ZIL-4906

The ZIL-4906 at a glance: a rescue vehicle for the space programme

When a spacecraft lands off target, the crew may come down in forest, swamp, deep snow or water, far from roads. The Blue Bird complex was built for exactly that. One vehicle, the ZIL-4906, carries a crane to lift the descent capsule onto its load bed. The second, the ZIL-49061, carries the crew and doctors. A third, the ZIL-2906 screw-propelled vehicle, rides on the 4906 and continues the search where even the six-wheeler cannot go. The vehicles were painted bright blue so that they would be easy to see from the air, which gave the complex its name. The history of ZIL explains how the plant came to run such a bureau, and all ZIL models are in the ZIL catalogue.

Why the Blue Bird was needed

The problem became clear in March 1965, when the Voskhod 2 capsule with Pavel Belyaev and Alexei Leonov landed far from its target in snow-covered forest. The automatic landing system had failed, the crew had to bring the capsule down by hand, and rescuers could not reach them for two days. According to the old 1cars text, Sergei Korolev then asked Grachev's bureau for a vehicle that could get through almost any terrain, including deep snow in a forest.

Grachev's team had already worked out a clear philosophy for off-road vehicles. It called for the lowest possible weight, the biggest possible tyres, maximum ground clearance and central tyre-pressure control. Wheel hub reduction gears, locked drive to all wheels, steering on the front and rear axles, independent torsion-bar suspension and sealed brakes completed the list. Almost all its vehicles could swim. The bureau was also among the first to pump air into units that worked under water to keep water out of them.

From PEU-1 and PEU-2 to the ZIL-4906

The first answer was the PEU-1 search-and-evacuation unit, a six-wheeled amphibian with a light steel frame and a glass-fibre body. It crossed two-metre ditches with ease and impressed its customers, but only 13 were built. The old 1cars text says the ZIL management refused a series of 30 for lack of resources.

The PEU-2, or ZIL-5901, of spring 1970 went to the other extreme. It was 11.7 m long, 3.3 m wide and about 3 m high. Two ZIL-375 V8 engines gave a total of 360 hp, and it had large glass-fibre wheels, room for ten people and a crane for the capsule. It reached 73 km/h on land and 10 km/h in water. But it was too big to fly in a transport aircraft and needed a special permit for public roads.

The ZIL-4906 was the compromise. The brief required that the vehicles could be carried in Il-76 and An-12 aircraft and by Mi-6 and Mi-26 helicopters. The designers therefore kept the size down to 9,250 × 2,480 × 2,537 mm and made the glazed cab roof removable. By our calculation, the 4906 is 2,450 mm shorter and 820 mm narrower than the PEU-2. It was the last project completed by the bureau during Grachev's lifetime.

Aluminium frame, glass-fibre hull and six-wheel steering

The Blue Bird vehicles are built on a frame of aluminium sections that carries a sealed glass-fibre hull. Like the PEU-1, they have three axles; the first and third are steered, and all six wheels have independent torsion-bar suspension. The driver can change the tyre pressure on the move. In water, two propellers at the rear, driven from the transfer case, push the vehicle, and the steered wheels turn it.

The old 1cars text adds a detail about the steering. To keep the vehicle stable at speed, it turned at first only with the front wheels, and the rear wheels joined in once the front wheels had turned by about 5 degrees. The first cars used a hydrostatic link to the rear steering, but a rigid mechanical connection proved more reliable and was reinstated.

The ZIL-130 V8 on land and in water

The engine is the ZIL-130 petrol V8 used in the ZIL-130 truck, rated at 110 kW (150 hp). It drives a five-speed gearbox and a transfer case with an inter-axle differential and a low-range reduction gear in the same housing. Side shafts take the power to the wheels on each side, and a separate drive goes to the propellers. Compared with the twin-engined PEU-2, the 4906 has less than half the power, but it is lighter, shorter and air-transportable.

ZIL-4906 specifications

Variants of the Blue Bird complex

The passenger 49061 has a cab for the driver and three crew members, with navigation equipment, a radio compass and two roof hatches. Behind it, a cabin in the hull carries three passengers and three doctors, with stretchers, medical equipment, food lockers, heaters, an independent air heater and air conditioning, and enough supplies for three days. Its windows are toughened safety glass, and twelve lamps light the cabin at night.

The ZIL-2906 screw vehicle reaches 16 km/h in water, 20 km/h in swamp and 45 km/h on snow. Unloading it from the 4906 takes about half an hour.

In service: the complex at work

The Blue Bird complex entered service in 1981. According to the old 1cars text, 12 cranes, 14 passenger vehicles and 5 screw vehicles were built within about ten years. All three types carried radio and direction-finding equipment and could stay in contact with each other, the ground base, aircraft and the landed crew. The vehicles stayed in service after 1991 with rescue teams supporting crewed space flights. Their strengths were their reach and their independence; their weaknesses were the high cost of such a small series and the limited speed of a heavy amphibian on hard roads.

Preserving the Blue Bird today

With only about 26 six-wheelers built, the ZIL-4906 and 49061 are among the rarest Soviet vehicles. Surviving examples belong to museums and state collections and do not appear on the open market. Their scale is easier to grasp when set against familiar vehicles in the size comparison tool, and other Soviet vehicles of the era are collected in our Soviet classics.