The Lebaudy Patrie was a semi-rigid airship built for the French army in Moisson, France, by sugar producers Lebaudy Frères. Designed by Henri Julliot, Lebaudy's chief engineer, the Patrie was completed in November 1906 and handed over to the French army the following month. The Patrie bears the distinction of being the first airship built specifically for military service.The Patrie's predecessor, known as "Le Jaune" ("The Yellow (One)") because of its yellow lead chromate protective coating, was donated by Lebaudy Frères to the French army in September 1906 and was therefore the first airship to see military service in France.
In 1907, from her base at Chalais-Meudon near Paris, a successful series of military manoeuvres was conducted with the airship by the military command, which included a visit by France's President of the Council Georges Clemenceau. Following the successful completion of these operations, in November 1907 the Patrie was transferred under her own power to her operational base at Verdun, near the German border.
On 29 November 1907, the Patrie became stranded in Souhesmes, due to a mechanical fault. The following day, a storm rolled in and the Patrie was torn loose from her makeshift moorings and, despite the efforts of some 200 soldiers who tried to restrain the airship, she was carried away by the high winds and lost from sight. Had the rope to the emergency gas-release system been attached, her loss could possibly have been avoided. After being blown across the English Channel and passing unseen over England during the night, the Patrie was sighted over Wales and Ireland on 1 December. The airship made a brief landfall near Belfast, before rising again to be blown out over the Atlantic Ocean. She was last sighted by the crew of a steamship off the Hebrides and was never seen again.
Despite the loss of the Patrie, the Lebaudy Brothers went on to complete a sister-ship, the République, for the French Army. Several airships of a similar design to the Patrie were ordered and delivered to export customers, including Russia and Austro-Hungarian Empire.
Development
The military uses of airships at the time were considered to be the dropping of bombs (from an altitude at which they were deemed to be out of range of ground-based weapons) and reconnaissance. M. Julliot, the designer of the Patrie, stated that "each of the French ships can carry thirty, and on short journeys, even fifty torpedoes of 10 kilogrammes (22 lb) each." For reconnaissance purposes the Patrie was equipped with "a mounting for a telephotographic apparatus, and for a 100-candlepower acetylene searchlight". A contemporary author related that "from a height of the Patrie observed the smallest movements of formed bodies of troops at the Satory camp and obtained very clear telephotographs of them."
Semi-rigid airships were considered more suitable for military use because, unlike rigid airships, they could be deflated, stored and transported by land or by sea. The Patrie was a semi-rigid airship manufactured by the French sugar magnates Paul and Pierre Lebaudy and designed by their chief engineer, Henri Julliot. She was the second Lebaudy airship, and "surpassed her predecessor in both size and method of construction".Vivian (c1921) p.253. The company's first airship, simply known as the Lebaudy,The first Lebaudy airship, Lebaudy 1, underwent a series of reconstructions and was renamed 1bis, 2, 3 and 4 consecutively, thus making the Patrie only the second, completely new Lebaudy airship. and dubbed by the French public "Le Jaune" ("The Yellow (One)") because of the yellow colour of the lead chromate paint on its cloth exterior, was considered the most successful airship then in operation.
Design
Overview
The main structural components of the Patrie, like those of its predecessor, were the envelope (or "gas-bag"), a nickel-steel frame or keel, and a gondola suspended from the frame on steel cables. Contained within the envelope was a ballonet, the function of which was to ensure that sufficient gas pressure was maintained in the envelope at all times, irrespective of the degree of expansion or contraction of the lifting gas. Attached to both the gas-bag and the gondola were active and passive control surfaces to provide lateral and vertical stability and to give the pilot directional control over the airship.
The gondola, constructed of nickel-steel tubing, was suspended some 3.4 meters (11 feet) below an elliptical steel frame (or keel) attached to the bottom of the gas-bag, under the centre of lift. Between the frame and the envelope and linking the two was a small hemp net. The net was attached by wooden toggles to a canvas band sewn directly onto the envelope, and the frame was attached to the net by further toggles. This permitted the easy removal of the frame from the envelope. The frame itself could also be dismantled for ease of transport.
The open gondola offered the crew and passengers little protection from the elements. It was common for there to have been two pilots, two engineers and two passengers on board during test flights and military missions. Ballast, in the form of 10- and 20-pound (4.5 and 9.1 kg) bags of sand, could be jettisoned through a pipe set into the floor of the gondola. Other equipment included "a 'siren' speaking trumpet, carrier pigeons, iron pins, ropes for anchoring the airship, a reserve supply of fuel and water, and a fire extinguisher".
Envelope and ballonet The Patrie'''s envelope was composed of four alternating layers of cotton cloth and vulcanised rubber (the envelope of its predecessor, the Jaune, comprised three layers). The outside layer was of cotton cloth, covered with lead chromate to prevent the actinic components of sunlight from destroying the rubber skin which formed the second layer. This second layer prevented leakage of the hydrogen lifting gas from the envelope. The third layer was of cotton, which was protected by the rubber fourth and final layer from damage caused by the hydrogen. This final rubber layer was thinner, and therefore lighter, than the first. The rubber sheeting for the second and fourth layers was supplied by the German company Continental AG.
