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[2.0] Sikorsky S-70B Seahawk / Variant Summary

v1.0.0 / 01 oct 03 / greg goebel / public domain

* When the US Army decided to acquire the Black Hawk, the US Navy decided to acquire a modified version, the "S-70B Seahawk", for maritime warfare and other roles. This chapter discussed the Seahawk branch of the family, and also provides a summary list of Black Hawk and Seahawk variants.

[2.1] US NAVY S-70B / SH-60B SEAHAWK

[2.1] US NAVY S-70B / SH-60B SEAHAWK

* The US Navy had obtained good and useful service from their "Light Airborne Multipurpose System (LAMPS)" helicopter, based on the Kaman Seasprite and introduced in the early 1970s. The Seasprite LAMPS Mark I featured a sophisticated avionics suite and was optimized for the maritime warfare role, with a secondary SAR capability.

Improvements in sensors and other avionics gear led to consideration of a Seasprite-based "LAMPS Mark II", but the Seasprite simply wasn't big enough to carry the gear required by the Navy, and so the service began to cast around for a more capable helicopter as the basis for a "LAMPS Mark III". LAMPS III would provide an over-the-horizon search and strike capability for US Navy frigates and destroyers. The Army was just beginning evaluation of the Sikorsky UH-60A and Boeing-Vertol UH-61A for the UTTAS competition, providing two candidates for the LAMPS III requirement.

In 1977 the Navy performed an evaluation of the two types of helicopters. The Sikorsky entry, which had been modified to naval requirements and given the company designation "S-70L" (later "S-70B"), was selected as the winner of the competition on 1 September 1977, leading to award of a full development contract on 28 February 1978. The Navy was influenced in their decision by the Army's selection of the Sikorsky entry. IBM Federal Systems was to integrate the LAMPS avionics system, which the company had been developing since 1974.

Five "YSH-60B Seahawk LAMPS III" prototypes were ordered, with the first performing its initial flight on 12 December 1979, though it was not fitted with much of its operational avionics suite. The first production "SH-60B" performed its first flight on 11 February 1983, and the type was in operational service in 1984. First operational deployment was in early 1985.

* The Seahawk's general lines are very similar to those of its Army Black Hawk brother. The external dimensions are the same, and there is 83% parts commonality between Army and Navy machines. However, there are clear differences as well. Some of the differences are hard to see. For example, the airframe is corrosion-protected and fitted with buoyancy elements for maritime operation. Other subtle changes include:

Some of the other changes are more obvious. The most important is the LAMPS electronics suite, which includes:

There is a stub pylon behind the cabin door on each side for carriage of a total of two Mark 46 homing torpedoes or two 455 liter (120 US gallon) external fuel tanks.

The fact that the Seahawk has a bigger kit of built-in gear makes its empty weight substantially greater than that of the Black Hawk, 6,190 kilograms (13,650 pounds) versus 4,820 kilograms (10,625 pounds). The Seahawk's maximum takeoff weight is also greater, at 9,925 kilograms (21,885 pounds), compared to the Black Hawk's 9,185 kilograms (20,250 pounds).

The Seahawk was originally fitted with uprated GE T700-GE-401 turboshafts, with 1,260 kW (1,690 SHP) each, to handle the greater weight. The engines are also corrosion-protected for maritime operation. The transmission system was uprated to handle the more powerful engines. The engines were later upgraded to T700-GE-401Cs with 1,420 kW (1,900 SHP) each. Top speed is lower due to the heavier weight and greater external clutter of the Seahawk.

The Seahawk's landing gear is its most obvious distinguishing element. It features a two-wheel tailwheel, moved forward to the rear of the main fuselage, and taller main gear to permit clearance for the drum radome. The landing gear is simplified compared to the Black Hawk, as the heavy-duty shock absorber system of the Army version was judged unnecessary. The window and door arrangement was also substantially modified, with the door on the left eliminated and the door on the right reduced in size.

Three crew are normally carried, including a pilot, a copilot / airborne tactical officer, and sensor operator ("senso"). Most of the data is transferred to the parent vessel for processing, but the crew handles the terminal attack themselves. The Seahawk can be fitted with an external rescue hoist on the right side to support its secondary SAR role, as well as belly cargo sling hook for "vertical replenishment (vertrep)" missions.

