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22nd June 1926, Page 12
22nd June 1926
Page 12
Page 13
Page 14
Page 12, 22nd June 1926 — AN EPOCH-MARKING MOTOR COACH.
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Apart From the Use of a Six-cylinder Engine, the New L.G.O.C. Coach Opens Up a New Field in Passenger Body Construction.

THE engineering department of the London General Omnibus Co., Ltd., is accustomed to being faced with problems or with special demands that normally would be considered a tax upon the drawing office and the works, and it has the reputation of being able to deal with such problems and to cope with the demands in an astonishing way. The reputation of the 'department will have been enhanced materially by its speedy production of the new six-cylinder all-weather coach, which we briefly described in our issue for June 15th, for it is a fact that eight weeks before—that is, about the middle of April—the vehicle was only being discussed by the commercial manager of the company and the engineering department. Just what had initiated the idea of putting into the motor coach tour service of the company a type of vehicle which would offer all the advantages embraced in the term " all-weather " we do not Icrlow, but it is highly probable that a feeling of disgust at 1920 weather underlay the whole idea. And it is a testimony to the sagacity of the commercial manager that the coaches so far completed have carried out a fair proportion of their duties in drenching rain almost from the moment they were put uponthe road I Let us express the hope that the " all-weather " idea may be further justified by floods of sunshine during the remainder of the summer season !

In eight weeks the all-weather coach has been designed, its special features have been developed and a small fleet of the vehicles has been wholly or partly completed— which is really an accomplishment. Certain components are of A.E.C. construction, but so crammed with orders is the Walthamstow factory that the new chassis was assembled and completed at the Chiswick overhaul factory of the L.G.O.C. Of those constituting the first batch, six will be employed on the L.G.O.C. service of coach tours and two on the National Omnibus and Transport Co.'s coach service.

The two main principles laid down for the design of the coach were, first, a light fast vehicle, with absolutely smooth, silent running, and, secondly, a coach which, whilst giving protection against weather of the type which has made us' Britons what we are, should be low, unusually safe, very roomy and comfortable, and, last but not least, should have practically 'no inflammable materials in its construction.

The first stipulation has been complied with by equipping the chassis with a six-cylindered sleeve-valve engine which is able to develop its full torque at all speeds by reason of the control thermostatically of the temperature of the cooling water, the power being transmitted through worm gearing and rack and pinion drive to pneumatic-tyred rear wheels. The second stipulation has been met by developing a body built entirely of metal and by good design in which full advantage is taken of maximum permitted dimensions. The only wood, which we found in the whole vehicle consisted of two thin packing pieces interposed between the chassis frame and the body girders.

The engineering department of the L.G.O.C. have in view a further development of bus body construction in which wood will be displaced largely by steel, and they are using the coach body construction as a means of experimenting with a unit system by which, in the ease of damage to a bus body, a panel with its support pillar sections can be removed and replaced as quickly as any detail of the chassis itself can be changed. It is felt that the engineer has not yet brought his experience and knowledge to bear on coach building and that the time is fully ripe for him to do so. If he does, gone will be the days of slow and laborious hand work, production and replacement will be expedited and labour troubles diminished.

The chassis of the new coach calls for a brief description, but we shall not need to go into full details, because in so many respects it conforms to the company's standard practice as exemplified chiefly in the N.S. type of bus. The frame is very deep in section, namely, 220 mm, or slightly over 9 ins. However, it is constructed of light-gauge steel so that the weight is kept to the minimum. It is cranked upwards for each of the axles and tapers towards the ends. It has six tubular cross members and a channel-section body bearer at the extreme rear. The petrol tank is carried Immediately behind the rear axle, suspended in straps from cross bearers. A sub-frame attached to the first and second cross members carries the engine, and the gearbox is suspended at three points on the third and fourth cross member. The fifth cross member carries the bearing which supports the propeller shaft, and the sixth cross member stiffens the frame at the anchorage for the front end of the rear springs.

The transmission line is placed 3 ins, to the left of the centre solely in order to provide room for the driver inside the width of the frame and to bring all controls to convenient points. This lack of conformity between the centre line of the chassis and the transmission line is not at all noticeable, even when one is looking at the front of the vehicle, the aperture in the radiator casing for the starting handle being inconspicuous. The axle shafts are, of course, of unequal length, but that appears immaterial and the unequal disposition of load is counterbalanced by increasing the camber of the near side springs by half an inch.

