Sikorsky CH-53 Sea Stallion

Sikorsky CH-53 Sea Stallion

The CH-53 Sea Stallion is the most common name for the Sikorsky S-65 family of heavy-lift transport helicopters. Originally developed for use by the United States Marine Corps, it is also in service with Germany, Iran, Israel, and Mexico. The United States Air Force operated the HH-53 "Super Jolly Green Giant" during the late- and post-Vietnam War era, updating most of them as the MH-53 Pave Low.

The dimensionally-similar CH-53E Super Stallion is a heavier-lifting, improved version designated S-80E by Sikorsky. Its third engine makes it more powerful than the Sea Stallion, which it has replaced in the heavy-lift mission.

Development

In 1960, the United States Marine Corps began to seek a replacement for their HR2S piston-powered helicopters. On 27 January 1961, the Marine Corps began working with the other three U.S. armed services on the "Tri-Service VTOL transport", which would eventually emerge as the Vought-Hiller-Ryan XC-142A tiltwing. The design became more elaborate and the program stretched out, causing the Marines to drop out when they decided they would not receive a working machine in a satisfactory timeframe. In the end, the XC-142A, although a very innovative and capable machine, never entered production.[1]

In March 1962, the US Navy's Bureau of Naval Weapons, acting on behalf of the Marines, issued a request for a "Heavy Helicopter Experimental / HH(X)". The specifications dictated a load capability of 8,000 pounds (3,600 kg) with an operational radius of 100 nautical miles (190 km; 120 mi) at a speed of 150 knots (280 km/h; 170 mph). The HH(X) was to be used in the assault transport, aircraft recovery, personnel transport, and medical evacuation roles. In the assault transport role, it was to be mostly used to haul heavy equipment instead of troops.[1]

In response, Boeing Vertol offered a modified version of the CH-47 Chinook; Kaman Aircraft offered a development of the British Fairey Rotodyne compound helicopter; and Sikorsky offered what amounted to a scaled-up version of the S-61R, with twin General Electric T64 turboshafts and the dynamic system of the S-64, to be designated the "S-65". Kaman's proposal quickly died when the British government dropped its backing of the Rotodyne program. Competition between Boeing Vertol and Sikorsky was intense, with the Chinook having an advantage because it was being acquired by the United States Army. Sikorsky threw everything into the contest and was awarded the contract in July 1962.[1]
The YCH-53A prototype in 1964

The Marines originally wanted to buy four prototypes but ran into funding problems. Sikorsky, determined to keep the deal, cut their estimate for development costs and said that the program could be done with two prototypes. The military bought off on the proposal, and in September 1962 Sikorsky was awarded a contract for a little under US$10 million for two "YCH-53A" prototypes, as well as a mockup and a ground-test airframe.[1]

The development program did not go entirely smoothly, due to a shortage of engineering resources plus various failures of subcontractors and the government, but these problems were gradually overcome. There was also the problem that U.S. Secretary of Defense Robert S. McNamara was pushing to maintain "commonality" between the armed services by using the Chinook, but the Marines managed to convince McNamara's staff that the Chinook could not meet their requirements without numerous expensive changes.[1]

All these obstacles overcome, the first YCH-53A performed its initial flight at the Sikorsky plant in Stratford, Connecticut, on 14 October 1964, about four months behind schedule. The Marines had already placed an initial production contract for 16 helicopters in September. Flight trials went more smoothly than expected, helping make up for the lost time in development. It received the military designation and name "CH-53A Sea Stallion".[1] Delivery of production CH-53s began in 1966.[2]

The CH-53A arrived in Vietnam in January 1967 and proved useful, eventually recovering even more downed aircraft than the CH-54. A total of 141 CH-53As were built, including the two prototypes.[1] The United States Navy acquired 15 CH-53As from the USMC in 1971 for airborne mine countermeasures (AMCM) activities. The helicopters had more powerful T64-GE-413 turboshafts installed and the received the designation "RH-53A".[1]

