Eko Triyanggono: Utility Helicopter

Showing posts with label Utility Helicopter. Show all posts

Bell UH-1 Iroquois - Huey

The Bell UH-1 Iroquois (unofficially Huey) is a military helicopter powered by a single, turboshaft engine, with a two-bladed main rotor and tail rotor. The helicopter was developed by Bell Helicopter to meet the United States Army's requirement for a medical evacuation and utility helicopter in 1952, and first flew on 20 October 1956. Ordered into production in March 1960, the UH-1 was the first turbine-powered helicopter to enter production for the United States military, and more than 16,000 have been produced worldwide.

The first combat operation of the UH-1 was in the service of the U.S. Army during the Vietnam War. The original designation of HU-1 led to the helicopter's nickname of Huey. In September 1962, the designation was changed to UH-1, but "Huey" remained in common use. Approximately 7,000 UH-1 aircraft saw service in Vietnam.

Design

The UH-1 has a metal fuselage of semi-monocoque construction with tubular landing skids and two rotor blades on the main rotor. Early UH-1 models featured a single Lycoming T53 turboshaft engine in versions with power ratings from 700 shp (522 kW) to 1,400 shp (1,040 kW). Later UH-1 and related models would feature twin engines and four-blade rotors. The width was decided by the length of a standard Army medical litter.

All aircraft in the UH-1 family have similar construction. The UH-1H is the most-produced version, and is representative of all types. The main structure consists of two longitudinal main beams that run under the passenger cabin to the nose and back to the tail boom attachment point. The main beams are separated by transverse bulkheads and provide the supporting structure for the cabin, landing gear, under-floor fuel tanks, transmission, engine and tail boom. The main beams are joined at the lift beam, a short aluminum girder structure that is attached to the transmission via a lift link on the top and the cargo hook on the bottom and is located at the aircraft's centre of gravity. The lift beams were changed to steel later in the UH-1H's life, due to cracking on high-time airframes. The semi-monocoque tail boom attaches to the fuselage with four bolts.

The UH-1H's dynamic components include the engine, transmission, rotor mast, main rotor blades, tail rotor driveshaft, and the 42-degree and 90-degree gearboxes. The transmission is of a planetary type and reduces the engine's output to 324 rpm at the main rotor. The two-bladed, semi-rigid rotor design, with pre-coned and under-slung blades, is a development of early Bell model designs, such as the Bell 47 with which it shares common design features, including a dampened stabilizer bar. The two-bladed system reduces storage space required for the aircraft, but at a cost of higher vibration levels. The two-bladed design is also responsible for the characteristic 'Huey thump' when the aircraft is in flight, which is particularly evident during descent and in turning flight. The tail rotor is driven from the main transmission, via the two directional gearboxes which provide a tail rotor speed approximately six times that of the main rotor to increase tail rotor effectiveness.

The UH-1H also features a synchronized elevator on the tail boom, which is linked to the cyclic control and allows a wider center of gravity range. The standard fuel system consists of five interconnected fuel tanks, three of which are mounted behind the transmission and two of which are under the cabin floor. The landing gear consists of two arched cross tubes joining the skid tubes. The skids have replaceable sacrificial skid shoes to prevent wear of the skid tubes themselves. Skis and inflatable floats may be fitted.

Internal seating is made up of two pilot seats and additional seating for up to 13 passengers or crew in the cabin. The maximum seating arrangement consists of a four-man bench seat facing rearwards behind the pilot seats, facing a five-man bench seat in front of the transmission structure, with two, two-man bench seats facing outwards from the transmission structure on either side of the aircraft. All passenger seats are constructed of aluminium tube frames with canvas material seats, and are quickly removable and reconfigurable. The cabin may also be configured with up to six stretchers, an internal rescue hoist, auxiliary fuel tanks, spotlights, or many other mission kits. Access to the cabin is via two aft-sliding doors and two small, forward-hinged panels. The doors and hinged panels may be removed for flight or the doors may be pinned open. Pilot access is via individual hinged doors. While the five main fuel tanks are self-sealing, the UH-1H was not equipped with factory armour, although armoured pilot seats were available.

