Throughout the 1960’s and 1970’s, the flightdeck of smaller US Navy frigates and destroyers would almost certainly have been occupied by a Kaman Seasprite helicopter. Now in the autumn of its life with the US Navy, the Seasprite, however, is not yet ready for a swansong. Foreign sales of the latest version of the design, the SH-2G are going strong with orders for 25 from Australia, New Zealand and Egypt plus a number of other Southeast Asian countries expressing interest in a design that is over forty years old.
It is perhaps testimony to the success of the original design that it is still flying effectively in the 21st century. Many of the original 250 manufactured airframes have been upgraded many times with the addition of new rotor blades, avionics and electronics.
The designers at Kaman, who had many years of experience in developing intermeshing twin rotor helicopter designs, decided in the late 1950’s to design a conventional helicopter suitable for use onboard US Navy frigates and destroyers to compete in the LAMPS I program. In the 1950’s, the use of helicopters onboard ships was still in its infancy and Kaman’s inventiveness added much to the collective knowledge. To speed the design process Kaman engineers decided on a single engine design. The blueprints were christened as company design K-20. Subsequently, this designation was changed to HU2K-1 and after a short construction period, the first prototype took to the air for the first time on 2nd July 1959. Another designation change occurred on 1st October 1962 when the HU2K became the H-2. Kaman would manufacture 190 UH-2A and UH-2B single engined Seasprites for duties as diverse as liaison, utility, SAR and combat rescue (four YUH-2A, 84 UH-2A, 102 UH-2B)
By 1968, however, single engined Seasprites were being phased out of service to be replaced with twin engined HH-2C and HH-2D rescue helicopters.
The benefits of twin engined helicopter operations were becoming obvious, especially at sea where the extra engine could be a lifesaver. The Kaman Seasprite so equipped first appeared in the ASW role in October 1970 when the Navy selected the SH-2D as an interim LAMPS platform. This version saw the introduction of an undernose radome containing the advanced Litton LN 66 search radar. An ASQ-81 Magentic Anomaly Detector (MAD) was fitted on the starboard fuselage pylon whilst a removable sonobouy rack was put in the fuselage port side with space enough for 15 sonobouys. Twenty HH-2D’s were converted to SH-2D standard and entered United States Navy service in 1972.
The first SH-2F LAMPS 1 aircraft was received by the US Navy in May 1973. Its main role was to extend the outer defensive screen of a carrier battlegroup, the Seasprite also had a long list of secondary roles, such as liaison, SAR and Vertrep roles to perform. The SH-2F was a major improvement over previous variants and amongst many improvements the SH-2F had upgraded General Electric T58-GE-8F engines offering 1,350shp. New longer life advanced 101′ rotorblades with a design life of 3000 hours offered reduced replacement costs. Other innovations included an overall improvement in aircraft performance, reliability, maintainability and strengthened landing gear. To improve the SH-2F’s ability to operate from smaller warships the helicopter’s tail wheel was relocated forward by 1.83m/6ft) for greater deck edge clearance. These and other modifications enabled the SH-2F to operate at higher all up weights than the SH-2D. The SH-2F featured an improved Canadian Marconi N66HP surface search radar. This radar was capable of spotting small surface targets, including periscopes and airmen’s helmets in the sea.
Two Mk46 torpedoes were carried to attack submarines, with modifications the SH-2F could also carry depth charges. The US Navy eager to get as much value out of the Seasprite as possible fought for funding for an upgrade for the earlier variants. Eventually funding was approved and the conversion program using 16 SH-2Ds and eight other variants was completed in 1982.
By the early 1970’s, the primitiveness of the LAMPS 1 program was beginning to show and thus a new LAMPS 2 program was instigated. All the major US helicopter manufacturers entered the competition. Kaman’s submission was with two YSH-2Es as testbeds for the Navy’s LAMPS 2 programme with a new Texas Instruments APS 115 radar in a reconfigured nose in March 1972. Despite positive signs, the United States Navy decided to cancel the LAMPS 2 programme later the same year. LAMPS 2 would eventually be replaced by LAMPS 3 and for this competition Kaman proposed a derivative of the SH-2 known as SeaLamp as a contender for the LAMPS 3 requirement that was later won by the Sikorsky SH-60B Seahawk.
Following a review of the strength of the US armed forces, the new Reagan Administration authorised a large scale build-up in military capability in 1981. Part of the program was to build the US Navy up to a fleet of 500 ships. Most of these ships would require a helicopter and therefore in 1981 Kaman received an order for 60 new build SH-2Fs in addition to those already converted from earlier airframes. The last six of them were delivered as SH-2Gs.
From 1987, 16 SH-2F’s received a package of modifications to allow them to operate in the Persian Gulf. The package included the provision of an AN/ALQ-16 FLIR under the nose, AN/ALQ-47 and AN/DLQ-3 missile warning and jamming equipment and new radio’s. During the Gulf War, SH-2F’s tested the ML-30 Magic Lantern laser sub surface mine detector with great success. Magic Lantern was developed by Kaman and uses pulses of laser light to detect sea mines in the upper water column’ (depths of down to ships keel level) using a process called LIDAR (Light detection and ranging).
