Following are the principal dimensions of the six-cylinder motor:
- Bore 5 inches.
- Stroke 61⁄2 inches.
- Crank-shaft diameter throughout 2 inches.
- Length of crank-pin and main bearings 31⁄2 inches.
- Diameter of valves 3 inches (23⁄4 inches clear).
- Lift of valves 1⁄2 inch.
- Volume of compression space 22 per cent. of total.
- Diameter of wrist-pins 13⁄16 inches.
- Firing order 1-4-2-6-3-5.
The horse-power developed at 1200 revolutions per minute is 130, at 1300 revolutions per minute 140, at 1400 revolutions per minute 148. 1400 is the maximum speed at which it is recommended to run these motors.
TWELVE-CYLINDER ENGINE
A twelve-cylinder V-type engine [illustrated], is also being built by this company, similar in dimensions of cylinders to the six. The principal differences being in the drive to cam-shaft, which is through spur gears instead of bevel. A hinged type of connecting rod is used which does not increase the length of the motor and, at the same time, this construction provides for ample bearings. A double centrifugal water pump is provided for this motor, so as to distribute the water uniformly to both sets of cylinders. Four magnetos are used, two for each set of six cylinders. The magnetos are very accessibly located on a bracket on the spur gear cover. The carburetors are located on the outside of the motors, where they are very accessible, while the exhaust is in the center of the valley. The crank-shaft on the twelve is 21⁄2 inches in diameter and the shaft is bored to reduce weight. Dimensioned drawings of the twelve-cylinder engine are given at [Figs. 242] and [243] and should prove useful for purposes of comparison with other motors.
Fig. 242.—Dimensioned End View of Wisconsin Twelve-Cylinder Airplane Motor.
