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Here is some information I found in ‘Les Moteurs a Pistons Aeronautique Francais' Volume 2 page 80 and 81 about French aero engines under development in June 1940 and their subsequent fates. I hope others find it as fascinating as I do!
A warning, this is my own translation and my French is very poor – my apologies! I have placed in bold passages I am very unsure of – my French dictionary does not contain much in the way of technical terms. The original pages are here
http://i115.photobucket.com/albums/n291/nsumner/Image0009.jpg
http://i115.photobucket.com/albums/n291/nsumner/Image0010.jpg
If any of our French friends wish to correct any errors I might have made I would be grateful to them!
"The Mathis 'Vega'
"This engine was produced in 1938 by Mathis under the designation ‘Vega 42 A’, It was a liquid cooled 42 cylinder radial (7 banks of 6 cylinders) and during bench testing in 1939 produced 2,300 HP at 3,000 rpm. It weighed 1,280 kg. In comparison with foreign engines of the time it was very advanced, the Mathis company even succeeded in carrying out some flight tests. It was hoped to develop the Vega 42 engine until it produced 2,800 HP at 3,200 rpm.
"In 1940 Mathis and George hid the prototype from the invaders in the Pyrenees and despite a great deal of difficulty continued to carry out tests under the control of the Official Services (The Pratt & Whitney Wasp Major R.4360 of the same era, was a 28 cylinder engine of 3,000 HP, but Mathis had succeeded in building his Vega engine of 42 cylinders giving 2,300 HP before the war.). After the war a new engine of 4,600 HP was studied on the guiding principle of the Vega. But as the other engineers who had continued similar studies were to find this class of engine was superseded by turbine engines.
"The Potez 28 D
"In 1940, Ménétrier studied a 28 cylinder (4 banks of 7 cylinders) air cooled engine with the same unit cubic capacity as the 8 and 12 cylinder engines. This engine, known as the 28 D, delivered 2,000 HP. Four engines were bench tested.
"In 1941, the government directed Potez to study a large engine in the 4,000 HP class using the same principles as the 28 D. Ménétrier constructed the 28 F of 3,200 HP. It was liquid cooled and had a cubic capacity of approximately 60 litres. By 1943 the 28 G of 82 litres cubic capacity (156 X 160 mm) had been developed and was to give 4,000 HP.
"With the withdrawal of the Potez company to Rodez and Saint-Etienne, the parts had to pass the line of demarcation. They were hidden in many bags of potatoes. During the journey, a German soldier found a pinion in the truck driven by Ménétrier who explained that "It is a part of my car" and the engine was thus saved. The 28 F was intended for the projected transatlantic seaplane Laté 636, which was later envisioned with HS 18 S engines of 1,500 HP. In 1945, although the 28 G was nearly complete it needed additional funding but the Government stopped its development.
"The Voisin 42 M
“Having made the acquaintance of Gabriel Close in 1938, P. L Weiller, then the Director of Gnome-Rhone, asked him to undertake the study of a large engine of 2,000 HP with a view to developing it towards outputs of 3,000 to 4,000 HP while keeping its diameter to 1 metre (including the cowling). This limitation corresponded to size of the 14 cylinder Gnome – Rhone 14 M engine of 700 HP that G Voisin had succeeded in bench testing with a power output 14 HP greater than that of standard Gnome – Rhone engines.G. Voisin put himself to work and designed in less than two months a 42 cylinder liquid cooled engine (6 banks of 7 cylinders), without valves. It had a cubic capacity of 61 litres and was to provide a calculated power of 2,200 HP.
"Judging the principle of sleeve valves too complex G. Voisin then decided to adopt the cylinder size of the Gnome-Rhone 14 M (122 X 116 mm) giving a cubic capacity of 57 litres. Corresponding to three Gnome-Rhone 14 M engines, all 42 cylinders comprised wet liners screwed in to the cylinder head. The rods were assembled on rollers ordered by a pinion train.
"A bank of 7 cylinders was bench tested towards 1944/1945, confirming the performances calculated and making it possible to test the connecting rod assembly and the distribution. The engine was almost entirely machined and assembled when it was abandoned in 1949. G Neighbor also had a project for an engine of the same type, planned for 4,000 HP with a cubic capacity of 114 litres."
