The Ka-27 is the anti-submarine helicopters of Russian Navy. And the Ka-28 is the export variation of Ka-27, as well as the Ka-29, a naval combat and transport helicopter developed from Ka-27. Three of them are all designed and manufactured by the Kamov Design Bureau. The first prototype flew in December 1974. The Nato name the Ka-27 and Ka-28 Helix. More than 60 Ka-27/28s and 15 Ka-29s are served in Russia.
The Ka-27 can detect submarines at a depth of 500m and running at speeds up to 75kph. The helicopters can operate in conditions up to sea state 5 and at ranges up to 200km from the take-off pads. The operating time of one mission could be 4.5h, with 45min fuel remained.
So it is able to work in all weather conditions and destroy the giant submarines by its 533mm torpedo. In a combat mission, the Ka-27 alway act in a dual team, one for detection, one for hunting.
Like other Kamov designs, the Ka-27 is fitted with a coaxial main rotor with folding blades. The composite blades are fitted with an electric thermal de-icing system. The Ka-27 is allowed to be stowed in small shipborne hangars by the aerodynamic and design parameters. The 4-point landing gear provides for safe take-off and landing. Corrosion-resistant materials have been used in the construction to ensure normal operation in active sea environments. The ballonet flotation devices for emergency landing on water is fitted.
Two 1660hp TV3-117KM turboshaft engines powered the Ka-27. The Ka-28 is powered by two TV3-117VK turboshaft engines.
For navigation and to detecting surfaced submarines and responder beacons, a radar system is equipped. The VGS-3 dipping sonar detects submarines, determines the coordinates and transfers the data in semi-automatic mode to data transmission equipment. The mission computer carries out automatic control, stabilisation and guidance of the helicopter to the mission areas to attack targets.
The helicopter also has a magnetic anomaly detector(MAD) and an airborne receiver to detect and guide the helicopter towards sonar buoy radio transmissions. There are 16 to 24 buoy installed, detect range 10km each. The export version Ka-28 also has an IFF (interrogation friend or foe) system.
Due to the unique qualities of a coaxial rotor layout the Ka-27 features high power-to-weight ratio, small dimensions, maneuverability, simplicity of control and safety of flight operations from ship decks in stringent sea conditions and turbulent atmosphere. Simplicity of piloting techniques and perfect flight-navigational package make it possible for one pilot to fly prolonged combat missions above reference-free water surface in any time of the year, day-and-night, and in IFR conditions. The cockpit is wide and the view area is clear, the pilot seat is on the left, easy to look forward and downside, the navigator and weapon system operator are on the right. The best thing for pilot of Ka-27 is that, there is no tail rotor, so they do not need to step on the pedal which means they can stand up to watch when needed.
After target is detected the on-board avionics suite in combination with the automatic control system of the helicopter solve the task of bringing the helicopter to the designated point and automatic firing of the weapons selected by the pilot.
The flight control system can record 8 different flight paths and separate paths can be grouped to build new path.
In fact when doing some typical fly actions, the pilot does not need to move his hands at all.
The helicopter is armed with one 533mm homing torpedo, one torpedo rocket, ten PLAB 250-120 bombs and two OMAB bombs. The 533mm torpedo is fitted in a heated torpedo bay, ensuring the reliability of weapons in low-temperature weather conditions. Russian chose 533mm torpedo becasue they did not have small size and reliable torpedo in the 1970`s. But 533mm torpedo has a good point is that it can destroy most of the submarine in the world, and the western helicopter just has two 324mm torpedo, the warhead may not destroy the dual carapace submarine.
The accessory of Ka-27 is 1/4 less than original designed helicopters, as well as most of them are the same used by land based helicopters of Russia. So the cost and the maintain funds of Ka-27 remains in a very low level.
The disadvantage of Ka-27 mainly focus on the eletronic system. The vacuum tubes took many space of the fuselage and the radar size is so big that the torpedo bay is hard to placed. And according to some historical reasons, Kamov refused to use the Mil helicopter`s flat cabin and fuselage fuel tank, so a large fuel tank sets in the center of the cabin. The 4 ponit landing gear is excellent but make it hard to equip pylons. Another problem is that the ballonet flotation devices does not work well at all.
Variants include the Ka-27PS search and rescue version and Ka-28 ASW model. The Ka-29 combat/transport helicopter and Ka-31 surveillance variant are in operational service.
Let`s work on details of the Ka-28. The Ka-28 helicopter has two rotors of 15.9m diameter each. The polymeric composite blades are equipped with electrical thermal de-icing system and blade folding system allowing to keep the helicopter in the ship hangars. The four-leg non-retractable landing gear can operate from ship decks in the sea state conditions of up to ±10 degrees. The Ka-28 and Ka-27 have differs from some on-board equipment units, "friend-or-foe" identification system and larger fuel system capacity - 4,470l.
The Ka-28 have been exported to Cuba, India, Syria, Vietnam and Yugoslavia. China recently took three Ka-27s and five Ka-28s to operate from their Russian-built Sovremenny destroyers.
The Ka-29 is the naval combat and transport helicopter based on Ka-27. The Ka-29 is to land navy and infantry units with armament from ships, offering fire support for seaborne assault troops. The structure is similar to the Ka-27 except the nose. The Ka-29 has been in service with the Russian Navy since 1985. The cargo cabin accommodates 16 armed troops, or four stretcher patients and seven seated casualties with one medical attendant, or at least two tons of cargo. It is powered by two TV3-117V turboshaft engines.
The Ka-29 can carry four weapon pylons. It can be armed with rockets, bombs and machine gun pods mounted on the weapon pylons. Tanks or container pods can be carried, too. Bombs and containers can be also arranged in the Ka-29's torpedo bay, inherit from Ka-27. And a 7.62mm flexibly mounted machine gun with 1,800 cartridges is fitted. A number of measures are taken to increase combat survivability, including armour protection.
The Ka-31 is the radar picket hellicopter of Ka-27 family, with a 6 meters antena.