jeudi 18 octobre 2012

The French Strike Air Forces in 1940: The Amiot 143 (Enriched 13 / 03 / 2017)

An old advanced bomber

The Amiot 143 is an old bomber used by the French Air Forces during the Battle of France. 

The prototype Amiot 140 flew first in April 1931. 

The definitive version (Amiot 143) was ordered in October 1933 and the 138 aircrafts were all manufactured three year later. 

Actually, she was seen as a modern bomber. 

Her fuselage was very narrow, in order to obtain the highest possible speed notwithstanding of her huge fixed landing gear.

Amiot 143 (on the previous site of the aerial base of Dijon) - technical data on Aviafrance

The top speed was 310 kph - the 295 kph given at 3400 m indicating a top speed at least 1200 m higher, inducing about a 15 kph increase of speed - the ceiling was 8000 m and the bomb load reached 1600 kg. 

Her performances seemed good for the times.  

OK, the Martin B10, which flew one year later, was 10% faster, but her bomb load was ~40% less important. 

This aircraft used retractable landing gear which were not ready in France for such heavy planes. 

However, if you want to compare the Amiot 143 with her British counterpart, see the Handley Page Heyford, which flew only a half year before her and was some 80 kph slower (230 kph). 

Handley-Page Heyford 

The Amiot bomber, fast and easy to fly, satisfied her pilots and the high rank officers. 

She was intensively used for trans-African raids where she demonstrated her great sturdiness.

Few modifications could, however, have given this aircraft a better efficiency. 

Using variable pitch air-screws, fitting a more refined landing gear and replacing the fore gunner by 3 to 4 machine guns would have saved weight and fineness (the huge turret was a true air brake, with only one 7.5 machine gun). 

Personal document of the author - An easy - but never done - modification of the Amiot 143
The fore turret is away, replaced by 4 fixed machine guns

If French seemed not interested this way, the Handley Page engineers were!  

The Hampden bomber was a very clever evolution of the layout solutions found in the Amiot 143. 

She was the fastest British strategic bomber before the much more potent Avro Lancaster replaced her.

Personal document of the author - Prototype of the HP. Hampden. The glassed nose was deeply modified for the subsequent aircrafts

An inefficient night use

Among all the Amiot 143 manufactured, only 91 were in operational use by the Armée de l'Air in September 1939. 

Thirty five of the others being relegated to flying schools.

Unfortunately, the intensive duties of the Amiot bomber had worn their engines out. 

But nobody thought to change them for new and more powerful engines.

So, they were specialized in night operations, which, during the Phoney War, were only to drop propaganda leaflet written by distinguished but completely "inefficient" poet (Alexis Leger, alias Saint John Perse).

One problem was the long duration of the night flights. 

The logical consequence was that once they had landed, it was not conceivable to the squadron commander to send back these bombers above the enemy lines. 

What's a pity!)

So, during the night between the May 11 and the May 12, 1940, the crew of a Potez 637 of the recce II/33 Squadron discovered the three huge columns of the Guderian armored divisions advancing throughout the Ardennes. 

All German vehicles were travelling on full beam. 

Unfortunately, when they landed, nobody of the Division Aérienne had decided to send all night bombers to attack already the invaders!

Personal document of the author - An artist impression of the Guderian Panzer Korps crossing the Ardennes during the night of the May 11, 1940, as reported by the crew of a Potez 637 of GR II/33

Just a moment for the dream, if it has be done: 
  • the German Flak was inefficient (not in place);
  • there was, actually, not efficient night fighting for Germans (which begun to be effective by the mid -!

Even with a low rate of bombing efficiency, all 3 roads will be blocked, the Guderian movement will be stopped, the surprise will be over! 

The Corap Ninth Army will be placed in good conditions, and so on...

A late "suicidal" (?) strike

When, 2 days later, the Air staff, now aware of the great danger of a breakthrough of the French front by the German armies, decided to sent all available bombers to block them: It was the famous - "suicidal" - mission to Sedan

One gathered only 20 bombers which were sent to attack the German ship bridges on the Meuse river. 

The orders were to attack from an altitude of 750 m AGL (~2500 feet)!

At this altitude, the Amiot 143 engines cannot use their superchargers and their cruising speed cannot exceed 180 kph! 

A very good option for the Flak servants! 