The UH-1H's dual controls are conventional for a helicopter and consist of a single hydraulic system boosting the cyclic stick, collective lever and anti-torque pedals. The collective levers have integral throttles, although these are not used to control rotor rpm, which is automatically governed, but are used for starting and shutting down the engine. The cyclic and collective control the main rotor pitch through torque tube linkages to the swash plate, while the anti-torque pedals change the pitch of the tail rotor via a tensioned cable arrangement. Some UH-1Hs have been modified to replace the tail rotor control cables with torque tubes similar to the UH-1N Twin Huey.

Specifications

General characteristics

Crew	1-4
Capacity	3,880 lb including 14 troops, or 6 stretchers, or equivalent cargo
Length	57 ft 1 in (17.40 m) with rotors
Width	8 ft 7 in (2.62 m) (Fuselage)
Height	14 ft 5 in (4.39 m)
Empty weight	5,215 lb (2,365 kg)
Gross weight	9,040 lb (4,100 kg)
Max takeoff weight	9,500 lb (4,309 kg)
Powerplant	1 × Lycoming T53-L-11 turboshaft, 1,100 shp (820 kW)
Main rotor diameter	48 ft 0 in (14.63 m)

Performance

Maximum speed	135 mph (217 km/h; 117 kn)
Cruise speed	125 mph (109 kn; 201 km/h)
Range	315 mi (274 nmi; 507 km)
Service ceiling	19,390 ft (5,910 m)
Rate of climb	1,755 ft/min (8.92 m/s)
Power/mass	0.15 hp/lb (0.25 kW/kg)

Armament

Variable, but may include a combination of:

2 x 7.62 mm M60 machine gun, or 2 7.62 mm GAU-17/A machine gun

2 x 7-round or 19-round 2.75 in (70 mm) rocket pods

2 x 7.62 mm Rheinmetall MG3 (German Army and German Luftwaffe)

2 x .303 Browning Mk II (Rhodesian, twin machine guns mounted on port side)

DISCLAIMER: The material content provided on this page is generated by another sources and consequently features user-generated content. While we do our best to stop offensive material appearing, ekotriyanggono.com cannot be held responsible for all of the material that may be displayed on this page. If you object to any article or picture, please leave us a comment in this page.

Bell UH-1Y Venom

The Bell UH-1Y Venom, also called Super Huey, is a twin-engine medium size utility helicopter, part of the United States Marine Corps' H-1 upgrade program. The helicopter is also called Yankee for its variant letter, Y.

The UH-1Y is currently in full-rate production to replace the USMC's aging fleet of UH-1N Twin Huey light utility helicopters first introduced in the early 1970s. The UH-1Y was to have been remanufactured from UH-1Ns, but in 2005 it was approved for the aircraft to be built as new.

Development of Bell UH-1Y Venom

In 1996, the United States Marine Corps launched the H-1 upgrade program by signing a contract with Bell Helicopter for upgrading 100 UH-1Ns into UH-1Ys and upgrading 180 AH-1Ws into AH-1Zs. The H-1 program created completely modernized attack and utility helicopters with considerable design commonality to reduce operating costs. The UH-1Y and AH-1Z share a common tail boom, engines, rotor system, drive train, avionics architecture, software, controls and displays for over 84% identical components.

The Y-model updates an airframe that has been central to the Marine Corps aviation in Iraq. The Huey has many mission requirements including command and control (C2), escort, reconnaissance, troop transport, medical evacuation and close air support. Typically detachments of 2-4 Hueys have been deployed with detachments of 4-8 Cobras. The forward mounted weaponry of the Cobra combined with the door guns of the Huey provides a 240° field of fire.

Over the years new avionics and radios, in addition to modern door guns and safety upgrades, have greatly increased the UH-1N's empty weight. With a maximum speed of approximately 100 knots (190 km/h) and an inability to lift much more than its own crew, fuel and ammunition, the UH-1N, while useful, is limited in its utility.

