Loire 210 (1935)

Loire 210 (1935)

Aéronautique Navale: 19 built total

The French Naval Fighter

A forgotten model, this French naval aircraft was the first dedicated naval fighter, also usable for reconnaissance and primarily intended to serve on the Commandant Teste. The Loire 210 was a French single-seat catapult-launched fighter seaplane designed and built by Loire Aviation for the French Navy. With only 19 built it entered service in the summer of 1939, most being lost due to wing structural weakness and the rest grounded.

The Loire 210 was designed to meet a 1933 French Navy requirement for a single-seat catapult-launched fighter seaplane. The prototype first flew at Saint Nazaire on 21 March 1935. The fuselage came from the earlier Loire 46 fitted with a new low-wing which was foldable for shipboard stowage. It had a large central float and two underwing auxiliary floats and was powered by a single nose-mounted Hispano-Suiza 9Vbs radial engine.

Context

French Historical Context and genesis

France between the two wars needed to keep its colonies linked at all times in order to survive. There had been a constant development and rejuvenation of the fleet almost from scratch, centered around six elderly dreadnoughts and two rather fast and modern battlecruisers. At the end of the twenties, to that lot, 2 aircraft “carriers” entered the list, with the Béarn and Commandant Teste, the latter dedicated to seaplanes. France could still, at most, build some 60,000 tons of aircraft carriers each not over 8,000 tons of standard tonnage.
Part of the staff still resisted the idea, but a concession at least was to have catapults installed on capital ships and cruisers, for two reasons, the location of the enemy, and its treatment by artillery through airborne spotting, and ASW warfare, with bombs and depht charges.
The notion of controlling the sky above the fleet still met a lot of scepticism in the high command, which ignored Mitchell’s tests in the US to overcome the same scepticism, and this traduced by two shotcomings in the “Royale” in 1939: No radar, despite the technology was already there in France, and lack of efficient anti-aircraft defense. At this game, the French fare no better than most navies, and the wakeup call was brutal: The French naval command realized their mistake when reported the Ju 87 Stuka attacks, first in Norway, and later at Dunkirk.

Until 1939, only the Imperial Japanese Navy (notably because of the influence of Yamamoto) gave consideration to the Naval Air force and make it an unsurpassed instrument in 1941.
For the Marine Nationale, all the remarkably fast and seaworthy cruisers and destroyers built were only turned against surface threats and AA defense (in French “DCA” or “Defense Contre Avions”) was only made ready to deal with close and slow-moving targets with 37 mm guns, the most common caliber on the latest ships, with a ceiling at best to 5,000 m znd in reality closer to 1,500 m. A dive bomber started to make its resource well above this. The rest comprised 25 mm Hotckiss guns, and 13.2, still Hotchkiss, heavy machine guns. Both were operated by hand and with 300 kph biplanes in mind. Some started to realize this inadequacy (as well as in many other fields) and real effort were made from 1935. A model many times faster and with longer range was worked on, but as for so many other ordnances, they still were not enough in May 1940. The very notion of a massive air attack was still far from decision-makers, which, like the ones at the head of the army were stuck in WWI. But the lack of effective AA did not prevented some to propose an alternative: A naval fighter.

The Marine National looks at a first naval fighter

So, as said above, some in the Navy though that a way to circumvent the lack of a good AA weapon, a process that could take years, it was far easier to contact a manufacturer to put a fighter on floats. This was also driven by the rivalry with Italy after the readjustments of the Washington Treeaty and the new naval context in the Mediterraean. Both the young fascist state and the old Republic looked at ways to consolidate and protect their colonial Empire. Some in aviation circles looked with interest as developments in naval fighters on the other side of the Alps.
There was so a revival of the idea of a catapultable fighter seaplane in the navy, following a note from Commander Lartigue (and future admiral) dated 1931.

The Bernard H52 C1 (1933)


Bernard H110 (pinterest)
The aircraft company Bernard at the time, based on its own ideas and without order, worked on a fighter seaplane prototype, the H52 C1. It was relatively modern for the time,
all-metal cantilever monoplane, to better resist rough conditions at sea, and was powered by a Gnome & Rhône 9K, 500 hp. 9.30 m long for 1,460 kg empty, 1,890 kg on takeoff with a 11.30 m span and 18.20 m² surface, a leading edge slat over its entire span. It was not going to break records or run for the Schneider cup with 330 km/h at 4,000 m (range 600 km, climb rate 4,000m in 9 minutes) but at least was an interesting endeavour.

At the same time the Morane-Saulnier 225 was the Béarn own naval fighter, it had the same engine, but without the bulky floats. Both were armed the same way, adequate for the time, two Darne 1933 7.5 mm LMGs. The Bernard 52 flew well but no program was done and no order followed. The concept as still ignored by the top brass.
Lartique’s note however, reinforced by this first model, eventually after two years started to make its way into a program.

1933 specifications for a floatplane fighter

There was a reunion, after which specification laid down specified that this naval fighter was to have a maximum take-off weight of no more than 2,000 kg and it had to be powered by a Hispano-Suiza 9V 700 hp engine shared by the Dewoitine 332, 333 and even the 338 trimotor, considered very reliable, a plus at sea.
The structure had to be however fabric-covered which conpletely contradicted the performance requirements.
In the end, this new catapultable fighter seaplane was to reach 300 km/h at 3,500 m and reach this altitude in 12 minutes. These were very low requirements, which again, show the total misunderstanding of the Air Combat needs. The Nieuport 42 fighter (1924) already made 5,000 m in less than 13 minutes, without compressor or variable-pitch propeller, showing the state of affairs more than a decade later. Also in 1932 top speeds went to 380 km/h routinely for land-based models. To deepens the case, the same speed was asked for the Latécoère 298 program, a torpedo bomber, the same year.

The choice of a Hispano-Suiza 9V, for a fighter plane, with a diameter of just 1.45 m degraded performance on a single engine. Thus, based on a so little-inspired specifications set, it is surprising that competitors even bothered to answer.

