Something that is not talked about in either the plans or the construction manual is the toe-in adjustment for the wheels. This is a fairly critical procedure, because if any toe-out is present, the aircraft will be very difficult to control while taxiing and during the takeoff and landing roll.

The amount of toe-in is function of the length of the airplane. It is set by aligning the fore-aft centerline of each tire with a point that is located at a distance of ten times the aircraft length, on the extended centerline of the bird. Since the WAR Corsair is 15.9 feet long, the aiming point would be 159 feet away.

It is easier to solve this problem by trigonometry than by actually sighting over the tire to this point. Measure the distance between the centers of the tires and then halve this amount. This figure (about 3.07 feet), along with the 159 feet from above, give you two sides of a right triangle. Dividing the 3.07 feet by the 159 feet results in a number that is the tangent of the angle you are seeking. The angle is found by looking through a table of trigonometric functions until this value of the tangent is located, or is very closely approximated. The desired angle is then read from the table (about 1 degree).

The toe-in angle found by these calculations is fairly small, and as such is difficult, if not impossible, to set by the eyeball method. A more precise way of doing things involves measuring the distance from the front spar face to the inboard center of the wheel axle. Then wedge a straight piece of wood inside the axle from the inboard side. This should be just long enough to reach about half an inch short of the aircraft centerline. The remaining half inch or so is taken up by a nail driven in the end of the stick, after which the head is clipped off and the end ground to a point. Make sure that this stick is pushed inside the axle all the way, so that if forms a true extension of the axle centerline toward the middle of the airplane.

Draw a line across the bottom fuselage skin that is directly beneath the front face of the spar. Draw another line perpendicular to the first, along the centerline of the airplane, and measure off on it the same distance that was found between the axle and the spar. Drop a plumb line from this spot down to the end of the stick extending from the axle. Twist the wheel so that the end of the nail touches the string, which now makes the axle parallel to the spar face.

The problem now becomes one of how much to twist the wheel to achieve the proper toe-in. Block up a board beneath the airplane with one edge directly below the centerline of the bird and just touching the point of the nail in the end of the stick. A plumb line dropped from the front of the fuselage will help in lining up this board. Mark the spot where the end of the nail touches.

The next step is to calculate the distance rearward from this spot that the nail must move to set the toe-in. This is done once more by using the tangent of the angle. The value of the tangent was determined in the original problem, and the only measurement needed is that from the end of the nail to the center of the great strut. Multiply this amount, converted to inches, by the value of the tangent and you have the distance the nail must move aft of the first mark to set the toe-in ( .67 inches). (The numbers used in both these examples are representative figures ONLY.

You should make actual measurements from your aircraft and set of plans.) All of the procedures described here must be accomplished with the aircraft resting on the gear with the engine installed, and the tail propped up so that the fuselage is level. The reason for making these adjustments after the engine is mounted is to approximate the actual weight distribution of the finished airplane as closely as possible. It would help even more to have someone sit in the cockpit during this procedure.