Sunday, 27 December 2020

A flame relit - the aeronautical industry in France 1944-1950- Le Fana Special issue - Leduc ramjets




Much has been written and said about the French Air Force in the years immediately before the Second World War, much of it inaccurate. However, whilst the valour of their pilots cannot be underestimated, like many other continental countries France was unprepared for war, and this unpreparedness showed up in the quality and quantity of aircraft available to their air force. The good types that the Armée de l'Air had were not available in sufficient numbers to make any difference, as like many other countries the aviation industry was organised almost on an 'artisan' basis, unable to switch rapidly to full-scale industrial production when the need arose. And political inertia and interference also meant that time and effort was expended on a number of types that were not suitable for their intended purpose. The French government of the day eventually recognised this, and nationalised the aviation industry in 1937; even then, it was not brought under full-scale state control, thus leaving the nation unprepared for the Blitzkrieg of 1940. France was far from atypical in this respect. It is also a fallacy to think that the French aircraft industry had been 'devastated' by German occupation - a notion that rather conveniently draws a veil over the extensive French collaboration that went on with the Germans, especially in the aeronautical field.

Following the defeat and subsequent armistice in June 1940 the Vichy French authorities had very quickly opened negotiations with their new German masters.  On the table was an offer to produce spares for German aircraft manufacturers and establish overhaul and repair facilities for aircraft operating from French territory and in so doing preserve industrial capacity in aviation and preserve employment and some of their manufacturing base in France. In making themselves useful to the Germans, they hoped to avoid all their workers being drafted east to work as 'Auslandarbeiter' in German aircraft factories. This offer was quickly taken up and led to the establishment of so-called Frontbetriebreparatur or FBR plants - advanced overhaul facilities. Junkers set up their FBR at Villacoublay south of Paris. With Ju 88s operating from no fewer than thirty eight aerodromes throughout France at the height of the Battle of Britain the French quickly gained a certain amount of expertise on this particular type. This was 'collaboration', albeit (one suspects and hopes) with a degree of nose-holding and possible tolerance of a degree of sabotage and back-pedalling, in the hope and expectation of better times to come. The Vichy Government thereafter concluded the so-called Wiesbaden Agreement with the Reich to bring the French aircraft industry fully into alignment with German production, with one aircraft or engine out of every three being retained for Vichy, the other two going to Germany. Certain types, such as the Messerschmitt Bf.108, Siebel Si.204 and Fiesler Fi.156 Storch were intended for wholesale transfer of their production to France. And indeed, even the Focke Wulf Fw 190 was intended for this move (and the post-war Armée de l'Air was briefly equipped with home-built Fw 190s, known as the NC.900). While some would argue that the French were not constructing war machines for the Germans, it is nonetheless the case that producing large numbers of transports and seaplanes enabled German industry to concentrate on fighters and other offensive weapons.

As the Germans were expelled from French territory during 1944, determined efforts got underway to re-establish the French aviation industry. As would be the case with other Allied nations, great interest was shown in all manner of weapons systems and aircraft produced by the aircraft manufacturers of the Third Reich. There was another motive for what was to follow - the parlous state of French industry and a total lack of foreign currency naturally led the French to want to seek to exploit the huge quantities of war materiel - spares, parts, tools and jigs - left behind by the retreating Germans. Their factories had produced hundreds of machines for the Germans (both German and French types, eg some 600 Caudron C.445 twins) and they had large stocks of German parts and equipment.

 Thus it was that in 1944, the Liberation saw a French aircraft industry ready to move quickly into full-scale production to help rebuild the economy. And as a member of the Allies, France shared in the uncovering of German high technology aviation - and quickly took advantage of that opportunity to quickly produce home-grown examples of the new and exciting jet aircraft. Most of the German types that the French produced were obsolete. In the meantime their 'German' equipment was cost-effective and usually of reasonable quality. These were the reasons that led to the decision to use the Jumo 213 to power the SO-8000 - the British Griffon was too expensive to be imported. The S.N.C.A.S.O. ejection seat came directly from Heinkel. The Me 208 was due to go into series production in France - it did post-war as the Nord 1100 Noralpha.

However in the immediate post-war environment the French were now much more interested in trying to catch up with the new jet and jet engine technologies in which they lagged way behind. They were soon testing examples of the Me 262, He 162, Me 163 and appropriating German materiel and scientists just as the other powers were doing. It was not long before their own outlandish designs were flying, eg SO 6020, 4000, 6000, SO M2. The Arsenal VB. 10 (below) first flew in July 1945.



 But the French penchant for "interesting" politics meant that this initial surge of innovation was quickly diluted as designers and factories turned out a bewildering variety of weird and wonderful shapes, both piston- and jet-engined. Some were successful; others were not. Some, like the Dassault MD.450 Ouragan, saw series production and service; others, like the Nord 1500 twin-engined torpedo bomber, were less successful - the Nord in part because its torpedo bay was too small for the torpedoes the French had access to at the time...


 This 'special edition' of the French magazine 'La Fana de l'Aviation' tells the story of the six years following liberation and the bewildering variety of aircraft the French industry turned out. In a changing world, the aviation industry everywhere had a hard time keeping up, and France was no exception.

First flight of the Leduc ramjet carried aloft on the SE Languedoc 'mother-ship'







The Leduc ramjet prototype could not take off unassisted (ramjets cannot produce thrust at zero airspeed and thus cannot move an aircraft from a standstill) and was therefore intended to be carried aloft by a parasite aircraft mother ship, such as the four-engined AAS 01A & -B German-origin designs or the French-designed Sud-Est Languedoc four-engined airliners, and released at altitude. Following test flights of the AAS 01/Leduc 0.10 composite, independent unpowered gliding tests began in October 1947. After three such flights, the first powered flight from atop an AAS 01 mother ship was made on 21 April 1949 over Toulouse. Released in a shallow dive at an altitude of 3,050 m (10,010 ft), the engine was tested at half power for twelve minutes, propelling the aircraft to 680 km/h (420 mph).

In subsequent tests, the 0.10 reached a top speed of Mach 0.85 and demonstrated the viability of the ramjet as an aviation powerplant, with a rate of climb of 40 m/s (7,900 ft/min) to 11,000 metres (36,000 ft), exceeding that of the best jet fighters of the time.
Of the two 0.10s originally built, one was destroyed in a crash in 1951 and the other severely damaged in another crash the following year. Both pilots survived with serious injuries.

Generally similar to the 0.10, the Leduc 0.11 featured a Turbomeca Marbore I turbojet on each wingtip, to provide better control during landings. This first flew on 8 February 1951, but was converted back to 0.10 standards (and thereafter referred to as Leduc 010 n°03) a few months later after problems occurred, including misting of the pilot's windows, powerplant synchronization, and wing deflection caused by the turbojets. The engines were replaced by inert mass balances. This aircraft flew 83 test flights and is preserved at Le Bourget.