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Aviation History
1919
1919 - 0871.PDF
JULY 3, 1919 endurance tests during which the power, speed, fuel con sumption, etc., are read off and noted. When prolonged tests have failed to reveal any more improvements, and not till then, the engine is installed in an aeroplane and given its flying tests. If any defects are developed during these, the engine is returned to the works and the defective parts re-designed and tested until satisfactory* when all the tests on the bench as well as in the air, are gone through again. It will be obvious from the brief indication given of the thoroughness of the experimental work done on an engine before it is allowed to pass from the experimental into the production factory, that the Cosmos engines are not just designed to look pretty on paper and excellent in theory> but have to pass through the hard tests of practical experience^ in which faulty or unsatisfactory design is ruthlessly scrapped.' By thus insisting on perfection, and refusing to accept any thing short of what he demands of his engines, Mr. Fedden is laying for the Cosmos engines a foundation on which to build a great reputation in future commercial aviation. It has already been pointed out that the Cosmos Engineering Co., Ltd., is concentrating on one type of aero engine, the radial air-cooled. Within this type, however, four different models have already been designed, two of which are in production, while the other two, although they have been experimented with, have not yet fully convinced Mr. Fedden that they are ready for passing into production. From what has been said regarding the thoroughness of the Cosmos testing, it will be realised that when the other two models are placed on the market, they may be expected to perform according to promise. The Cosmos " Mercury " Engine Of the two models which have passed into production the "Mercury" was designed first. It was designed in 19*7 and perfected in the early part of 1918. This engine was produced to conform to the special requirements of the Government, i.e., it was designed within the limits of 42 ins. maximum diameter, its overall dimensions being 41I ins. The "Mercury" is a 14-cylindered radial engine, with its cylinders in two rows of seven each, the cylinders of the back row being placed opposite the spaces between the cylinders of the front row. The main features of the engine are as follow : Bore and stroke 4$ ins. by 5IJ ins. Normal power (calibrated on Froude dynamometer) 315 b.h.p. at 1,800 r.p.m. Maximum b.h.p. 347 at 2,000 r.p.m. Total weight with full equip ment, including carburettors, magnetos, Remy distributor and coil, and Constantinesco gun gear—587 lbs. (This weight does not include exhaust pipes, as these are specially designed to suit the machine into which the engine is being fitted.) The cylinders are of steel, machined from the solid, with fins formed integral with the cylinder barrel. The cylinder head is a separate aluminium casting carrying the valves and valve rockers and, owing to the heat conductivity of this separate cylinder head, the cooling is more effective, while the liability to distortion is claimed to be reduced to a minimum. There are three valves per cylinder, two exhaust and one inlet. The valves are operated via push rods located at the rear of the cylinders, by a double cam ring at the back of the engine. The crankshaft is of the two-throw type, and runs on roller bearings. As the drive is direct, the propeller shaft is integral with the crankshaft. The con necting-rods are of special design to accommodate the roller bearings. It might be mentioned that both the crankpins and crankshaft and also the connecting-rods are case-hardened and ground. The crankcase is a one-piece casting, the holes for the cylinders being arranged in a slight spiral to accommodate the grouping of the connecting-rods. The back of the crank- case is provided with a rigid circular flange of large diameter through which pass the bolts attaching the engine to the fuselage. This simple form of support has been found quite satisfactory in practice. Between this circular flange and the back cover of the crankcase are the two circular induction chambers through which the two-cylinder groups are supplied with gas from two carburettors. Dual ignition is provided, by two M.L. 7 cyl. magnetos in conjunction with the 14 cyl. Remy distributor and coil. Lubrication is on the dry sump principle, there being two spur-gear pumps, one of which is a delivery pump sucking oil from the tank and delivering it, under pressure, of course, to the hollow crankshaft and other bearings, separate leads going to the auxiliary drives. Another pump sucks the oil EI SI Removal of Air Ministry Meteorological Branch THE Air Ministry Meteorological Branch has removed to Canada House, Kingsway. The address for