The Y-model upgrades pilot avionics to a glass cockpit, adds further safety modifications and provides the UH-1 with a modern FLIR system. However, the biggest improvement is an increase in engine power. By replacing the engines and the two bladed rotor system with four composite blades the Y-model will return the Huey to the utility role for which it was designed. Originally the UH-1Y was to have been remanufactured from UH-1N airframes, but in April 2005 approval was granted to build them as new helicopters.

Bell delivered two UH-1Ys to the U.S. Marine Corps in February 2008. As of September 2009, the UH-1Y is in full-rate production, with the Marine Corps expected to have 21 by the end of the year. The Marine Corps plans to eventually buy 160 of the Y-models to replace their inventory of N-models, with aircraft deliveries to be completed by 2016.

Bell UH-1Y Venom Design

The UH-1Y variant modernizes the UH-1 design. Its most noticeable upgrade over previous variants is a four-bladed, all-composite rotor system designed to withstand ballistics up to 23 mm. A 21-inch (530 mm) insert just forward of the main door has been installed for more capacity. The UH-1Y features upgraded engines and transmission, a digital cockpit with flat panel multifunctional displays, and an 84% parts commonality with the AH-1Z. Compared to the UH-1N, the Y-model has an almost 125% increased payload, almost 50% greater range, a reduction in vibration, and higher cruise speed. The UH-1Y can keep up with the other helicopters it is escorting. The UH-1Y will have more power to maneuver. Ground forces commanders riding in the Y-model will have radios, firepower and the range to match the transport helicopters carrying their troops.

The Lockheed Martin target sight system (TSS) incorporates a third-generation FLIR sensor. The TSS provides target sighting in day, night or adverse weather conditions. The system has various view modes and can track with FLIR or by TV. It is also used on the AH-1Z Viper and the KC-130J Harvest HAWK.

Bell UH-1N Twin Huey

The Bell UH-1N Twin Huey is a medium military helicopter that first flew in April, 1969. The UH-1N has a fifteen seat configuration, with one pilot and fourteen passengers. In cargo configuration the UH-1N has an internal capacity of 220 ft³ (6.23 m³). An external load of 5,000 lb (2,268 kg) can be carried by the UH-1N. The CUH-1N (later CH-135) Twin Huey was the original version, first ordered by the Canadian Forces.

Development

Based on the stretched fuselage Bell 205, the Bell 212 was originally developed for the Canadian Forces (CF) under the designation CUH-1N Twin Huey. Later the CF adopted a new designation system and the aircraft was re-designated as the CH-135 Twin Huey. The CF approved the development of the aircraft on 1 May 1968 and purchased 50 aircraft, with deliveries commencing in May 1971.

The US military came very close to not procuring the Twin Huey. The purchase of the aircraft for US military use was opposed by the Chairman of the House Armed Services Committee at the time, L. Mendel Rivers. Rivers took this position because the aircraft powerplant, the Pratt & Whitney Canada PT6T was produced in Canada. The Canadian government had not supported US involvement in Vietnam and had opposed US policies in southeast Asia, as well as accepting US draft dodgers. Rivers was also concerned that procurement of the engines would result in a negative trade deficit situation with Canada. Congress only approved the purchase when it was assured that a US source would be found for the PT6T/T400 engines. As a result the United States military services ordered 294 Bell 212s under the designation UH-1N, with deliveries commencing in 1970.

Unlike in the Canadian Forces, in US service, the UH-1N retained the official name "Iroquois" from the single engined UH-1 variants, although US service personnel refer to the aircraft as a "Huey" or "Twin Huey". The Bell 412 is a further development of the Bell 212, the major difference being the composite four-blade main rotor. The UH-1N has also been developed into the upgraded, four-blade UH-1Y

Design

The UH-1N's main rotor is powered by a PT6T-3/T400 Turbo Twin Pac made up of two Pratt & Whitney Canada PT6 turboshaft power turbines driving a single output shaft. They are capable of producing up to 1,342 kW (1,800 shp). Should one engine fail the remaining engine can deliver 671 kW (900 shp) for 30 minutes or 571 kW (765 shp) enabling the UH-1N to maintain cruise performance at maximum weight.