* A total of 150 SH-60Bs had been delivered by the mid-1990s against a total requirement of 260. During operations in the Persian Gulf from 1987, a total of 25 SH-60Bs were fitted with countermeasures and other enhancements under the "Middle East Force Modification (MEF-MOD)" program, which included:

The Seahawk served with distinction in the Gulf War, flying boarding parties to support blockade operations; flying mine patrols; performing CSAR operations, rescuing an F-16 and an AV-8B pilot; transporting SEAL teams on special operations; and providing defensive sensors for US Navy surface elements. Seahawks carried an oversized chaff round named an AIRBAC that was ejected from a sonobuoy tube, providing a heavy cloud of chaff to frustrate Iraqi antiship missiles, which actually did not turn out to be much of a threat.

Even before the Gulf War, a "Block I" SH-60B upgrade was underway, featuring avionics enhancements such as a GPS navigation receiver and dual MIL-STD 1553B digital avionics buses; provision for mounting a GECAL 50 12.7 millimeter machine gun; and support for the improved "Mark 50 Barracuda" torpedo, which can dive deeper and has a smarter seeker than the older Mark 46, and for the AGM-199B Mark 2 Mod 7 Penguin antiship missile. The left stub stores pylon was extended to allow carriage of an external fuel tank along with the traditional two stores. The right stub pylon could not be extended since it would get in the way of the rescue hoist.



* The US Navy also acquired another version of the S-70B for the close-in carrier group antisubmarine warfare, with this variant designated the "SH-60F Ocean Hawk". The Ocean Hawk deletes the RAST gear, which is not required as the SH-60F operates off carrier decks, and replaces the LAMPS III suite with a much less elaborate offensive avionics suite, centered around a Bendix AN/AQS-13F dipping sonar. Radar, ESM, and the datalink were deleted. The sonobuoy array was deleted, but there is a sonobuoy tube in the floor of the cabin, and a rack of eight sonobuoys that can be dropped manually through the tube.

The SH-60F also has a wider left stores pylon, allowing the helicopter to carry a total of three Mark 50 homing torpedoes, or two torpedoes and an external fuel tank. The SH-60F has a sling hook to allow it to perform vertrep duties.

In addition, the Ocean Hawk serves as a "plane guard", standing by during carrier takeoff and recovery operations to pick up pilots who end up in the drink. It is fitted with a rescue hoist on the right side for this role. Initial flight of an SH-60F was on 19 March 1987, with the type going into service in 1991, just in time for Gulf War service.

* The Navy also used the S-70B airframe as the basis for its own covert operations / CSAR variant, the "HH-60H Rescue Hawk". Unlike its Army and Air Force counterparts, it does not have an inflight refueling probe, though it can be fitted with external tanks. It does have:

Of course, the Rescue Hawk has an external rescue hoist on the right side of the machine. A 7.62 millimeter M-60D machine gun was originally fitted on a pintle mount in each door (the HH-60H has doors on each side but no forward window in which to mount a gun), but these were upgraded to more potent GECAL 12.7 millimeter machine guns. Initial flight of the HH-60H prototype was on 17 August 1988, with initial service deliveries in 1989. A total of 45 Rescue Hawks were ordered.

* The US Coast Guard also ordered a SAR variant, designated the "SH-60J Jayhawk" or "Medium Range Recovery (MRR)" helicopter, which can be described generally as a Rescue Hawk stripped of combat gear such as HIRSS exhaust suppressors and defensive countermeasures, and of course armament such as machine guns and torpedoes. It retains the stub pylon arrangement of the Rescue Hawk to carry up to three external tanks, and RAST gear can be fitted for operation off of HAMILTON and BEAR class cutters.

The Jayhawk is equipped with a Bendix-King RDR-1300 search and weather radar in a thimble radome on the nose, and also has a radio direction finder and an ILS/VOR landing/navigation receiver. It has an external hoist, on the right side of the fuselage and with a load capacity of 272 kilograms (600 pounds), can carry a searchlight, and the cockpit is NVG compatible.

Four crew are carried, including pilot, copilot, flight engineer / hoist operator, and rescue swimmer. When fitted with three 455 liter (120 US gallon) external tanks, the Jayhawk has an operational radius of 480 kilometers (300 miles), an endurance of 45 minutes at that radius, and a capacity of six passengers on the return flight.

Sikorsky received a contract for the type in September 1986. Initial flight of the Jayhawk prototype was on 8 August 1990, with the type going into service in July 1991. In October, USCG Jayhawks made headlines by rescuing nine crew from the 106-year-old schooner ANNE KRISTINE in storm conditions, and then rescuing four people off a pleasure boat the next day.

42 production machines were delivered, painted in bright, high gloss orange-red and white "creamsicle" colors that immediately announce the type as "US Coast Guard" at first glance. While its primary mission is SAR, it is also used in law enforcement, environmental protection, and drug interdiction roles.



