Lioré et Olivier H-24 with Air France

By: Gérard Hartmann
Translation: Rob Mulder

The seaplane LeO H-24 is the culmination of a brilliant series of studies undertaken at Lioré et Olivier first at Levallois and then Argenteuil by Marcel Riffard, Edmond Benoit, Paul Asancheeff, Jean Poitou, Stephi Konovaitchoukoff and Sébastienne Guyot. These studies lead to an ultramodern monoplane with an enclosed cabin accommodating ten passengers, and was to replace the small H-19 on Mediterranean routes of Air Union. Between 1929 and 1936 the project H-24 was revised several time and gives rise to a series of eight variants of remarkable seaplane. It was built in a total of twenty-one samples, all built in Argenteuil.
Aerodynamic studies conducted by the Riffard-team, especially by Sébastienne Guyot, one of the best aerodynamicists, led to a low monoplane flying-boat with semi-elliptic shaped wing, two 500hp Renault Type 12 Jb Popular V12 engines mounted in tandem.

The prototype LeO H-240 flew for the first time in November 1929 in Antibes, flown by the company’s pilot Lucien Bourdin. Despite a fuselage built entirely of wood, the H 240 had a wing of twenty-eight foot wingspan and a meter thick at the root containing several reservoirs with a total capacity of 1500 litres of gasoline. Inherited from the type H-180, the new wing was cantilevered (all structures are hidden in the thickness), which manufacturer began to have some experience with. The flying-boat was presented to the French press in December 1929 and the US press on 1 February 1930.

While CAMS 53 carried only four to six passengers, the LeO H-240 offered ten seats with considerable comfort (ancestor to the business class) or twelve seats with barest possible comfort (economy class). It could carry them over 800 km and made it possible to make the crossing of the Mediterranean non stop.

From front to the stern of the aircraft, we find the cockpit, followed by an enclosed cabin for eight to twelve passengers in the centre of gravity, followed by a baggage hold in the back of the aircraft. The prototype aircraft undergoes 01 made extensive testing at St. Raphael in 1930 before sold to the company Aéropostale. Two other prototypes were built delivered 1930 to Air-Union and Compagnie Générale Aéropostale, where they serve as laboratory.

Registrations prototypes LeO H-24

After receiving their certificate of airworthiness and been tested by these companies (completing 250 hours of uneventful flight), the three prototype H-240s were modified and stored until 1934. The new H-241 and four-engine H-242 were preferred, due to new international regulations on commercial flights across the seas and oceans condemning the four above the twin engines, which was considered safer.

At the end of 1932, the prototype H-240 No. 03 registration F-AKDX, made “memorial” voyages from Marignane in the Mediterranean to Ostia, with on board Mermoz, and Gimie Dabry, heroes South Atlantic.

Powered by four engines 350 hp Hispano-Suiza 9 QDR 350 hp (nine cylinders little lower on power, but supposed to be have a great robustness), in accordance with regulations, the Lioré et Olivier H-241 looked like a larger and heavier version of the H-240. Built in 1932, the new machine was capable to carry ten to fifteen passengers during a 1000 km flight in a comfortable cabin (comfortable chairs, luxurious drapes, heating and lighting) and well lighted. For the first time on a seaplane of Lioré et Olivier, the H-241’s hull is made of metal, duraluminium and anodized to better withstand the sea water and sea air. This type of fuselage could be found on all later seaplanes of Lioré et Olivier. Available after the H-242, type H-241 was not ordered.
Keeping the general characteristics of the prototype of the LeO H-240 and the dimensions of the H-241, type H-242 (designed in 1931) was powered by four Gnome & Rhone seven cylinder radial Kd Titan Major and developing each a maximum power maximum of 370 hp at 4,600 meters altitude.

Each engine weighed only 280 kg, 55 kg less than the 9QDR, developed at cruising speed 350 hp. And unlike Hispano-Suiza radial engines, these engines were certified to 275 hours of full thrust. The propellers were also manufactured by Gnome & Rhone. Under these conditions, the maximum speed of the aircraft was 220 km/h and the cruising speed was 195 km/h, and considered as very high at the time. The fuselage was entirely made of metal, developed from the LeO H-241.

