CYCLING & MOTOR NOTES

Otago Witness, Issue 3495, 8 March 1921, Page 42

CYCLING & MOTOR NOTES

By

DEMON.

Close students of motor-cycle design have always been of the opinion that there was considerable room for improvement in motor cycle brake mechanism. This. part of the construction has always constituted one. of the weak points in many—indeed, rhe majority of the designs,-—and it is pleasing to note the determined manner in which many firms are now tackling the question of improved braking. For ail but the lightest of motor cycles, the shoe type of brake, as applied in so many instances to the front wheel, may be ruled out as almost entirely ineffective, and at the best, it can only be regarded as a makeshift auxiliary to the rear wheel brake, irhould the latter be in want of adjustment or, for other reasons, have become even partly inoperative, reliance, if centred on the front wheel biake, is likely to prove misplaced. The rear wheel, as the driving wheel, is undoubtedly the proper medium for braking effect, but where for any reason preference is shown foi a system in which both wheels are braked, then the mechanism should be of a kind which can bo relied upon as really effective, even with the fastest and heaviest of motor cycles. There are several forms of brake mochanLm which can without difficulty be applied to front wheels, and no excuse therefore exists for continuing a pattern that so; ,es only to nice), the conditions which obtain in the ease of pedal cycles and low-powered motor cycles. not looked upon as a thing beyond in{-

pro vement, for a bicycle reliability test over a distance of 940 miles was to be decided on French roads last month. The contest was divided into 15 daily runs of about 62 miles each. Awards were made on a marks basis, 10 points being- last for any renewal en route of any part of frame, or forks; 5 points in respect to crank, bottom bracket spindle, saddle pin, or saddle frame, handle-bar, brake, mudguard, rim, tyre cover or tube replacement. Any chain trouble or broken hub axles called for a loss of 10 points, and a broken saddle spring 3 points. On even.ihe worst of our roads it would be a poor New Zealand machine that could not go through such a test without loss of points, under similar conditions to the French competition. TAIL LIGHTS OH MOTOR LORRIES. Complaint that many motor lorries failed to carry tail lights or numbers was made at a meeting of tho Wellington Automobile Club last week. It was stated that dozens of motor-lorry owners were not complying with the by-laws in this respect, yet if a motorist committed a similar breach he was fined. The secretary (Mr H. -J. Stott) .said the club had written to the City Council and Police Department on the matter several times. It was decided to communicate with the authorities again on the subject. BRAKING ON STEEP GRADES. Tlior - are still many motorists who fail to avail themselves of braking with the engine on steep grades. They frequently are under the misapprehension that braking with the engine is a strain on the car. The answer to this misapprehension is simply this: It does not require any more effort to restrain a car from rolling down hill by the use of the engine than it requires to propel that same oar up the same hill. The retarding effect of engine-braking is accomplished through friction; and the friction must bo overcome whether the car is driving the engine or the engine is driving the car. The only thing to worry about in this connection is to reduce the speed of the car sufficiently to avoid racing the engine.

-—The film rights of one of the bestknown American novels were sold for £IO,OOO.

RELIABILITY TRIAL. On Saturday next the Otago Motor Club will hold a reliability trial and also a club run to Timaru. Members of the Canterbury Automobile Association have arranged to have a club run to Timaru on that date to meet the members of the O.M.C. who journey there. The trial will bo a one-way trial this year, ending at Timaru. Controls will be held at Palmerston, Oamaru, Waimate, and Timaru. Secret checks will also be hold along the route, partly to prevent speeding and also to assist in getting a winner. Merely running into four controls on time is no test for the modern motor cycle, given ordinary freedom from tyro and mechanical troubles. An average speed of 20 miles an hour will be run to Palmerston, and 24 miles per hour beyond that town to Timaru. Twenty minutes will be allowed each competitor for dinner at Oamaru. The first rider leaves Distance on the Trial Course.— Dunedin at 9 a.m. ; is dire to arrive at Palmerston at 10.48, at Oamaru at 12.25 j p.m., leaving again at 12.45 J. Due at Waimate at 2.0£ p.m., and Timaru at 3.8 p.m. Competitors ride at two-minute intervals. There will be three classes —viz., (1) solo motor cycles, open; (2) side-cars, private owners; (3; side-cars, trade riders. The prizes are —Class I: .First prize. £2 2s; second, 15s. Classes II and III: First prize. £4 4s; second, 30s. All prizes to he trophies. Tuned in to— Miles.

D ESI C N OF MOTOR CYCLES.

A paper on motor cycle frame design was recently read before tlio English Institution of Automobile Engineers by Mr Douglas Leechman. After a brief historical reference to the ovolution of the diamond frame for bicycles, the author pointed out how this design was adapted for the motor prole. In the early days of the movement there was a considerable diversion of opinion •6 to the best position in which to mount tbs engine. Finally, the Werner Brothers’