Competing designs are evaluated

Dewoitine presented the HD 502 (a navalized D 500 on floats) with an Hispano 12X, which was eliminated from entry due to this engine choice. Dewoitine still, made racing seaplanes for the Schneider Cup. Something the naval staff feigned to ignore. The company had the potential to be the French Supermarine.
The Bernard 110 was also proposed, a development of the previous 52, but the company soon retired, bankrupt.
Potez also knocked at the door with the Potez 453, but its design was marred by poor seakeeping on takeoff handling.
Romano also participated with its model Romano 90 float-biplane, which proved thee fastest on paper at 352 km/h based on its radial engine or 420 kph with the Hispano Suiza 12Y, while being very agile. It was eliminated due to poor seakeeping again. The company however derived from it a Romano 83 and a Romano 92 land fighters which saw action during the Spanish Civil War.
Surprisingly, probably the best fighter seaplane at the time was not even proposed by its manufacturer as it did not answer the specifications (and in time !). This was the Nieuport-Delage 123, flying by early 1934 and seeing 12 built for Peru. The Peruvians bought in addition six conversion kits later refurbished with 780 hp Petrel engines and capable of 330 km/h.

Loire emerged at the winner

The only one which seemed to “take the cake” at the end of this process was Loire. The company was known by the Navy, and its go-to seaplane maker up to that point. The Marine Nationale already had the LGL 800 series (by association with Gourdou lesseure), which was the standard catapulted model of the Marine Nationale since 1930.

Loire proposed the model 210, which seemed promisjng on paper and had elready the Marine’s trust. The prototype was approved in the first round, a prototype was financed, which made its first flight in the spring of 1935. It was tested without incident. Test pilot reported it was easy to manouver. It was also sturdy enough to be catapulted, prepared to taking off in 9 seconds (The Navy requested 15) and after presuading the commission that an all-metal structure was preferrable, it showed good seakeeping as well.
This was in large part due to the unusual choice of a single main-float, degrading speed but helping marine performances. This was the choice retained by IJN naval fighters by the way. Next, the prototype went through official tests, and went through all classic aerobatics. Test pilot again, found it no heavier than land fighters. Official tests ended by the fall of 1935 with an elogious report, and the top speed of 304 km/h at 3,500 m bagged as well.
The company will manage to improve the model during production further, and this figure went to 315 km/h in part due to a more aerodynamic cowling, and it was rated for a max ceiling of 8,000 m, well within the range of most bombers at the time.

A wasted opportunity

In the end, the Loire 210 was quite comparable to the Italian IMAM Ro 44 used from 1943. The Navy though, only had a limited need for these numerically, and only vague ideas on how to use it. Based on minimal provisions in squadron and replacements, only 20 were ordered, 19 just delivered by Loire, by late 1936. In between aviation technology leaped forward, and Loire worked on improving its model, trying to convince the Navy to accept the upgrade (seen later). Alas, this was refused.
Not only that, but the Navy ordered the model unofficially, precluded any manufacturing. It was made official and signed only by May 12, 1937, six months beyond schedule, and thus when delivered in 1938 (based on a 1933 order !). As a result by that time, the Loire 210 was already obsolete, but it was still better than nothing.
Two were lost during tests, and apparently the navy lacked imagination on how to used these and even further procrastinated about their effective deployment.
The Navy by the time should already had looked for a successor and used the 210 to experiment various tactics, helping to define criteria for choosing a successor, but it never happened (see later). The Loire 210 became the one and only serial floatplane fighter of France, and by extension, of the allies at large in WW2.

Design of the Loire 210

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General design

The Loire 21 design was straightforward for this category. The fuselage was well balanced but with a cockpit pushed to the rear, a long nose following the massive cowling of its engine, but also straight wings with a light dihedral, more comparable to biplane wings than monoplanes. The prototype Loire 210.01 was unique for its use of a large central float completed by two other smaller ones under wings.

The fuselage was inspired by the Loire 46 ground-based fighter in its general outlines, with a structure made up of welded steel tubes covered with light Duralumin alloy panels, except for the ends of the wings, covered with treated canvas, as requested by the naval staff.

The open cockpit open placed well behind the wings did not ensure a good visibility when landing or taxiing, and was given a front windshield and a rear headrest. The central float was quite long, protruding about 2 meters from the front of the fuselage. Wings are cantilever (low position), are solidarized to the fuselage and the float by an array of V-type struts. The wings are straight with rounded ends, whereras outer panels have a slight positive dihedral. The impont innovation is that these could fold backwards to reduce bulk, facilitate stowage onboard. The tail is of the conventional type but rather large to compensate for the inertia in flight caused by the large central float.

Powerplant

The engine retained was the The Hispano-Suiza 9Vbs, 9-cylinder radial engine rated for 720hp, and up to 980 hp whe upgraded and pushed at max power. It was protected by a cowling, redesigned and fitted with bosses to fir the cylinder heads. It was driving a three-bladed metal propeller which was so large the large single float below had an indentation to to avoid contact.

Maximum endurance was 3 hours at 195 km/h (585 km) and 2 hours at 250 km/h (500 km).
However, even after the first flight, knowing what were they making, the company soon tested new engine configurations to boost the performances. Loire-Nieuport soon performed its own tests with the Gnome et Rhône K14, offering a 27% better torque. This led to a prototype named Loire 211 which reached 330 km/h. The company also worked on the question of a reduction gear and tested the Gnome-Rhône (GR) 14N for an expected 350 km/h. They also proposed to fit the Gnome-Rhône 14 “Mars” rated for 700 Hp or in alternative an inline-conversion to the Hispano-Suiza 14 Ha offering the same output in 1936, expected to go past 360 km/h with a much better range and overall performances across the board.

Armament

The armament comprised four Darne 7.5 mm LMGs, on par with the coming the Bloch 151, one of the main French fighters of 1939. The prtotype however was given only a pair of Darne Mle 1933 7.5 mm machine guns. The whole machine lacked power to lift off any more offensive payload. No provision was made to carry bombs.

