four frame pieces. Two 20-foot pieces joined in this
way will give a substantial frame, but when suitable
timber of this kind can not be had, three pieces, each 6
feet 11 inches long, may be used. This would give 20
feet 9 inches, of which 8 inches will be taken up in the
two joints, leaving the frame 20 feet 1 inch long.

Installation of Motor.

Next comes the installation of the motor. The kinds
and efficiency of the various types are described in the
following chapter (IX). All we are interested in at
this point is the manner of installation. This varies
according to the personal ideas of the aviator. Thus one
man puts his motor in the front of his machine, another
places it in the center, and still another finds the rear of
the frame the best. All get good results, the comparative
advantages of which it is difficult to estimate. Where
one man, as already explained, flies faster than another,
the one beaten from the speed standpoint has an advantage
in the matter of carrying weight, etc.

The ideas of various well-known aviators as to the
correct placing of motors may be had from the following:

Wrights--In rear of machine and to one side.

Curtiss--Well to rear, about midway between upper
and lower planes.