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Aviation History
1923
1923 - 0184.PDF
APRIL 5, 1923 By reason of the heavy flanges at each side of the big end., this bearing is exceptionally rigid, and in service shows a very long life. The articulated rods are of round hollow section of chrome nickel steel, bronze bushed at both ends. The knuckle pins which attach these to the master rod are fixed in the latter by clamping plates, one for each two pins, which not only hold them in place but prevent any rotation. By means of this system, all the knuckle pins can be removed through the opening formed by removing the front and intermediate covers, by merely removing the four locking plates and withdrawing the knuckle pins with a special form of puller which is provided. This can be done without removing the engine from the plane. The wrist pins float in both the pistons and connecting rods, and are held in place by small aluminium buttons, pressed into the ends of the hollow pin. The pistons are of conventional design and made of aluminium alloy with a 8HP i-M jn MO /600 ! f, &* *.P r" 1 1 rrfn a & r —r—i ^n a 1 *i II 11i f HOC —wPiu „,'. »AW ! 1 1 N T1 fl 1 *' 0 1**- S9 • 1 — Ma f\ ft • I— M -J- I f i 1I ! THE 220 H.P. LAWRANCE Jl AIR-COOLED AERO ENGINE : Power-curve chart. heavy flat head, and are provided with four rings above the pin and one in the skirt. The skirt ring, and the lowest upper ring are bevelled for half their surface, the bevel being toward the top, and act as wiper rings to prevent excess oil getting into the cylinders. The lubricating system consists of two oil pumps, one of which draws oil from the tank and delivers it to the crank- shaft, and another, which draws oil from the sump and returns it to the tank. These pumps are at the rear of the engine, and are driven by spur gears from the lower end of the synchroniser drive shafts. Incorporated in the casing of each pump is a chamber con- taining a strainer which can be removed separately or as a unit with the pumps. On the pressure pump is an oil by-pass valve controlled by a heavy spring, which is intended as a safety valve in case of too sudden warming up of the engine in cold weather, when the pressure might rise to a point where damage might occur. The oil flows from this pump through a fine mesh screen to a bearing on the rear of the crankshaft which is provided with spiral grooves at this point, so as to prevent oil leakage. It flows from here into the shaft, and also is led by small ducts to the top of the synchroniser drive ball-bearings, the fuel pump and electric generator and tachometer drive gears. The oil in the crankshaft travels through an ample passage to two holes located in the crank pin, where it is fed to the bearing by a pressure of approximately 50 lbs. Through small holes in the bearings it is led to the interior of the knuckle pins and thence to the knuckle pin bearings. The oil escaping from these bearings and from the sides of the main connecting rod bearing is thrown into the cylinders and lubricates the wrist pins, pistons and cylinders. The remainder of the oil in the shaft travels to the front end of the engine, where a small quantity escapes through a special jet, which projects into the inside of the shaft to prevent its possible obstruction by sediment. This oil sprays on the interior of the cam bearing, and also lubricates the cam followers and rollers and the cam drive and magneto drive mechanism. The remainder of the oil flows to the front end of the engine, where it escapes into an oil collector bearing. An adjustable oil pressure valve is located at this point maintain- ing any desired oil pressure in the system. The excess oil is then led back to the tank. The oil which is thrown off from the moving parts flows by gravity into a sump, from which it is drawn through a strainer to the oil return pump and thence to the tank. The inlet system consists of three NAS4 Stromberg car- buretors and three separate ring-shaped manifolds, each one of which acts as an independent intake system for three cylinders at 1200 from each other. The carburettors are equipped with altitude control, con- sisting of an auxiliary air inlet controlled by a throttle admitting air to a point between the Venturi and the main throttle. The flow of air through this passage also by means of a small communicating hole sets up a slight depression in the float chamber thus diminishing the flow of fuel at the jet. The float chambers are located at the side of the jet so that steep angles of climb and descent have no effect on the level of the fuel in the jet. The intake tubes leading from the crankcase to the cylinders are joined by rubber hose connections, thus allowing for ex- pansion and contraction and for slight errors in alignment. The ignition system consists of two Splitdorf SS9 magnetos having variable advance both running anti-clockwise at one and one-eighth engine speed. The rated power of the engine is 200 h.p. at 1,700 r.p.m-. but actually one engine developed considerably more than this. The accompanying horse-power curve shows a horse-power of about 215 at 1,700 r.p.m. which is the average performance of the engines now being produced. It will be seen that this power runs to 245 h.p. at 2,000 r.p.m-, and that the m.e.p. nowhere falls below 128 lb. per sq. in. The fuel con- sumption at full throttle is less than 0-05 lb. per h.p. hour when adjusted for maximum horse-power. When adjusted for minimum consumption, a figure as low as 0-46 lb. per h.p. hour can be obtained. The oil consumption is 0-03 lb. per h.p. hour. The same engine when fitted with 6 to 1 high-compression pistons and using a fuel consisting of half benzole and half aviation spirit, develops nearly 240 h.p. at 1,700 r.p.m. and 270 h.p. at 2,000 r.p.m. NOTICES TO AIRMEN Franco-Belgian Aerial Corridor 1. AN additional aerial corridor between France andBelgium, for the passage of machines flying on the London- Brussels northern route, has been established. This is acoastal corridor, 5 kilometres in width, commencing from the North Sea. 2. Previous Notices.—Para. 2 of Notice to Airmen No. 5of 1923 is amplified by this notice. (No. 21 of 1923.) Paris-Brussels : Official Route 1. THE following route between Paris and Brussels has been denned by the French and Belgian authorities :—- Between Le Bourget and St. Quentin.—The main road (route nationale) via Senlis, Verberie, Compiegne, Noyon and Ham. St. Quentin and the Belgian frontier.—The main road from St. Quentin to Cambrai as far as a point 3 kms. N. of Bellen- glise. From this point, the secondary road which runs in a straight line through Nauroy, Estrees, Maretz, west of Le Cateau, the western edge of the forest of Mormal, Bavai, Hon, La Ruelle and Curgies. The Belgian frontier and Mons.—The continuation of the above road through Sars-la-Bruyere, Eugies, Frameries and Cuesmes. Mons and Hal.—The road through Nimy, Soignies and Tubize. Hal and Brussels.—The Wilbroeck canal to the neighbour- hood of Haren aerodrome. 2. Rules of the Air.—The rules to be observed in following an officially recognised route are laid down in Notice to Airmen (No. 64 of 1922.) (No. 23 of 1923.) 184
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