⚙ Loire 210 specifications

Gross Weight 2,100 kg (4,629 lb)
Lenght 9.51 m (31 ft 2.75 in)
Wingspan 11.79 m (38 ft 8.25 in)
Height 3.80 m (12 ft 5.25 in)
Wing Area 20.3 m2 (218.5 sq ft)
Engine Hispano-Suiza 9Vbs radial piston engine , 537 kW (720 hp)
Top Speed 299 km/h (186 mph, 162 kn)
Cruise Speed 199.5 km/h (124 mph, 108 kn)
Range 750 km (466 mi, 405 nmi)
Climb rate 9.4 m/s (1,897.8 ft/min)
Ceiling 8,000 m (26,250 ft)
Armament 4 x 7.5 mm (0.295 in) Darne machine guns (wing-mounted)
Crew 1 Pilot

Variants & Operational History

Loire 210.01: First prototype
Loire 210: Single-seat fighter seaplane, 18 serial models
Loire 211: Prototype with a more powerful Gnome-Rhône 14K engine, never adopted.
French Navy: Escadrille HC.1, Escadrille HC.2

The prototype Loire 210.01 was brought to Saint-Nazaire (Atlantic) to carry out its first flight tests within the company from March 21, 1935. Next it was sent to the Maritime Aviation based in Fréjus-Saint-Raphaël (Mediterranean) for its official tests from June 1936, comparative evaluation, declared winner, and 20 ordered on March 19, 1937. The Production model saw the addition of four machine guns in the wings, and first flew on November 18, 1938.

The aircraft entered service with the French Navy in August 1939. The Loire 210 entered service in HC.1 and HC.2 squadrons. Within three months, five were lost due to structural failure of the wing. All the remaining ones were grounded and withdrawn from use. The investigation shown structural problems with the wings. The manufacturer’s estimation of the strenghening work was judged too costly, and the French Navy decided to withdraw the model and and disband the units. This put an end to the Floaplane fighter experipent in France.

These 20 seaplanes were to be used from catapults, one per cruiser or capital ship each (18 ships total), in complement of the observation models. A full squadron was to be provided to Commandant Teste.
They were to be distributed evenly between naval formations, but only in Indochina and Atlantic, not the Mediterranean. For recovery, the French applied the German-developed idea of “notched carpet” (8 m wide, 12 m long, sliding down towards the wake of the carrier ship and the pilot when landed at sea, bled speed voluntarily by zigzagging and aiming for the center of this “ramp” to had the floats hooked, and the ramp brought aboard. The La Galissonière class cruisers and their square stern were tailored to operate these, but they never were equipped with the Loire 210, only the Loire 130.
However even if deployed, the Loire 210 was already doomed by technological progress in 1939. Nevertheless, it was the only one able to spot and destroy Axis floatplanes and naval recce models. The Focke-Wulf 200 was way faster at 360 km/h in top speed, the Loire 210 would have stood no chance to catch it in some circumstances (if spotted too late for example). However for cruising it was well below 260 kph and had a lot of inertia and was certainly less agile. Even with four puny MGs, and despite a generous array of MG.34, the FW.200 was easy meat for the 210.

But this is prospective. The reality is that the Navy’s obstination for a massive engine and canvas-wrapped structure, and then excessive delays, doomed the whole program. Even loire itself, probably discouraged by that attitude, did not persisted in the concept. The Loire 210 fighter seaplane was withdrawn from service after three accidents due to structural issues, excessive vibrations, and the French fleet operated from September 1939 to the armistice of June 1940 without air cover and weak, inadequate AA. What happened in Norway demonstrated the case in ample terms, and Admiral Lartigue, the one that started the idea, renounced it by the end of November 1939. All trained pilots from Loire 210 were sent to land fighters and dive bombers thrown into the hopeless furnace of May 1940.
Meanwhile instead of perfecting the skills of its air group (neglected for years), used Béarn for taxxingr trucks and aircraft from the US via Canada -neutrality obliges- insisted on completing the Richelieu and Jean-Bart instead of focusing on the promising new aircraft carriers of the Joffre class and even ordered, far too late, and eventually realizing the wasted potential, ordered the Dewoitine HD 780 floatplane fighter, based on the excellent land model, far too late. None saw service, the sole propotype was abandoned unflown and scrapped.

Read More

Books

LES HYDRAVIONS A FLOTTEURS 1ère partie – Les Ailes Françaises Gérard BOUSQUET

Links

https://aviadrix.blogspot.com/2013/06/lhydravion-de-chasse-loire-210-ou.html
https://clausuchronia.wordpress.com/tag/loire-210/

Loire 210 floatplane prototype
by u/JoukovDefiant in WeirdWings


https://en.wikipedia.org/wiki/Loire_210
https://fr.wikipedia.org/wiki/Loire_210
http://fighters.forumactif.com/t87225-concours-aeronavale-loire-210-dujin-1-72
https://www.aviafrance.com/loire-210-aviation-france-3934.htm
https://aviationsmilitaires.net/v3/kb/aircraft/show/18517/loire-210

Model Kits

https://www.super-hobby.fr/products/Loire-210-Prototype.html#gallery_start
http://www.kitreview.com/reviews/loire210reviewbg_1.htm

Gallery


Illustration by the author of the Loire 210 Number one (prototype), in service on Dunkerque, 1938

Prototype in flight, 1935 (cc)

One of the serial model in 1939 (pinterest)

Catapult launch (FLICKR)
Loire 210 hoisted crane
Loire 210 hoisted crane

Loire 210 hoisted aboard an unidentfified ships by crane (pinterest, destinationsjourney.com)

Gourdou-Leseurre GL-800 series

Gourdou-Leseurre GL-800 HY series (1926-1938)

Aéronautique Navale. L2, L3, GL-810, 811, 812, 813, 830, 831, 832 HY (108 built)

The French Catapulted Plane 1930-40

The interwar saw the development of catapulted aviation throughout Europe and France was no exception. After signing the Washington Treaty, France was forbidden to built more battleships and concentrated on cruisers: The Duguay Trouin class was the first of them, launched from 1923 onwards. They were completed in 1926 and needed a catapulted aircraft, a first for the French Navy.
At the time, the offer only comprised two models, which were planned for these cruisers, already ageing:
The Besson MB.35 and F.B.A.17 were potential candidates.


The Besson MB.35 which first flew in 1926, nicknamed “Passe Partout”, was a French two-seat spotter and observation floatplane intended for the French Cruiser submarine Surcouf stowed in a sealed hangar. Only two prototypes were built, one destroyed on trials and the other onboard. Considered too small for other uses than this one, the small floatplane was not adopted for French cruisers.

FBA 17 in 1923, Duguay Trouin class
FBA 17 in 1923, on a Duguay Trouin class cruiser

The second candidate was the F.B.A.17. From the Franco-British company F.B.A. (Franco-British Aviation Company) [see FBA on WW1 French naval aviation page]. The model 17, which first flew in 1920, was similar in general layout to World War I models, as a pusher, also exported to the Polish, Brazilian navies. The one looked for had fittings to be catapulted from warships. Six were built under licence by the US Coast Guard. The ones used on French cruisers initially was known as the 17 HL.2. The pusher configuration was judged ideal due to the interference-free location of the engine and France would return to this configuration years later with the Loire 130. In between it looked at a faster model, with a more conventional approach.

