RAH-66 Comanche, USA

The RAH-66 Comanche was a prototype helicopter manufactured in tandem by Sikorsky and Boeing Helicopters. Touted by the US military as the first step towards an all-stealth airborne fleet, the Comanche was intended to replace the AH-1 Cobra and OH-58 Kiowa, as well as supplement the AH-64 Apache.This helicopter is the first type in the world which can detect the presence of biological and chemical weapons in the atmosphere.

Comanche design

The airframe was crashworthy and ballistically tolerant to 23mm gunfire. The radar cross section has been minimised, primarily by the precisely shaped fuselage and internal weapons configuration.
The helicopter had a composite five-bladed bearingless main rotor and an enclosed composite fantail tailrotor for increased anti-torque capability. The rear rotor was able to withstand impact by 12.7mm rounds and provided a 180° turn in 4.7 seconds in hover mode and an 80kt snap-turn-to-target in 4.5 seconds.
The Comanche had two identical cockpits for the pilot and the co-pilot, which were sealed and had a positive pressure air system for protection against chemical and biological warfare. The fly-by-wire flight control system was triple redundant.

The cockpit was fitted with a pilot's night-vision system from Lockheed Martin and the pilots had a wide field of view (35° × 52°) Kaiser Electronics helmet-integrated display sighting system (HIDSS). HIDSS employed active matrix liquid crystal display (AMLCD) technology. The targets were designated and the weapons fired from collective and sidestick control push buttons.
Each integrated cockpit had Harris Corp flat screen liquid crystal displays, a colour display for a digital moving map system, tactical situation and night operation display.
Northrop Grumman provided the Comanche's integrated communications, navigation and identification (CNI) suite. The CNI suite will feature secure multiwave, multiband multimode wireless communications, link 16, satellite communications and enhanced position locating reporting system (EPLRS) via the tactical internet.

Weapons

The Comanche carried its weapons internally and had a weapons bay on each side of the fuselage. The missiles are mounted on the weapon bay doors which open sideways. The internal weapon bay could be fitted with Stinger, Starstreak or Mistral air-to-air missiles; TOW II, Hot II or Longbow Hellfire air-to-ground missiles; Sura D 81mm, Snora 81mm, Hydra 70 rockets; or the army counter air weapon system.
The number of missiles on each door mounting varied, for example each door could hold three Hellfire or six Stinger missiles. The helicopter could be reconfigured with optional stub wings fitted with multiple weapon pylons which carried an additional four Hellfire or eight Stinger missiles.
The Comanche was equipped with a turreted gun system from General Dynamics Armament Systems. The stowable externally powered three-barrel 20mm Gatling gun was capable of firing 750 or 1,500 rounds a minute. The gun was mounted on a Giat composite turret (weighing 127kg) under the nose of the helicopter. The 500 round ammunition supply system could be reloaded in less than eight minutes by two crew members.

Fire control and observation

The Comanche was equipped with a suite of passive sensors and a computer-aided Northrop Grumman mission planning system, which carried out sensor data fusion, high-speed analysis and correlation of the sensor data. Northrop Grumman TASS (target acquisition system software) functions included automatic target tracking and target threat management.
Lockheed Martin Missiles and Fire Control has developed the EOSS (electro-optics sensor system) which comprised: EOTADS target acquisition and designation system, including solid-state TV sensor, two-colour laser rangefinder / designator and second-generation focal plane array long-wave FLIR (forward-looking infrared); and NVPS night-vision pilotage system with a second FLIR. The first complete EOSS system was delivered in June 2003.
The Comanche was fitted with a fire control radar (based on the Longbow millimetre wave radar on the AH-64D Apache helicopter), developed by Northrop Grumman Land Combat Systems and Lockheed Martin Missiles and Fire Control.
The helicopter countermeasures suite included an AN/AVR-2A(V) advanced laser warning receiver from Goodrich Electro-Optical Systems (formerly Raytheon) of Danbury, Connecticut, and the ITT AN/ALQ-211 SIRCM (suite of integrated radio frequency countermeasures) suite, as well as infrared jammers.

Navigation and communications

The helicopter had a global positioning system, a radar altimeter and an attitude heading reference system (AHRS) from Northrop Grumman (formerly Litton).
It was equipped with an identification friend or foe (IFF) interrogator and a dual jam resistant VHF-FM / UHF-AM Have Quick tactical communications system.

Engines

The Comanche was equipped with two T-800-LHT-801 turboshaft engines from LHTec with a maximum rated power of 1,432shp each. The internal fuel capacity of the helicopter was 1,142l.