In April 1932, a scale model of 1:1 was built at Argenteuil built by the company’s carpenters and under supervision of the direction of engineering André Viollea. They made an interior according to specifications from the French company Air Union, which wanted luxurious facilities.

In June 1932 Air Union ordered fourteen flying-boats of the Type H-242. Construction of the series began at the Argenteuil factory in the late 1931. Registered as F-AMOU, the first of the series made its first flight in the month of March 1933 at the hands of test pilot Bourdin of the firm Lioré et Olivier, while further deliveries were taken for the first time in the air by his colleague Hervioux. Bourdin was then in charge of testing civilians (H-24-6) and military (H-46) prototypes. From the third aircraft the load factor increased by 8% by simply adding a Townsend cowling ring. The maximum speed increased from 220 km/h to 250 km/h, the cruising speed was 220 km/h. This improved model is referred to as H-242/1. Several H-242 were then converted into H-242/1, such as serial numbers 1, 3, 4 and 5.

Air Orient, which operates the airline Marseille – Hanoi via Damascus, Bangkok and Vientiane, was interested in the LeO H-242, but she preferred first of all the SPCA and its CAMS 63. Only in March 1935 and under the colours of Air France two LeO H-242 were put into service on this line and made one flight seven days per week.

In 1933, Air Union introduced the H-242 on the line Marseilles – Algiers, Marseilles – Tunis via Ajaccio Marseille – Naples, Athens and Tripoli. Its fourteen H-242s were transferred to Air France in  August 1934, after the company had merged with Air Orient.

Opened in 1934, the Marseille – Algiers from April 1935 provided a fast service between Paris
and Algiers, in just nine hours. The line Marseille – Tunis in the same way connected the capital Tunis in less than twelve hours (1935). The landing in Corsican was deleted. Passengers only regret that Air France had suspended the fast link Paris – Algiers (flown in one and the same day) during the winter season.

Very popular with officials of the Republic, this line allowed them during the summer season to travel from Paris (Le Bourget) at 7.15 hrs, arrive in Algiers at 15.50 hrs, to spend the afternoon at work, and return the next day to Paris (the distance between Algiers and Paris is 1,500 km). In 1935, Air France considered to double the service and use the 20-seater CAMS capable of flying at a cruising speed of 300 km/h. That would bring Algiers just five hours from Paris.
In February 1936, the line is to Indochina renamed “Ligne France – Extrême-Orient” (France – Far East Line). The H-242 aircraft of Air France flying across the Mediterranean were named by their destination “Ville de Tunis” (City of Tunis), “Ville d’Alger” (City of Algiers), “Ville de Tripoli” (City of Tripoli) and “Ville de Beyrouth” (City of Beirut).

Despite plans from Air France to replace the flying-boats by new CAMS-flying boats the Lioré et Olivier LeO H-242 would still provide transportation across the Mediterranean under the colours Air France for six years, until 194. They had a peaceful life; that is to say without history … almost!

Production Lioré seaplanes and Olivier H-242 series

Air France wanted to offer these lines operated by 20-seater fling-boats capable of cruising at 300 km/h. The manufacturer at Argenteuil studied in 1932 a new version, the H-243, an twin-engine H-24, powered by two 770hp Gnome & Rhone engines or two 940 hp Hispano-Suiza 14 Ha hp (these engines, actually meant for the LeO-45, were the American Wright engines that were never registered in France), capable of flying at  a cruising speed of 300 kph. The French navy got interested in the project of the H-243 as it had wider hull. But the project remained a project. Aimed more widely to all transcontinental flights commercial, the LeO H-244 project, dating from 1933, gave birth to a high speed flying boat. It was to be powered by two 880hp V12 Hispano 12 Y. Later, once available, these would be replaced b the 14 ha of 940 hp. The prototype, according to calculations, should be even faster than previous versions, and exceed 310 kph. The new prototype was a biplane and should also receive rear stabilizers. This project is of interest to Air Union, but is abandoned when the company becomes Air France in August 1933.

