samedi 12 avril 2014

The Loire 210, obsolete? Yes, but so useful for the Campaign of Norway... (Cleaned 30 / 07 /2017)

(Sources : A good paper on the Loire 210 fighter by Gérard Bousquet published in AirMagazine n° 57 in February 2013
the Hors-Série #1 of Avions, 1994, by Lucien Morareau, absolute master of the French Aeronavale history, who also published  
two recent  papers in Avions # 197 and # 198 on the Loire 210, in  2014, 
and some other sources, like the tiny Floatplanes #6 of William Green)



Air cover for the French Navy  


I had already written the big problem of the French fleets (click here) in almost all the seas or oceans they were involved: Once some hundreds of kilometers away from friendly coasts, they were defenseless against all aerial threat.

Remember that the Washington treaty on naval forces allowed only 60,000 tonnes of aircraft carriers to the French Navy. 

France had two carriers in the 30's. 

The Béarn was a rather classical aircraft carrier, able to carry at most 40 aircrafts, but she was plagued by an over-complicated system of lifts, protected by armored doors, all of this implying large engines in the aircraft hangar and were very time consuming during military operations.

The other French carrier was the little seaplane carrier Commandant Teste, able to carry 26 sea planes with 4 catapults and five cranes.

The lay out of this boat was sufficiently good to be copied by the Imperial Japanese Navy.


From the other hand, the recent battleships, the cruisers and even some colonial vessels had catapults to put seaplanes in the air.

Most of these sea planes were only scout planes, some times with a limited bombing capacity (one or two 75 kg bombs).  


In 1931, the admiral-to-be Lartigue had, very logically, taking into account this poor amount of aircraft carriers, expressed the need of a complement of air cover of the French fleets by seaplane fighters. 


In some post WW II influential publications, you may read that such an idea was already obsolete. 


Nevertheless, many naval countries have tested seaplane fighters from the end of the 30's to the beginning of the 50's: 

  • In Great Britain, the Blackburn Roc was transformed in hydro-fighter, a very strange idea, knowing the definitively bad aerodynamics of the carrier based Roc. Her top speed was 270 kph.
  • After that, a Grumman Martlet was fitted with float.


  • But an undoubtedly greater success was obtained when a Spitfire Mk V was successfully transformed in floatplane fighter - three were ordered by the Royal Navy - as was transformed, a bit later, a Spitfire Mk IX.





A splendid picture of a Spitfire Mk IX on this site (610 kph !)


  • The Imperial Japanese Navy proceeded similarly with the Zero A6 M2-N able to fly at 435 kph and to climb at 5,000 m in less than 7 minutesThe today narrative is this aircraft was unsuccessful, but 327 machines were built!
  • They developed also the exceptional float plane Kawanishi N1K1 Kyofu, able to fly at 490 kph, to climb to 4,000 m in 4' 11" (97 machines were built, too late).


In all cases, such fighters could have been available to cover their fleets against enemy bombers as they were able to land on any water surfaces, because nobody can destroy such kind of "airfields"


Moreover, this idea revived at the end of the WW II with two jet fighters. 




 Saunders-Roe SR.A/1 - A very good aircraft.

The first one was the British Saunders-Roe SR.A/1, conceived during WW II, flying successfully from 1947 to 1951, but she was abandoned after the withdrawal of the engines manufacturer... 

Another hydro-fighter was build in the USA, the Convair F2Y Sea DartShe was under-powered but flew faster (high subsonic). 

Unfortunately for the concept, she was flown after the victory of the supporters of the giant aircraft carriers. 

Some interesting French projects were also submitted actually by Latécoère but none of them was accepted.



The wishes of the French Navy in the 30's


A program was published by the French Navy in 1933, 2 years after the study of Lartigue (!), and specifying:
  • A speed of at least 300 kph at an altitude of 3,500 m,
  • A maximum weight not exceeding 2,000 kg, in order to be launched by the existing compressed-air catapults,
  • The altitude of 3,500 m must be reached in less than 12 minutes,
  • The engine chosen was the Hispano-Suiza 9 V providing 700 hp and actually seen as very reliable, as they powered the tri-engined Dewoitine passenger airliners,
  • A fabric covering of the structure at the very moment of the triumph of the stressed skin! It was likely a colonial point of view, as the need to prepare the maintenance with easily available materials... 
One might be disappointed by several of these specifications.