The United States Marine Corps (USMC) modified a large number of their UH-1Ns with a Stability Control Augmentation System (SCAS) which provides servo inputs to the rotor head to help stabilize the aircraft during flight. This modification removed the gyroscopic "Stabilization Bar" on top of the main rotor head, instead relying on the computer system for stability.

Variants

U.S. variants

UH-1N Iroquois

Initial production model, used by the USAF, USN, and USMC. Over the years the primary operators, the USMC has developed a number of upgrades for the aircraft including improved avionics, defenses, and a FLIR turret. The USAF plans to replace their UH-1Ns with the Common Vertical Lift Support Platform to support the service's ICBM activities.

VH-1N

VIP transport configuration

HH-1N

SAR variant.

UH-1Y Venom

A UH-1N replacement and upgrade as part of the H-1 upgrade program for the USMC, designed to coincide with a similar upgrade for the AH-1W attack helicopter to AH-1Z Viper standard, with common engines and other major systems.

Canadian variants

CUH-1N Twin Huey

Original Canadian Armed Forces designation for the UH-1N utility transport helicopter.

CH-135 Twin Huey

Canadian version of the UH-1N. Canada purchased 50 CH-135s with deliveries starting in 1971. The aircraft were retired from the Canadian Forces starting in 1996 and struck off strength in December 1999. 41 of the surviving CH-135s were acquired by the US government in December 1999 and transferred to the National Army of Colombia and Colombian National Police. At least one CH-135 was destroyed in combat. 135135 was transferred to the Colombian National Police and flown by the Dirección Antinarcóticos (DIRAN). It was destroyed on the ground by FARC rebels on 18 January 2002, following an incident in which it was forced down by gunfire. Two CH-135s are on display in museums, one at the Canada Aviation Museum in Ottawa and one at the National Air Force Museum of Canada at CFB Trenton.

Italian-built variants

Agusta-Bell AB 212

Civil or military utility transport version. Built under license in Italy by Agusta.

Agusta-Bell AB 121EW

Electronic warfare version for Turkey.

Agusta-Bell AB 212ASW

Anti-submarine warfare, anti-shipping version of the AB 212 helicopter, built under license in Italy by Agusta. Operated by the Italian Navy, Hellenic Navy and Islamic Republic of Iran Navy, Peru, Spain, Turkey, and Venezuela.

The AB-212ASW is a Model 212 Twin Huey with a prominent radome above the cockpit. Early production had a dome-shaped radome, while later production had a flatter "drum" radome. A left side winch is used for dipping the Bendix ASQ-18 sonar. Other changes include structural reinforcement for a gross weight of 11,197 lbs (5080 kg), ECM, shipboard deck tie-down attachments and corrosion protection. Armament is two Mk 44 or Mk 46 torpedoes or two depth charges in the ASW role and four AS.12 air-to-surface wire-guided missiles for the anti-shipping role.

UH-72A Lakota

The US Army's LHX program began in the early 1980s, proposing two helicopter designs with a high percentage of commonality of dynamic components. One was a light utility version ("LHX-U") for assault and tactical movement of troops and supplies, the other was a light scout/attack version ("LHX-SCAT") to complement the growing development of the AH-64 Apache. As the program was developed, the light utility version was dropped and focus was placed on the light attack reconnaissance version, which eventually became the RAH-66 Comanche.

In 2004, the Department of Defense and the US Army made the decision to terminate the RAH-66 program. As part of the termination, the Army was allowed to keep the future years' funding programmed for the Comanche. To replace the capability that the Comanche was supposed to offer, the Army planned several programs, including three new aircraft. The Army Staff decided that these three aircraft, the Armed Reconnaissance Helicopter (ARH), the Light Utility Helicopter (LUH), and the Future Cargo Aircraft (FCA) (later renamed Joint Cargo Aircraft, or JCA), were to be existing, in-production commercial aircraft modified for Army service.