* The US Navy has been planning to eliminate seven different types of helicopters to standardize on two: the "MH-60S Knighthawk" and the "MH-60R Multi-Mission Helicopter (MMH)". Describing these machines is a bit confusing, partly because there have been a number of changes in plans and designations over the course of both programs.

* The MH-60S Knighthawk was originally the "CH-60S", and as that older designation suggests, it was originally intended to be a utility and transport helicopter, a replacement the Navy's now-antiquated Boeing CH-46 Sea Knight, which is likely where the "Knighthawk" name came from. However, the scope of the effort expanded, and in fact the MH-60S is just as much a "multi-mission" machine as the MH-60R MMH -- it's just that the sets of missions are different.

The MH-60S is intended to not only replace the CH-46 Sea Knight in the utility and transport role, but operate in the CSAR / special operations role as a replacement for the Navy HH-60H Rescue Hawk, and in the mine countermeasures role to replace the Sikorsky CH-53E Sea Dragon. Although the Navy originally thought of refurbishing old S-70Bs for the program, mission creep meant that the price of refurbishing floated up towards the price of new machines until it made more sense to buy new machines.

To add a bit to the confusion, the MH-60S is based on the S-70 / UH-60L airframe, featuring the tailwheel under the tailfin, not moved forward as it is for S-70B machines; the overall window and door arrangement of the UH-60L; compatibility with the ESSS stores pylons; and such items as armored aircrew seats, cable cutters, and infrared exhaust suppressors. However, the MH-60S is a hybrid, featuring a large amount of kit from the SH-60B Seahawk, including marinised T-700-GE-401C engines; the Seahawk dynamic system; a rotor brake, automatic blade folding, and a folding tail; hover inflight refueling capability; plus the jettisonable cockpit doors and rescue hoist from the Seahawk.

It also features a new, state-of-the-art glass cockpit with four 20 by 25 centimeter (8 by 10 inch) color flat panel displays and dual GPS navigation systems, plus a new cargo handling system. The Navy is currently working with the Army on a "Common Engine Program" that will provide an improved powerplant for the Knighthawk, to be fitted in late production machines or retrofitted to operational machines.

In the CSAR / special operations role, the MH-60S will generally be fitted with pintle-mounted machine guns and the ESSS pylons. A field kit will also be installed to provide a FLIR imager and laser target designator for Hellfire missiles; a defensive countermeasures suite; extended-range fuel tanks; moving map displays; downed aircrew location equipment; and armor floormats. In this configuration, the MH-60S can also be used for naval surface warfare. The Navy currently plans to buy 52 such kits, with the Knighthawk going into service in the CSAR / special operations role in 2006.

A kit is also being defined for the mine countermeasures role. The primary tool for mine countermeasures will be the British Aerospace Archerfish expendable underwater vehicle. A kit is also be developed that includes a laser sensor to detect and target mines under water and a 30 millimeter cannon to destroy the mines. The cannon will fire special shells designed to pass straight through water. The MH-60S will not use a towed minesweeping sled, and in fact it seems unlikely that the Knighthawk is powerful enough to tow such a cumbersome piece of gear. The MH-60S is expected to enter service in the mine countermeasures role in 2005.

The Navy awarded Sikorsky a contract to begin formal development of what would become the MH-60S in 1997, with the first production machine performing its initial flight in January 2000. A batch of 30 low-rate production machines followed, leading to service entry in February 2002 and commitment to full-rate production in August 2002. 237 MH-60S Knighthawks will be purchased in all. CH-46 Sea Knights are now being replaced in service by Knighthawks, with full retirement of the Sea Knight expected in 2004.

* The MH-60R, which some sources identify as the "Strikehawk", is a more straightforward update of the original Seahawk, using the S-70B airframe but featuring:

Armament will include homing torpedoes, Penguin and Hellfire missiles, and a door-mounted machine gun. The MH-60R is intended to replace the SH-60B and SH-60F. The first test machine performed its initial flight in July 2001, with three test machines delivered to the Navy in that year. Low-rate production is now under way and full production is expected in 2005. 243 MH-60Rs will be delivered in all. Although the initial test and low-rate production machines have been rebuilds, it now appears that the full production machines will all be new-build rotorcraft.



* Although the Seahawk has not been exported in anywhere near the numbers of the Black Hawk, there are still a number of foreign users.