The United States Air Force ordered the HH-53B in September 1966 and first flew on 15 March 1967. It added a refueling probe, drop fuel tanks and a rescue hoist and featured upgraded T64-GE-3 engines. The Air Force used the HH-53B for combat search and rescue (CSAR).[3] HH-53C was an improved CSAR variant with a smaller 450 US gallons (1,700 L) for improved performance. It also added more armor and better communication systems. The CH-53C was similar except it lacked a refueling probe. It was used by the USAF for more general transport work.[4]
HMH-362 CH-53Ds landing

Heavy lifting in tropical climates demanded more power, so the Marines decided to acquire an improved variant, the "CH-53D", with uprated engines, originally the T64-GE-412 then later the T64-GE-413. The CH-53D also included an uprated transmission to go with the more powerful engines, and a revised interior to permit a load of 55 troops.[1]

The initial flight of the CH-53D was on 27 January 1969. The CH-53D served alongside the CH-53A through the rest of the Vietnam War. A VIP transport version designated, "VH-53D" with plush accommodations was used by the Marines for the US presidential flights.[1] The US Navy also acquired CH-53D based helicopters for mine sweeping. These were designated "RH-53D" and included mine sweeping gear such as a pair of 0.50 BMG (12.7 mm) Browning machine guns for detonating mines. The Navy received 30 RH-53Ds beginning in 1973. After the RH-53Ds were in service, the RH-53As were handed back to the Marines and restored to CH-53A configuration.[1]

During the 1980s, Israeli Air Force's CH-53 Yas'ur fleet was upgraded and improved by Israel Aircraft Industries, along with military high-tech firm Elbit Systems. The project – which ended only in 1997 – improved the CH-53 avionics, robustness and extended its life span by at least two decades.

In 1989, some of the CH-53As being retired by the Marines were passed on to the U.S. Air Force for training, with these helicopters redesignated "TH-53As". The TH-53As were stripped of most operational equipment and painted in USAF camouflage colors.[1]
[edit] Design

The Sea Stallion has a fuselage design similar to the Sikorsky S-61R/Jolly Green Giant series. It has a passenger door on the right side of the fuselage behind the cockpit and a power-operated rear loading ramp. The fuselage was watertight, though not intended for amphibious use, and only landed on water in emergencies. The Stallion has mechanical flight controls which are backed by three independent hydraulic systems. Armor protects crew and vital systems.[1]

The CH-53A carries a crew of four; pilot, copilot, crew chief, and an aerial observer, a load of 38 troops, 24 litters with medical attendants, an internal cargo load of 8,000 pounds (3,600 kg) or an external load of 13,000 pounds (5,900 kg) on the single-point sling hook. The CH-53A is equipped with a pair of 7.62 mm M60 machine guns that point out to each side of the fuselage.[1]

The CH-53A features the six-bladed main rotor and four-bladed tail rotor from the S-64 Skycrane. To save space on board naval vessels, the tail boom and the rotors folded. The rotor system was initially driven by twin General Electric T64-6 turboshaft engines providing 2,850 shaft horsepower (2,130 kW) each, with an engine on each side of the forward fuselage. It was later produced with the T64-1 with 3,080 shp (2,300 kW) and then the T64-16 with 3,485 shp (2,599 kW).[1] The HH-53B featured T64-3 engines producing 3,080 shp (2,300 kW).[4]
CH-53D releasing flares near Naval Air Station Patuxent River, 1982.

The CH-53D features uprated engines, initially T64-GE-412 with 3,695 shp (2,755 kW) then the T64-413 with 3,925 shp (2,927 kW) with an uprated transmission. Its interior added seats to allow for 55 troops. CH-53Ds are generally armed with twin .50 BMG (12.7 mm) M2/XM218 machine guns. In later years, CH-53Ds have been fitted with defensive countermeasures including an AN/ALE-39 chaff dispenser and an AN/ALQ-157 infrared countermeasure.[1]

Later production CH-53Ds featured a Blade Inspection Method (BIM) scheme to detect cracks in its metal rotors. BIM involved pressurizing the interior of the rotor blades with nitrogen. If a crack is present pressure is lost and a red indicator on the rotor blade tip was tripped. Later, the BIM system was connected to a cockpit display. BIM reduced the need to swap out rotor blades on a routine basis.[1]
[edit] Operational history
[edit] United States
A CH-53 performing a helocast insertion during training off Hawaii

The CH-53/HH-53 has had much combat experience during its lengthy service, with the U.S. military during the Vietnam War and as a Special Operations helicopter, and the Israeli Air Force.