Since its inception, Air France is pursued by a black misfortune. Flying material that was in good hands of private (and well paid) pilots of Air Union was catastrophically in the hands of pilots of the national society. In its first year, Air France has received 155 million francs in subsidies from the state, a sum equivalent to the operating budget of a single packet Transatlantic. In 1934, Air France operated with 258 aircraft, 253 crew and operated 40 000 km of airlines through 29 countries on four continents. The state budget was insufficient an also placed competition under pressure. Its management is torn by internal political-financial conflicts in the France of that time. Despite their perfect reliability during their first year of service, the flying boats of Lioré et Olivier were victims of several accidents during their live in the colours of Air France.

In 1935, a seaplane filled with passengers and flown by experienced French pilot Marceau Méresse avoids a crash at sea. He managed to put down the flying-boat on sea after the abstraction of a propeller blade.

On 8 May 1936, the LeO H-242/1, F-ANQG “Ville de Nice” (c/n 10) had to make a forced landing 80 km from its starting point, fortunately without damage for the crew and passengers. This was due to an error of the mechanic, who had closed the fuel supply instead of opening it.

On 9 February 1938, the LeO H-242/1, F-ANPC “Ville de Bone” (c/n5) was lost on landing in Marignane. The pilot hit a pier due to the poor visibility prevailing in southern France, killing its crew and four passengers (seven deaths).

On 13 August 1940, the earlier mentioned Méresse Marceau, while on a scheduled service between Algiers and Marseilles, was attacked by four British fighters. Méresse, an experienced pilot who had been flying flying-boats since 1927, had solid nerves, managed to bring the flying boat down at the port of Algiers unfortunately with four dead and eight wounded, despite two engines unusable and tanks drilled.
Projects for flying-boats capable of carrying 20 passengers at speed of 300 kph failed, and Air France was forced to improve the flyng-boats in use. The H-242 received different types of makeovers: One makeover was the adding of the Townsend ring that dates back to 1934, giving the engines a more aerodynamic teardrop. Then the versions 242/1 front cowlings were of the type NACA (in 1935).

Version H-242/1 was 44 cm lower than the H-242 from 1932. The machine had 580 kg higher empty weight, due to new developments. Improved aerodynamics allowed also the transport of thirteen passengers instead of eight in H-240 and eleven in the H-242. Range of H-242/1 increased from 800 to 1000 km, just as its competitor the CAMS 53.

The flying range was increased for safety reasons – in case of headwind during the crossing – and the new version also had a ceiling of 4,000 meters to get above the turbulence, against only 3,500 metres in the H-242 standard, providing better conditions for passengers.

Features for the LeO H-242/1. Source: Manufacturer (Arnaud Delmas)

From 1934 to 1939, seaplanes and Olivier Lioré H-242 were in service between Marseilles and North Africa in the colours of Air France. They carried ten to fifteen passengers at 200 kph in comfortable conditions, and making one flight per day for four to six hours, depending on weather conditions. In 1935, Air France took delivery of the Lioré et Olivier H-246, a more modern flying-boat, capable of flying considerably over 300 kph and carrying twenty passengers, under all weather conditions.
The H-246 is a new flying-boat, very different from the H-24. Begun in 1936, the construction of H-246 would last more than two years. Pursued by SNCASE, it would not be ready until September 1939, when the government requisitioned the commercial flying-boats for French Navy. Meanwhile, the eleven LeO H-242s were still remaining in regular service, totalling each an average of 2,000 flying hours, without technical problems related equipment. The flying-boats LeO H-242/1, finally and despite their age at the time, proved for Air France to be profitable and very reliable.
The aircraft Lioré et Olivier H-24 has probably impressed Belgian cartoonist Hergé as he used this a flying-boat in 1946 in the album “Tintin and the Broken Ear”.

Following the failure of the H-246, the H-242/1 remained in service on the lines of the Mediterranean until November 1942. On 10 November, Marshal Petain received a letter from Berlin ordering him to requisition all French planes and seaplanes. This was followed by the invasion of southern France. Ten LeO H-242/1 were still in service and delivered to German. Neither Lufthansa nor the Luftwaffe were willing to take in service these veterans of the sky, and they ended their days in the hands of Italian pilots. Six of them were delivered to the Italian airline Ala Littoria SA. The H-242 were scrapped by the Italians in 1943.