In 1956, the US Navy set up a design competition for a new, high-speed, long-range multipurpose helicopter. The contest was won by the Kaman K-20, and the American company accordingly received a contract to build 12 aircraft designated HU2K-1. Trials were lengthy, partly on account of the number of innovations made to the aircraft, and the first models, designated UH-2A Seasprite, only went into service at the end of 1962.

This was a conventional type of turbine-powered helicopter, with a four-blade main rotor and three-blade anti-torque rotor, retractable tailwheel landing gear and a streamlined fuselage. The sealed hull enabled it to float in calm water. Eighty-eight UH-2As were built, and the sea-grey aircraft with its fluorescent markings became a familiar sight on American aircraft carriers. Its successor, the UH-2B, was virtually identical except for the removal of some items of equipment, which were, however, available as optional extras.

Kaman modified one UH-2B air-frame for the US Army Transportation Research Command, by installing a General Electric J85 turbojet on one side of the fuselage, thereby transforming the K-20 into a compound helicopter. In this configuration, the aircraft achieved a speed of over 360km/h. Several of the UH-2B were acquired and evaluated by the US Army for fire support, armed with a four-gun M6 turret and two attachment points for Miniguns and unguided rockets.

Originally single-engined, the Seasprite was redesigned in 1964 with twin GET58-GE-8 turbines and the conversion was so successful that over 100 UH-2As and UH-2Bs were subsequently converted into UH-2Cs, whilst almost as many became HH-2Cs and HH-2Ds. The HH-2C was an armed and protected version, 12 of which were supplied to the US Navy for use on large destroyers. The HH-2D models were obtained by converting 31 single-engine helicopters to the standard of the HH-2C, but without the weapons and protection. The US Navy then considered the possibility of using the Seasprite for ASW and this gave rise to the SH-2D for the LAMPS (Light Airborne Multipurpose System) programme; it was similar to the HH-2D but had a search radar in a cylindrical radome beneath the cabin, MAD gear and sonobuoys (a few aircraft were also tested with dipping sonar). The launchable weapons consisted of two Mk.46 torpedoes or antiship missiles. Twenty HH-2Ds were transformed into the SH-2D ASW variant, while 194 of the SH-2F version, which is still in service, have been built. These differ from the SH-2D in having a new rotor and stronger landing gear. In 1983 Kaman resumed production of the SH-2F to meet further US Navy orders.

G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984

During 1956 the US Navy held a design competition to finalise the details of its requirement for a high-performance all-weather utility helicopter. Kaman was adjudged the winner and in late 1957 received a contract for four prototype and 12 production Kaman HU2K-1 helicopters; this designation was changed later to UH-2A and the name Seasprite allocated. Of conventional helicopter configuration with four-bladed main and tail rotors, the type is powered in current versions-by two 1007kW General Electric T58-GE-8F turboshaft engines. The Seasprite has been built in many versions, and these are enumerated below.

VARIANTS

UH-2A: initial production version powered by one 932kW General Electric T58-GE-8B turboshaft engine; equipped for IFR operation; 88 built

UH-2B: production version, generally similar to UH-2A, but equipped only for VFR operation; 102 built

UH-2C: redesignation of UH-2A/ UH-2B aircraft following installation of two T58-GE-8B turboshaft engines

NUH-2C: redesignation of one UH-2C after being equipped to carry and launch Sidewinder and Sparrow III missiles for evaluation

NUH-2D: redesignation of NUH-2C when re-equipped for use to study operation of helicopters from small non-aviation ships

HH-2C: search and rescue version of UH-2C with chin-mounted Minigun turret, waist machine-gun positions and extensive armour protection. First version to introduce four-bladed tail rotor; six conversions from UH-2C

HH-2D: search and rescue version similar to HH-2C, but without armament and armour; 67 conversions from earlier single-engined Seasprites

SH-2D: ASW anti-ship missile defence version to meet US Navy's LAMPS (Light Airborne Multi-Purpose System) requirement; 20 conversions from HH-2Ds

YSH-2E: two evaluation conversions of HH-2Ds with advanced radar and LAMPS equipment