The CH-53D served alongside the CH-53A through the rest of the Vietnam War, with both types performing a final service at the end of the conflict in performing evacuations of personnel from Saigon and Phnom Penh.[1]

U.S. Air Force HH-53 Super Jollies were the primary search-and-rescue helicopter in Southeast Asia between 1967 and 1975, inserted the Operation Ivory Coast rescue team into the North Vietnamese prison camp at Son Tay in 1970, and carried the Marines who attempted to rescue the crew of the SS Mayagüez. Marine-flown Navy Sea Stallions were the rotary-wing element of Operation Eagle Claw, the attempted rescue of American hostages in Iran in 1980 that ended in disaster and embarrassment at "Desert One".

The CH-53 is operated by the United States Marine Corps and Air Force in support of Operation Iraqi Freedom and Operation Enduring Freedom in Iraq and Afghanistan. It is also operated by the Navy in support of Operation Iraqi Freedom and Operation Enduring Freedom throughout the region, deployed out of a squadron in Bahrain.

On 12 October 2004 Heavy Lift Helicopters of Apple Valley, California received the first of two CH-53D Sea Stallions from Davis-Monthan Air Force Base for conversion into firefighting aircraft. This modification yields a "Fire Stallion."[5]

On 17 September 2007, VMM-263 of the Marine Corps was deployed with ten MV-22B Ospreys, a tiltrotor aircraft.[6] V-22 Ospreys will replace the Marine Corps CH-46Es and CH-53Ds, but not their CH-53Es. The new CH-53K is planned to supplant the Navy and Marine Corps' CH-53Es by 2015.
[edit] Israel
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In August 1968, an IAF delegation went out to the Sikorsky plant in Connecticut, USA, to choose the IAF's next assault helicopter. The delegation was looking for a helicopter with augmented payload carry capacity, highly maneuverable and robust, that could survive direct hits from different caliber projectiles. They examined Boeing's CH-47 Chinook, and Sikorsky's CH-53. Lessons that had been learned in the Six Day War led the delegation to choose the Sikorsky.

The CH-53 was bigger and stronger than the IAF's other helicopters, and represented a new generation of assault helicopters - a leap forward in terms of rescue operations, transport missions and tactical troop landings.

In September 1969, in the course of the War of Attrition, the first two CH-53s arrived at the port of Ashdod, and received their Hebrew name, Yas'ur (Petrel). They were sent into action in short order. On August 6, 1970 the first Yas'ur squadron was established. They are the main cargo helicopters of the IAF, carrying troops and heavy equipment.

In 1969, during the War of Attrition, IAF Yas'ur CH-53s landed in Egypt and conveyed a captured Soviet advanced radar system back to Israel for examination by Israeli scientists and engineers (see Operation Rooster 53).[7] In the 1973 Yom Kippur War, the Yas'urs moved artillery batteries around the fronts, evacuated wounded soldiers and rescued pilots from behind enemy lines. In one engagement, a Yas'ur was damaged by cannon fire from a MiG-21 but returned safely to base. Since 1973, Yas'urs have also been used by the IDF to land and extract Sayeret commandos on deep raids into Lebanon and Syria.

During the 1980s, Israel Aircraft Industries, along with military high-tech firm Elbit Systems, upgraded and improved the IAF Yas'ur fleet. The project, ended in 1997, improved the CH-53 avionics, robustness and extended its life span by at least two decades.

