Leyland Hippo Mark II (1943)
6x4 10t truck. 1,000 produced 1943-45.
The Leyland Hippo Mk II was a heavy 6x4 General service cargo truck, used by the British Army and Royal Air Force in World War II as well as in the immediate post-war years.
Development
The Leyland Hippo Mk II was a continuation of the model develiped and produced between 1939 and 1940, the Leyland Hippo Mk I. Some 330 had been delivered. They followed the same pattern as all standard trucks in 1940. The mmodel was also known internally as the Leyland WSW17. The Hippo Mk I was a militarised version of the pre-war Leyland Hippo. Part of the standardization measures, had been to put out standard roadwheels, storage and tooling, lights, markings, as well as an open military cab and body. It served well but has limitations, starting wit its cost, given its low production.
So Leyland proposed the army its Hippo Mk II, a new design integrated all the critics directed on the formmer Mark I and taking in accounts all the planning for D-Day made in late 1942 and early 1943. Leyland joined the Royal Ordnance and Transport Corps by concluding trucks rated with a 10 long tons (10 t) cargo capacity offered far more logistic advantages over smaller vehicles, 1 or 1.5 tons lorries that abunded in the Army in 1939-40.
Design of the Hippo MkII started thus in late 1943 but it took time brefore production commenced late 1944. The Hippo Mk II however took too long to developed and arrived too late to see service even after D-Day. Still an average of 1,000 were in service by May 1945, far more than the Mark I, as Leyland modrnized and expanded its facility reserved for the Mark I. Thus, the Mark II remained in service with the British Army and the Royal Air Force into the 1950s. In 1945 also appeared the Mark IIA, but it arrved too late for production to make a difference. Further orders were cancelled and production stopped after the current order was cancelled.
Hippo I postwar, aircraft exhibition
1959 Leyland Hippo I R.A.F Refueller
Design
Chassis and general design
The Leyland Hippo Mk II had ladder chassis frame made for a wheeled 6x4 configuration, with a single directional axle forward, and doubled wheels fixed axle aft. It had a new 2-man enclosed steel cab, with pull-down windows, unlike the Mark I that had an open cab with canvas, the top portion of the cab however could be removed, in order to reduce the overall height, notably for shipping. This was a sensible feature as a COE was generally taller indeed than traditional bonnet models. The wheelbase was of 4.7m (BC 1.4m), the internal body length was 5.94m and the internal body width of 2.21m and the internal body height was 1.98m.
The Leyland II had an all-metal structure, with a metal cab with bomber 4-angled roof and round hatch for the co-driver to man a 7. mm Bren Mahine gun as defence underway. Otherwise this truck was unarmed and unprotected. There were even no racks for rifles. Both the driver and co-driver had personal small arms however, Sten or Wembley pistol. They also had a flare and a smoke grenade. Being a COE the engine blowk was basically under the feet of the driver, with a standard radiator in front. There were two doors with handles for a windows, a split windscreen with opening upper half (folding downards for cooling), two wipers for the upper part, but no upper sun protection.
The chassis rear comprised a rack for two spare wheels side by side behind the cab, an auxiliary fuel tank, then the main cargo body and flatbed wth wooden sides attached by a metal frame with cross-members for longitudinal and vertical strenght. The side panels were fixed but not the rear panel. The truck also had two 70-gallon fuel tanks mounted midway along either side of the chassis, a heavy-duty tow-bar stowed under the right rear driving well, and rear storage racks for jerrycans, plus forward toolboxes and stowage bins for utilities all under the flatbed. The truck had a five arches, fixed, with transverse bar roof for a tarpaulin, usually windowless, to be fitted as weather protection.
Mobility
As for the engine it was a semi-COE (Cab over engine), powered by a 100 bhp (75 kW) in house Leyland six-cylinder inline diesel. Transmission used a five-speed gearbox, and two-speed auxiliary gearbox (Gears Five forward and one reverse). The Brakes were hydraulic, servo-assisted vacuum hydraulic on all wheels. There was no winch. The Mk II has single tyres at the rear, but the next the Mk IIA diverged by having narrower dual wheels at the rear, and so it also needed to have two spare tyres front and rear.
The front one was below the cab, the second below the chassis at the rear. There was however a towing eye on the right side of the bumper, standard while lights, red lights and direction lights all forward, then red lights and white lights on the rear panel. The range is generally estimated around 840 km unladen. The 36x8s tyres were standard at the time. After owner experience, it was established engine and gear box oil need changing after 20,000 miles.
Use
The Hippo I and II were used as much as the RAF as the Army in 1944-45. The latter motly had their walls removed, and the flatbed used to load large aircraft parts, fuselage and wings, between workshops and forward airfields. Otherwise they carried heavy duty cargo, more rarely troops, being bound to roads most of the time, part of the British transportation network in Europe pas D-Day. None was operational yet in June 1944. They took part however in the Avranches break, the August-September Falaise gap offensive, crossing of the Rhine and Arnhem campaing and latter British and Commonwealth push into the low countries in 1945 and in Germany, notaby to Hamburg.
There is one Hippo II preserved at Duxford and many more in private collection today. They had a solid reputation for thoughness and reliability as heavy duty trucks, well appreciated by their drivers, wkth a solid range, but lacking proper off-road capabilities. As promised, their heavy payload was a bonanza as it was more efficient, notably in terms of mileage per consumption.
specs. |
| Lenght | 27 ft 3 in (8.31 m) |
| Width | 8 ft 1 in (2.46 m) |
| Height | 10 ft 11 in (3.33 m) |
| Weight | 8.3 long tons (8.4 t) |
| Crew | 2 (driver, co-driver, +16 troops in this config.) |
| Propulsion | 6-cyl. inline Leyland L6 diesel 100 bhp (75 kW) at 1,800rpm |
| Transmission | 5F1Rx2 |
| Suspension | 6x4 Live axles on semi-elliptical multi leaf springs |
| Payload | 11.4 long tons (11.6 t) |
| Speed (road, unladen) | 30 mph (48 km/h) |
| Range | Unknown, 840 km unladen |
| Production | 1000+ |