The LUH program was initiated in early 2004, with an initial stated requirement for 322 helicopters to conduct Homeland Security, administrative, logistic, Medical Evacuation (MEDEVAC) and support of the Army Test and Training Centers missions. The LUH contract was released in late July 2005. At least five proposals were received. The competitors included the Bell 210 and Bell 412, MD Explorer and AW139. EADS North America (EADS NA) marketed the UH-145 variant of the EC 145 for the program.

On 30 June 2006, the Army announced that the EADS NA entry had won the competition for the LUH contract, the value for which was estimated as being worth over $3 billion. In August, the UH-145 airframe was officially designated the UH-72A by the Department of Defense. The UH-145 award was confirmed in October 2006 following protests from losing bidders.

Despite the impact of the four-month delay associated with the protests, EADS NA was still able to deliver the first UH-72 on time during a ceremony in December, at which time the name Lakota was also formally announced for the type, in line with the Army's long-standing tradition of giving its helicopters Native American names. The LUH marked EADS NA's largest DoD contract to date, and added to existing programs including the U.S. Coast Guard's HH-65 Dolphin and HC-144A and various other defense and security systems contracts.

The Lakota received full rate production (FRP) approval on 23 August 2007. This will allow the Army to buy the full quantity of aircraft, planned at 345 through 2017 as of June 2008. The UH-72A is being produced at American Eurocopter's facility in Columbus, Mississippi. Production was transitioning from local assembly of aircraft kits received from Eurocopter Deutschland to full local production, which was slated to begin in March 2009. In December 2009, the Army ordered 45 more UH-72As to increase the order total to 178. The 100th Lakota was delivered in March 2010 from EADS NA to the US Army. By late August 2011, 180 had been delivered.

Operational History

The first aircraft was delivered to the United States Army on 11 December 2006 in Columbus, Mississippi. On 12 December 2006, General Richard A. Cody, Vice Chief of Staff of the Army, and Joe Red Cloud, a chief of the Oglala Sioux Tribe, Lakota nation, accepted the first UH-72A in an official ceremony. The Army estimated that delivery of the planned 345 aircraft would continue until 2017.

The first production helicopters were sent to the National Training Center (NTC), Fort Irwin, California for medical evacuation missions in January 2007. On 20 June 2007, the NTC's United States Army Air Ambulance Detachment (USAAAD) became the first operational unit to field the Lakota. On 10 July 2007, the Training and Doctrine Command (TRADOC) Flight Detachment at Fort Eustis, Virginia became the second Army unit fielded with the UH-72A.

A report published in August 2007, by the Operational Test and Evaluation Directorate (DOT&E) noted that, although the Lakota "is effective in the performance of light utility missions" it was prone to overheating during operations in the desert conditions of Fort Irwin, when not equipped with air conditioning systems. In response, vents were added in the doors to increase cabin air flow; air conditioning has been installed on some Medical and VIP versions also added air conditioning units for crew comfort.

The Joint Readiness Training Center (JRTC) located at Fort Polk, Louisiana received their first aircraft on 7 September 2007. On 16 January 2009, the United States Military Academy received two UH-72As, replacing two UH-1H helicopters for VIP transport to and from the academy. The helicopters also support the cadet parachute team and cadet training missions. The U.S. Naval Test Pilot School received the first of five UH-72As in September 2009. The UH-72A replaced the TH-6B Cayuse as the prime training aircraft for the test pilot school's helicopter curriculum.

By March 2010, the Lakota entered service in Puerto Rico, Kwajalein Atoll, and the U.S. Army’s missile test range in Germany. On 20 December 2010, a UH-72A assigned to the Puerto Rico National Guard became the first UH-72A to experience a fatal accident. The aircraft crashed at sea off the coast of Puerto Rico, and all six personnel aboard were killed.