The most amazing one was the engine. 


OK, the seamen liked very much any kind of radial engines, but, for a fighter, it was the most irrelevant choice, because the fuselage cross section will suffer from the cross section of such an engine. 

And the HS 9 V had a huge diameter of 1.45 m, inducing a fuselage cross section larger than 1.7 m², which had to be added with the two or three floats, the masts and the wings... 

Aerodynamically speaking, it was the worst solution.



Following the same inappropriate way, the use of fabric covering was a total non sense, aerodynamically speaking.

So, the choice of a speed limit of only 300 kph was understandable but not wise. 

It is somewhat amazing to remember the program published in the same period for a torpedo float-plane - the Latécoère 298 - specified exactly the same top speed.


Indeed, a seaplane fighter could never be as nimble as her land-based counterparts. 

This implying her purpose could not be the establishment of a total air mastering over all skies but over their own fleet in deep seas.

To be useful near the enemy coasts, seaplane fighters needed to attack their target by surprise just at sunrise... So, they needed the highest possible top speed!


Moreover, the land-based fighters issued from the older contest of the French Air Force had demonstrated, at the end of 1932, top speeds from 360 kph to 380 kph with engines providing less than 700 hp. 

Taking into account the maturation of significantly more powerful engines (Hispano-Suiza 12 Y and Gnome & Rhône 14 K), it was possible to obtain at least the same speed than the 2 years older land-based fighters.

Some studies were developed by other companies.

  • Dewoitine proposed a float plane straightforwardly issued from the D 500 (winner of the land based fighters contest).

  • Bernard proposed his model 110, a scaled up derivative of his Bernard 52 float plane.

  • Potez proposed the model 453, issued from the scout flying boat Potez 452, but this fighter experienced complicated take offs.

  • The biplane Romano 90, the fastest of the contest (350 kph), outstandingly maneuverable, experienced some difficulties during take off, but his "Polish" upper wing dissatisfied her pilots during mock up combats. Nevertheless, a derivative of the float plane was built in Belgium to be sold to the Republican pilots in the Spain War.

Just for information, the only French fighter sea-plane to be sold to a foreign country were the Nieuport 123 which was rejected as land-based fighter by the French Air Forces! 

However, 12 of such aircrafts were ordered by the Peruvian Air Force. They were land-based (top speed ~365 kph) but also convertible to float planes. 

The top speed of the float plane variant was 320 kph with their Lorraine Petrel engine providing 720 hp. It was said the sold fighters were using of a more powerful variant of the engine (780 hp), enabling her to reach a top speed of ~335 kph.



The Loire 210


She take-off for the first time the March 201935 and the preliminary tests were successful.

The Loire was easy to fly, easy to land on the sea, as usual with a main center-lined single float (at the expense of performances), a solution retained later for the float-plane variant of the Japanese Zero as also for her more recent stablemate Kyofu.


Her take-off duration was only 9 seconds with a variable pitch air-screw, 11 seconds with a fixed pitch one (the rejection threshold for the Navy was 15 seconds).



The aerobatics was easy but the commands were heavier than those of the carrier based fighters.


The catapult trials were very successful, the first ones being done without pilot but also without crash!


The top speed of the prototype - at altitude - exceeded 304 kph at 3,000 m (the top speed of the series machines is often said to have been 315 kph between 3,500 - 4,000 m. 

Exhaust pipes would have been useful!

The service ceiling exceeded 8,000 m.

The climbing times were:
·                       1,000 m in   1’ 42”
·                       3,000 m in   5’ 19”
·                       3,500 m in   6’ 26”
·                       4,000 m in   9’ 24”
·                       6,500 m in 19’ 00”

The maximum flight duration was 3 hours at 200 kph and 2 hours at 250 kph.

The armament consisted in four 7.5 mm Darne machine guns in the wings, a rather light punch.

The official trials were finished at the Fall of 1935.


Personal document of the author - Loire 210, from standard (smooth cowling), before to be put on her catapult 


The Loire-Nieuport company staff, perfectly aware of the aeronautical evolution, wanted to enhance the speed capabilities of his fighter. 

So, they replaced the initial Hispano 9 V with a Gnome & Rhône 14 K.