Enters Gourdou-Lesseure

Loire Gourdou-Lesseure LGL 32 in May 1927

The Gourdou-Leseurre started operations at the end of WW1. Their contribution was a fighter, the Type A or GL.1, 1918 fighter prototype (parasol), showing superior performances to contemporary fighters, and ordered to 100 planes until cancelled after unsucessful trials. The company was active between 1917 and 1934. From 1925 to 1928, Gourdou-Leseurre was a subsidiary of a shipyard: Les Ateliers et Chantiers de la Loire. The devices built by the company during these 3 years carried the prefix LGL.
The company lext released the better Gourdou-Leseurre Type B (GL.2) which this time was produced to around 20, followed by GL.21-24 series, reaching 100. One of these, the GL.22ET.1 was used for trials aboard the aircraft carrier Béarn, but it’s the Dewoitine D.1 which became in 1925 the carrier’s first dedicated naval fighter. With the later GL.30 series, the company repeated its successes, with a model largely produced, also exported with some still active in 1939. The company later associated with Loire, to form the group LGL more specialized in high performance floatplanes, but the association was defunct in 1934, Loire going on alone, untimately delivering the excellent Loire 130, the French Walrus.

Development of the L3 series floatplanes

The good reputation of the company for fighters prompter the Navy to enquire about both an adaptation of the fighters on floats, which resulted in a Twin-pontoon floatplane version converted from LGL.32 prototype, called the LGL.32 HY (For “HYdravion”). It set a world altitude record on 28 March 1927, but only one prototype was built. It was not adopted as an onboard naval fighter.
Instead, the Navy wanted in 1925 already a larger model dedicated to observation and reinforced to be catapulted. The prototype L-2, was built in 1926-27 with a steel tube fuselage, almost rectangular wooden wing. The tail was two vertical fins above and below and the fuselage and wings were all fabric covered, with a 283 kW (380 hp) Gnome-Rhône 9A Jupiter engine left uncowled. The prototype was demonstrated in Copenhagen on the hope to gain orders.

Six prototype L-3s were constructed with a 313 kW (420 hp) GR Jupiter and steel spars instead of wooden ones plus stronger struts for catapult launching. The French navy ordered 14 production GL-810 HY aircraft based on the L3, the first flying in September 1930 at Les Mureaux. In 1931, 20 of the improved GL-811 HYs were ordered to operate from Commandant Teste, then 39 GL-812 HYs and 13 GL-813 HYs.

  • Gourdou-Leseurre L-2: Initial prototype, catapult-launched floatplane observation model.
  • Gourdou-Leseurre L-3: Six prototypes with revised structure.
  • Gourdou-Leseurre GL-810 HY: Initial production: 24 produced for the Aeronavale.
  • Gourdou-Leseurre GL-811 HY: Developed version: 20 built from 1931.
  • Gourdou-Leseurre GL-812 HY: 29 built 1933-34.
  • Gourdou-Leseurre GL-813 HY: 13 built.

Gourdou GL-810 HY

Elaborated from the L-2 and L-3, the GL-810 is really the start of the lineage, with little changes over the years, a bit like classics such as the Fairey III. The Gourdou-Leseurre 810 was a low-wing monoplane with floats, its fuselage is fabricated in steel tubes and covered in canvas, while its wing were in wood. It was given a Gnome et Rhône Jupiter 9 Aa under Bristol licence: This was a 9-cylinder air-cooled engine rated for 420 hp. It was connected to a two-bladed wooden Leseurre propeller, with fixed pitch. The wings were caracteristic for their semi-thick profile (wood framing covered with canvas), and had long and deep fins which could be removed in five minutes.

Its vertical stabilizer also had a characteristic design, with two roughly triangular fins above and below the tail, framing the horizontal stabilizer. It was clearly inspired from WWI German floatplane types, still allowed for control while keeping the vertical section low for easier storage. Its design changed from the 810 to the 820, more rounded, and inequal in span upper and lower. The next series 830 had no lower stabilizer at all but the hotizontal surfaces sat very low on the fuselage, as were the main wings, with a dihedral.

Gourdou GL-811 HY

These 20 three-seater on-board observation seaplane derved from a prototype that flew first on March 10, 1932. They had folding wings. Same low wing monoplane, three seats, with two underwing Floats, steel tube fuselage covered by canvas and wooden wings.
Wingspan: 16.00 m, Length: 10.49 m, Height: 3.56 m, Total area: 41.00 m²
Empty mass: 1690 kg Total mass: 2460 kg
One Gnome & Rhône 9Ady 9-cylinder 420 hp, 200 km/h top speed
Ceiling: 5800m, Autonomy: 560 km
Armament: One synchronized 7.7 mm hood MG twin rear mobile 7.7 mm Vickers, 150 kg of bombs

Gourdou GL-812 HY

Three-seater observation model which first flew on November 29, 1933. 29 built for the Aeronavale. Like previous models a low wing 3-seats monoplane* with two floats,steel tube fuselage, wooden wing. *One pilot, one observer, one tail machine-gunner
Wingspan 16.00 m, fuselage length 10.49 m, height 3.86 m, wingspan 41.00 m². Empty mass: 1690 kg Total mass: 2460 kg
Propulsion one Gnome & Rhône 9Ady 9-cylinder radial rated for 420 hp. Top speed 200 km/h, ceiling 6,000m, 560 km autonomy.
Armament: 1 synchronized 7.7 mm hood forward machine gun, twin mount flexible 7.7 mm Vickers aft, 150 kg of bombs.

Gourdou GL-813 HY

Three-seater derived from the 812, first flight on October 22, 1934, 13 units built, same fuselage, three seater, but new tail.
Wingspan: 16.00 m, length: 10.49 m, height: 3.86 m, total wing area 41.00 m². Empty weight 1,690 kg, operational TO max 2,460 kg
Propelled by the same Gnome & Rhône 9Ady, same performances, same armament. The 812-813 were maintained in service in 1939 but replaced by the 830 series and sent to training units or in the colonies.