Mi-24 Hind Attack

The Mi-24, the first helicopter to enter service with the Russian Air Force as an assault transport and gunship, was developed on the basis of the Mi-8's propulsion system. Additional missions include direct air support, antitank, armed escort, and air to air combat. The helicopter was used extensively in the Afghanistan War, becoming the "signature" weapon of the conflict. The Mi-24 is a close counterpart to the American AH-64 Apache, but unlike this and other Western assault helicopters it is also capable of transporting up to eight troops. The Russians have deployed significant numbers of HINDs in Europe and have exported the HIND to many third world countries.
The Mil-series of helicopters stem from the design bureau of Mikhail Mil. Nearly all Soviet-era helicopters are from the Mil design bureau, except for the Kamov helicopters. The Mi-24 was the first purpose-built helicopter gunship in the Soviet military forces. Unlike the slimmer US-made AH-1G Cobra, however, the Mi-24 was not designed solely as such; the Hind was larger due to a 6-to-8 man troop compartment in the lower fuselage, as it was meant both as troop transport and attack helicopter. The Hind has four main wing hardpoints along with two on the wingtips; a typical load consists of four large unguided rocket pods and a pair of wingtip double launch rails, each with two guided anti-tank missiles. NATO designated the production "Hind A", the pre-production "Hind B", and the unarmed trainer models "Hind C."

The design of the Mi-24 is based on a conventional pod and boom, with a five-blade main rotor and three-blade tail rotor. It has retractable tricycle nose-wheel landing gear.
The two crew (pilot and weapons operator) are accommodated in tandem armoured cockpits with individual canopies and flat, bulletproof glass windscreens. The main cabin can accommodate eight troops or four stretchers.

Mi-24 Hind upgrades

Russian Army Mi-24s are being upgraded with new avionics including thermal imagers. Other upgrade packages are available, including that of Denel / Kentron of South Africa which includes Eloptro infrared sighting systems and Kentron Mokopa anti-tank missiles, and IAI Tamam which has HMOSP (helicopter multi-mission optronic stabilised payload) with FLIR, TV and autotracker, embedded GPS (global positioning system) and cockpit multi-function displays.
The 'Visegrad Four' - Czech Republic, Hungary, Poland and Slovakia - signed an agreement in February 2003 to jointly upgrade up to 105 Mi-24D/V helicopters to Nato standards. This agreement was later abandoned.
However, two Polish Mi-24s were upgraded to Nato standard as prototypes. In February 2004, BAE Systems was selected as integrator for the avionics systems, which will include an integrated electronic warfare suite.
In December 2005, Bulgaria signed a contract for the upgrade of 12 Mi-24 helicopters to a team led by Lockheed Martin and Elbit. However the contract was subsequently cancelled in February 2007.

Weapons

The helicopter has six suspension weapon units on the wingtips. The Mi24D (Mi-25) and the Mi-24V (Mi-35) are equipped with a YakB four-barrelled, 12.7mm, built-in, flexibly mounted machine gun, which has a firing rate of 4,000-4,500 rounds a minute and a muzzle velocity of 860m/s. The Mi-24P is fitted with a 30mm, built-in, fixed gun mount; the Mi-24VP with a 23mm, built-in, flexibly mounted gun.
The Mi-24P and Mi-24V have four underwing pylons for up to 12 anti-tank missiles. The Mi-24V (Mi-35) is armed with the Shturm anti-tank guided missile system. Shturm (Nato designation AT-6 Spiral) is a short-range missile with semi-automatic radio command guidance. The 5.4kg high-explosive fragmentation warhead is capable of penetrating up to 650mm of armour. Maximum range is 5km.

The Mi-24V can also carry the longer-range Ataka anti-tank missile system (Nato designation AT-9), as can the Mi-24P. The Ataka missile's guidance is by narrow radar beam, and the maximum range of the missile is 8km. The average target range is between 3km-6km. The target hit probability of the Ataka missile is higher than 0.96 at ranges 3km-6km. The missile has a shaped-charge 7.4kg warhead, with a tandem charge for penetration of 800mm-thick explosive reactive armour.
All Mi-24 helicopters can also be armed with rockets and grenade launchers.

The Mi-24D is equipped with the KPS-53A electro-optical sighting pod. The most recent Mi-24V and P variants have a digital PNK-24 avionics suite and multifunction LCD cockpit displays, and Geofizika ONV1 night-vision goggles, along with NVG-compatible cockpit lighting. They are fitted with the Urals Optical and Mechanical Plant GOES-342 TV/FLIR sighting system and a laser rangefinder. Countermeasures include infrared jammer, radar warner and flare dispensers.

Engines

The helicopter is powered by two Isotov TV3-117VMA turboshaft engines, developing 2,200shp each. The air intakes are fitted with deflectors and separators to prevent dust particle ingestion when taking off from unprepared sites. An auxiliary power unit is fitted.
The internal fuel capacity is 1,500kg, with an additional 1,000kg in an auxiliary tank in the cabin or 1,200kg on four external tanks. The fuel tank has self-sealing covers and porous fuel tank filler for increased survivability, and the exhaust is fitted with infrared suppression systems.