12/31/2011. Remarks by Johan Visschedijk: "Regarded widely as the very quintessence of aerodynamic cleanliness at the time of its debut at the Salon de l'Aéronautique held in Paris in 1936, the elegantly-contoured Amiot 341 was undoubtedly an impressive creation, with its efficient circular-section stressed-skin monocoque fuselage to which the shoulder-mounted wing had been carefully faired.
Presented as a high-performance long-range postal aircraft, the shapely Amiot 341, designed by M. Calvy and his assistants Lambert and Girodin of Avions Amiot (Société d'Emboutissage et de Constructions Mécaniques) at Colombes, was quite obviously intended for more militant tasks than that of delivering mail, and the fact that it featured bomb-bay doors hardly supported the contention that the primary role of the new Amiot product was pacific. Indeed, it came as no surprise when, a year later, on December 6, 1937, this aircraft was flown for the first time at Istres as the Amiot 340-01 three-seat bomber.
Powered by two 920 hp Gnome-Rhone 14N 0/1 radial engines, the Amiot 340-01 was flown from Istres to the CEMA (Centre d'Essais du Matériel Aérien) at Villacoublay on March 21, 1938 for official trials. During these trials the aircraft was fitted with close-fitting engine cowlings to reduce drag, and the STAé (Service Technique de l'Aéronautique) informed Avions Amiot of the various modifications that it considered necessary, including provision of accommodation for a fourth crew member.
However, before the Amiot 340-01 could be flown back to Istres for these changes to be made, the prototype had a part to play in the game of bluff and counter-bluff that was being conducted between France and Germany in that last year of uneasy peace in Europe. The French Chief of Air Staff, General Vuillemin, had been invited to visit Germany, and the sole example of the Amiot 340, with all indications of its prototype status deleted and sporting the red cocotte emblem of Vuillemin, was selected to fly the Chief of Air Staff to Staaken airfield near Berlin on August 16, 1938, returning to Villacoublay on August 21. It is not known if the visit persuaded the Germans that the advanced Amiot bomber was already serving with the Armée de l'Air; at least the Germans succeeded in convincing General Vuillemin that their experimental He 100 fighter was in mass production for the Luftwaffe!
In November 1938, the Amiot 340-01 was re-engined at Istres with two 1,020 hp Gnome-Rhone 14N 20/21 engines, provision was made for an additional crew member with a single 0.295 in (7.5 mm) MAC 1934 machinegun on a flexible mount firing through a ventral hatch aft of the bomb-bay, and redesigned tail surfaces were introduced, the single fin-and-rudder assembly being supplanted by oval end plate fins and rudders, marked dihedral being applied to the tailplane. In this form and redesignated Amiot 351-01, the prototype resumed flight trials on January 21, 1939 at Istres, and was flown to the CEMA at Villacoublay in the following month, still sporting the red cocotte emblem of Vuillemin, as seen above and in photo 8579.
In 1938, Calvy's team had instituted some redesign of the basic Amiot 340 to meet the STAé demands resulting from intial trials with the Amiot 340-01, this having produced the Amiot 350 series comprising one standard airframe capable of accepting a variety of different power plants. Thus, the Amiot 350 was intended to be powered by two 920 hp Hispano-Suiza 12Y 28/29 engines, the Amiot 351 was to have 950 hp Gnome-Rhone 14N 38/39 radials, the Amiot 352 was a version with 1,100 hp Hispano-Suiza 12Y 50/51 engines, and the Amiot 353 had 1,030 hp Rolls-Royce Merlin IIIs. The introduction of 1,070 hp Gnome-Rhone 14N 48/49 engines, and reversion to a single fin-and-rudder tail assembly similar to that of the original Amiot 340-01 resulted in the Amiot 354, and with 1,130 hp Merlin X engines this variant became the Amiot 356.
Essentially the Amiot 350 production series aircraft differed from the Amiot 351-01 in having a wing of reduced span and area, an increase in overall length, and, in the case of those variants retaining the twin fin-and-rudder tail assembly, substantially enlarged end plate vertical surfaces. Furthermore, the raised cockpit canopy, which, on the Amiot 351-01, was offset to port, was both widened and lengthened, and repositioned centrally on the fuselage.
The Hispano-Suiza-powered Amiot 350 was not proceeded with, and the first production aircraft to fly was the Amiot 351 No.1 which was completed in the summer of 1939 and, owing to the extensive differences between this and the Amiot 351-01, was sent to Orleans-Bricy for CEMA trials, flying there for the first time on November 3, 1939. A few days later it was joined at Orleans-Bricy by the second production aircraft, the Amiot 354 No. 2 (a common sequence having been adopted for all Amiot 350 Series production numbers as the airframes were identical apart from the tail surfaces which were interchangeable), this being returned to Avions Amiot for modifications on December 19, 1939, resuming CEMA tests on January 10, 1940.
