HH-101A Caesar medium-lift helicopter is designed and developed by AgustaWestland, a Finmeccanica company, based on the AW101 Combat Search and Rescue variant to meet the future operational requirements of the Italian Air Force.
The helicopter entered service with the Air Force’s 15th Wing in Cervia in June 2015. It is intended for special operations and personnel recovery missions and can also be used for search and rescue (SAR), medical evacuation (medevac) and slow mover intercept (SMI) operations.
A total of 15 HH-101A Caesar helicopters have been ordered to replace the Italian Air Force’s current fleet of Agusta / Sikorsky HH-3 Pelican amphibious medium-lift helicopters. The first two aircraft are configured for personnel recovery and special forces missions.
Maiden flight of the first HH-101A took place at AgustaWestland’s Yeovil facility in the UK in March 2014.
HH-101A Caesar helicopter design and features
The HH-101A Caesar helicopter features a versatile design and crashworthy airframe. It can be operated autonomously in harsh weathers and hostile environmental conditions and has a 30-minute transmission run-dry capability.
It is fitted with five advanced profile composite main rotor blades and four fully articulated tail rotors. The aircraft has efficient landing gear with castering / steerable nose-wheels permits safe for landing on rough terrains. Other features of HH-101A Caesar include a hydraulically-operated rear ramp, large cabin windows, and a wide cargo door.
The 22.83m-long and 6.66m-high helicopter has a rotor diameter of 18.6m, empty weight of more than 5,500kg and maximum gross weight of 15,600kg. A cargo hook attached to the helicopter supports external loads up to 4,536kg.
The HH-101A can be configured to accommodate a crew of up to five members and 20 fully-equipped personnel or six crew and eight special operation troops. An active control of structural response (ACSR) is installed to reduce the crew fatigue.
Search and rescue equipment aboard the HH-101A includes a wireless intercom system, medical treatment module, dual rescue hoist, sea tray, controller, fast roping / rappelling, and stretcher racks. The air-to-air refuelling and hover-in-flight refuelling capabilities of the helicopter provide extend the flight endurance.
Cockpit and avionics
The NVG-compatible glass cockpit provides superior situational awareness for the operators. It is installed with five 10in x 8in displays, synthetic vision system, digital map, integrated mission console, and a mobile phone. Operators are provided with helmet-mounted displays with head tracker.
LIDAR obstacle detection system
The Obstacle Proximity LIDAR System (OPLS) uses three independent fixed Laser Imaging Detection and Ranging (LIDAR) sensors, a central computer (a GE MAGIC 1) and a dedicated control panel. It can present a 360º representation of adjacent obstacles (closer than 25m) on the aircraft’s existing Multi-Functional Displays with a two level aural tone as the clearance distance reduces. Source aerossurance.com
The integrated avionics suite consists of four-axis automatic flight control system (AFCS), traffic collision avoidance system (TCAS), helicopter terrain awareness systems (HTAWS), proximity detection system, TETRA radio communications system, and a mission recorder, as well as direction-finding and automatic identification systems (AIS), LIDAR obstacle detection system, and satellite communications (satcom) systems.
It also features an instrument flight rules (IFR) navigation suite, advanced 360° active electronically scanned array (AESA) radar, health and usage monitoring systems (HUMS), and high-definition electro-optical sensors.
Advanced 180° Gabbiano radar
Gabbiano Radar Family’s high level of modularity and flexibility allows for operation on-board Unmanned Aerial Vehicles as well as both fixed and rotary wing manned platforms.
The two basic Gabbiano configurations (T20 and T200 Power) are available with nose-mounted or bellymounted antenna, providing respectively a ±90° and 360º surveillance. Moreover, antennas of several sizes/characteristics, tailored to the specific application, are available.
▪ Low weight, low power consumption
▪ LPI capability
▪ TWS: > 200 targets
▪ ECCM capabilities (frequency agility, jammer avoidance etc.)
▪ Digital/ Programmable waveform generator
▪ Short blind zone
▪ High resolution modes
▪ Maritime surveillance, up to 220NM
▪ High reliability
▪ Standard and flexible interfaces
▪ Dual channel digital receiver
Weapons onboard HH-101A Caesar helicopter
The HH-101A Caesar helicopter is fitted with three M134 7.62mm pintle-mounted Gatling-type machine guns on both sides as well as on the rear ramp.