From the most serious authorities (the monthly publications Avions, and Aéro Journal), we know the moods of the implied squadrons commanders were low.

Among the bombers involved were 6 modern LéO 451 which used their speed, leaving their colleagues.

All others were on Amiot 143 bombers. 

They were escorted by only 12 Morane-Saulnier 406 which, for the first time, were able to follow their bombers! 

Yes, I know it, I'm a naughty - old - boy...

The lay out of this formation is a bit simplistic: They flew in 4 rows of 3 planes, each group of 3 affecting a V shape. 

It was not the better method to cross the fires.

Once the light Flak has ceased fire, the German fighters were attacking.

The losses: Less impressive than expected

However, the pilots having flown clearly higher than the prescribed level, they were in shallow dive until their targets and flew at 300 km/h.

This was a good way to survive. 

Even if 2 bombers were downed above the target and one was obliged to make an emergency landing, all others went back to their respective airfields, with some damages. 

On the German Wikipedia page (2012) about this bomber, you can read the German claim: 12 among the 13 Amiot being downed. 

It's a good illustration of 2 honest - but contradictory perceptions - of the same facts. 

All the bombers were damaged but one. Among the 12 remaining, 2 were downed with all hands and one must land. 

The 9 remaining were all damaged, but the exceptional sturdiness of this aircraft allowed a safe return to the airfields. 

Once there, and taking into account the following events, it was likely that none were repaired and all were staying where the have landed, giving a clear confirmation of the German claim. 

Nevertheless, in other war circumstances, some of these planes could have been reusable.

In the following days, this kind of missions were reserved to faster aircrafts. 

The remaining Amiot 143 were used to drop supplies to Dunkirk, a very hard and risky task.

During the Battle of France, 300 tons of bombs were dropped by them. 

Since the beginning of the war, 45 Amiot 143 were lost, some by accidents (without any relationship with an air battle), some others by bombing or strafing and only few by the enemy fighters, demonstrating simultaneously the soundness of the Amiot design and the weakness of the Messerschmitt armament.

I persist to think these bombers were irrelevantly used by the French High Command.

The Amiot 144 : Approved, ordered, cancelled!

{Source : Les Ailes,# 790, August 6, 1936, p. 3}

Félix Amiot belonged to these engineers always interested to upgrade their aircrafts.

He understood how negative were the turrets and the fixed undercarriage for the drag of his bomber.

So, he re-designed :
  • The disgraceful front turret, in order it could be almost totally embedded in the fuselage.
  • The wings, reducing their area to 91.4 m², 
    • modifying the wing tips,
    • tapering the wings,
    • the ailerons were also used as flaps, allowing a 25% lowering of the landing speed.
    The empty weight arose up to 5,800 kg (an 950 kg increase). 

    The normal take off weight was 9,000 kg, but the maximal one was 11,500 kg, the wing loading varying from 98 to 126 kg/m².

    All these modifications had good repercussions on the fineness of the bomber without disturbing the industrial scheme of the Amiot 143.

    The new model was designated Amiot 144.
    She retained the same Gnome et Rhône 14 Kirs engines delivering 800 hp at 4,000 m. 

    The fuel weight varied from 1,300 kg (1,730 liters) up to 3,000 kg (4,000 liters).

    The Amiot 144 displayed good flying qualities and her performances were significantly better than those of tha Amiot 143.

    The top speed was 355 kph at 4,000 m and 325 kph at 6,000 m. 

    With 1,200 Cv engines (GR 18 L), one expected 390 kph.

    The landing speed was 90 km/h.

    Climbing to 4,000 m needed 13 minutes (6,000 m needed 22').

    The service ceiling was 8,500 m.

    At the cruse speed of 300 kph (60 km/h better than the Amiot 143), the total range was 4,000 km.

    The French deciders, accustomed to the short range needed to strike on the German target (Berlin is at 880 km from Paris), did not understand the positive implications of such a large range.

    For example, with the Amiot 144, it would be easy to release bombs on targets in the vicinity of Namsos during the Campaign of Norway.

    The bomb weight may be 2,000 kg. 

    25 bombers were logically ordered. 

    They would have been useful to upgrade the Amiot 143 equipped bomber units, which were worn out.

    The French administration decided to replace the ordered Amiot 144 by "new" Amiot 143. 

    De profundis...

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