NATO reporting name: Hoodlum-A

TYPE: Light twin-engined multipurpose helicopter.

PROGRAMME: Prototype first flew 1965; production aircraft entered agricultural service in Soviet Union 1970; 850 built. It is widely used on air ambulance services and is suitable for many other applications, including cargo and passenger transport, forest firefighting, mineral prospecting, pipeline construction, laying transmission lines and a number of military duties, including search and rescue.

The space aft of the cabin, between the main landing gear units and under the rotor transmission, is able to accommodate a variety of interchangeable payloads. For agricultural work the chemical hopper (capacity 900kg) and dust spreader or spraybars are fitted in this position, on the aircraft's centre of gravity. This equipment is quickly removable and can be replaced by a cargo/passenger pod accommodating four or six persons, with provision for a seventh passenger beside the pilot. Alternatively, the Ka-26 can be operated with either an open platform for hauling freight or a hook for slinging bulky loads at the end of a cable or in a cargo net.

A version for geophysical survey has an electromagnetic pulse generator in the cabin and is encircled by a huge 'hoop' antenna. It carries a mounting on the port side of the fuselage for the receiver 'bird' which is towed at the end of a cable, beneath the helicopter, when in use. The receiver is lowered by an electric winch and the cable is cut by automatic shears if its traction should exceed the authorised limit.

As an air ambulance, the Ka-26 can carry two stretcher patients, two seated casualties and a medical attendant. A winch, with a capacity of up to 150kg, enables it to be used for search and rescue duties. Ka-26s used in this role in Russian coastal areas are each fitted with three large inflatable pontoons, to permit operation from water. Items of equipment carried inside the cabin can include lifejackets and MLAS-1 inflatable dinghies for individual rescues, LAC-5 dinghies each able to carry five persons, PSN-1 rafts and emergency radio beacons. During tests, the hoist has been used to tow boats in Sea State 5 conditions.

When operating as an agricultural sprayer, the Ka-26 originally discharged its chemical payload at 1.5-12 litres/s. The rate of discharge in a dusting role was 1.5-12kg/s. Up to 120 ha could be sprayed during each flying hour at the rate of 50kg/ha. As a duster, 140 ha could be treated at the same discharge rate. 50 ha could be top-dressed with chemical fertilisers each hour, at a rate of 100kg/ha. These work rates were improved substantially by the introduction of an atomiser for liquid chemicals in 1978, followed by a centrifugal spreader for granular chemicals and dust in 1979.

To protect the pilot against toxic chemicals in the agricultural role, the cabin is lightly pressurised by a blower and air filter system which ensures that the cabin air is always clean. The flying and navigation equipment is adequate for all-weather operation, by day and night. VHF and HF radio are fitted, together with a radio compass and radio altimeter.

Because of its small size and manoeuvrability, the Ka-26 can be operated from platforms on small ships such as whalers and icebreakers, and a Soviet fishing boat operating in the North Atlantic in early 1970 carried a Ka-26 for fish spotting duties. This aircraft was equipped with inflated pontoons to permit alighting on the water.

In mid-1969, a Ka-26 was tested in Siberia and northwest USSR as a forest protection version able to deliver six firemen and their equipment speedily to the site of a forest fire. In the spring of 1972, Ka-26s joined Mi-1, Mi-2 and Mi-4 helicopters in operations to clear ice from Soviet rivers, by landing demolition teams on thick ice floes and destroying thinner ice fields from the air.

CUSTOMERS: Delivered for civilian use in 15 countries; military operators include the Hungarian Air Force.

DESIGN FEATURES: Airframe comprises backbone structure carrying flight deck, coaxial contrarotating rotors, landing gear, engine pods and twin tailbooms; space aft of flight deck, between main landing gear units and under rotor transmission, can accommodate interchangeable modules for passenger/freight transport, air ambulance, aerial survey, forest firefighting, mineral prospecting, pipeline and power transmission line construction, search and rescue, and (of primary importance) agricultural equipment.

POWER PLANT: Two 242.5kW Vedeneyev M-14V-26 air-cooled radial piston engines, mounted in pods on short stub wings at top of fuselage.

ACCOMMODATION: Fully enclosed cabin, with door on each side, fitted out normally for operation by single pilot; second seat and dual controls optional. Cabin warmed and demisted by air from combustion heater, which also heats passenger compartment when fitted. Air filter on nose of agricultural version. For agricultural work, a chemical hopper (capacity 900kg) and dust spreader or spraybars are fitted in module space, on the aircraft's centre of gravity. This equipment is quickly removable and can be replaced by a cargo/passenger pod accommodating four or six persons, with provision for a seventh passenger beside the pilot; or two stretcher patients, two seated casualties and a medical attendant in ambulance role. Alternatively, the Ka-26 can be operated with either an open platform for hauling freight or a hook for slinging bulky loads at the end of a cable or in a cargo net.

