uxiliary Planes.

Here again there is great diversity of opinion among aviators as to
size, location and form. The striking difference of ideas in this
respect is well illustrated in the choice made by prominent makers as
follows:

Voisin--horizontal rudder, with two wing-like planes, in front; box-like
longitudinal stability plane in rear, inside of which is a vertical
rudder.

Wright--large biplane horizontal rudder in front at considerable
distance--about 10 feet--from the main planes; vertical biplane rudder
in rear; ends of upper and lower main planes made flexible so they may
be moved.

Curtiss--horizontal biplane rudder, with vertical damping plane between
the rudder planes about 10 feet in front of main planes; vertical rudder
in rear; stabilizing planes at each end of upper main plane.

Bleriot--V-shaped stabilizing fin, projecting from rear of plane, with
broad end outward; to the broad end of this fin is hinged a vertical
rudder; horizontal biplane rudder, also in rear, under the fin.

These instances show forcefully the wide diversity of opinion existing
among experienced aviators as to the best manner of placing the rudders
and stabilizing, or auxiliary planes, and make manifest how hopeless
would be the task of attempting to select any one form and advise its
exclusive use.

Rudder and Auxiliary Construction.

The material used in the construction of the rudders and auxiliary
planes is the same as that used in the main planes--spruce for the
framework and some kind of rubberized or varnished cloth for the
covering. The frames are joined and wired in exactly the same manner
as the frames of the main planes, the purpose being to secure the same
strength and rigidity. Dimensions of the various parts depend upon the
plan adopted and the size of the main plane.

No details as to exact dimensions of these rudders and auxiliary planes
are obtainable. The various builders, while willing enough to supply
data as to the general measurements, weight, power, etc., of their
machines, appear to have overlooked the details of the auxiliary parts,
thinking, perhaps, that these were of no particular import to the
general public. In the Wright machine, the rear horizontal and front
vertical rudders may be set down as being about one-quarter (probably a
little less) the size of the main supporting planes.

Arrangement of Alighting Gear.

Most modern machines are equipped with an alighting gear, which not
only