Initial production orders for the Amiot 350 Series placed in 1938 called for 30 Amiot 351s, 60 Amiot 353s and 40 Amiot 354s, but prior to the start of WW II supplementary orders had been placed for 30 Amiot 351s, 100 Amiot 353s and 35 Amiot 356s. These orders were to be augmented soon after the conflict began by contracts for 560 Amiot 352s, and a further 30 Amiot 351s and five Amiot 356s to bring total contracts to 890 aircraft.
Production of the fuselages was undertaken by the Amiot plant at Colombes, the wings were manufactured by the Chantiers Aéronautiques de Normandie at Cherbourg, and the tail assemblies were produced at SNCAC's Billancourt factory, final assembly taking place at Le Bourget.
All Amiot 350 Series aircraft were basically similar, their structure comprising a circular-section stressed-skin monocoque fuselage built in three sections, and a wing built up on a main spar and two auxiliary spars with stressed-skin covering and built in two halves which attached directly to the fuselage mainframes. The electrically-operated undercarriage was fully retractable, each main member comprising two oleo legs and two inclined articulated struts which raised the wheel backwards into the tail of the engine nacelle. The crew comprised a navigator-bombardier in the extreme nose with a 0.295 in (7.5 mm) machinegun on an SAMM-AB20 (Type 161) flexible mounting, a pilot seated above the forward portion of the bomb-bay, a dorsal gunner with a 0.787 in (20 mm) Hispano-Suiza 404 cannon on a SAMM-AB34 power-operated flexible mount above the aft end of the bomb-bay, and a radio-operator with a 0.295 in (7.5 mm) machinegun firing through a ventral hatch. All fuel was housed in the wing inboard of the engine nacelles.
Prior to November 1939, it had been intended to complete a proportion of the Amiot 350 Series aircraft on order as four-seater reconnaissance aircraft, but this order was rescinded and all aircraft were delivered as bombers. Only a few Amiot 351 B4 and 354 B4 had been completed by the beginning of 1940, despite the urgency that was attached to the service introduction of the bomber, five having been taken on charge by the Armée de l'Air. A further 12 had been taken on charge by March 1, 1940, although the Armée de l'Air had anticipated delivery of 80 aircraft by this date.
Of those aircraft that had been delivered only six had the 0.787 in (20 mm) dorsal cannon installed, inadequate supplies having necessitated the installation of a 0.295 in (7.5 mm) machinegun in lieu of the heavier weapon in the others (aircraft Nos. 7 to 46 inclusive were to be delivered without the cannon). Owing to the inadequacy of the single small-caliber weapon, a trio of 0.295 in (7.5 mm) Dame machineguns on a single flexible mount was considered as dorsal armament, and firing trials with this installation were conducted with one machine at Cazaux in the spring of 1940, but as supplies of the Hispano-Suiza cannon were expected to improve, the triple-gun mounting was not adopted as standard.
Production continued at an extremely slow tempo, a total of 21 aircraft having been taken on charge by April 1, 1940, as compared with the 285 aircraft planned. By May 1st the Armée de l'Air had accepted 37 aircraft, and by the end of the month 17 Amiot 351 B4s and 40 Amiot 354 B4s had been accepted, and conversion of some Groupes de Bombardement to the new aircraft had begun.
While production tempo had been slowly building up several further Amiot 350 Series aircraft had been under development, including the Amiot 355 prototype, this being the 12th production airframe fitted with 1,200 hp Gnome-Rhone 14R 2/3 radials, these being similar to the GR 14N of the Amiot 351 and 354 but fitted with two-speed superchargers. This aircraft was being readied for flight testing at Le Bourget early in June, and with the approach of the German forces it was hurriedly flown to Pau, eventually being placed in storage at the Base de Stockage at Clermont-Ferrand-Aulnat.
Prior to the debut of the Amiot 355 another prototype, the Amiot 356-01, had commenced its flight test program. Apart from having the more powerful Merlin X engines and a single fin-and-rudder tail assembly, the Amiot 356 was essentially similar to the 353, and the prototype was evacuated from Villacoublay where it was undergoing CEMA tests and flown to Toulouse. Yet a further experimental Amiot 350 Series aircraft was the Amiot 357 high-altitude bomber with pressurized accommodation for the crew and a pair of turbo-supercharged Hispano-Suiza 12Z(HS-89ter) engines. Intended to operate at extreme high altitudes, the Amiot 357 was nearing completion at Le Bourget on June 14, 1940 when the Amiot plant was occupied by German forces.