Jane's Helicopter Markets and Systems

The year of 1956 saw the beginning of the wide-scale application of helicopters in the Soviet national economy. The need arose for helicopters capable of spreading fertilizers in the fields, orchards and vineyards and of combatting pests and weeds. To this end Ka-15M and Mi-1 helicopters were fitted with agricultural equipment. Operational experience gained with these types revealed the need for a dedicated helicopter with a bigger cargo-lifting capacity for performing a wide range of agricultural duties. This requirement was met by the Ka-26 featuring a modular design with interchangeable mission equipment (the "flying chassis").

In January 1964 the Soviet government issued a directive on the creation of the multi-purpose Ka-26 in two versions: the agricultural version capable of carrying 600-700kg of chemicals and the transport version for carrying passengers over distances of up to 400km. At the time our Civil Aviation already operated the agricultural version of the Mi-2 multi-purpose helicopter. The Kamov OKB was faced with the task to build a more cost-effective aircraft and did so with success. The Ka-26 design effort was headed by deputy chief designer M.A.Kupfer; Yu.I.Petrukhin was the leading designer and V.S.Dordan the leading engineer in charge of the flight tests.

The first circuit flight of the Ka-26 took place on August 18, 1965; the prototype was flown by test pilot V.V.Gromov. The State trials were successfully completed in the autumn of 1967 and production was launched in the town of Kumertau at a factory which had been purpose-built in 1962. The leaders of the OKB and its specialists rendered invaluable assistance in the setting up and development of the new aircraft factory. Their efforts were not wasted - the Kumertau Aircraft Production Association is currently continuing production of helicopters bearing the Kamov emblem, albeit helicopters of a new generation.

Between 1967 and 1970 several modifications of the Ka-26 were designed and tested: a shipboard version, an air ambulance version, a geological survey verson, a "flying crane", a highway patrol version etc. In its basic configuration the helicopter can be fitted with quickly detachable equipment packages, such as: passenger (cargo) cabin, cargo platform, hopper and spraybars for crop-spraying etc, and thus can be converted into any of the required versions within 1.5-2 hours. Due to the Ka-26's unusual modular design the specific versions were not allocated designations of the generally adopted style (i.e., with suffix letters), although they were just as numerous as, for example, those of the Mi-2 helicopter in the same class.

In the Ka-26 helicopter the Kamov OKB made its first large-scale use of parts and subassemblies made from composite materials. These included rotor blades, engine cowlings, the hopper for chemicals etc. The main achievement, however, was the organization of mass production of glassfibre rotor blades which ensured stability of aerodynamic characteristics under varying climatic conditions. Composite rotor blades had 5000-hour service life; in contrast, the metal blades of contemporary helicopter rotors had service life of less than 600-800 hours. The design and production technology of the blades have been patented in five countries outside the former Soviet Union; this know-how formed the basis for the production of improved new-generation rotor blades.

Single-rotor helicopters with a tail rotor are in production in Russia, the USA, France, Germany, Great Britain, Italy and elsewhere. It is an open secret that the helicopter design bureaux of these countries make use of the achievements of their competitors. When designing co-axial helicopters, N.I.Kamov's OKB virtually does not have to borrow from foreign experience, because it is exactly the Kamov OKB that "dictates the fashions" in this field. The company's rotorcraft possess so-called "patent purity". It was not least this circumstance that enabled the Ka-26 as the only Soviet helicopter to be certificated in accordance with US FAR 29 airworthiness regulations. It was also the only Soviet helicopter to be sold abroad on a commercial basis; the Ka-26 was exported to 17 foreign countries. For more than 30 years it has been doing its job with dignity. The total flying hours amassed by the type amount to 2,907,000 hours. In 1980 and 1982 the Ka-26 established five world records.

G.Kuznetsov "OKB Kamov - 50 years", 1999

The Kamov Ka-26, which has the NATO codename Hoodlum, was announced in January 1964 as a light commercial helicopter with twin-turbine powerplant and a design making it easily convertible to meet the requirements of several roles. The primary task envisaged for the Ka-26, however, was agricultural.

The main need for such a helicopter was in remote areas, and so the Kamov design bureau opted for its standard co-axial contra-rotating twin rotor configuration, but powered by a pair of 325hp Vedeneev M-14V-26 radial piston engines because of the need for minimum fuel consumption. To leave the area under the transmission and rotor assemblies free for the payload, the engines were installed in pods at the ends of shoulder-mounted stub wings, the engines and transmission being connected by drive shafts with flexible couplings.