Gourdou GL.120


The Gourdou GL.120 HY was an interwar prototype military aircraft made in France by aircraft manufacturer Charles Gourdou (one of the founders of Gourdou-Leseurre), and aeronautical engineer Georges Bruner. It was a twin-engine float plane, intended to serve as a reconnaissance aircraft and naval bomber.

The first flight of the prototype was in June 1, 1940 and it was motorized by two Renault 6-cylinder inverted-V engine Inline 140 hp each, It had a wingspan of 12m, a fuselage 9.14m long, height of 3.06m and wing area of 18.40 m2. Performances were less than stellar with 110-120 km/h crusing speed, 250 km/h top speed, and a ceiling of only 5,700m (Wing loading 87 kg/m2, Load factor 5.7).
Armament was planned to be 8x 10 kg inboard bombs (bomb bay) and two external Darne 7.5mm machine guns, one forward fixed and one rear mobile MG.

The Gourdou GL-810-20 in Operations

The first flight of the 810 took place on the Seine at Saint-Maur-des-Fossés, where it was made. It left for the CEPA in order to carry out its official tests, all passed without any particular difficulty. When completed, the model was used for demonstrations expecting foreign orders, notably in Scandinavia, until reformed in 1928, being ordered to six by the Navy (L-3 for the Hispano Suisa 9 Ac rated for 420 hp and various steel spar reinforcements to be catapulted).
The GL-810 was deployed from the colonial Bougainville-class sloops, such as the Rigault de Genouilly but also were part of the first air group deployed by Commandant Teste as a seaplane transport.

Gourdou GL-821 HY/ HY O2


The GL-821 HY torpedo boat first flew in January 28, 1936, with a single prototype produced, powered by a Gnome & Rhône 9Kfr engine rated for 750 hp. It was armed with a forward Darne 7.5 mm machine gun in the right wing and the usual rear flexible mount with two Lewis MGs, and could carry a 18-in torpedo (457 mm). It differed from the base model GL-810.
The sub-variant O2 first flew in October 1937. It had for the first time an enclosed cabin, three-bladed propeller and could carry the same torpedo or 300 kg of bombs.

Gourdou-Lesseure GL 83 series

In 1934 the spmit with Loire, following strong difference of views and disagreement saw both companies partying out, both still courting the French Navy to fill the needs of the Aeronavale. In 1930, indeed, the French Navy issued the need for a light coastal patrol seaplane for its colonies. Gourdou-Leseurre designed a prototype that took up the lines of his previous GL-830 HY but with a less powerful Hispano-Suiza 9Qa engine (250 hp versus 350 hp). This prototype will be built under the designation GL-831 HY. The GL-831 HY flew for the first time on December 23, 1931. In 1933, the French Navy placed an order for 22 units, under the designation GL-832 HY, which will be still powered by a Hispano-Suiza engine but a little less powerful than the prototype (230hp instead of 250hp).

The GL-832 HY was a low-wing monoplane with a metal airframe whose wings and floats were covered with canvas. The aircraft was equipped with wide wings in order to support the load of a catapult launch. These could be folded up to facilitate storage on board a ship. Note that the empennage used a particular configuration due to the presence of reinforcing bars connecting the horizontal planes and the rear of the fuselage. The two crew members were installed in tandem open cockpits, each equipped with a windshield. The maiden flight of the first production aircraft was on December 17, 1934 and the last aircraft produced on February 12, 1936.

GL 832

Like the earlier GL.810 and Potez 452, the GL.832 HY was a two-seat monoplane floatplane which became the standard light catapulted reconnaissance cruiser model of the French Navy in the mid-30s. This model was also useed in colonial areas, and deployed from Colonial sloops, lowered in water with a crane to take off.
The prototype GL.831-0I flew with a 9-cylinder air-cooled radial engine Hispano-Suiza 9Qa rated for 250 hp. On January 25, 1932, after its factory trials it took off and arrived in Saint-Raphael for its final, official testing. In May 1932, flights were interrupted after issues were reported and changes made to the design: The floats rudders and tail unit were reshaped among other. Testing resumed in July 1932 and the newt year an order for six production aircraft (Navy designation GL.832 HY) followed, all provided with the new, more powerful Hispano-Suiza 9Qb (230 hp).

Fuselage & general design

Gourdou-Leseurre_GL-832
The fuselage was no longer mixing steel and canvase but all-metal, with a stressed skin, notably for the front part sheathed with duralumin, while the back kept a canvas cover, all the framing being in aluminium. Unlike the previous GL.810-820, the vertical tail was rounded with no lower section, the vertical rudder sat low on the fuselage (it was mid-height before) while the profile of the main wings was reviewed and some dihedral introduced.
The tow-floats design was kept, with space cables in “X” as before, and V-struts connecting the underwings and base of the fuselage. This left an important gap to carry a payload, but being underpowered, the GL.830 serie carried none.

Powerplant

The company asked for permission to use then the more powerful 9Qd type in development, but the fleet command considered range was more important than speed, and so the 9Qb was adequate as it was. Therefore, the 9 Qb engine was retained for the full production of the GL.832, all 30 of them.
The Hispano-Suiza 9 Qb was a radial engine rated for 230 hp, derived from the Wright R-975 Whirlwind built under licence. To be more precise, it was a variant of the Licence built R-975 J-6 Whirlwind, with the same performances.

Armament

As for machine-guns they had a forward Darne Modele 1926 7,62 mm (0.8 in) on the hood, and a twin aft of the same on a flexibkle mount aft for defence. It was also planned to carry 150 kg of bombs (330 lb) but these were likely as three 50 kgs (110 Ib) models, under the fuselage. No photo shows them ever mounts, and that could have been a liability due to the weak power-to-weight ratio in any case.

Detailed specs

Specs LGL 812 HY

Crew: 2: pilot, observer
Fuselage Lenght 9.75 m (32 ft)
Wingspan 14 m (45ft 11in)
Height 3.5 m (11ft 6in)
Empty weight: 2,135 kg (4,500 lb)
Gross weight: 2,835 kg (6,250 lb)
Powerplant: Hispano Suiza 12Xcr V12 engine, 510 kW (690 hp)/4,000m
Propellers: 3-bladed fixed-pitch propeller
Maximum speed: 380 km/h (240 mph, 210 kn)
Cruise speed: 299 km/h (186 mph, 161 kn)
Endurance: 3½ hours
Range: 1,200 km (750 mi, 650 nmi)
Service ceiling: 9,500 m (31,200 ft)
Armament – Guns Forward MG, twin aft MG.
Armament – Bombs 1x 150 kg (/ lb) bomb

GL.381:

First flight 23 december 1931, one prototype built.
Diemsnions: Wingspan: 13.00 m Fuselage Length: 8.74 m, Height: 3.48 m, total wingspan 29.50 m². Empty mass: 1,110 kg Total mass: 1,400 kg. Propulsion 1 Hispano-Suiza 9Qa 250 hp, top speed 220 km/h.
Ceiling 5,500m, Autonomy: 1,000 km, armed with a rear mobile Vickers 7.7 mm machine gun.