In the Gulf War an SH-2F, aboard the frigate USS Vreeland, flew with the ML30 fitted. It flew over 80 missions in the Northern Persian Gulf and detected large minefields in areas previously thought to be clear of the mine threat. A more advanced version of the system was then ordered and installed on SH-2G’s, called Magic Lantern Advanced Development Model (ML-ADM). A unique feature of Magic Lantern is the ability to use and control multiple independent receivers. The receivers can be set to image the same area at different depths to increase the search rate of each sweep.
By 1994, the SH-2F once operated by 11 squadrons was phased out of frontline service.
SH-2G
The SH-2G programme began in 1985 when Secretary of the Navy John Lehman told a Senate panel that it would be more cost effective to upgrade an operational helicopter than to develop a new one. Kaman’s prototype YSH-2G flew for the first time on 2nd April 1985. This aircraft was, however, a conversion of an SH-2F airframe to be used as a testbed for the powerplant, two new General Electric T700-GE-401/401C turboshaft engines each rated at 1,723 shp. The new engines are heavier and more powerful than previous installations but give 10 percent greater power and 20 percent lower fuel comsumption. The General Electric T700-GE-401/401C engines give the 13,000lb Super Seasprite far better power margins than the heavier (22,000lb) Sikorsky SH-60B Seahawk.
Kaman have also invested heavily into developing new composite main rotor blades. Their second generation Composite Main Rotor Blades (CMRB2) were successfully flight tested on an SH-2G in August 1996. These new rotor blades have an expected life time of around 15,000 hours, with a consequent reduction in maintenance and through life costs. The (CMRB2) composite blades have been selected by Australia for its SH-2G(A).
The SH-2G Super Seasprite is now, (January 2000), routinely only on short hulled FFG-7 Oliver Hazard Perry’ class frigates which cannot accommodate the Sikorsky SH-60B Seahawk. These frigates are operated by the Naval Reserve Force (NRF). Under a May 1996 plan these ships were to be replaced in the Reserve by long hull FF-7s which can use the SH-60B/R, leaving the future of US useage of SeaSprites in some doubt.
Less than a year later in May 1997 the Quadrennial Defense Review (QDR) called for an accelerated program to retire all FFG-7s. It is expected that the still very capable FFG-7′ Oliver Hazard Perry frigates will find foreign buyers when sold by 2001 with Greece, Turkey, Taiwan and Spain being favourites to purchase them. The United States Navy has intentionally shed its low end capability to protect its high end (destroyers, cruisers and aircraft carriers). Despite this, the US Navy is still likely to shed seven early Spruance’ class destroyers which might otherwise have been candidates for further SH-2G operations. Again these capable destroyers will probably find further service with a foreign power.
In 1987 when the US Navy placed an order with Kaman for 103 new build SH-2Gs and the conversion of 61 SH-2Fs to the later standard the cold war was still very real. By 1989 the Cold war was over and the need for the aircraft was no longer pressing. The US Navy quickly shrank its requirements for smaller surface vessels and helicopters. Only 24 of the SH-2Gs had been completed. These aircraft were then allocated to the Reserve Squadrons HSL-84 Thunderbolts’ at NAS North Island and HSL-94 Titans’ at NAS Willow Grove in Pennsylvania. Each squadron operates eight aircraft whilst a single SH-2G operates out of NAS Paxuatent River on developmental work.
NOT GOING JUST YET!
Whilst the end may be sight for the SH-2G in United States Navy service, Kaman’s venerable design is still winning construction orders from foreign powers. Most notably Egypt, New Zealand and Australia.
The New Zealand and Australian orders are linked through the two countries ANZAC frigate program. Kaman offered the SH-2G variant to both countries and despite various differences between the two nations, the Seasprite will enter full operational service with the two navies in the first few years of the 21st century. The New Zealand Seasprite designated SH-2G(NZ) will have a new belly mounted APS-143 pulse compression radar. Night vision equipment, LR 100 electronic support measures suite fitted to detect, locate and classify any Infra red emissions. To offer an effective strike capability, the SH-2G(NZ) can be armed with two Maverick TV or infra red guided missiles. The Royal Australian Navy, however, decided to arm their helicopters with the Penguin long range anti ship missile system instead of the Maverick.
Before final acceptance into Australian service, the SH-2G(A) is flight testing a new, all digital Automatic Flight Control System (AFCS) which will fly the Super Seasprite through an automatic approach to the ship or hover. It will also maintain set heading, altitude and airspeed for point to point navigation.
The SH-2G is available with the world’s most advanced Integrated Tactical Avionics System (ITAS). ITAS integrates helicopter sensors such as FLIR, radar and ESM with shipborne sensors and weapons to provide the most lethal integrated weapons system available
Kaman are keen to expand the view that the Seasprite is just an ASW mission dedicated vehicle. The SH-2G is capable of Surveillance, SAR, troop insertion and many varied utility missions, including load moving. The SH-2G is capable of transporting 4,000lbs on its permanently mounted cargo hook.
The Kaman Seasprite, it seems will be in operational service with many of the world’s navies for many years to come. This despite the fact that the basic design from which the current SH-2G derivative is based is over forty years old, having first flown from Kaman’s Bloomfield, Connecticut factory on 2nd July 1959.