The first prototype flew in 1965, and state trials were successfully completed in the same year, allowing it to enter limited production during 1966.

The compact size and manoeuvrability of the Ka-26 proved a great asset for agricultural work, and the pod-and-boom design of the fuselage highly effective. The fuselage forward of the stub wings is a minimal pod with the crew cabin at the front, while the glassfibre tail unit is carried on twin booms and has conventional flying controls.

The design thus leaves the area under the engines and on the centre of gravity free for the payload. For agricultural work a 900kg hopper can be fitted, the load being spread by spray-bars or dust-spreaders under the hopper and aft of the tail assembly. For passenger operations the Ka-26 can be fitted with a detachable pod for six passengers on tip-up seats, and for freight work this pod can be used to carry up to 700kg.

The Ka-26 is thus a valuable general-purpose helicopter, despite the 'obsolescent' feature of piston engines. The greater weight of these units compared with turbines has been compensated by the use of lightweight materials in the airframe. Each of the interchangeable rotor blades, for example, is made of plastic, and weighs only 25kg; and much of the fuselage is made of aluminium panels sandwiched in glassfibre. Apart from saving weight, such features also reduce the problem of metal corrosion from the chemicals carried in the agricultural role.

Bill Gunston "The Illustrated Encyclopedia of Commercial Aircraft", 1980

The first indication that his bureau was working on the design of a new, twin-engined general-purpose utility helicopter was given by Nikolai Kamov himself in January 1964. The prototype of this aircraft, the Ka-26, was flown for the first time in 1965, followed by a small pre-series batch and the first production Ka-26's during 1966. In its general appearance the Ka-26 shows a marked similarity to the Kaman H-43 Huskie, except that it retains the typical Kamov-type 3-blade co-axial rotor arrangement, whereas the American machine has separate rotor heads and intermeshing blades. The rotor blades, and parts of the fuselage of the Soviet aircraft, are of plastic and glassfibre construction.

The basic Ka-26 airframe comprises the 2-man crew cabin, rotor head and stub wings, with the engine pods at their extremities and twin tailbooms to the rear supporting the tail assembly. The tail unit is akin to that of a fixed-wing aeroplane, consisting of a tailplane and elevators and fins and rudders with a pronounced toe-in angle. The engines of those Ka-26's so far seen are Vedeneev radials, and not the Isotov shaft turbines that had been anticipated by western observers, but it is possible that later production aircraft could be turbine-powered. This would make the Ka-26 an even better proposition for a Ka-15 replacement, for the piston-engined Ka-26 has three times the load-carrying ability of the earlier type.

Considerable versatility of role is made possible in the Ka-26 by the use of interchangeable kits or units in the space behind the crew cabin and beneath the rotor head. These may take the form of a freight platform for a 900kg load; a winch for externally-slung crane loads; dust hoppers or liquid chemical tanks for agricultural use; a 'people pod' with a bench seat for 3 passengers along each side; or a similar cabin pod to accommodate a stretchers, 2 sitting patients and a medical attendant. Other likely applications of the Ka-26 include Arctic search and rescue, and ice, fishery or forestry patrols, either from land bases or ships' platforms. The Ka-26 is normally equipped for single-pilot operation, but dual controls can be fitted if desired. Six Ka-26's were ordered by an operator in Southern England in April 1967, the first order ever placed by a British customer for an aircraft designed and built in the USSR.

K.Munson "Helicopters And Other Rotorcraft Since 1907", 1968

The Ka-26, designed at the beginning of the sixties, is built for maximum simplicity and versatility as a "lifting system" consisting of the powerplant, contra-rotating rotor assembly, cabin, landing gear and twin endplate fin tail unit. Loads and containers of various kinds can be installed immediately behind the cabin, beneath the rotors: a pod for six passengers, an open platform, tanks for liquid or solid insecticides or other products, and spray bars for agricultural use. A variant for geophysical survey is equipped with an electromagnetic pulse generator in the cabin and a big hoop antenna outside. Thanks to its compactness and stability, the Ka-26 can operate from small platforms and has been fitted with floats and used for fish-spotting.

The Ka-26 went into service on a large scale in 1970 and has been exported for both civil and military use.

G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984

- Kamov announced the Ka-26 in 1964 and the aircraft entered large-scale agricultural use in the USSR in 1970.

- Search-and-rescue variants have a winch for towing rescue boats.

- Full instrumentation is provided for flying by day or night, and in all weathers.

- In 1962 Ka-26s joined other helicopters transporting demolition teams whose task was to keep Soviet rivers free of ice.

- A towed 'bird' receives reflections from the emitter of the prospecting version.

- All payloads are carried at the Ka-26's centre of gravity.