Operations

The LG 81 series were used on the Duguay-Trouin class (1923), Duquesne class (1925) and Suffren class (1927), until replacement by the Loire 130.
The French Navy used the GL-832 HY on light cruisers such as the Émile Bertin, Primauguet and on some colonial Avisos, operated with a crane. When WW2 broke out, the type was still in active service, and not withdrawn until 1942.
In 1936, the French Aeronavale made a PR coup by making a 1st flight over Wallis, French protectorate island in the Pacific Ocean on May 12, 1936. It was performed by the GL-832 HY n°5 of the aviso Savorgnan de Brazza , piloted by Sub-Lieutenant Paul Marraud, deposed at sea by crane in Mata Utu Bay and making a one-hour reconnaissance flight to recognize the bays which can accommodate seaplanes, in order to create a French naval air base here, mid-way between strategic locations. The island remained unoccupied before a WW2 US Catalina landed here, followed by a USN expeditionary force developing a large number of infrastructures, notably an air base and naval facilities still used today.

Illustrations

LGL.830
Loire-Gourdou-Lesseure GL-813
LGL.830
Loire-Gourdou Lesseure GL-832

Gallery


GL L-2, L’Aéropile, October 1927

GL L-2, L’air, May 15, 1928

GL L-3 L’aéronautique March 1928

GL-810 HY, catapult tests from the cruiser Tourville in 1928

GL-810 HY, Les Ailes, October 6, 1927

GL 810 serie on catapult ready to launch

The same launched, probably a Duguay Trouin class cruiser, date unknown, early 1930s

GL.810 at sea, just landed

A GL.832 being launched from the catapult of Primauguet, 1937

Read More

Books

Donald, David, ed. (1997). The Encyclopedia of World Aircraft. Prospero Books. p. 463.
Cortet, Pierre (June 2000). “Rétros du Mois” [Retros of the Month]. Avions: Toute l’Aéronautique et son histoire (in French) (87): 6.
Vice-Amiral Roger Vercken, Histoire succincte de l’aéronautique navale, Armées, ARDHAN, 1993, 173 p.

Links

On aviafrance.com generic
secretprojects.co.uk
aviadejavu.ru
Besson_MB.35
Gourdou-Leseurre_GL.30
Gourdou-Leseurre_GL-812_HY
Gourdou-Leseurre_GL-832_HY
https://www.aviafrance.com/gourdou-leseurre-gl-810-hy-aviation-france-9309.htm
https://www.aviafrance.com/gourdou-leseurre-gl-820-hy-aviation-france-9313.htm
https://www.aviafrance.com/gourdou-leseurre-gl-821-hy-02-aviation-france-9315.htm
https://www.aviafrance.com/gourdou-leseurre-gl-821-hy-aviation-france-9314.htm
On airwar.ru/

Model Kits

Only known, Dujin 1/72 kit: https://www.scalemates.com/kits/dujin-da7274-gourdou-leseurre-gl832hy–238650. The prototype Loire Gourdou Lesseure LGL-32 Hy Height record plane also was made at the same sclae by Omega Models, and the Dujin kit was also distributed by Everest.

Loire-Nieuport LN.40 (1938)

Loire-Nieuport LN 40 (1938)

LN 401 Aéronautique Navale; LN 411 Armée de l’Air: 152 built total

The French “Stuka”

France had no dive bomber for its naval aviation in the late 1930s, just as the type became popular, being explored by all aviations and starting with France’s neighbour, Germany. In 1936, a specification by the Air ministry Pierre Cot was emitted for an improved version of the prototype Nieuport Nid.140, now part of Loire and conducting giving Loire-Nieuport LN.40. The serie was finalized as a gull-wing inline engine sturdy machine, tailored for carrier service: The Béarn, and the future Joffre class. 152 were built in all, production resuming for the Vichy Air Force in 1941. None ever operated from Béarn, the bulk bing used (and lost) in operations of May over France and later in June over Italy.

About the Nieuport Ni 140


The Loire-Nieuport LN.140 prototype in 1934. Note the rear turret and fixed undercarriage wih massive fairings
In the early thirties the old Nieuport company (founded 1911), started to show interest in possibilities offered by dive bombing tactics which was pioneered briefly by the Royal Air Force in 1917-18. The exercize stressed excessive structural efforts and required special attention in construction. However, beyond this, the precision offered by a dive bomber proved to be promising, in particular in naval warfare, perhaps even more than for the air force.

At the time, the Marine Nationale bolstered since 1928 a single aircraft carrier, the Béarn. In the 1930s, she was mostly given sturdy ad well-crafted biplanes, the Levasseur Pl.5,7,9,10 types used for bombing, torpedo-bombing and reconnaissance. Fighters were parasol types such as the Wibault 75, then Loire Gourdou-Lesseure 32, Dewoitine 376, superseded in turn at the end of the 1930s by the Morane 226. The naval staff saw with interest what a dive bomber could do, seeing what the USN tried from its own fleet CVs of the Lexington class.

Specifications were emitted in 1932 by the air ministry for a derivative of the Loire 140. Between 1932 and 1936, Nieuport-Delage developed a two-seat dive bomber called Nieuport Ni.140, for the Aéronautique Navale, the semi-independent aviation arm of the French Navy. It was renamed Loire-Nieuport LN.140 after Nieuport was absorbed by Loire, forming the Loire-Nieuport company in 1933. The first of two prototypes, LN.140-01, was flown on 12 March 1935. Unfortunately it crashed in July during a forced landing and was never repaired. The second indeed, LN.140-02 was more advanced already, but eventually development was abandoned after it crashed also in July 1936.

Levasseur PL.101
Levasseur PL.101 (1933), standard recce/bomber onboard Béarn

The workload was shared (as the production) between Loire and Nieuport. The team was led by the chief engineer Pillon, which from the started drew a model characterized by a low-positioned wing, inverted gull, and fixed landing gear and completely faired. It also had a two-seat tandem cockpit.

