At the start of World War I observation balloons, the use of which was discontinued in France in 1912, were needed on the battlefield, and the Germans used them in large quantities called Drachen. The French who did not have any in their boxes therefore began to copy these German balloons.

While he was mobilized on 1st August 1914 to command the 21th company of balloonists, Albert Caquot performed some aerial observations in a spherical ball type from 1880, then found that the information given by the observers are not reliable due to the instability of the aerostats which makes them sick even in light winds. He then designed a new balloon stabilized by three inflatable rear lobes arranged at 120°. He then sent his plans and calculations to the Atelier de Chalais-Meudon in October 1914 and was received by the director of the establishment in November; but he is not convinced by his idea. Despite everything, he decides to entrust the realization of Caquot’s plans to a team of designers from his design office, they are carried out in a week. In the meantime General Hirschauer, who is in charge of aviation at the Ministry of War, orders that a test be carried out. Caquot then obtained authorization to build a prototype, which was done in February 1915.

The Caquot type L balloon is then compared to a spherical balloon and a copy of Drachen. It immediately proves to be more efficient, its hull offering minimum resistance to the wind. It managed to withstand winds of 90 km / h against only 54 km / h and 36 km / h for the Drachen and the spherical balloon. Its performance is due to the ovoid shape of the balloon which allows less aerodynamic resistance, and above all to its three inflatable tail units at the rear but based on an internal structure fixing them rigidly to the hull at an angle of 120°. This makes it possible to avoid the pendulum movement of the balloon during gusts of wind, which made observers sick.

Despite these conclusive tests, series production is not launched. However, an English naval officer, who attended the prototype tests, told Caquot that the British navy was trying to equip its fleet with captive balloons, but that they could not withstand bad weather. He then asks her to help them. By examining the constraints, Caquot realizes that the aerostats must resist winds of 125 km / h since in addition to the wind is added the speed of the ship. He then designed a specific braked winch that allowed the balloon to be carried away by too strong gusts and then return once the gust was over.

This ability proved itself in an account of a “free balloon” flight taken by Capt. F. H. Cleaver, commanding officer of the RFC’s No. 1 Kite Balloon Section on October 27, 1915:

The speed and direction of the wind was tested and found to be 15 m.p.h. by the air meter. The balloon was then let up and marched for 300 yards to the winch; it was easily controlled by the balloon party. The winch was shackled on and I and Lieut. Beaufort ascended; the wind appeared to be increasing, the speed was again taken from the balloon and found to be 30 m.p.h. The guy of the right sail carried away, which caused the balloon to oscillate considerably, thus increasing the strain on the cable and rigging. On this an order was immediately given to haul down. The winch, whose power is only 6 horse failed; the wind was rapidly increasing in strength and on again being tested the speed was found to be 40 m.p.h. Fortunately for the occupants of the balloon the cable then parted, had it not done so the rigging most certainly would have gone. The valve rope was immediately pulled and as soon as the end of the cable or any part of it touched the ground, the balloon in spite of the loss of gas naturally was lightened owing to being relieved of the weight of a portion of the cable, and ceased to descend and at times rose; this coupled with the heat of the sun causing the gas to expand and the balloon to become still lighter, was responsible for what might appear to be a long flight, which owing to the speed of the wind was carried out at 40 m.p.h. A perfect landing was effected in 45 minutes without any damage to the balloon, occupants and instruments.

These qualities quickly proved the Caquot to be the best balloon design on the Western Front and all the combatant nations eventually adopted it.

In June 1915, Albert Caquot became director of the mechanical aerostation workshop at Chalais-Meudon, where he had new aerostats built in large series according to his plans. On July 10, 1916, the British Aviation Inspector requested M type balloons from the War Department. Between July and the end of November 1916, 46 M type balloons were built in Chalais-Meudon for the British, subsequently ‘others are built in the UK. Three types of balloons with a capacity of 750 cu.m, 820 cu.m and 1000 cu.m. The first equip small ships used for the research of submarines, they are served by two men from an altitude of 500 m; the larger ones are used aboard squadron ships for the adjustment of fire and are served by a crew of three observers at 500 m altitude or two at 1000 m. This use of Caquot balloons allows the British Navy to reduce its losses. In 1917, the French navy, noting that its losses due to torpedoing were becoming higher than those of the British, then decided to adopt the Caquot balloons as well. The French Navy uses types P and P2 on its smaller units for protection against U-boat attacks, and the Type R to direct the fire of its larger ships. In July 1918, it had nearly 200 balloons and 24 units designed to work with them.

The French Army, for its part, trained 76 units during the war equipped with Caquot balloons. These balloons are used for artillery tuning and general observation of the battlefield.

In 1917, when the Germans began to bombard Paris with aircraft, Albert Caquot proposed to make barrages with low volume balloons, the cables of which would force the bombers to climb higher and reduce their load. This idea is taken up by the British in September 1917. At the end of the war, there are Caquot type of balloons, mainly with M 900 cu.m and R 1000 cu.m.

The Caquot balloon entered service in other Allied armies and then in others including the new Polish army.

In France, the production of balloons was 319 units per month in 1919. The first models are of type L and M, and finally the Caquot balloons are produced in four different formats:

P – 750 m³ (capacity – two observers at the height of 500 m)
P2 – 820 m³
M2 – 930 m³
R – 1000 m³ (capacity – two observers at the height of 1000 m or three at 500 m)

During the war, one of the British Caquot balloons fell into the hands of the Germans who made a copy called Ae 800 for Achthundert english 800 which was a reference to the cubic meter capacity.

General Ernst von Hoeppner, commander of the German Luftstreitkräfte freely admitted that German balloons put in service after 1916 were patterned after a captured British example. Caquots and their German copies eventually served on all fronts and with naval forces operating in the Atlantic and Mediterranean. The improved Caquot could ride higher, and fly in higher winds than the Parseval-Sigsfeld, so it quickly replaced the Drachen, even among the Luftschiffertruppen.

During the war, France was from 1915 the leading power in the field of ballooning and built nearly 4,200 captive balloons: 1,700 observation balloons and 2,500 barrage balloons.

The Caquot balloon was manufactured in large numbers, including a thousand in the United States between 1918 and 1919.

The United Kingdom built others during World War II where they were used until the 1960s to test parachutes, for non-combat aerial observation and photography.

Gallery

P
Capacity: 50 m³
Payload: two observers
Altitude: 500 m

P2
Capacity: 820 m³

M2
Capacity: 930 m³

R
Capacity: 1000 m³ / 32,200 cu.ft
Payload: two observers to 1000 m / three observers to 500 m
Length: 92 ft
Diameter: 32 ft
Cruising speed: 75 km / h
Max wind speed: 70 mph