Laffly S15T (1935)
Light 6x6 Tractor, 411 built 1937-40
The Laffly S15 was a family of all-terrain military vehicles sharing the 6x6 drive chassis and anti-ditching rollers. They were built in the late interwar as a light artillery tractor, used by French forces during World War II. But also declined into specific variants such as the S15R personal carrier, the low-profile
W15T, the S15C ambulance, the W15 TCC tank hunter and its armoured sub-variant prototype of 1940 as well as the S15 TOE colonial armoured car.
About the Laffly Mil. vehicles lineage
S15 T with tarp in the Hindu Kush
Laffly was originally a known heavy vehicles manufacturer in France, delivering trucks and buses for the civilian market and for the military. For this, the company developed its range of all-terrain vehicles, notably introducing its trademark advanced transmission, innovative suspension system and extra bumper roller to overtake any obstacles. These recipes were already tested on the S15T light artillery tractor, and S15R personnel carrier and reconnaissance vehicle.
Development of the S15T
The Laffly S15T was developed as a light artillery tractor and primary for towing light field artillery such as modernized 75 mm mle 1897 field gun and Canon de 105 court mle 1935 B howitzer. Both were revamped versions of a WW2 design. Two main chassis types were designed, the S15 R and the S15 T in 1934, the latter having reduction gears that limited the maximum speed but increased the payload. Laffly indeed proposed a common base for multiple applications for the Army and the S15 R was the first built and tested in 1935, in southern Algeria, in a desertic environment with no roads. It was tested in real conditions by the 1st REC.
The S 15 C, L2, RAM and TOE were based on the S15 R3 chassis. The S15 C and L had only four-wheel drive rear wheels, like the S15 R2 prototype.
The Laffly S15 T followed the S15 R, intended for artillery traction in 1935. Its wheels were fitted with reduction gears which limited top speed but increased payload. The first S15s were delivered in 1937.
Design of the S15T
The S15 T had the same Hotchkiss 4-cyl. engine, capacity 2,300 cubic cm. rated for 52 ch at 3,200 rpm as in the S15 R and S15 C. It was capable of 51 km/h on flat, with large roadwheels and small wheelbase for maximal grip on all terrains. However it was recoignised as underpowered. The frame had side members, with three axles and all-wheel drive. The front steering wheels axle was caracterized by an helical shock absorber, while the rear axles remained independent, susoended on leaf springs. A pair of small idler wheels were positioned on the nose of the vehicle to better deal with embankments and steps and a second pair placed between the first and second axles under the driving cab, to help overcome bumps. This was typical of these chassis.
The S15T had the largest payload and weight (light) at 3,900 kgs, with 1,400 Kgs carried in the vehicle, crew and ammunitions in the rear raised storage bin, integral to the open hull, an open torpedo type body. The crew sat in three seats beneath the driver and artillery commander seated on the front row forward, exiting the vehicle though small doors. There was alsoo a folded tarpaulin behind the crew. The vehicle measured 4.70 m long for an overall width of 1.80 m, height of 2.35 m. Autonomy is unknown, by relations probably around 400 km. It seems a few S15 T were also sold to Romania alongside a serie of 40 R35 tanks in 1937.
More variants
Mike Bell drawings, CC
S15 T (tracteur) was the standard light 75 mm and 105 mm modernized field gun tractor. One driver, 4 gun crew.
S15TL (Tracteur d'artillerie long), extended chassis 5 m long, 2,245 m high, 1.85m wide, 45 kph.
S15 TT (téléphone) was developed for telephone-based rear echelong artillery, only three made.
S15 TC (colonies, "colonial") self propelled gun with a 75 mm mountain gun model 1919/1928 in the rear flatbed, new cabin with tarpaulin.
The closely related S15R
The Laffly S15R was a 6x6 all-terrain liaison vehicle ("VLTT" stand as for "Voiture de Liaison Tout Terrain"). It was a as a personnel carrier and reconnaissance vehicle, sharing a same chassis with the S15T but having a lighter rear cab and different transmission. The different, lighter rear cab came also with a different transmission allowing for less torque and higher road speed. It was thus more capable for its reconnaissance missions but was later criticized as too conspicuous. The lighter, lower V15R was designed as a reaction.
In service
Around S15 T had been produced by Laffly until 1940, distributed to infantry's organic light field artillery units. They saw action in May-June 1940, but their slow speed meant they were soon taken in the wave submerging Frenc Forces in general. Many had been sent also in North Africa and remained wth Vichy French units after the armistice. The two 75 mm field guns brought in the Kufra raid were initialement carried on modified S15 T colonies, but they broke down en route and never arrived to the Italian fort.
| Specs Laffly S15T |
| Dimensions : | 4.7 x 1.8 x 2.35m |
| Total weight : | 3.900 kgs. |
| Useful load : | Carried weight 1400 Kgs, towed load 1,800 kgs. |
| Crew : | 1+4 crew |
| Propulsion : | Hotchkiss 4-cyl. 2.3L, 52 ch 3,200 tr/min |
| Speed : | 51 km/h (30 mph) |
| Range : | c400 km |
| Production | 411 in 1940 |
Links/Src
The TCC variant on tank afv
On the S15 family
S15 on scalemates
wardrawings.be
littlewars.se
corre-lalicorne.com
worldwar2-bodong.blogspot.com
François Vauvillier, « La voiture de liaison tous terrains Laffly S15 R 1934-40 », Histoire de guerre, blindés et matériel, no 75 2007
François Vauvillier, Tous les Laffly militaires, 1914-1940, Histoire & Collections
Axworthy, Mark; Scafes, Cornel; Craciunoiu, Cristian (1995). Third Axis, Fourth Ally: Romanian Armed Forces in the European War, 1941-1945. London: Arms and Armour.
G.N. Georgano, World War Two Military Vehicles: Transport & Halftracks, Osprey Publishing, 2004
Vauvillier, F. & Touraine, J.-M. L'automobile sous l'uniforme 1939-40, Massin, 1992
Tavard, Christian H. Les tous terrains LAFFLY 1934-1945, "L'automobiliste" n. 54, 1980