The construction of two prototypes at Issy-les-Moulineaux plant was completed in 1934. They were given for one time the prefix JNV but since Gustave Delage joined the company in 1914 and decided to leave the company in 1934, the original suffix Ni was kept. The appearance was quite close to the Junkers Ju 87 developed at the time, and such similarity had German Government denouncing and accusing Pillon of plagiarism and espionage during the German occupation. It was also the origin of the “French Stuka” moniker.

LN 40 Prototype, rear view
LN 40 Prototype, rear view.
The Ni-01 140 early short tests assesses characteristics in March and by July, started more arduous manoeuvers, which led ultimately to a crash landing, being completely destroyed as the result. The second prototype in November already fixed some issues, tested many changes notably in the overall wing design, tail, and fairing, now shorter. The crash happened when the pilot was diving, trying to correct its alignment. He died in the attempt.

These two crashed at the time were enough to convince the French Navy commission to reject the proposal. Despite this failure, the prototypes still showed what they could achieve without looking at foreign models, and with further development, could be developed as a modern, superb dive bomber ready for mass production. The base tree that was developed led to a “navalized” version called Loire-Nieuport LN-401 and a land one, the LN-411, both aiming at production in small series, when upon precisely production issue under the Popular Front, Nieuport was merged into the state consortium SNCAO (Société Nationale des Constructions Aéronautiques de l’Ouest) around Bréguet in Bouguenais, and Loire-Nieuport based in St Nazaire, Normandy. Under its own name, the consortium only managed to create the seaplane SNCAO 30 for the Navy, the fighter SNCAO 200, the naval (land-based) torpedo-bomber SNCAO CAO.600 or the CAO.700. All were prototypes, their development dragging until 1940. Meanwhile, both Bréguet and Loire-Nieuport produced their own, more sucessful models.

Development of the LN-40 serie

LN 40 general scheme
LN 40 general scheme, showing also the longitudinally pivot-folding wings.
From the experience gained with the Ni-140 prototypes, Pillon’s team in 1936 started development of a lighter, nimbler and single-seat shipboard dive bomber. It was designed with a semi-retractable undercarriage and had revised tail and control surfaces. The first prototype was startet at the Issy Les-Moulineaux plant near Paris, in 1937, designated LN 40 No. l. However it only made its first trials at nearby Villacoublay in June 1938. Onboard was SNCAO’s chief test pilot Pierre Nadot.

Flight trials revealed the need for additional vertical tail surface area, and auxiliary balancing fins added to the tailplane. The prototype as modified was ready to start its official trials in September 1938. Further trials went on at the naval test center of Saint Raphael (south of France, Riviera) and after they were successful, the prototype started a serie of always dangerous dives in November. But this time it went well: In all, the prototype made 15 dives. Soon also, ten arrested landings were made onboad Béarn. Six preserie LN 40s were ordered in 1937 already even as prototype trials were not done. This first production batch was later standardiized as the LN 401. An additional 36 were then ordered for the French Navy, in February 1939. Deliveries started quickly, by mid-1939, since the tooling already was made ready in 1938 for the preserie.

The land-based Armee de l’Air LN 411

Meanwhile, the Armée de I’Air followed the trials and was impressed enough to pursue the development of the army model, already convinced by reports coming from axis experience in the Spanish civil war, notably with the Junkers 87A Stuka. The air ministry ordered 40 of the modified land-based version called LN 411. They differed in having non-folding wing and no arrester hook as well as other detail modifications. On October 1939, after many trials, the French Air Force however concluded that the LN 411 performance were too inferior for successful operation and thus, it was agreed with the French Navy that the next batch of 39 LN411 ordered were taken over for it’s own branch. The only remaining model was kept and converted as the prototype LN 42 (see later).

Design


LN 401 blueprint. Note a convetible floatplane version was also studied for the Navy, with a belly main float plus two underwings, or two main floats under the undercarriage fairings. It was never developed further.

The LN 40 serie was an inverted gull wing monoplane. This arrangement was chosen just for the reason its manually operated wing folding mechanism could be situated at a convenient height for the operators. But it had an impact on the air flow nevertheless. It had a monocoque fuselage inspired by the experiental Ni-161 fighter. All fuel storage were housed in the broad wing center section.

The lower half of its rudder was divided vertically to be opened opened in two segments at right angles. They acted as such as dive brakes. There was also a crutch beneath the fuselage, which swung forward to ensure the bomb cleared the propeller when released. The main undercarriage structure retracted rearwards, and still remained semi-exposed when retracted, with the wheels vertical.

The landing gear tubes and suspensions were protected by the front fairing which, when folded up, blended with the wing. Empty weight was 2,243 kg, fulluy loaded 2,835 kg respectively, and overall dimensions were a length of 9,75 m, for 3,5 m in height at the tip of the tail, for a span of 14 m and wing area of 24,75 m2.

Engine & Performances

The LN 401 was powered by a Hispano-Suiza 12Xcrs 12-cylinder (V12), liquid-cooled engine, rated for 690 hp at 4,000 m (). It could reach a top speed of 320 km/h at sea level, 380 km/h at 4,000 m. Maximum cruising speed was 340 km/h, range 1,200 km which was largely enough for naval operations behind the horizon (by comparison the Dauntless reached 1,794 km and was much faster).

Armament



Onboard armament as designed comprised a single engine-mounted 20-mm Hispano-Suiza cannon (which was quite powerful at the time for a dive bomber), plus and two, more standard wing-mounted 7,5-mm Darne machine guns. Its bomb load was limited however, as the belly rack only supported a single 225-kg of the BEA 1938 type or a single 150-kg Type 12. This was mostly the fact of using a 700 hp engine, whereas the Dauntless was almost twice as powerful, with a Wright R-1820-60 Cyclone of 1,200 hp. It could also carry more underwings for strafing attacks, ten 10 kg (22 lb) on 15 kg (33 lb) bomblets.

