Starting a fire

In times of shortage, smart manufacturers do everything possible to keep their products going. And in wars there is usually a shortage of fuels. This also happened at the end of the 1930s, prior to the outbreak of WW2. Several companies started marketing gas generators for use on cars, lorries and agricultural vehicles.

There were several principles that could be applied here. There was the variant using wood to be burned directly, while others used the very tough burr wood. Charcoal was also a common fuel used at the time. The latter implied, though, that before the vehicle could be driven, wood first needed to be burned to be turned into charcoal.

Various companies focussed on the production of these installations. Georges Imbert was one particularly well-known name in this field, developing the technology in a usable form back in 1920. But Renault also built its own gas generators and for some time, the manufacturer supplied furnaces in which charcoal could be made.

Julien Figuet bought this special Renault AFVH of September 1941-vintage some six years ago. After purchasing it, he didn’t hesitate to start the restoration of the tractor, together with his brother Sébastien and father Claude. He’d bought the tractor only, knowing it was sold from the Renault works with a gas generator as indicated by the AFVH code on its oval plate. So next, he went looking for such an installation in order to revive the Renault in its full former glory. He found the desired installation, which had originally been fitted to a Deering tractor. He could have bolted the generator to the front of his own tractor for convenience sake and leave it just like that. But Julien wanted the Renault to run on both petrol as charcoal. By June 2019 it was ready. At a regional show for classic agricultural tractors, and together with his brother and father plus fifteen more Renaults, he did not only show the restored tractor for the first time. By then he’d also made the AFVH run on charcoal. Goal achieved!

Julien found his Renault tractor in the Orne department in Normandy. Julien: “The photos that we received from the seller made the tractor look better than it actually was. Fortunately the engine was not seized and we had it running pretty quickly. The previous owner had once blasted and sprayed the bonnet, but it had become rusty once again. Fortunately it turned out to be quite complete, so we didn't have to look for too many parts, although the body needed the necessary work. Because the original gas generator had been removed, all the beams on which the installation was mounted had disappeared. And so anything that was needed to bolt it on had to be remanufactured once again.”

If you look at the front, you will see a large and tall boiler on the right and a smaller one on the left. The large one is the boiler in which the charcoal is burned. This creates a gas that is passed through pipes to the second ‘boiler’. That one actually is a very large filter. The filtered gas next goes to the carburettor. Because the engine must be able to run on both petrol and charcoal gas, two carburettors have been fitted under the hood. They almost appear to have melted into one. Directly behind the radiator you’ll find the carburettor for petrol while the second, larger one is mounted directly on the intake manifold. This is the one for the filtered gas.

When compared to the standard AFV tractors that run on petrol, the right-hand side of Julien’s tractor has been modified to accommodate the added generator parts. The tractor also makes a stronger impression than a standard AFV, although a normal AFV remains when the gas generator is removed.

The AFV was the successor to the compact YL. That tractor used the 1.5-litre engine known from Renault’s Celtaquatre passenger cars. The AFV used the same structure as the YL did, but now mated to a 2.4-litre 85 engine as known from the Vivaquatre. Production of the AFV, without a gas generator, started in January 1938. At the end of that year, 260 units rolled out of the factory. Until September 1939, an additional 169 units were added, giving a grand total of 429 units. In October 1940, after a year of no production, Renault started up again. In the last three months of that year, another 79 units were built, along with 7 of the AFVH with their gas generators. In 1941 another 722 units of the normal AFVH could be added plus 25 more AFVH’s, specifically built for the narrow grapevines. A few dozen of the normal petrol versions were also produced in both standard as small variants. Production continued steadily up until 1942 with 305 AFVH units and 47 gasoline variants. In 1943 an additional 125 AFV units were made. It is not unthinkable that a number of standard petrol-run AFVs built in Billancourt had gas generators retro fitted to them. In December 1943 the very last Renault AFV came out of the factory, giving a definitive production figure of 531 AFVs on petrol plus 1,186 with a gas generator.

The one seen here, as restored by the Figuet family, looks as if it is new. All the mechanicals have been taken apart, with every part having been cleaned and repainted. The AFVH is now light grey with red lines again, exactly as it left the factory in its year of production. Quite a while ago. If we see Julien trying to start the Renault and driving it outside, it becomes clear that a great deal of technical development has taken place in eighty years time.

En detail...

Renault AFVH

Specifications

Engine: 

4 cylinder petrol Renault type 703, bore x stroke 85 x 105 mm, displacement 2,384 cc. Power 20 hp at 2.000 rpm. Three speed gearbox, two types of final drive 11 x 66 or 14 x 63, maximum speed at maximum rpm 3.5 - 10.8 km/h.
Suspension: 

Front axle of a closed profile suspended in the middle to keep all wheels on the ground on uneven surfaces. Brake on a drum on the gearbox output shaft . Drum brakes on the rear wheels in the road version. Tyres normal/white: front 140 x 60/4.75 x 16, rear 900 x 24.
Dimensions: 

Length 3,400 mm, width 1,350 mm on pneumatic tyres, 1,300 mm on steel wheels, wheelbase 1,500 mm. Weight: 1.800 kg of which 1.000 on rear wheels. Tensile force depending on the hardness of the ground: 1st gear 1,100 kg, 2nd gear 800 kg, 3rd gear 350 kg. Double hitch: locking hook at the top and a hole bar at the bottom. Rear left mounted drive pulley to be disengaged by means of a lever. Engine speed 800 r/min at an engine speed of 2,000 r/min. Rear power take-off with 574 r/min.
Performances: 

Consumption 3 to 4 litres of petrol per hour / 4 to 6 kilograms of charcoal for six hours of work.