was intended to be automatically stable in both senses; whereas
the Wrights deliberately produced a machine which was entirely
dependent upon the pilot's skill for its stability. The
dimensions of the Voisin may be given for comparative purposes,
and were as follows: Span 33 feet with a chord (width from back
to front) of main planes of 6 1/2 feet, giving a total area of
430 square feet. The 50 horse-power Antoinette engine, which was
enclosed in the body (or 'nacelle ') in the front of which the
pilot sat, drove a propeller behind, revolving between the
outriggers carrying the tail. The total weight, including Farman
as pilot, is given as 1,540 lbs., so that the machine was much
heavier than either of the others; the weight per horse-power
being midway between the Santos-Dumont and the Wright at 31 lbs.
per square foot, while the wing loading was considerably greater
than either at 3 1/2 lbs. per square foot. The Voisin machine
was
experimented with by Farman and Delagrange from about June 1907
onwards, and was in the subsequent years developed by Farman; and
right up to the commencement of the War upheld the principles of
the box-kite method of construction for training purposes. The
chief modification of the original design was the addition of
flaps (or ailerons) at the rear extremities of the main planes to
give lateral control, in a manner analogous to the wing-warping
method invented by the Wrights, as a result of which the end
curtains between the planes were abolished. An additional
elevator was fitted at the rear of the fixed biplane tail, which
eventually led to the discarding of the front elevator
altogether. During the same period the Wright machine came into
line with the others by the fitting of a wheeled undercarriage
integral with the machine. A fixed horizontal tail was also