speeds. For all ordinary running, a direct-coupled generating set, consisting of a four-cylinder vertical 51) h.p. Wolseley petrol engine and a Siemens dynamo, supplies direct current to two Siemens traction-type motors. Each motor drives a pair of track wheels, through the medium of a reducing gear and coupling rod.
Although a petrol-electric system of transmission is employed, it is obvious that the necessary current, for both the gyrostats and the propulsion of the vehicle, (-mild he " picked up " from an overhead cable: or. any other form of power generator and transmiseinit system could be employed. The introduction of toothedgearing for the gyrostats is, of course, undesirable, but these might be driven by a high-speed turbine.
The trial runs were made over a hastily-laid single track of steel rails weighing 75 lb. per linear yard, eu
sleepers about 3i ft. long; the ground was not specially prepared for the track—the sleepers were simply laid on the top of the turf, or road, as the case may be. Owing to this absence of ballast for the track high speeds were not attempted during the day, and, eensequently, the 20 h.p. engine wasquite equal to the task of moving the car and its load of some 40 passengers at a reasonable speed. In spite of the repeated efforts of the assembled company, the vehicle could not be induced to show any tendency to roll, and, when standing on the platform, the machine gave the passengers an heiiression that it had ample stability.
The first trial was made on the morning of the 10th inst., some few hours before the time at which the clemonetration in Berlin, announced by Herr Seheil (a photograph of whose in:whine we reproduce) was to oce-us'. A further demonstration of the Brennan machine was given later in the day. and this was attended by Cul. J. A. Ferrier. CE., RE., the commandant at the Chatleini School of Military Engineering, am! other ILE. officers. Prof. H. S. Hell-Shaw . F.R.S., President of the Institute of Automobile Engineers, was also present during the afternoon. By arranginghis first demonstration for the morning, Mr. Brennan now has the distinction of producing, not only the first scheme and working model, hut also the first practicable machine of a sire that may he commercially used. So far Mr. Brennan'e experiments with gyrostats for vehicle control have been confined to machines that ace intended for use on steel or (eller well-defined tracks, hut we see no reason why the principle should not be applied to motor-propelled road vehicles, for both passenger and goods traffic. The ease of travellin.g that may be obtained with a single-treck vehicle is greatly snperitir to the bestimesible results obtainable with a double-track ear. and, although we have previously held rather different views, we are now inclined to think that, were the gyrostats located low down on the chassis, the tendency to side-slip would be somewhat ream-ed.