Practical Hand Book of Gas, Oil and Steam Engines / Stationary, Marine, Traction; Gas Burners, Oil Burners, Etc.; Farm, Traction, Automobile, Locomotive; A simple, practical and comprehensive book on the construction, operation and repair of all kinds of engines. Dealing with the various parts in detail and the various types of engines and also the use of different kinds of fuel.

by John B. Rathbun

(47) The “V” Type Motor.

An example of the “V” type motor is shown by Fig. 22, which is a front elevation of the Frontier aeronautic motor, a type that occupies a minimum of space with a minimum of weight.

Fig. 22. End Elevation of Frontier 8 Cylinder “V” Type Motor.

The cylinders are cast separately and are furnished either with iron or copper water jackets, the copper jackets being deposited over the cylinder barrels by an electrolytic process in much the same way as that of the celebrated French Antoinette. Bolts passing through flanges on the bottom of the cylinder fasten them to the base. A special aluminum alloy is used for the base which is cast in a single piece with webs to receive the bearings. A unit crank-case insures perfect alignment, prevents a greater part of the oil leakage, and forms a much stronger construction than the usual split pattern. A chamber is provided for the cam shaft at the apex of the case through which issue the push-rods. Shafts and piston pins are hollow. All push rods are adjustable for wear and have steel balls running on the cams which eliminate the possibility of mis-timing through wear.

Lubrication is by a bronze pump geared from the crank-shaft and is connected to an oil tank located in the base from which the oil is forced through the crank-shaft up through the hollow connecting rods to the piston pins, thence to the cylinder walls, the surplus returning to the tank in which the strainer is located.

The circulating pump is driven from the cam shaft as shown in the cut and supplies the cylinders and radiator with water through the copper water manifolds which are designed to give an equal supply to each cylinder. Exhaust manifolds are of seamless steel tubing.

The cylinders are 4⅛ bore × 4⅜ stroke, and develop 60 to 70 horse-power at 1,100 revolutions per minute, which speed has been attained with an 8-foot 6-inch propeller having a pitch of 5 feet. Without radiator or propeller, the iron jacketed motor weighs 312 pounds, and copper jacketed weighs 290 pounds, the latter making a difference of 22 pounds in the weight.

A high tension Bosch magneto is used which is mounted on a pad cast on the top of the crank-case and is driven from a gear meshing with the cam shaft gear. Connection is made from the magneto to plugs placed over the inlet valves in the valve caps.

A 100 horse-power aero engine of the “V” type is shown by Figs. 23–24–25, which is built by the All British Engine Company for the aeronautical branch of the English War Department. It has eight cylinders of 5 inch bore, by 4¼ inch stroke, and develops its rated horse-power at 1,200 revolutions per minute. Data from “Aero,” London.

Fig. 23. Longitudinal Section Through A. B. C. 100 Horse-Power “V” Motor.

The crankshaft, which is of three per cent nickel chrome steel, having an ultimate tensile strength of 157,000 lbs. per sq. in., is of distinctly large diameter, and is carried in plain bearings lined with white metal. It is provided with four throws, each crank pin being arranged to take the big end bearings of two connecting rods from cylinders on opposite sides of the crank case. There is a bearing between each throw, and in order to reduce the overall length of the engine the cylinders are staggered on the crank case. The H section connecting rods are stamped out of steel having a tensile strength of 90,000 lbs. per sq. in., and for the purpose of lubrication a hole is drilled from end to end down the center of the web. As mentioned before, the cylinders are staggered, and there is no overhanging of the big end bearings at the point of attachment to the connecting rod. The bearings themselves are lined with white metal. The small end bearings are provided with phosphor bronze bushes, and the piston pin is of steel bored out hollow and hardened.

Fig. 24. Valves and Valve Motion of A. B. C. Motor. (“Aero,” London.)

A very interesting detail of the engine is the combination of the water outlet pipe from the top of the cylinder with the bearings for the rocking arms (which are steel stampings) actuating the valves. This is shown in Fig. 25. A hollow steel column is bolted to the top of the cylinder and protrudes from the water jacket, which is fastened to it with the usual shrunk ring. To this column is attached a hollow T shaped pipe of phosphor bronze, the column of the T piece forming the outlet for the water. On one arm of the T piece the exhaust rocker takes its bearing and on the other the inlet rocker. Each T piece arm is connected to its fellow on the next cylinder by means of rubber pip.

Fig. 25. End Elevation of A. B. C. Motor.