The new engine was more powerful and, also, had a 27 % better cross section, allowing a lower fuel consuming in flight.

The modified aircraft was re-designated Loire 211 and flew at a top speed of 330 kph, but unfortunately, the engine was not fitted with a reduction gear box and the air-screw, running too fast, was not optimal. 


It was anticipated that with an reduction gearbox and a better air-screw, the Loire 211 were able to fly at 350 kph. 


Another study was proposed, using the Gnome & Rhône 14 Mars 700 hp engine, allowing a  200 kg lighter empty-weight and a 60 % slimmer fuselage cross-section.

This proposal was really promising, even the speed was to be quite identical to that of the Loire 211, the combat radius would have been very larger, allowing a much more interesting tactical role, as also the capability to embark these fighter on lighter ships (much more numerous).

The only aerodynamic evolution was the NACA cowling which adopted a quite smooth shape (but a too large air-intake).




The French Navy ordered the less performing variant!



Very late, at the end of 1936, some one full year after the termination of the official tests (!), the French Navy informed unofficially the Loire-Nieuport company twenty Loire 210 examples were ordered. 

But the official order was emitted only the May 12, 1937.

These delays - whose narrative have said they were justified by "experiments" - were totally abnormal. 

What kind of "experiment" could have been made with only one prototype? 

It was possible, indeed, to made true - dedicated to the war - experiments!

For example, one could have used fighter groups of at least three prototypes (even if they were issued from different factories) during long flight around a real fleet doing realistic combat simulations of the defense of the fleet against big aircrafts as were the civilian one but experimental Laté 521, or against Laté 290 and later Laté 298 torpedo bombers.

So, the more relevant tactics could have been selected and perfected, as also, the needs for a more modern fighter, knowing the recent advances in aerodynamics.

Obviously, all these experiments were to do from the tropical or equatorial regions to Arctic or Antarctic, to know all possible shortcomings associated to the different climatic conditions. 

Unfortunately, to my knowledge, none of such experiments were done.

The very late ordering had forbidden the awareness of the true capabilities allowed (or not) by such sea plane fighters.



A fighter protecting the Fleet, far from the enemy coasts, when you have no aircraft carrier... 



The twenty ordered Loire 210 could be installed on the catapult of a battleship or a cruiser. 


In 1939, the French Fleet gathered 18 ships able to launch the Loire 210: The Lorraine battleship, the Dunkerque and Strasbourg battle cruisers, the seven 10,000 wt heavy cruisers, the seven La Galissonnière class light cruisers and the Commandant Teste seaplane carrier. 

So, if these aircrafts have been equally distributed between the existing French naval forces (North Atlantic, South Atlantic, Indian Ocean, Indochina and French Polynesia), there could be only two or three of these float planes for each fleet (taking into account several machines for training or repair).

Another distribution could have been done, with only three fleets equipped, e.g. one for the North Atlantic, one for the South Indian Ocean and one for the Indochina. 

In tolerable sea conditions and only during daylight, with about 5 fighters for each fleet, it would had been possible to maintain two fighters in readiness and two other as reinforcement, the last being in maintenance. 

In case of real attack, four fighters were available. 

So, the possible enemy heavy scout planes - the only aircrafts able to fly really far from the coasts - could be downed, allowing all the desired secrecy for the involved French fleets.


One technical problem remained: How to retrieve the launched fighters?


The first current solution found was to pick up the fighter with a crane. This process was perfect in peace times. 

During a battle, it was too time consuming, endangering the ship and the fighter. 

Moreover, in rough sea, the likelihood to achieve such a goal became very little.

So, the French naval engineers had elaborated an interesting method (may be inspired by a German experiment). 

A notched carpet was lowered at the stern of the ship (the notches being made of piece of timber). 




Personal document of the author - Gourdou-Leseurre 812 climbing on the notched carpet as would do the Loire 210


The float plane pilot had to follow the ship with the excess of speed resultant of his landing and to climb on the middle of the notched carpet on which the float will be quickly hooked, allowing the sailors to retrieve both the aircraft and her pilot.

It was a sporting and rather daring method, but, after a thorough training, the retrieval of the aircrafts was very faster. 

One shortcoming was the difficult maintenance of these carpets.

Nevertheless, such carpets, tested successfully on the Commandant Teste, were fitted on the recent and excellent light cruisers of 7,500 tonnes. 