Detailed specs

Comparison between the LN 401 and 411
Comparison between the LN 401 and 411. Apart the hook there is not much to tell them apart but looking at their wings’ gull slip, fixed on the latter case

Specs LN 411 (largest production=

Crew: One pilot
Fuselage Lenght 9.75 m (32 ft)
Wingspan 14 m (45ft 11in)
Height 3.5 m (11ft 6in)
Empty weight: 2,135 kg (4,500 lb)
Gross weight: 2,835 kg (6,250 lb)
Powerplant: Hispano Suiza 12Xcr V12 engine, 510 kW (690 hp)/4,000m
Propellers: 3-bladed fixed-pitch propeller
Maximum speed: 380 km/h (240 mph, 210 kn)
Cruise speed: 299 km/h (186 mph, 161 kn)
Endurance: 3½ hours
Range: 1,200 km (750 mi, 650 nmi)
Service ceiling: 9,500 m (31,200 ft)
Armament – Guns 1x nose 20mm Hispano HS404, 2× wings 7.5 mm (.303 in) Darne machine guns.
Armament – Bombs 1x 225 kg (496 lb)/165 kg (364 lb) bomb, 10×10 kg (22 lb)/15 kg (33 lb) bombs

Operations

The first sixteen LN 401s were undergoing acceptance trials in November 1939, when issued to Escadrilles AB2 and AB4. Béarn at the time was engaged in taxiing to France warplanes purchased in the USA via Canada, and so the LN 401s never started shipboard operations training. Instead, they remained shore-based for their whole career. Escadrille AB4 converted later from the LN 401 to the LN 411, in April 1940. The former LN 401s were distributed among Escadrille AB2, a conversion unit created at Lanvéoc-Poulmic (Britanny) and the remainder parked in a war reserve at Cherbourg.

By May 10, 1940, AB2 and AB4 had 12 aircraft each, the former being relocaed at Berck, Pas de Calais, and the latter, still undergoing training, at Cherbourg-Querqueville. AB2 made first sorties with the LN 411s of AB4 from Berck on May 17th. Two days later, ten were lost on their objectives to a firce FLAK during an attack by 20 aircraft on the crossroads at Berlaimont, falling on elements of the 7th and 5th Panzer Divisions. Only ten went back and reached Berck.

They had been already so badly damaged by shrapnel that on the following day only three were serviceable to mount another attack, on the Origny Bridge (Oise River). There, FLAK was less intense and moreover they arrived after a squadrons of 11 US-built Vought 156 from AB1 Sqn. The latter took the brunt of the Luftwaffe and were all short down, allowing the LN 401s to reach their objective and drop their bombs. And only one was lost. On May, 21st, another was shot down, leaving only one, just repaired, truly airworthy machine.

At the time, orders for the LN 401 and 411 were still placed and before May 29, 1940, some 152 aircraft had been delivered total. Only a small proportion were completed, but between distribution and lack of pilots they were just parked, awaiting their fate. Between these new machines and those repaired, both squadrons were fully reconstituted with a total of 10 LN 401s and 411s, on 22 May. Operations were suspended as the ground personnel already was captured in the Boulogne area.

Both squadrons moved to Hyeres, southern France on June 4th. They flew some reconnaissance missions along the Italian coastline, and when Italy declared war on France, started air cover missions at least for French Navy during Operation Vado, the shelling of Genoa on June 14th. On 17-18 June, 13 machines bombarded the port of Imperia. On the 23-25th, the two squadrons, like most active units evacuated from the north, flew to Africa. These arrived in Bone, Algeria. On 1st August, the two Sqn. were redesignated 2AB and 4AB, and converted later to Martin 167s bombers, also evacuated.


Crashed LN401 N°6 in May 1940
The surviving LN 401s and 411s were disassembled for long term storage. In 1941 the Chateauroux SNCASO plant assembled under German control 24 LN 401s and 411s from recovered components, authorized as part of the air defence in thee unoccupied zone (Vichy air force). In November 1942, when after Operation Torch, the German launched their occupation of Vichy France (Operation Paula), those in storage at Bizerte-Karouba were destroyed by an Allied bombing raid during the landings.

The upgraded LN 402 and 42

A single LN 402 was tested by the Armee de l’air with a 860 hp Hispano-Suiza 12Y31 engine. It was still incomplete at Issy Les-Moulineaux plant by June 1940 when captured. Next was developed the LN 401. It had the same fuselage as the LN 401-411 but with an upgraded 1,100 hp engine and redesigned wings to cope with the faster air flow, with reduced span (13 m) and 21 m2 wing area.

The prototype was transported by rail to Istres, Southern France, making short runs on the airport, and a few flying hops as reported, to be later hidden in a farm at Flayosque, Draguignan, alongside the SO 30N commercial transport prototype. Never discovered by the Germans, after the liberation the LN 42 was transported to Toussus-le-Noble airport for official trials. It flew on August 24, 1945. But the program went no futher as aviation technology made giant leaps in between, and the next summer in 1946, it was fitted with a reversible-pitch Escher-Wyss propeller. It flew with it on October 28, 1946. However at that stage the new Armee de l’Air estimated it was now totally obsolete and decided to have it scrapped.

Read More and Sources

books

Les Bombardiers en piqué Loire-Nieuport
Lucien Morareau, Les aéronefs de l’aviation maritime : 1910-1942, Paris, ARDHAN, 2002
Enzo Angelucci et Paolo Matricardi, Les avions, t. 3 : La Seconde Guerre mondiale

links

aviastar.org
histaviation.com
On wikipedia EN
aviafrance.com
ww2aircraft.net
wardrawings.be
militaryfactory.com
avionslegendaires.net
forum.warthunder.com
aviadrix.blogspot
histoiredumonde.net
On fandavion.free.fr LN411
On fandavion.free.fr LN42
On secretprojects.co.uk

Model Kits

On scalemates – Special Hobby | No. SH48058 | 1:48
More on the same site
Loire-Nieuport LN.411 Azur 1:48, CMB 1:72 resin. That’s about it.


LN 401 N°8, AB-4, Berck, May 1940.


LN 411, wheeltrain down, reconstituted AB-4, June 1940


Vichy Air Force, LN 411, Hyeres AB Fall 1942



The French aircraft carrier Béarn

Loire_Nieuport_LN-40_left_photo_LAerophile
Loire_Nieuport_LN-40
Loire_Nieuport_LN-40
Photos from L’aerophile August 1943

Wing design bueprint
Wing design bueprints

Wing design bueprint
Wing design bueprints

Cockpit interior
Cockpit interior

Ailerons drive scheme
Ailerons drive scheme

Ni161
The loire-Nieuport Ni 161 prototype, a related development fighter, three prototypes built.