THE VOISIN BIPLANE.
While the Wrights were busily engaged in developing their biplane in America, a group of enthusiasts in France were experimenting with gliders of various types, towing them with high speed automobiles along the roads, or with swift motor-boats upon the Seine. As an outcome of these experiments, in which they bore an active part, the Voisin brothers began building the biplanes which have made them famous.
As compared with the Wright machine, the Voisin aeroplane is of much heavier construction. It weighs 1,100 pounds. The main planes have a lateral spread of 37 feet 9 inches, and a breadth of 7 feet, giving a combined area of 540 square feet, the same as that of the Wright machine. The lower main plane is divided at the centre to allow the introduction of a trussed girder framework which carries the motor and propeller, the pilot’s seat, the controlling mechanism, and the running gear below; and it is extended forward to support the elevator. This is much lower than in the Wright machine, being nearly on the level of the lower plane. It is a single surface, divided at the centre, half being placed on each side of the girder. It has a combined area of 42 square feet, about half of that of the Wright elevator, and it is only 4 feet from the front edge of the main planes, instead of 10 feet as in the Wright machine. A framework nearly square in section, and about 25 feet long, extends to the rear, and supports a cellular, or box-like, tail, which forms a case in which is the rudder surface for steering to right or to left.
Diagram showing details of construction of the Voisin biplane. C, C, the curtains forming the stabilizing cells.
A distinctive feature of the Voisin biplane is the use of four vertical planes, or curtains, between the two main planes, forming two nearly square “cells” at the ends of the planes.
At the rear of the main planes, in the centre, is the single propeller. It is made of steel, two-bladed, and is 8 feet 6 inches in diameter. It is coupled directly to the shaft of the motor, making with it 1,200 revolutions per minute. The motor is of the V type, developing 50 horse-power, and giving a speed of 37 miles per hour.
Diagram showing the simplicity of control of the Voisin machine, all operations being performed by the wheel and its sliding axis.
The controls are all actuated by a rod sliding back and forth horizontally in front of the pilot’s seat, having a wheel at the end. The elevator is fastened to the rod by a crank lever, and is tilted up or down as the rod is pushed forward or pulled back. Turning the wheel from side to side moves the rudder in the rear. There are no devices for controlling the equilibrium. This is supposed to be maintained automatically by the fixed vertical curtains.
Voisin biplanes at the starting line at Rheims in August, 1909. They were flown by Louis Paulhan, who won third prize for distance, and Henri Rougier, who won fourth prize for altitude. In the elimination races to determine the contestants for the Bennett Cup, Paulhan won second place with the Voisin machine, being defeated only by Tissandier with a Wright machine. Other noted aviators who fly the Voisin machine are M. Bunau-Varilla and the Baroness de la Roche.
The machine is mounted on two wheels forward, and two smaller wheels under the tail.
This description applies to the standard Voisin biplane, which has been in much favor with many of the best known aviators. Recently the Voisins have brought out a new type in which the propeller has been placed in front of the planes, exerting a pulling force upon the machine, instead of pushing it as in the earlier type. The elevating plane has been removed to the rear, and combined with the rudder.
A racing type also has been produced, in which the vertical curtains have been removed and a parallel pair of long, narrow ailerons introduced between the main planes on both sides of the centre. This machine, it is claimed, has made better than 60 miles per hour.
The first Voisin biplane was built for Delagrange, and was flown by him with success.