In 1989, Yas'urs were used to fight a huge blaze on Mount Carmel. They performed dozens of low flyovers into the smoke and flames, dumped 700 tons of water on the fire, and doused it.
[edit] Germany
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German Army CH-53G at RIAT 2010
A German Army door gunner mans an M3M onboard a CH-53

In 1966 the German military evaluated both the CH-53 and CH-47 Chinook as a replacement for the H-21 and H-34G helicopters with an initial requirement for 133.[8] The purchase of the CH-53 was approved in June 1968 but due to budget constraints only 110 were ordered.[8] Following the delivery in 1969 of two pre-production helicopters from Sikorsky the production aircraft were licence built by VFW-Fokker at Speyer in Germany.[8] The first German-built helicopter flew from Speyer on 11 October 1971 and was delivered to the Erprobungsstelle der Bundeswehr 61 flight test centre at Manching on 1 December 1971.[8]

The German Army flying units received 110 type CH-53Gs. Except for the first two, all machines were built in Germany. The first flight made by a German CH-53G was made in 1971, followed in March 1973 by the delivery of the first machines to The 35th Army Flying Regiment in Mendig, and shortly afterwards to the newly formed 15th Army Flying Regiment.

In order to meet ever more demanding specifications, over time the CH-53G received modifications designed to improve its service life and operational capabilities. These involved three major upgrades: new missile warning and self-protection systems; provision for two external fuel tanks allowing range to be increased to 1800 km when carrying 36 armed soldiers or a 5500-kg payload; and addition of a night vision goggles-compatible cockpit for night low-level flying capabilities. All CH-53Gs were upgraded by Eurocopter Germany by early 2001.

German flying units have carried out a whole range of international missions under the auspices of NATO and the UN, in Kosovo (KFOR) and also with IFOR, and more recently with ISAF in Afghanistan. Due to the lower cargo capacities of the NH-90, service life extensions for at least a portion the CH-53 fleet are envisioned, bringing its useful life out to approximately the year 2030.
[edit] Variants
A CH-53D in Iraq, June 2006
VH-53D used by HMX-1
CH-53G of the German Army Aviation Corps during an exercise in Bosnia

YCH-53A
Two prototypes with two 2,850 shp (2,130 kW) T64-GE-3 engines.

CH-53A
Initial production for USMC, 139 built.

RH-53A
CH-53A re-engined with two 3,925 shp (2,927 kW) T64-GE-413 engines as Airborne mine countermeasures (minesweeper) versions for the United States Navy, 15 conversion.

TH-53A
Stripped CH-53As used for training by the United States Air Force.

CH-53D
CH-53A with improved transmission, larger cabin for 55 troops and automatic rotor blade folding for the United States Marine Corps, 126 built.

RH-53D
United States Navy mine countermeasures version of the CH-53D, fitted with 0.50 in guns and provision for air refueling, 30 built for the USN and six for Imperial Iranian Navy Aviation (since 1979, the Islamic Republic of Iran Navy Aviation).

VH-53D
Two CH-53Ds for USMC VIP transport

CH-53D Yas'ur
CH-53D exported to Israel. The Yas'ur 2000 version are helicopters upgraded and improved by the Israel Aircraft Industries to extend life span past 2000. The Yas'ur 2025 is a further upgraded version with new systems and new gearboxes.[9]

VH-53F
Six unbuilt VIP helicopters for the US Navy/Marine Corps.

CH-53G
German base version of the CH-53D for German Army Aviation Corps. A total of 112 were produced including 2 pre-production and 20 assembled by VFW-Fokker and 90 built by Sprey.[10] As of 2007[update], 89 German CH-53s were in service, with 80 planned to be in service in 2014. All German CH-53s are going to receive T64-100 engines (in 3 batches, 1st batch has already been installed, 2nd batch is currently being installed and 3rd batch is planned with funding made available). All will receive IFR-capability.[11]

CH-53GS
Update of 20 CH-53Gs with additional missile counter measure, upgraded communication and navigation system and two external fuel tanks in late 1990s.[10] They later received the first batch of T64-100 engines to operate in hot&high conditions as they prevail in Afghanistan as well as MG3 and M3M machine guns.[12] A CH-53GS/GE update has also been ordered to provide combat search-and-rescue (CSAR) capability to 26 helicopters.[13][14][15]

CH-53GE
A configuration based on CH-53GS combat search-and-rescue (CSAR) capabilities.[13] The upgrade configuration was formerly known as CH-53GSX.[citation needed] It further updates with modern electronics, two external fuel tanks, counter measures and dust filters for the engines. Upgrade was ordered to support Afghanistan deployment.[12]

CH-53GA
Update of further 40 CH-53Gs with new flight deck, new flight control system, autopilot, navigation and communication systems, FLIR, ECM and missile counter measures as well as provisions for additional internal fuel tanks. The CH-53GA helicopter successfully completed its first flight in February 2010.[16] The upgrade is to be completed in 2013.[17]

For other variants, see HH-53 "Super Jolly Green Giant"/MH-53 Pave Low and CH-53E Super Stallion.

