C.M.U.A. Parade Progress.
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The Examination Papers, which were Set for Driver Candidates in the Championship Section last Saturday, are Reproduced Below.
The arrangements ior the holding of the sixth annual parade are well advanced. The examination for the championship prizes has been held, and the marks have been allotted by the examiners. We understand that the papers show a high standard of knowledge on the part of a number of the men who took part, and we make other references to this section of the organization on page 165 of this issue. The text of the papers is given herewith. We learn that the Parade Committee has agreed to allow certain non-competing owners to muster their vehicles in proximity to the competing vehicles, but quite separately from them. This decision has been taken on the application of Messrs. Auborn and Heaviside, the well-known toffee and sweet manufacturers, of John Street, York Road, S.W., which firm will send a fleet of six well-kept machines. Although ineligible for prizes, these vehicles will, in the opinion of their owners, add to the brightness of the occasion, and it is probable that other non-competing vehicles will be allotted stations, although intimations in advance are requested. Indirect support of the parade, on these lines, is, of course, entirely at the discretion of owners, although the Parade Committee, acting in conjunction with the police who will be on duty on Whit Monday, will have effectual control. The Parade Committee is not in a position, at the moment of our going to press, to announce the exact location of the parade area, but we are able to state that it will be not very far from Trafalgar Square. Fuller information will be published not later than Thursday next.
General Instructions to Candidates.
Head each sheet with your name and the number of the question you are answering on it.
You must make an attempt to answer the first. six questions.
You may also attempt to answer any six of the remaining questions, but not more than twelve questions altogether are to be attempted.
Note.—It will be far better for you to do only the six compulsory questions and do them very well than to attempt more than you can do in the time allowed for the examination—three hours. You will get no additional marks for answering more than twelve questions.
The numbers which are given in brackets at the end of each question indicate the number of marks allowed for a correct and carefully-written answer to that question.
Questions for Drivers of Steam Wagons and Tractors.
1. Write a short description of the machine which you drive ... ... (25) 2. How would you take out a faulty tube from your boiler and replace it with a new one '? (25) 3. How would you set the valves of your engine ? Give a sketch of a slide valve, and state what is the effect of giving inside and outside lap (25; 4. What is the chief cause of the formation of scale in a boiler, and how may it be mini mized? ... Sketch and describe the safety valves of your boiler (25) 6. What. is the cause of priming, and how may it be prevented? ... ... (25) 7. What do you consider is a fair rate of coal (or coke) and water consumption per mile for the machine which you drive ? ... (20) S. What kind of wheels and tires are fitted to your machine, what are its load and legal speed, .and what would be its legal speed if it were used to haul a trailer? ... (20) 9. Sketch and describe either a water-tube or a fire-tube boiler, and state which seams are single-riveted and which are double-riveted (30) 10. Why has the compound type of engine been generally adopted in preference to the simple single-cylinder type ? 11. Why are the cranks of two-cylinder engines generally set at right angles instead of oppo site to each other ? (20) 12. What is wire-drawing, and what is the cause of it Can you show on an indicator diagram how such diagram would be affected by wiredrawing? ...
13. What do you understand by clearance and cushioning, and can the amount of cushioning be increased or reduced by altering the amount of inside lap of the slide valves ?
14. What steps are usually taken to prevent cylinder condensation ?
15. How does a feed pump work ? Give a brief description and a sketch of the pump on your machine if it has one ... (25) 16. What would you do before lighting up your boiler fire ? If the gauge showed half-glass of water would you take that as evidence that there really was water in the boiler? ... (20) 17. What is the object of fitting a flywheel and in what respect does its work differ from that of a governor? (40) L8. For how many miles of running would you expect the following parts to wear without needing renewal, adjustment, or repair:— Firebox ; boiler tubes ; firebars ; cylinders ; big-ends ; main bearings ; valves ; changespeed gears and bearings ; axle bearings ; wheel bushes and final-drive gears or chains ? (25) (20) (35) (35) (20) Questions for Drivers of Petrol•engined Vehicles.
1. Write a brief description of the vehicle which you drive ... ... (25) 2. Describe how you would time your engine if you had to reassemble it, there being no marks to guide you. At what parts of the stroke do the inlet and exhaust valves open and close ? State in each case whether the piston is travelling up or down the cylinder, and at what point does the ignition occur ? :3. Explain exactly the cause of an engine " popping " back into the carburetter, and what(25) you would do to stop it „.
4. If the float of your carburetter developed a leak, how would you detect it, and what
effect would it be likely to have on the en
gine? Give a sketch, and describe some form of carburetter with which you are ac quainted, and state what you know of its means of adjustment. How may petrol be saved, firstly, by method of driving, and, secondly, by adjustment of the carburetter ? (25) b. Explain the various causes of knocking in an engine, and give causes of big-end failures (25) 6. State, as far as you know, all the causes of engine over-heating ... (25)
7. What parts of your machine are likely to need replacing after the following mileages are
completed :—l0,000; 20,000; and 30,000? (25) A van runs 300 miles a week, and consumes the following stores: One gallon of petrol (1s. per gallon) for each 7 miles ; one gallon of oil (2s. per gallon) for each 250 miles ; tires cost 75 per set, and rim 12,000 miles ; other
expenses including wages, I5s. 6d, per week. What is the cost per vehicle-mile ... (25)
9. Sketch and describe a differential gear. What is the object of fitting such a gear, and would anything serious happen if it seized while travelling along a straight road ? ... (30) 10, What is the difference between a high-tension and a low-tension magneto ? Give a detailed diagrammatical sketch of any type, and state what sort of a spark you would get if the condenser were to break down. Why do you only need one wire to connect up a low-tension magneto to a multi-cylinder engine ? „.
11.
Some vehicles are fitted with one set of brakes on the back wheels, and the other on one of the gear shafts, whilst other makes have both sets acting directly upon the road wheels. Which type do you prefer ? and give your reasons ... (20)
14. What is the legal speed of your machine? Does it run on steel or rubber tires, and what load does it carry ? Would its speed have to be reduced to meet the requirements of the Heavy Motor Car Order if a trailer were
hauled? ... (20) 13. Supposing that your machine were not pulling well what would you do to improve matters ?. ... (30) 14. What do you consider is the best form of final drive to the road wheels for vehicles of the following load capacities :--30 cwt., three tons and five tons? Give your reasons ... (30)
15. If your vehicle were fitted with a gearbox of the type shown in the following sketch, and the number of teeth in the gears were as there shown, state exactly how you would manipulate the clutch, change-speed lever and engine control to change gears from third to top, and from third to second, without appreciably checking the speed of the vehicle or clashing the gears. Assuming that when running on third-speed gear the bottom shaft (that connected to the cardan shaft) is running at 400 revolutions per minute, what will be the engine speed while driving through that gear. and what will be the engine speed on second gear when the bottom shaft is rotating at 300 revolutions per minute ? What is the use of a clutch stop, and when is it used? [Sketch reproduced on page 170.—ED] (40)