correspondence is : Secretary, Air Ministry (F.O. 5), Canada House, Kings- Hjjfjgj from the crankcase and delivers it back to the main supply- There are two niters in the oil system. The Cosmos " Jupiter " Engine Although differing in many details from the " Mercury," the " Jupiter" engine has many features in common with its prototype. It is, however, a nine cylindered single-row engine. It will be marketed in two types, series 1 being of the direct-drive type, while in the series 2 type there is an epicyclic reduction gear giving 1,300 r.p.m. to the propeller shaft. The direct-drive engine has the following main features : Bore and stroke 5! ins. by y% ins. Normal power 450 b.h.p. at 1,800 r.p.m. Total weight including car burettors, magnetos, electric starter, Constantinesco gun gear, and all accessories, 662 lbs. The series 2 engine is rated at 500 h.p. Except for the difference in dimensions the cylinders of the " Jupiter " are, generally speaking, similar to those of the " Mercury," having the same separate aluminium head, which has again been successful in avoiding distortion and maintaining a high B.M.E.P.; about 118 lbs., we believe. There are four valves in each cylinder, two inlets and two exhausts. The crankshaft, needless to say, is of the single-throw type and is a solid shaft made of Ki steel, running in roller bearings. The connecting-rod assembly differs from that of the " Mer cury " in that there is a master connecting-rod with eight articulated rods. The master rod has a white-metal lined bearing. The crankcase is a two-piece aluminium casting, split vertically, with long bolts passing right through the crankcase and holding the engine to the fuselage. One of the most interesting features of the " Jupiter " engine is the induction system. There is an annular induction chamber, provided with a cover, machined on the inside, into which is fitted a spiral aluminium casting which forms the distribution system of the engine. The pitch of this spiral casting is such that by bolting the three carburettors on to the cover of the annular induction chamber one carburettor feeds three cylinders in proper rotation. This forms a special, patented feature of the " Jupiter " engine. The advantages claimed for it are that it ensures an excellent distribution of the mixture, and at the same time obviates cutting-out of the engine in the event of one cylinder getting out of commission, as each of the three carburettors has an entirely separate induction system, isolated from the other two. As in the " Mercury," dual ignition is provided, the two magnetos being Thomson-Bennett 9 cyl. driven by bevel gearing off the crankshaft. As will be seen from the rear view of the engine, the magnetos are mounted at an angle to the back cover, so that when the engine is installed in an aeroplane the contact breakers, etc., are readily accessible. The lubrication system is similar to that of the " Mercury," ie., it is of the dry-sump type, with two pumps ; one delivery pump and one suction pump. Both the " Mercury " and the " Jupiter " engines have, as already mentioned, passed their bench and flying tests, and have gone into production. The former was installed in a Bristol scout, which gave the following performance : Climbed to 10,000 ft. in 5 mins. 25 sees. ; to 20,000 ft. in 16 mins. 15 sees. Speed at 10,000 ft. 143 m.p.h. The " Jupiter " fitted on a Bristol " Badger " biplane, has also given very good results, as the following performance figures indicate : Total weight of machine, including pilot and passenger, military load, two machine guns, etc., 2,800 lbs., engine revolutions on ground, 1,550 r.p.m.; average revs, when climbing at 80 m.p.h., 1,600 r.p.m. ; revs, flying level at 7,000 ft., at a speed of 125 m.p.h., 1,850 r.p.m. The times for climbing were : 2,000 ft. in 1 min. 4 sees.; 4,000 ft. in 2 mins. 10 sees. ; 6,000 ft. in 2 mins. 33 sees. ; and 7,000 ft. in 4 mins. 15 sees. The figures relating to the performance of the " Badger " are not official, but were, we understand, obtained during preliminary tests. As already mentioned, the Cosmos Engineering Co., Ltd.. will market, later on, two more models. One of these will be a three-cylinder radial air-cooled with a bore and stroke of 5| ins. by 6$ ins. It will be known as the " Lucifer," and is expected to develop about 100 h.p. for a weight, complete of about 220 lbs. The second model will be a large one of about 1,000 h.p., and will, in effect, consist of a two-row " Jupiter." The bore and stroke will be 6J ins. by 7$ ins., and the weight is not expected to exceed 1.400 lbs. complete. E 13 way, London, W.C. The telegraphic address will be as heretofore, Flyingdom, Phone, London. Requests for weather reports by telephone should be made to Holborn 2951, Extensions 520, 521, 522, 523, 524 or 525. I
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