Why That Stunned Silence ?
Page 60
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REFERRING to the article headed " Vehicle Stability
Essential on Motorways" in your issue dated January 30, your comments in the same publication seemed to express incredulity regarding the suggestion from Mr. G. Grime, of the Road Research Laboratory, that four-wheeled light vehicles would give better stability if braked on three wheels. You also said that nobody had challenged Mr. Grime or inquired whether he had tried out this theory in practice.
I would like to draw your attention to a paper presented to the Automobile Division of the Institution of Mechanical Engineers in 1954 by Mr. H. J. H. Starks, Ph.D., and Mr. R. D. Lister, B.Sc.(Ent.), A.M.I.Mech.E., both of the Road Research Laboratory. It was entitled "Experimental Investigations on the Braking Performance of Motor Vehicles." It was stated in this that tests were carried out on a car in which (a) both rear wheels only were locked; (b) both front wheels only were locked. They were made on a level concrete surface having a uniform crossfall of about 1 in 40.
Graphs of the Lesults showed that in the first case the angular deviation of the vehicle was about 180 degrees at just over 30 m.p.h., whereas in the second case, where the front wheels only were locked, the deviation was not more than 10 degrees at the same speed.
When all four wheels were locked, those at the front first, the car proceeded in a straight path. On the other hand, if the rear wheels were locked more than 0.5 sec. before those at the front, there was some deviation, its direction being governed by the crossfall of the surface, but if locking of one of the rear wheels was delayed, then no side movement occurred until this wheel was held.
Further tests with only three wheels locking showed that if there was no braking on one rear wheel the vehicle travelled sensibly straight when braking from speeds up to about 50 m.p.h. With no braking on one front wheel, however, the deviation was similar to that obtained when both rear wheels were locked.
Havant, Hants. J. 0. STARLING, M.S.A.E., G.I.Mech.E.
Early Origin of Demountable • Bodies
JFIND a considerable amount of interest in my weekly perusal of The Commercial Motor, which covers the whole field of road transport in a most thorough manner. Looking through some of my cuttings from it covering 50 years, I see no features which have been lost, but many new ones which seem worthwhile.
From my own angle, your test reports have always been very good, whilst your extension of these to include servicing items is a most commendable feature and I am sure that you have heard quite a lot of " excuses " regarding some of them.
Your correspondence columns provide plenty of opportunity for readers to express their views. In this connection Mr. Lort-Williams, who wrote in your issue dated January 30, would have to go back more than 60 years before he could claim truthfully to find the origin of the "demountable-body scheme." The old Lancashire and Yorkshire Railway, long before 1900, used detachable bodies or "flats," as they were called, in order to save waiting and handling time in works, warehouses and goods yards. At a warehouse a loaded flat could be slung onto (.24 a horsed lorry, taken to a goods yard and transferred in i. few minutes to a railway goods wagon ready for dispatch It was a common sight, even in a small goods yard, to see a crane carrying a large steel " X " at the end of the jib. This was held at its centre by the crane hook and from each end of the four arms hung a chain terminating in a hook. Two loops or rings on each side of the flat allowed the whole to be slung for transfer.
Before 1910 a Leyland catalogue showed one of their chassis equipped with a few cross-bearers shaped to accommodate a standardized "flat." Such a machine was owned by Johii Berry and Sons, Ltd., of Accrington, and the. assembly could be seen leaving early and daily for a Manchester warehouse with a " flat " load of cloth. During the late afternoon the lorry would return with another flat loaded with skips of weft, probably collected in the Oldham area. This could no doubt be considered as an early type of palletizing applied to motor vehicles.
Even before this another chassis with a special type of " body " to carry rollers for tinplate was operated by Howard and Bullough, Ltd., of Accrington. In this case no platform was employed, but use made of cross-bearers divided horizontally and with holes lined with felt to accommodate rollers of various diameter.
Blackpool. TRANSPORT ENGINEER.
A Reader's Ideal Chassis
WITH the exception of the Tempo, which is not of British
design, almost all the light commercial vehicles in production in Britain at the moment suffer from one great drawback—high floors. Specialist bodybuilders who convert delivery vans into light passenger vehicles and caravans, sometimes increase the interior headroom by fitting extra high roofs. This method, however, naturally increases the overall height, raises the centre of gravity and usually gives a somewhat ridiculous appearance.
if chassis designers would put the horse before the cart, as did Citroen, the floor height could be dropped from about 26 in. to 14 in. with no loss of clearance.
When there are so many successful designs produced on the Continent which incorporate low floors, fully independent suspension, front-wheel drive and many other features which are not now unconventional but positively good, why do our British makers not do the same?
What has happened to the spirit of non-conformity which produced, say, the Jowett vehicle with a flat-twin engine, the B.S.A. van with front-wheel drive, the early Trojan with underfloor engine which could almost be driven up a wall, the Turner milk float with a two-stroke oil engine, and the Gilford low-level bus?
Here is what I would like to see for delivery work, carrying personnel, as a caravan, or even as a private car by those who have the foresight to realize that one day they may want to carry in it a wardrobe or a sack of cement: A vehicle with an overall length of 13 ft., width 6 ft., overall height 6 ft. 3 in., wheelbase 7 ft. 6 in., track 5 ft., independent suspension all round and a floor height of 14 in. I would also favour front-wheel drive, twocylindered horizontally opposed air-cooled oil engine of about 2-litire capacity under the front seats, aluminium framing with glass-fibre panelling, direct gear change, and rack-and-pinion steering.
Reading, Berks. I. THOMPSON.
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