system, in which the engine was mounted vertically in front of the bottom bracket, was adopted. At the same time, to make room for the engine, the lower end of the down tube from the steering head was cut away from the bottom bracket and attached to the engine instead. ’“Presumably with the object of mitigating' the injury done to the lower part of the frame, Werners introduced a horizontal tube below the tank, fixing the front end at an indefinite point on the bottom tube, and the rear end at an equally indefinite point of the seat tube. This construction may he well described as a. ‘mechanical offence,’ and it has exacted a heavy toll of the motor cycle trade. As in other branches of the motoring world, there was an in- | sistent demand for more powerful motor | cycles. This meant larger engines, larger sectioned belts, and wider belt lines. This should have been met by wider frames and wider bearings, but instead of this, the old widths of bottom bracket, rear huh, and frame were retained, the pedal cranks were violently distorted to clear the engine, and I che hack fork and stays were embellished ; with local detours to clear the belt rim. | That these devious methods have been so j largely perpetuated for something like 20 years is enough to justify, in the author’s opinion, the strictures which he and others have passed upon the design of modern motor bicycle frames, and that is by no means their worst feature.” From an engineering point of view, the motor cycle frame must he a compromise, the most difficult part to construct on scientific lines. Mr Deechman points out some of the principal and most glaring faults encountered, and goes on to describe the best methods of building up frames and the strains imposed on them. Owing to | the extent of the subject, the conventional type of frame only has been considered. I His own suggested construction is of the conventional outline, built up of completed triangles and employing all straight tubes. As he points out, front fork design could in many cases be greatly .improved by a more rigid adherance to engineering principles. An interesting statement is that a steel tube of a given size is as efficient, when

functioning as a. long strut, as a mild steel channel section of rather more than five times the weight. So the advocates of pressed steel construction are given the coup de crace. Finally, Mr. Beechman is right on the mark when he says that ‘‘such a vital item as the frame should not suffer in favour of mere accessories and fittings like mudguards, tanks, saddle-peak connections, and so forth.” FRENCH GRAND PRIX. The French Automobile Club has decided that the Grand Prix motor car race will be held on the Sarthe Circuit on July 23. Already 15 cars have entered. A brief outline of the history of this classic event will interest motorists. It may be recalled that after Thery (France) had won the Gordon Bennett race two years in succession, so that that trophy passed into the permanent keeping of the Automobile Club of France, it was decided to start a new series of races, in which the teams of three cars should represent makers, and not countries as in the Gordon Bennett races. The first of the grand prix races was held in 1806 on the Sarthe Circuit, and it was a two-day affair. On the second day, the cars were started in the order of finishing on tlio first day, with the actual time differences, so that it was as though all had started from scratch on the first day, and the first cross the finishing-line was tile winner. The only restriction was that the weight of the cars was limited to 1000 kilogrammes I (22001 b). The winner was Szisz, on a I Renault, whose average speed for the full I distance of 769 miles w r as 62.8 miles per I hour. A Clement was second, and Naz- * zaro, on a Fiat, third. The next race, in 1907, was on a fuel consumption basis, 30 litres (approximately six and a-half gallons) of fuel being allowed for each 100 kilometres (62 1-8 miles). The course was close to Dieppe, and consisted of 10 laps of 47.8 miles. The winner was Nazzaro, on a Fiat, his average speed working out at 70.6 miles per hour, Szisz, on his Renault, this time having to be content. with second place, with Baras, on a Brazier, third. For the third race, in 1908, the Dieppe circuit was used again, and there was another change in the regulations, the governing factor being a maximum piston area of 75.476 square millimetres, this representing a bore of 155 millimetres for four-eylindered engines, and 127 millimetres for six-cylinders. The result was a sweeping victory for German oars, a Mercedes, driven by Lautenschlagcr, being first, with an average speed of 69 miles per hour, while Benz cars, driven by Hemery and Hanriot respectively, were second and third. Then followed an interval of four years, the next race being in 1912, when once more the course was that of Dieppe. It was a two-day race, ten laps being run on the first and ten on the second. The winner was Georges Boillot on a Peugeot, at an average speed of 69 miles per hour, with Wagner, on a Fiat, second, ajid the third place

going to Rigal, on a Sunbeam. For the race of 1813, a course east of Amiens, in Picardy, was arranged. The oourse was a little over 19| miles round, and the 29 laps made a total distance of 669.9 miles. Petrol was allowed at the rate of 1 i 0 litres for every 100 kilometres, and there were weight limits of 800 kilogrammes minimum, and 1100 kilogrammes maximum. The winner was G. Boillot, at an average speed of 74 ipiles .per hour, with Goux, on another Peugeot, second, and Chassagne, on a Sunbeam, third. The last race was on July 4, 1914, one# month before the outbreak of war, the oourse being 23.4 miles round and having to be covered 20 time 3. The race was restricted to cars having a cylinder oapacitv not exceeding 4.5 litres, while the maximum weight limit was 1109 kilogrammes. The firet three places fell to Mercedes oars, the winner (Lautenschlager) completing the 468 miles at an average speed of 66.6 miles per hour. Second, place went to Wagner, and the third to Salzer. Goux, on a Peugeot, was fourth, and Resta, on a Sunbeam, fifth.

Waitati .. .. .. v# . 13.5 Kvansdale .. »» «-W fc , 15.5 Top of Kilmog „» 18 AVaikonai ti r . ... 27 ‘Palmerston .. M M 36 Pukewitahi .... .. M 41 Kartigi .. ... .. „ M 47 Hillgrove .. .« M 50 Waianakarua ». ** M 58 Herbert .. .. ,, %■- 61 klaheno .. .. 66 Totara .. „ M 70.5 *Oamarn .. 75 Pukeuri .. », „ *.* 80.5 Hilderthorpe .. 83.5 South Waitaki 88.5 M'N&mara's corner **■ »» 101 ‘Waimate .. .. *• *» 105 North Junction. .. a* m 108 Makikihi .. ... • * *» 113.5 Otaio M 117.5 St. Andrews .. .. *• *1 121.5 Pareora *• »• 123.5 •Timaru 132 * Signifies control.