These excellent cruisers had a square stern to ease the deployment of their carpet.

In French publications, you can read such maneuvers needed to limit the speed of the ship to 15 kts. 

Some captains complained it was dangerous and time consuming...

In my personal opinion, the true danger for any French fleet was especially to be spotted by a Focke-Wulf 200!

OK, this large German aircraft was theoretically faster than the Loire 210 – she had a speed excess of 45 kph - but, during an operation far from her own coasts, her pilots flied at no more than 260 kph, in order to save the flying range of his machine as also the capacity to return at home.

Moreover, she was not able to dive (or climb) as sharply as fighters could do.

By definition, the other crew members were watching for Allied civilian or military vessels, the watch of the skies being not very exciting. 

So, a Loire 210, relatively small and flying easily higher - at about 3,500 m - could approach in the sun by a weak slope dive and attack the recce bomber long before the FW 200 could accelerate enough to escape. 

Yes, the four Darne machine guns were light (0.3 cal.), but the FW 200 was very brittle, especially during escape maneuvers!



A broken Focke-Wulf 200 after her landing - a frequent picture - There is no clear evidence of battle damage...

Yes, I know this weakness because these wrecks have been published after the war. 

However, the Focke-Wulf 200 was an absolutely famous aircraft since her really brilliant crossing of the North Atlantic in August 1938. 

At this very moment, she was only a passenger liner – actually designated as Kurier - whose speed was mostly related to her aerodynamics and her lightness. 

The military variant Condor, with her protrusive gondola, her turrets and her armament, was unwisely overloaded and displayed a significant loss of her fineness.

Her total power increased from 3,600 hp to 4,800 hp, her empty weight was ~3,000 kg heavier and her take off weight was more than 8,000 kg (or ~50 %) heavier than the civilian FW 200! 

Any current strengthening of the structure could not fix so unexpected constraints (a complete redesign would have been the only fair solution).

So, such weakness could be easily expected, including by the German deciders.

Nevertheless, they bet on a weak likelihood of encountering fighters



From the other hand, Louis Bonte (in Histoire des Essais en Vol, Docavia #3) as said the problem of the Loire 210, was that if there was any encounter of land based fighters like the Messerschmitt Bf 109, the Loire 210 would be "an innocent victim".

This "honorable" person seemed to forget an important fact: The Bf 109 had a total range of only 660 km. 

At most, that allowed her a combat radius from 150 km up to 200 km. A very short distance, as it was demonstrated later during the Battle of Britain.

The least bullet impact in the engine, the water radiator or the oil one (or the fuel tank) would signify a very “uncomfortable” ditching on the sea, with a quasi lethal issue...

During the Campaign of France, the Dewoitine 520 was alone among the Allied single-engined fighter able to fly 1,500 km, allowing her to fly up to 400 km from the coasts (with some hazards, nevertheless...).



So, the seaplane fighters was needed for any fleet having no aircraft carrier to cover them.

Are you interested by a demonstration? 

OK, remember what happened in December, 1941, in Malaya.

The then-promising British admiral Thomas Phillips was in command of a fleet dubbed Force Z, consisting in four destroyers and two battleships, the HMS Repulse and the HMS Prince of Wales


This fleet appeared not very strong, having no cruiser and no protecting submarine.

None aircraft carrier was available to strengthen this force, the only one, the HMS Hermes, was left at Capetown "for lack of speed" had said the (full) admiral Phillips. 

It was the same expression used to left some Allied destroyers and cruisers at Singapore

Such judgments demonstrated the poor tactical sense of admiral Phillips.

Knowing the landing of Japanese forces in Malaya, the same December, 8, than the Pearl Harbor attack, admiral Phillips launched an attack of the Japanese convoy and instructed the RAF fighters to help the Allied ground forces, leaving his ships without air cover. 

Doing this way, he fulfill all the Japanese wishes. 

The December 9, one of the escorting destroyers signaled a Japanese scout plane in sight. 

OK, Phillips had no aircraft carrier, however, if each of his two battleship had a fighter float-plane on her catapults, even an as obsolete fighter as was the Loire 210, this scout plane could be easily downed. 

But, unfortunately, admiral Phillips had no fighter seaplane. 