The lead chromate gave the envelope the same mustard-yellow colour as its precessor, "Le Jaune"; the remaining surfaces were coloured sky-blue, as is evident in a contemporary artist's impression of the Patrie.
The Patrie's design as a semi-rigid airship required that the pressure of both the lifting gas in the gas-bag and the air in the ballonet be sufficient to maintain the airship's overall shape. Sufficient hydrogen was pumped into the gas-bag to enable the airship to ascend to its intended maximum operating altitude of , at which height the ballonet would occupy approximately one-fifth of the total gas-bag volume. Descent was made by releasing hydrogen from the gas-bag and then pumping air into the ballonet to take up the volume of the released gas, a process which was repeated incrementally until the desired rate of descent or altitude had been achieved.
To control the movement of the hydrogen and air within the envelope, the Patrie was equipped with five valves, some of which operated automatically, and others which could also be operated manually by the pilot via cords. The valves on the gas-bag released hydrogen automatically when the pressure exceeded two inches of water (inAq) (500 Pa, 0.723 psi); whereas the ballonet valves opened when the air pressure exceeded 0.78 inAq (195 Pa, 0.282 psi), thus ensuring that air was driven out of the ballonet before there was any loss of hydrogen from the gas-bag. The automatic operation of the valves was a factor in the duration of its final (unmanned) flight (see Final flight section below). The pressure in the ballonet was maintained by an engine-driven fan, for which an electrical back-up was provided so that the pressures could be maintained in the event of an engine failure or when the engine had to be switched off for maintenance purposes.Squier, G.O. (in Flight Magazine), p.121.
A release mechanism was provided on the gas-bag, such that, in an emergency, a pull on the attached rope would release hydrogen from the gas-bag. This rope was attached to ballast, so that it would also be activated automatically in the case of a catastrophic loss of ballast. Failure to attach this rope was to play a pivotal role in the loss of the Patrie.
Since a partially filled ballonet would cause longitudinal instability, due to the mass of air rolling fore or aft in the direction of pitch, two cloth partitions were used to divide the ballonet into three separate compartments; small holes in the partitions allowed the air to permeate gradually throughout the ballonet without affecting the stability of the airship.Squier, G.O. (in Flight Magazine), p.122.
Steering and propulsion
Directional stability was achieved by four fixed vanes, two vertical and two horizontal, attached at the rear of the gas-bag, and by a long vertical vane running along the main axis of the gas-bag from the centre of the elliptical frame to its rear. Horizontal motion was controlled by the movement of a balanced rudder at the rear of an empennage on a long boom, mounted below the gas-bag and aft of the gondola (see lead image). The empennage consisted of vertical and horizontal vanes arranged like the fletching of an arrow, behind which the vertical rudder was mounted. During a refit in 1907 the vertical vanes of the empennage were modified, as is shown in the accompanying illustration.
During trials it was decided that a greater degree of control over vertical motion was required, which would also allow the pilot to compensate for "involuntary rising or falling of the airship due to expansion or contraction of the gas, or to other causes". For this purpose a movable horizontal plane was installed above the car and near the centre of gravity, which resulted in the loss of gas and ballast being reduced to a minimum.Squier, G.O. (in Flight Magazine), p.123.
At a later date this single plane was replaced by two movable planes mounted either side of and above the gondola, attached to the bottom of the elliptical frame, as shown in the plan view published in the German "Jahrbuch der Luftfahrt" ("Aviation Yearbook") in 1911.Vorreiter (1911) These "ailerons d'ascension et de descente" as they were referred to at the time,Nacelle de Dirigeable. delcampe.com, Retrieved: 24 April 2012. are clearly visible in the still photograph taken from the short film "Decollage d'un ballon dirigeable" ("The Take-off of a Dirigible Balloon"), made in Moisson by the pioneering French film-maker Alice Guy-Blaché before her emigration to the United States in March 1907.
The pilot operated the controls at the bows of the gondola, forward of the engine; the engineer controlled the engine from his position at the stern. A 52-kilowatt (70 hp) Panhard et Levassor four-cylinder engine running at 1,000 rpm, mounted centrally in the gondola, drove two 2.6-metre (8.5 ft) diameter, two-bladed steel propellers that were mounted on cantilever arms, one on each side, rotating at 1,000–1,200 rpm in opposite directions to prevent torque forces from twisting the airship. The exhaust pipe, below the rear of the gondola, was covered with metal gauze and pointed downwards to minimise the fire risk. The fuel tank, with a capacity in excess of 280 L (61.6 gal), was housed below the gondola within a pyramid of steel tubing that was designed to protect the gondola and the propellers during landing.
Operational history
November – December 1906