If anyone has more information about these engines I'd be grateful to learn more.
A warning, this is my own translation and my French is very poor – my apologies! I have placed in bold passages I am very unsure of – my French dictionary does not contain much in the way of technical terms. The original pages are here
http://i115.photobucket.com/albums/n291/nsumner/Image0009.jpg
http://i115.photobucket.com/albums/n291/nsumner/Image0010.jpg
If any of our French friends wish to correct any errors I might have made I would be grateful to them!
"The Mathis 'Vega'
"This engine was produced in 1938 by Mathis under the designation ‘Vega 42 A’, It was a liquid cooled 42 cylinder radial (7 banks of 6 cylinders) and during bench testing in 1939 produced 2,300 HP at 3,000 rpm. It weighed 1,280 kg. In comparison with foreign engines of the time it was very advanced, the Mathis company even succeeded in carrying out some flight tests. It was hoped to develop the Vega 42 engine until it produced 2,800 HP at 3,200 rpm.
"In 1940 Mathis and George hid the prototype from the invaders in the Pyrenees and despite a great deal of difficulty continued to carry out tests under the control of the Official Services (The Pratt & Whitney Wasp Major R.4360 of the same era, was a 28 cylinder engine of 3,000 HP, but Mathis had succeeded in building his Vega engine of 42 cylinders giving 2,300 HP before the war.). After the war a new engine of 4,600 HP was studied on the guiding principle of the Vega. But as the other engineers who had continued similar studies were to find this class of engine was superseded by turbine engines.
"The Potez 28 D
"In 1940, Ménétrier studied a 28 cylinder (4 banks of 7 cylinders) air cooled engine with the same unit cubic capacity as the 8 and 12 cylinder engines. This engine, known as the 28 D, delivered 2,000 HP. Four engines were bench tested.
"In 1941, the government directed Potez to study a large engine in the 4,000 HP class using the same principles as the 28 D. Ménétrier constructed the 28 F of 3,200 HP. It was liquid cooled and had a cubic capacity of approximately 60 litres. By 1943 the 28 G of 82 litres cubic capacity (156 X 160 mm) had been developed and was to give 4,000 HP.
"With the withdrawal of the Potez company to Rodez and Saint-Etienne, the parts had to pass the line of demarcation. They were hidden in many bags of potatoes. During the journey, a German soldier found a pinion in the truck driven by Ménétrier who explained that "It is a part of my car" and the engine was thus saved. The 28 F was intended for the projected transatlantic seaplane Laté 636, which was later envisioned with HS 18 S engines of 1,500 HP. In 1945, although the 28 G was nearly complete it needed additional funding but the Government stopped its development.
"The Voisin 42 M
“Having made the acquaintance of Gabriel Close in 1938, P. L Weiller, then the Director of Gnome-Rhone, asked him to undertake the study of a large engine of 2,000 HP with a view to developing it towards outputs of 3,000 to 4,000 HP while keeping its diameter to 1 metre (including the cowling). This limitation corresponded to size of the 14 cylinder Gnome – Rhone 14 M engine of 700 HP that G Voisin had succeeded in bench testing with a power output 14 HP greater than that of standard Gnome – Rhone engines.G. Voisin put himself to work and designed in less than two months a 42 cylinder liquid cooled engine (6 banks of 7 cylinders), without valves. It had a cubic capacity of 61 litres and was to provide a calculated power of 2,200 HP.
"Judging the principle of sleeve valves too complex G. Voisin then decided to adopt the cylinder size of the Gnome-Rhone 14 M (122 X 116 mm) giving a cubic capacity of 57 litres. Corresponding to three Gnome-Rhone 14 M engines, all 42 cylinders comprised wet liners screwed in to the cylinder head. The rods were assembled on rollers ordered by a pinion train.
"A bank of 7 cylinders was bench tested towards 1944/1945, confirming the performances calculated and making it possible to test the connecting rod assembly and the distribution. The engine was almost entirely machined and assembled when it was abandoned in 1949. G Neighbor also had a project for an engine of the same type, planned for 4,000 HP with a cubic capacity of 114 litres."
If anyone has more information about these engines I'd be grateful to learn more.