That triggered the following events:
  • The I-58 submarine reported the position of the Force Z the December, 10. 
  • A twin-engined recce-bomber Mitsubishi G3M spotted the British fleet and  maintained contact.
  • The Japanese staff ordered the attack by several waves of bombers (flying only at 260 kph to allow them a safe return).
  • In no more than 3 hours, the brand new Prince of Wales battleship and the old Repulse battle cruiser disappeared from the surface of the sea. 
Only a handful Japanese bombers were downed.


Obviously, such a disaster had multiple causes. 


The first one was the overconfidence of Phillips who clearly despised the Japanese sailors and airmen as also their machines.

His second fault was to be too eager to go to combat, with his AA fire control disabled by the tropical moisture (he did not accept to left sufficient time for fixing the bugs), with a weak escort and no fighter cover.

His third fault had been to privilege the radio blackout over presence of an air cover.

But admiral Phillips was certainly not responsible of the excellent tactic used by Japaneses forces, as he was not responsible of the Churchill's orders.


Many very courageous men were killed because the Royal Navy was not aware of the mutation needed to the fleets by the appearance of the war planes... even one full year after her brilliant aerial attack against the Regia Marina fleet at Tarento!




The Loire 210: A delayed and very short operational career



The whole series of the Loire 210 was built between the November, 18, 1938 and the September, 8, 1939.


The French Navy had commissioned the first half of them between June and July 1939 and the second half from August to November.

The training proceeded normally but the new device triggering the fire of the guns - instead of a classical Bowden cable - was ill-conceived, adding 0.3 to 0.5 second delay before the shot! 

So the marksmanship of the pilots was annihilated, as it happened to the contemporary Morane-Saulnier 406 pilots.


Two of the Loire 210, #3 and #4, were respectively in board of the Dunkerque and Strasbourg battle cruisers at the 1st day of the nazi offensive against Poland.

They were used to train the AA, but never to elaborate defensive strategies...

Lucien Morareau (the greatest expert in the French Aéronavale history) tell us the different steps of training, fairly done, as, also, the annoyance of the captains of the ships the Loire 210 had to defend!

As all the other sailors in the World, but the Japanese ones, they were completely blind to the numerous weakness of their ships facing an aerial attack.

The French captains were badly sanctioned in July 1940 when, after the operation Catapult, some Swordfish of the Royal Navy attacked again the Dunkerque and killed 200 sailors!


There was a nasty legend about the Loire 210 fighter. 

It was said that this float-plane was ill-conceived and that crash had caused casualties.


Yes, 2 crash occurred, but none of them induced any injury. 


One was a landing at clearly excessive speed on a rather rough water, resulting of the written off of the entire float-plane.

The other occurred after a fighter pilot expressed some worries about his fighter. The Squadron Leader, L.V. Ziegler, take off with that fighter, launching a very savage session of aerobatics.

At the end of the descending trajectory of a loop, the central float drop out, followed by the folding of a wing just before the disintegration of the plane. 

Fortunately, the parachute opened automatically, saving L.V. Ziegler.

The actual explanations concluded to a left wing failure.



However, as Lucien Morareau tells recently on these accident, it seems likely that the mechanical links between the float and the fuselage and the wing were not sufficiently robust. 

It is also possible that the fabric covering of the wing induced a lack of rigidity of the whole assembly.

From the other hand, in several anecdotes, some pilots signaled a high level of vibrations.

If you consider the amazing number (22!) of the sustaining masts, such vibrations might have been created by them, endangering the structure of the aircraft.

Some judicious fairing might have avoided such vibrations and, also, improved substantially the top speed of the Loire 210...


Admiral Lartigue, who had triggered the program of the seaplane fighters, finally, stopped the experience at the end of November 1939, transferring the trained pilots to land based (and future carrier based) fighters or dive-bombers units.

At this very time, the French Navy used the Béarn as an aircrafts lorry, privileged the Richelieu and Jean-Bart Battleship against the Joffre and Painlevé aircraft carriers and ordered the fighter float plane Dewoitine HD 780!

All these decisions were absolutely inconsistent!

The time used to achieve quickly the 2 battleships could have been used to finish 3 aircrafts carriers, the armor plates could have permitted the finishing of the bunker in the Sedan vicinity, and so on.

 
So, in March 1940, when the Allies launched the Campaign of Norway, they did not have any air cover for their ships!










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