A small bracket projecting from the T piece forms a saddle on which the valve spring rests. This is a plain semi-elliptical leaf spring which works both valves. It is slotted at each end and slightly turned up so as to engage with a cotter pin passed through a slot in the end of the valve stem.

The crank case is of rather unusual design, being absolutely circular in section and machined all over. It is practically a tube with flanged portions bolted on to form the ends. Having no horizontal joints, it is strong and easily kept oil tight. Three radial arms, with slight webs and reinforced with steel columns down the center, support each bearing. The crank case is carried by four feet, which are arranged to accommodate three different widths of engine bearer. To the fore end of the crank case is bolted a long conical aluminum nose carrying at its extremity a compound push and pull ball bearing 6 in. in diameter, which supports an extension shaft bolted to the crankshaft by means of a flanged coupling.

Fig. 24-a. “Sixteen” Cylinder Favata Radial Type Aero Motor, Consisting of Four Groups of Two Cylinders Per Group. Cylinders are of the Double Acting Type and are Stationary.

At the outer end of this extension is a flange to which the propeller is bolted, but the arrangement is specially devised to make quick detachment possible. The boss of the propeller has a hollow hub and is plate bolted permanently to it by twelve bolts.

The direct nose is interchangeable with a speed reduction gear so that the propeller can be driven at a lower speed than the engine. Fitting this gear nose raises the center line of the propeller-shaft some 5¼ in. The gears are carried on substantial ball bearings, plain bearings being used also in such a way that they take up the load if the ball bearings through any cause should fail. The reduction is by means of silent chains. The arrangement of the gear wheels is plain from the drawing, and it will be noticed that there is no intermediate wheel between the crankshaft pinion and the camshaft wheel, which are of steel and phosphor bronze respectively. A separate gear wheel is provided on the camshaft for driving the magneto. The water and oil pumps are carried low down outside the crank case, and are driven by intermediate wheels at double the engine speed. The shafts are joined together through Oldham couplings, so that it is possible to remove the pumps separately. Both these pumps are of the gear type.

The camshaft is made in one piece with the cams, and is hardened, being drilled out for lightness. It is enclosed in a casing of steel tube, which is practically separate from the crank case, being attached thereto at one end by the timing gear case and at the other by a saddle. The camshaft is carried in six bearings. An interesting point is the fact that the gear wheels are bolted to flanges on the shafts instead of being attached by keys. Carried in the tube directly above the camshaft is a second shaft forming the fulcrum of the rocking arms for the cam rollers. A very interesting point is the provision of an arrangement for lifting the exhaust valves. The little rocking arms carrying the rollers which bear upon the cams are provided with webs, parallel with the camshaft and between it and the shaft carrying the rockers is a third shaft, the sides of which normally just clear the webs of the rocking arms on either side. This shaft is provided with wedge shape pieces along it, so that by sliding it along the wedges lift the rocking arms clear of the cams, and thus, through the tappet rods and rockers, the valves themselves are opened.

Fig. 26. Mesta Engines on Test Floor.

Not the least interesting particular of this engine is the thorough way in which the lubrication is carried out. Four of the bolts which attach the caps of the main bearings are prolonged through the bottom of the crank case, and serve to carry a detachable oil sump which holds sufficient oil for a run of six hours. As already mentioned, the oil pump is driven at twice the engine speed, and maintains a pressure of something like 110 pounds per square inch. It delivers directly into a straight steel tube placed along the bottom of the crank case, and from this tube a vertical tubular connection is taken to each of the caps of the main bearings. The crankshaft and crank pins are hollow, and, as in the previous engine, in the hollow portions tubes of a slightly smaller diameter are placed, the tubes being expanded over at the ends, so that closed annular spaces are formed which are used as lubrication leads. The lubricating oil passes through the main bearings into these annular spaces in the shafts, from them to the annular spaces in the crank pins, and so to the big-end bearings. From the big-end bearings it travels up the connecting rods to the gudgeon pins. It is interesting to note at this point that the connecting rods work in slots in the crank case which just allow sufficient clearance for their travel, in order to prevent the flooding of oil into the cylinders. A steel-lined oil lead is taken up to the saddle which supports the tubular camshaft casing at the propeller end of the crank case. The bearings carrying the camshaft are cut away at their lower edges clear of the tube so that the oil can flow along the full length of the casing, the level being sufficient to allow the cams to dip. Precautions are taken to keep oil from flowing out of the bearings, and the casing over the gears is specially arranged to prevent the oil from flooding below.