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Aviation History
1914
1914 - 0447.PDF
APRIL 25, 1014. British design of the double-motion rotary type, in which the cylinders and crank-shaft rotate in opposite directions and at the same speed of revolution—hence, although the relative speed of the cylinders to the crank-shaft is 1,600 revs, per min. as stated in the Table, the actual speed is only 800 revs, per min. This motor I/DCNT] bevel wheel with which a small pinion engages. This pinion is mounted on a bush supported in the wall of the crankcase, which can be rotated by means of a key from the outside, so that the cylinders may be readily assembled on or dismantled from the engine with the minimum of disturbance of other parts. The valves are operated directly from a camshaft which runs on ball-bearings, placed midway between the heads of the cylinders -, the camshaft being driven from the crankshaft by bevel gearing through a vertical driving shaft. Cast-iron pistons of special design to ensure lightness are fitted and the connecting-rods, which are of tubular form, run upon roller bearings on a nickel chrome crankshaft —the bearings being held in position by a strap that encircles about two-thirds of the circum ference of the shaft. Particular attention is drawn to the method of supporting the crank shaft, which weighs 14 lbs., in the main bearings, which are of the ball type. This construction is adopted for the purpose of obtaining great rigidity, and it will be seen that the bearing caps are held between the " horns " by trans verse bolts, while double U-bolts, which pass through columns formed integral with the crank- case to the upper surface, secure the bearing cap^ jn position against the ball-race. The special inclined crankwebs should also be noted, as these greatly facilitate the assembling of the ball and roller bearings upon the shaft. The propeller, as in many engines nowadays, is not directly coupled to thecrankshaft, but a special shaft, of ample length to resist lateral flexure and distortion, is provided suitably mounted nn ball bearings, and fitted with double-thrust bearings that can take either a thrust or a pull, the ratio of the gear-reduction being I"8 to I. Thus, with an engine speed of 1,620 revs, per Cross sectional elevation of the 100 h.p. E.N.V. engine has been in course of development for some time, and as far back as February, 1913, reference was made to it in FLIGHT ; but experiments carried out since then have justified die opinion of its inventor, and it has been shown that much higher speeds of revolution than that men tioned can be employed, if desired, without detriment, when it develops proportion ately greater power. With a compression pres sure of 75 lbs. per sq. in. the engine easily reaches its rated horse power at 1,600 revs, per min. The inlet and the exhaust valves are of a special concentric design and afford very large areas for the passage of the gases. We hope to deal with this engine fully in the near future. The E.N.V. Motor is by no means new to the aeronautical world, for as far back as 1908-09 Mr. Moore-Brabazon had one fitted upon his machine, but the E.N.V. Motor Co., of Willesden, N.W., has now formed to design and manufacture an entirely new engine which embodies many features of special interest. The cylinders are still arranged "en V" and provided with electrolytically-deposited copper jackets, but the cylinder con struction is much changed, as may be seen on an examination of the accompanying illustrations. The cylinders are held in place on an aluminium crank-case by a screwed collar that forms a part of a Longitudinal sectional elevation of the 100 h.p. E.N.V. engine. min., the propeller rotates at 900 revs, per min. The bottom half of the crank-chamber is an aluminium casting, and is attached to the upper half by straps that are secured by eye-bolts and nuts to lugs formed thereon ; whilst the engine is supported on two steel tubes that pass right through bosses cast integral with the crank-case. The water-circulating pump is of the centrifugal type, and is driven directly from the same end of the crankshaft as that at which the radiator, which is a fixed unit with the engine, is mounted. The multiple plunger oil-pump is seen in the box to the extreme right of the longitudinal sectional elevation, and is driven by worm and bevel gearing from the vertical driving shaft. A Bosch ILL. 447
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