One other aircraft closely related to the Amiot 350 Series was the Amiot 370 which, in fact, preceded the original Amiot 340-01 into the air, flying for the first time at Istres on July 25, 1937. Although it was to be widely stated that the Amiot 370 was a bomber, it was actually a parallel development to the Amiot 340 and intended solely for record-breaking purposes. Structurally similar to the prototype bomber, the Amiot 370-01 was powered by two 860 hp Hispano-Suiza 12Yjrs/krs engines, and surpassed even the Amiot 340 in purity of line as no raised cockpit canopy broke the upper line of the fuselage, the two crew members being housed in the nose entirely within the fuselage contours. Registered F-AREU, the Amiot 370-01 established a number of distance records in 1938.
By May 10, 1940, the Groupes de Bombardement I/21 and II/21 were in process of conversion from the Bloch 210 and possessed between them half a dozen Amiot 351s and 354s, the first operational flights having been undertaken by GB II/21 on April 28. On April 7, GB I/34 and II/34 had each taken delivery of one Amiot 354, these units, together with GB I/21 and II/21, forming Groupement 9. Despite their transitional state, these units were hurried into battle, performing operational sorties and simultaneously converting to the Amiot 351s and 354s as sufficient aircraft became available.
By June 20, the Armée de l'Air had officially taken 61 Amiot 350 Series aircraft on charge, although, in fact, this was not the final figure as a number of additional machines were taken over by the Groupes without the formality of official acceptance procedure during the days immediately preceding the arrival of German forces at Le Bourget on June 14, and at this time seven aircraft (Nos. 87 to 93) were awaiting collection. At least one of these (No. 87) was flown away before the German forces' arrival, landing at Oran on June 21.
Both Groupes of the 21e Escadre completed conversion to the Amiot 351 and 354 before the termination of hostilities, but retained Bloch 210s for night bombing sorties as insufficient Amiots were available for total re-equipment. GB I/34 retained Amiot 143s for the same reason, and although all GB II/34 crews had completed conversion by June 20, this unit flew no operational sorties with the new bombers as the few machines available were either destroyed on the ground or handed to other units.
Between May 10 and June 17 Amiot 351s and 354s undertook a number of daylight bombing sorties and nocturnal reconnaissance missions, 13 of these aircraft being lost by Groupement 9. In fact, only three of these were lost in action, one of these by the 21e Escadre and two by the 34e Escadre, the remainder being lost in training accidents or destroyed on the ground by bombing.
Following the disbandment of GB I/21, II/21, I/34 and II/34, the surviving Amiot 350 Series aircraft were placed in storage in the various Bases de Stockage, but several were subsequently overhauled for operation by Air France on high-speed services between Vichy France and overseas territories, fuel tankage being increased by the addition of auxiliary tanks in the bomb-bay. After the removal of military equipment and the installation of the long-range tanks, the Amiot 356-01 was registered F-BAGP and made its first commercial flight from Marignane to Algiers, Dakar, Casablanca, and back to Marignane in October 1941.
It was joined in Air France service by Amiot 354 No. 68 registered F-BAGQ, and together with the Amiot 370 F-AREU these aircraft flew frequently between Marignane and the African territories until November 1942. Amiot 354 No. 79 was also adapted for use by Air France as F-BAGT, together with an Amiot 351 registered F-BAGS, but for various reasons these aircraft were not placed in service. Amiot 354 No. 11 was converted as a VIP transport for Admiral Auphan, but this aircraft was destroyed in October 1942 while landing at Vichy, and Amiot 354 No. 10 was transported to Marignane on October 15, 1942 in order to be converted in the SNCASE plant to Amiot 356 standards by the installation of two Merlin X engines, but the total German occupation of November 11 frustrated this plan.
When German forces entered France's Unoccupied Zone they found one Amiot 354, one Amiot 356 and two Amiot 351s. One of the Amiot 351s was promptly adopted for transport duties on behalf of the Headquarters Staff of Luftflotte 3, and the other, together with the Amiot 356, eventually joined the strength of 1. Staffel of I/KG.200. In 1946, the surviving Amiot 354, which had been abandoned at Istres when the German forces withdrew, was fitted with two Pratt & Whitney R-1830 Twin Wasp engines and, redesignated Amiot 364, entered service with the Groupe de Liaisons Aériennes Ministérielles which operated this aircraft from Villacoublay."