When the motor is water-cooled, there will inevitably be some difficulty in finding room for a radiator of sufficient size. One scheme is to use twin radiators, one on each side of the fuselage, inside of the main frame of the running gear. Another plan is to place the radiator underneath the fuselage, using a supplementary water tank above the cylinders to facilitate circulation. These two seem to be about the only practicable arrangements, as behind the motor the radiator would not get enough air, and above it would obstruct the view of the operator.
It is impossible to generalize to much effect about the method of supporting the motor in the fuselage, as this must differ with the motor. Automobile-type motors will be carried on two heavy ash beams, braced by lengths of steel tubing of about 1 inch diameter and 16 gauge. When the seven-cylinder rotary Gnome motor is used, the crank shaft alone is supported; it is carried at the center of two X-shaped frames of pressed steel, one in front of and the other behind the motor. The three-cylinder Anzani motors are carried on four lengths of channel steel bent to fit around the upper and lower portions of the crank case, which is of the motorcycle type.
Considerable care should be taken to prevent the exhaust from blowing back into the operator's face as this sometimes carries with it drops of burning oil, besides disagreeable smoke and fumes. The usual plan is to arrange a sloping dashboard of sheet aluminum so as to deflect the gases down under the fuselage.
The three sections of the fuselage back of the engine section are usually covered on the sides and bottom with cloth like that used on the wings. Sometimes sheet aluminum is used to cover the section between the wing beams. However, those who are just learning to operate machines and are a little doubtful about their landings often leave off the covering in order to be able to see the ground immediately beneath their front wheels.
Fig. 35. Running Gear of Morane Type of Bleriot Monoplane
New Features. Morane Landing Gear. Although the regular Bleriot landing gear already described, has many advantages and ha.s been in use with only detail changes for several years, some aviators prefer the landing gear of the new Morane monoplane, which in other respects closely resembles the Bleriot. This gear, Fig. 35, is an adaptation of that long in use on the Henri Farman and Sommer biplanes, combining skids and wheels with rubber-band springs. In case a wheel or spring breaks, whether due to a defect or to a rough landing, the skids often save an upset. Besides, the tension of the springs is usually such that on a rough landing the wheels jump up and allow the skids to take the shock; this also prevents the excessive rebound of the Bleriot springs under similar conditions.
Another advantage which may have some weight with the amateur builder, is that the Morane running gear is much cheaper and easier to construct. Instead of the two heavy tubes, the four forks of oval tubing, and the many slides, collars, and blocks—most of them special forgings or castings—the Morane gear simply requires two short laminated skids, four ash struts, and some sheet steel.
The laminated skids are built up of three boards each of 5/8 by 2-inch ash, 3 1/2 feet long. These must be glued under heavy pressure in forms giving the proper curve at the front end. When they are taken from the press, three or four 1/2-inch holes should be bored at equal distances along the center line and wood pins driven in; these help in retaining the curve. The finished size of the skids should be 1 3/4 by 1 3/4 inches.
Four ash struts 1 1/4 by 2 1/2 inches support the fuselage. They are rounded off to an oval shape except at the ends, where they are attached to the skids and the fuselage beams with clamps of 1/16 inch sheet steel. The ends of the struts must be beveled off carefully to make a good fit; they spread out 15 degrees from the vertical, and the rear pair have a backward slant of 30 degrees from vertical.