The reason for the choice of the 25 h.p. Daimler engine was the fact that the engine employed on the L.G.O.C. bus was too heavy for the purpose intended. The Daimler engine seemed to fill the requirements, but under test with a vehicle weighing net 4 tons with the load in addition, power was found to fall off so soon as a speed of about 30 m.p.h. was reached. In one of the tests the radiator was blanked off, and it was then found that the engine developed its full power over a great range of speeds ranging from 30 h.p. at 1,000 r.p.m. to 75 h.p. at 3,000 r.p.m. This suggested the need for temperature control of the cool

ing water. The engineering department was able to secure the right to use the Lincoln radiator with thermostatic control of the venetian-blind shutters in front of it, and this radiator has been incorporated, an aluminium casing being cast to suit it. The thermostat is situated in the upper tank of the radiator just below the filler tap and, by means of rods and levers, varies the size of the apertures between the shutters according to the temperature of the water, thus maintaining a constant temperature of about 160 degrees Fehr.

The clutch is a single-plate disc running dry, and a choice is obtainable in the gearbox, which is either a three-speed with silent chains to the layshaft, or the fourspeed spur gear type, this latter being fitted to a vehicle going into billy districts.

The back axle is only slightly different from the type developed for the N.S. bus chassis, the differential casing being, as we have already said, placed 3 ins, to the left, but a different form of carrier has been introduced to support the brake shoes and brake-operating mechanism, because of the different angle of the shaft line.

The road wheels are steel discs with 36-in. by 6-in, pneumatic tyres, with twin tyres on the rear wheels.

The most important development in connection with the

all-weather coach is, as we have suggested, the new form of body construction in which metal only is employed. Our illustrations have been prepared with a view to making this form of construction clear.

The framework upon which the body is constructed is of T angle iron inverted, with eight cross members and two longitudinals, bolted at every junction, the longitudinals being broken at the wheel arches, the gap there being bridged by L angle iron. At the outer edges of each of the cross members are bolted flitch plates which extend to the top of the body side and bl-ace the body pillars.

Angle iron brackets extend from the sides of the chassis frame to the bottom of the pillars; thus the sides are thoroughly well supported, and as the floor framework is only 2 ins, deep, the packing pieces between it and the chassis frame are only 1 in. thick, the floor is raised only 21 ins, above the top of the frame and is, therefore. only 2 ft. 21 ins, above the ground. The flooring being of folded sheet-iron framed up in panels it is flush with the fops of the angle iron framework.

The body sides consist of separate panels, four main panels to each side, the one for the wheel arch in each ease being slightly larger than the other three, whilst behind the wheel arch there is a narrow panel on the off side, and on the near side a doorway ; behind these are two narrow panels followed by the curved corner panels. The back is made of two large panels. Each panel is constructed of a sheet of "silver-finish" sheet-iron with a lip turned over at the top and a bead rolled at the bottom. It is bent in at the bottom so as to give the body turn-under. At each end of the sheet iron panel is spot-welded a U-section steel half-pillar, and on to one end is spot-welded the moulding which will cover the join between the two panels.

In assembling the body, the panels are offered up in position with the flitch plate, already referred to, pinched between the two half pillars, one on each panel. An aluminium distance piece is employed where the bolt holes are drilled in the pillar sections, and the two half sections being bolted together with a flitch plate between them definitely secure the panels to the framework of the floor. Sheet metal box form girders are bolted to the pillars at the floor line and about a foot above it, thus stiffening the body longitudinally.

By this form of construction any panel can be removed with its half pillars at each end by undoino.' a few nuts and bolts, and it can be repaired or replaced as required, thud affording a ready means of dealing with damage.

The front of the body is constructed in exactly the same way, and on the quarters an aluminium casting forms the top rail, being dropped 6 ins, to accommodate the hood. For this hood the Beatonson patent char-i-bancs headwork is employed. The window channels are hinged to two nickel plated top rails which fall flush with the top of the body side and, when required, are raised to full height, thus allowing the windows to be raised. The hood is equipped with hoop irons which slide along the top rail. _

Bolted to the floor are two brackets for every double seat, the seats being very comfortably sprung 'and of the semi-armchair type; longitudinal double seats are ,employed over the wheel arches and a seat for four is.placed'across

the rear of the vehicle. .

The driver is located entirely outside of the body and can only be communicated with by an electric bell,. which is quite the right and proper thing. He has a separate canopy which is attached by press buttons to the front of the main hood and is fastened to the top of his own windscreen ; side curtains are also provided for his protection.

The overall length of the vehicle is 24 ft. n ins., the overall length of the body is 18 ft. 7/ ins., the overall width is only 7 ft. 51 ins., and the overall height (when the hood is raised) is 7 ft. fli ins.; hence it will be seen that the vehicle sits ektremely low on the ground. The wheelbase is 15 ft. 8 ins., and with an ample lock it can go practically anywhere.

Safety unsplinterable glass is used throughout the coach, and the general appointments., are extremely good.


People: Opens Up
Locations: Lincoln

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