Louis Breguet experimented with airplanes for many years at Douai, France, and gradually evolved, step by step, one of the best of the early flying machines. It is interesting to note that the first successful helicopter to lift a man was built by him and M. Richet in 1907, the total weight lifted being 1,100 pounds. The elegance of lines and the simplicity of his biplane resulted from patient and diligent study of the subject. This machine was especially remarkable for its lift and the wonderful steadiness with which it could “volplane.”
On April 8th, 1910, the Breguet biplane carried three people at once and flew with such great ease, that the attention of the aviation world was attracted to Douai. At Rouen, at Rheims, and at many other air races, the Breguet biplanes, piloted by Breguet himself and by Bathiat, not only won many prizes for passenger flights, but proved to be extremely speedy and reliable. During the French Army maneuvers, Breguet, with Captain Madiot, made some impressive reconnoitering trips. On September 1st, 1910, a flight was made with five persons aboard, the pilot and four passengers making a total load of 750 pounds. This performance was exceeded, by the same machine a few weeks later, when the pilot and five passengers made a flight, with a total load carried of about 860 pounds. But in the rapid advance of aviation in those dayds, that performance was soon exceeded by Sommer and Bleriot. On December 31st, 1910, the Breguet biplane made a distance flight of 205 miles.
Specifications from “Monoplanes and Biplanes,” by Grover Loening, 1911
The Frame
The Breguet biplane is one of the few present-day types in which wooden framework is practically eliminated. A long covered fuselage, rectangular in section at the front and semicircular at the rear, gradually tapers to a point, giving practically a “stream line” form. This frame is made of steel tubing at the front, but at the rear, where great strength is not so necessary, there are some wooden crosspieces. The motor is mounted at the front end; the planes arc also at the front; the pilot sits back of the planes with a passenger scat in front of him, approximately over the center of pressure; and at the rear are carried the rudders.
Main Wings
The framework of the main planes consists essentially of two main steel tube cross pieces to which are fixed the numerous ribs. The ribs are made of a U-shaped piece of aluminum sheeting,-and are fastened to the steel tubes by an ingenious elastic joint. The entire frame is covered with a specially smoothed and oiled fabric. The section of the planes is an evenly curved one, thick and blunt at the front and narrowing to a fine edge at the rear. The planes are not of the same size, the lower one being smaller than the upper. They are, however, directly superimposed, and are mutually supported and fixed to the framework by only four vertical steel tube struts. The “box cell” arrangement is altogether absent. The planes are braced by steel rods to the central frame, and the usual maze of cross-wires is eliminated.
This type of construction reduces the head resistance, and considerably increases the lifting force for a given horse-power. By reason of the great elasticity of the planes, they give a little under pulsations of the wind, and transmit the disturbing forces of the air waves to the frame, greatly diminished. The aeroplane is therefore suspended elastically in its element, and is in consequence assured of a higher degree of stability and a lesser fatigue of its parts. It is possible because of this elasticity that, similar as it is to the elasticity of a bird’s wing, the planes may profit by the “internal work of the wind,” and thus is explained, in a measure, their high lifting quality. The planes are about 7 feet apart. The upper ones are set at a slight dihedral angle. The spread of the upper plane is 43 1/2 feet, the spread of the lower plane 32 1/2 feet, and their depth 5 1/2 feet. The total supporting surface is 409 square feet.
Elevators
At the rear of the machine, mounted on a universal joint and held by springs, is a cruciform tail-piece, the horizontal surface of which serves as the elevation rudder. This surface normally is “non-lifting,” and has an area of approximately 25 square feet. By pushing forward on the steering column mounted in front of the pilot, the entire tail is turned down, thus lifting up the rear of the machine, reducing the angle of incidence of the main surfaces, and thereby causing the machine to descend. By pulling this column toward him, the aviator causes the machine to ascend.
The Direction Rudder
The vertical surface of the tail serves as the direction rudder, and is moved to either side by operation of the steering-wheel fixed on the control column.
Roll Control
The transverse equilibrium of the machine is controlled by the ordinary system of warping. By moving the entire control column, wheel and all, to the right, for example, the rear edge of the left plane is turned down, thus increasing the lift on that side.
Keel
The cruciform tail-piece not only serves as a rudder for both elevation and direction, but in its normal position acts as a stabilizing keel of great power. Due to the springy character of this member, the stability is made somewhat automatic. If a sudden gust should hit the under side of the tail, the machine would tend to tilt up at the rear, and therefore descend. But this same gust would cause the tail to be turned up by an amount exactly proportional to the strength of the gust. Since a turning up of the tail is the movement for ascent, the tendency for the gust to cause the machine to descend will be counteracted in proportion to the strength of the gust. Since, in addition, the weight of this machine is great, and its momentum therefore quite large, this form of stabilizing device does actually act, and very forcibly hold, the machine to its course.
Propulsion
The motor is placed at the front, and drives the propeller through reducing gear. A 40 to 50 horse-power motor is necessary, the usual types used being the Gnome, Renault or R. E. P. The propeller was formerly a three-bladed Breguet metallic one, but of late a two-bladed Chauviere wooden “Integral” has been used, almost 9 feet in diameter, 6 1/2 feet pitch, and rotating at 800 r.p.m.
Landing Gear
The landing gear is mainly on a set of two heavy rubber-tired wheels fitted on skids with oleo-pneumatic springs under the centre of gravity, and an extra heavy wheel and skid at the front to take very sudden landing shocks and protect the front of the frame, propeller, etc. This wheel can be turned as on an automobile.
Weight, Speed, Loading and Aspect Ratio
The total weight of the machine in flight varies from 1,100 pounds with pilot alone, up to 1,800 pounds with six aboard. The speed is approximately 53 miles an hour. The maximum pounds lifted per horse-power are 36, and maximum loading is 4.4 pounds per square foot of carrying surface. The aspect ratio of the upper plane is 7.9 to 1 - an extremely high value.
There is also a 60 horse-power “racing type” of Breguet biplane, for which a speed of 62 miles an hour is claimed. The characteristics of this machine are: Spread of upper plane, 40 feet; spread of lower plane, 30 feet; depth, 4 1/2 feet; surface area, 280 square feet; weight. 1,300 to 1,500 pounds; pounds per horsepower, 25; pounds per square foot, 5.4; and aspect ratio of 7.1 to 1.