[edit] Operators
CH-53 (dark blue) & CH-53E (light blue) operators (former operators in red)
Israeli Air Force CH-53D Yas'ur

Austria

* Austrian Air Force ordered two in 1968; took delivery in 1970; sold them to Israel in 1981 because of their high operating costs.

Germany

* German Army has 96 in service as of November 2008.[18]

Mexico

* Mexican Air Force acquired four S-65C Ya’sur 2000s from Israel in 2005,[19] and all are in service as of November 2008.[18]

Iran

* Iranian Navy received 6 RH-53Ds mine sweepers that were acquired before the Iranian Revolution.[2] Iran also gained four to five more RH-53s during Operation Eagle Claw.[citation needed] Islamic Republic of Iran Navy Aviation has 2 RH-53Ds in use as of January 2010.[20]

Israel

* Israeli Air Force has 33 CH-53s in service as of November 2008.[18]

United States

* United States Marine Corps has 178 CH-53D/E helicopters in inventory as of November 2008.[18]
* Heavy Lift Helicopters[5][dead link]

[edit] Accidents and incidents

Due to its large size and troop capacity, aerial accidents that involve CH-53 helicopters were some of the deadliest helicopter accidents ever.

* On 10 May 1977, 54 people were killed in a CH-53 crash in Israel.
* On 4 February 1997, two CH-53s collided in the "Helicopter Disaster" in Israel. A total of 73 people died in the accident.[21]
* On 26 July 2010, an Israeli CH-53 crashed during joint military exercises in Romania. Its crew of six Israeli airmen and one Romanian military observer died in the accident.[22]

[edit] Specifications (CH-53D)
A CH-53 from HMH-462 rests on a landing mat at a mountain-top fire support base in Vietnam in 1968.

Data from Deagel.com,[23] U.S. Navy history,[24] International Directory,[2] US Navy Fact File[25][26]

General characteristics

* Crew: 2 pilots, 1 or more crew chiefs
* Capacity: 38 troops (55 in alternate configuration) or 24 stretchers
* Length: 88 ft 6 in (26.97 m)
* Rotor diameter: 72 ft 2.8 in (22.01 m)
* Height: 24 ft 11 in (7.6 m)
* Disc area: 4098.1 sq ft ()
* Airfoil: NACA 0011 MOD
* Empty weight: 23,628 lb (10,740 kg)
* Loaded weight: 33,500 lb (15,227 kg)
* Useful load: 8000 lb ()
* Max takeoff weight: 42,000 lb (19,100 kg)
* Powerplant: 2× General Electric T64-GE-413 turboshaft, 3,925 shp (2,927 kW) each
* Width (stub wings): 28 ft 4 in (8.64 m)
* Width (fuselage): 15 ft 6 in (4.7 m)
* Rotor systems: 6 blades on main rotor

Performance

* Maximum speed: 170 knots (196 mph, 315 km/h)
* Cruise speed: 150 kt (173 mph, 278 km/h)
* Range: 540 nmi (1,000 km)
* Combat radius: 100 mi () 95 mi
* Ferry range: 886 nmi (1,640 km)
* Service ceiling: 16,750 ft (5,106 m)
* Rate of climb: 2,460 ft/min (12.5 m/s)
* Disc loading: 8.95 lb/sq ft ()

Armament

* Two door mounted .50 BMG XM218 machine guns. Some have a ramp mounted .50 BMG GAU-21 machine gun.
* German CH-53Gs can mount two 7.62 mm MG3 machine guns in the side doors, which are to be replaced by two .50 BMG M3M/GAU-21 machines guns in the doors and one on the ramp.