The Royal Australian Navy (RAN) acquired 16 "S-70B-2" machines, featuring an S-70B airframe and RAN-specified avionics. The avionics suite includes MEL Super Searcher X-band radar in a new, smaller radome; a CAE Electronics AN/AQS-504 internally-mounted MAD system; and AN/SSQ-81 Barra sonobuoys, along with sonar processing gear. The RAN S-70B-2s can carry Pengiun or Sea Skua light antishipping missiles, and are fitted with a rescue hoist on the right side.

Eight S-70B-2s were supplied directly by Sikorsky, and eight more were supplied as kits for assembly by ASTA in Australia. Some of the RAN Seahawks saw action in the Gulf War, these machines being fitted with an AN/AAQ-16 FLIR turret and an AN/AAR-47 missile warning system.

* Greece purchased five "S-70B-6" Seahawks for operation off of Greek Navy MEKO 200 frigates. These rotorcraft feature AN/APS-143(V)3 radar, Bendix AN/ASQ-18(V)3 dipping sonar, and can carry Penguin missiles. The S-70B-6s were delivered in the late 1990s.

* The Japanese Maritime Self-Defense Force acquired their own version of the SH-60B, license-built in Japan by Mitsubishi and of course designated "SH-60J", to replace license-built HSS-2B Sea Kings in JMSDF service.

The SH-60J, which has the Sikorsky company designation of "S-70B-3", has a configuration and capabilities similar to that of its SH-60B parent, but the avionics suite of the SH-60J is mostly Japanese-built. Japanese kit includes an HQS-103 dipping sonar; HPS-104 search radar; HLR-108 ESM system; as well as cockpit displays, datalink, flight management system, and ring laser gyro attitude and heading reference system.

US-built kit includes a Texas Instruments AN/ASQ-81D2(V) MAD; a General Instruments AN/ALR-66(VW) RWR; and an Edmac AN/ARR-75 sonobuoy receiver. The SH-60J does not have the SH-60B's 25-tube sonobuoy array, and presumably features a sonobuoy tube in the belly as fitted on the SH-60F. Production machines were powered by Ishikawajima-Harima T700-IHI-401C turboshafts, built under license from GE.

The initial two "XSH-60J" prototypes were delivered in stripped and broken-down form to be reassembled by Mitsubishi and fitted up with avionics systems. Initial flight of the first XSH-60J was on 31 August 1987, and the two prototypes were put through evaluation by the JMSDF. 101 production SH-60Js have been ordered, with the first performing its initial flight on 10 May 1991, with delivery to the JMSDF late that summer.

* On 8 August 2001, Mitsubishi conducted the initial flight of the first of two prototypes of an upgraded version of the SH-60J designated the "SH-60K", originally the "SH-60J Kai", where "kai" was short for "kaizen (modified)". It has a main cabin stretched by 33 centimeters (13 inches) just behind the cockpit and raised in height, with the expansion intended to accommodate a substantially revised avionics system, including a datalink.

Other new features include a glass cockpit with six color flat panel displays; defensive countermeasures, including a missile warning system and chaff-flare dispensers; carriage of depth charges and ASM-2 antiship missiles, not just torpedoes; and an improved rotor system that increases lift capacity. It is unclear how many SH-60Ks will be obtained, and if they will be upgrades, new production, or a mix of the two.

* Spain bought 12 Seahawks that were very similar to the SH-60B, but feature Bendix AN/AQS-13F dipping sonar. They are mostly operated from land bases but can be deployed on Spanish Navy frigates. They were given the designation "HS.23" in Spanish service.

* Taiwan has obtained ten "S-70C(M)-1 Thunderhawks" that are similar to the SH-60F Ocean Hawk, featuring Telephonics AN/APS-128C radar; Bendix AN/AQS-18(V) dipping sonar; a Litton AN/ALR-606(V) ESM system; and searchlights. They are deployed on the six Taiwanese Navy KWANG HUA I class guided missile frigates, which are derivatives of the US Navy OLIVER HAZARD PERRY frigates. The "S-70C" designation, meaning a commercial S-70, was clearly used as a political dodge.

* The Turkish Navy has bought eight S-70B Seahawks for ASW, surface warfare, maritime patrol, and SAR duties, with these machines operating from Turkish Navy frigates. The first Turkish Seahawk flew in early 2001, with aircraft deliveries beginning the same year and ending in 2002.



* US Army variants:

* International S-70A variants:

* S-70C variants:

* Special operations / CSAR S-70s:

* Naval S-70Bs:

* International Seahawk variants:

Other international variants of the Sea Hawk for which few details are available include Spain, which obtained 12 S-70Bs, and Turkey, which obtained 8 S-70Bs.



* Sources include:

* Revision history:

  v1.0.0 / 01 oct 03 / gvg
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