3 x M134 7.62mm pintle-mounted Gatling-type machine guns
(SEE NOTE 2)
|Army – M134D
Air Force – GAU-2B/A
Navy – GAU-17/A
|SHIP CLASS USED ON||Many|
|DATE OF DESIGN||about 1963|
|DATE IN SERVICE||1965|
|GUN WEIGHT||35 lbs. (16 kg)|
|GUN LENGTH OA||29.5 in (75 cm) including suppressor
Barrels are 22 in (55.9 cm) long
|RIFLING LENGTH||20 in (50.8 cm)|
|TWIST||Uniform RH 1 in 33.333|
|RATE OF FIRE
(SEE NOTE 3)
|2,000 to 4,000 rounds per minute|
- Barrel cluster rotates counterclockwise as viewed from the breech end.
- M134D is the minigun itself. Other designations are usually for the “gun assemblies” that include the mounting. The GAUSE designation appears only on text released with U.S. Navy photographs. It may represent a “sailor-alt” rather than an official U.S. Navy designation, although I have been unable to confirm that one way or the other. I have been told by USN personnel that the “SE” in GAUSE probably stands for “Shipboard Equipment” and refers to the entire gun and mounting assembly rather than to just the minigun itself.
- The original design of the 1960s had a fixed rate of about 6,000 rounds per minute. This was unsustainable over any period of time and the weapon was redesigned to add a transmission housing at the motor, giving the weapon a variable speed of 2,000 or 4,000 rounds per minute. On the newer Dillon Aero Inc. version, the rate of fire is determined by the gun drive unit used, with drive units giving either 3,000 or 4,000 rounds per minute available. There is no speed selection on this version other than by assembling a different gun drive motor to the the gun system assembly. The 3,000 ROF drive motor takes 0.5 seconds to spin up to speed and 0.25 seconds to spin down to stop. When the trigger is released, there is a delay until all six barrels have been cleared by fire. This ensures that no live ammunition is left in the firing chambers, thus eliminating cook-off problems. Source navweaps.com
An integrated electronic warfare system is installed to provide self-protection against radar, laser and infrared threats. It also protects the machine gun operators and the critical systems from ballistic threats. The cockpit seats are armoured to provide additional protection for the crew.
The helicopter also features large aircraft infrared countermeasures (LAIRCM), direct-attached storage (DAS), and directional infrared countermeasures (DIRCM).
In June 2011, Elbit Systems was awarded a contract worth $15m by Elettronica for the supply of ELT/572 DIRCM system for the HH-101A Caesar.
ELT/572 DIRCM system
The ELT/572 is able to effectively counter threats up to the third generation of sa ir. Its fi ber laser technology enhances dircm effectiveness by improving performance, reliability and effi ciency, reducing the installation constraints and the even more critical and complex settingup, alignment and maintenance operations.
The ELT/572 is composed of three units: the mirrored turret, the laser generator unit and the electronic unit. In dual turret configuration, the two dircm systems are correctly coordinated by means of a specifically designed multi-turret manager (patent pending): a function deployed in each subsystem and activated only in one subsystem at a time (the master subsystem) which is in charge of effectively coordinating the two sub-systems. Source elt-roma.com
Engine and performance
Powered by three civil-certified GE CT7-8E engines, the helicopter can reach a maximum cruise speed of 277kmph and a maximum range of 1,363km. Each engine has a take-off power of 1,884kW and a maximum continuous power of 1,522kW.
3 x GE CT7-8E engines
The T700 engine was designed for the US Army’s UH-60A Black Hawk helicopter as a result of lessons learned in Vietnam. The key requirements of this engine were reliability, operation under adverse environmental conditions and low maintainability.
The CT7-8 engine is the newest commercial derivative of T700 engine family. It has been designed jointly with FiatAvio from Italy to power the S-92 multirole helicopter. The CT7-8A engine features an advanced, higher-flow compressor designed with new three-dimensional aerodynamic technology, a full authority digital electronic control (FADEC) system, and hot-section and turbine components proven in millions of flight hours on the CT7-9 engine. Source deagel.com
|Low-Pressure Turbine / High-Pressure Turbine||2/2||2/2||2/2||2/2|
|Nominal Diameter (Inches)||15.6||15.6||26||29|
|Take off rating at Sea Level||1,625||2,000||2,634||1,870-1,950|
|SFC at take-off rating||0.474||0.454||0.452||0.455|
The helicopter has a standard internal fuel capacity of 5,135l, and carries 649l in a small USG auxiliary fuel tank and up to 1,389l in a large USG auxiliary fuel tank.
The aircraft has rate of climb of 8.5m/s, a service ceiling of 4,570m and a hovering IGE of 3,307m. It can endure for six hours and 50 minutes, when powered by two engines.
Main materail source airforce-technology.com