SH-2F: developed LAMPS version of which deliveries began in 1973; many early versions converted to this configuration and initial deliveries of new-production SH-2Fs began in 1984; all US Navy SH-2Fs, new or converted, are expected to remain in first-line service throughout the 1990s

D.Donald "The Complete Encyclopedia of World Aircraft", 1997

First flight 2 July 1959; successive versions for US Navy SH-2F put back into production in 1981; from 1967 all single-engined SH-2A/B Seasprites progressively converted to twin-engined UH-2Cs with General Electric T58-GE-8Bs; later modified to Mk I Light Airborne MultiPurpose System (LAMPS) standard to give small ships ASW, Anti-Ship Surveillance and Targeting (ASST), SAR and utility capability. Operational deployment of LAMPS Mk I to HSL squadrons began 7 December 1971. 16 SH-2Ds converted to SH-2F, with stronger landing gear, T58-GE-8F engines and improved rotor; first operational unit deployed to Pacific 11 September 1973. 54 new SH-2Fs delivered by December 1989, at which time total 75 in operation; another six ordered in FY87, but completed as SH-2G. First flight of SH-2F as YSH-2G T700 engine testbed, April 1985; first flight with full avionics 28 December 1989 and delivered 1991, followed by the six new-build SH-2Gs. June 1987, contract for conversion programme from SH-2F to SH-2G; 18 completed June 1994; rebuilds refurbished for further 10,000 flying hours. First production SH-2G flown March 1990; fleet introduction early 1993.

VERSIONS

SH-2F Seasprite: Initial production version, now only operated by Republic of China Navy.

SH-2G Super Seasprite: SH-2F upgrade initiated FY87; airframe changes included replacing T58 with T700-GE-401 engines; fuel consumption improved by over 20 per cent. Avionics improvements include MIL-STD-1553B digital databus, onboard acoustic processor, multifunction raster display, AN/ASN-150 tactical navigation display, and 99-channel sonobuoys. SH-2G qualified for dipping sonar, air-to-surface missiles, forward-looking infra-red sensors and various guns, rockets and countermeasures. Magic Lantern podded laser equipment for subsurface mine detection.

Detailed description refers to SH-2G

SH-2G(A) Super Seasprite: Upgraded model selected by the Royal Australian Navy for deployment aboard new ANZAC frigates and smaller offshore Patrol Combatants. Kaman/Litton highly automated Integrated Tactical Avionics System (ITAS) built around a four-colour multifunction display cockpit architecture which handles EFIS, engine and transmission data, tactical plots and sensor imagery. 11 ordered.

SH-2G(NZ) Super Seasprite: New build model ordered by New Zealand for deployment aboard new ANZAC frigates. Two crew/five passenger arrangement. Four ordered. First flight 2 August 2000.

SH-2G(E) Super Seasprite: In 1994 Egypt announced its intention to buy 10 SH-2F from the US Navy inventory. These aircraft were upgraded to SH-2G configuration and delivered in 1997/98. The Egyptian SH-2G(E) aircraft are equipped with the AlliedSignal AQS-18A dipping sonar.

CUSTOMERS: US Navy operates 16 SH-2Gs; Taiwan 12 ex-US Navy SH-2Fs; Egypt 10 SH-2Gs; 11 SH-2Gs ordered by the Royal Australian Navy and four SH-2Gs for New Zealand for delivery in 2001.

DESIGN FEATURES: Main rotor rpm 298; main and tail rotor blades folded manually; nose opens and folds back for shipboard stowage; lateral pylons for torpedoes or tanks; MAD bird in holder extending from starboard sides.

FLYING CONTROLS: Main rotor blades fixed on hub; pitch changed by trailing-edge tabs. Development flight tests completed of second-generation composite Main Rotor Blades (CMRB-II) aboard a naval SH-2G. New blades have an extended service life of 15,000 flight hours and give reduced fuel consumption and improved hover performance. Extra lift is equivalent to 225kg additional payload. Production blades will fly on the first SH-2G(A) prototype by third quarter 1999. New all-digital Automatic Flight Control System (AFCS) is under test.

STRUCTURE: All-metal airframe with flotation hull; titanium main rotor hub and second-generation Composite Main Rotor Blades (CMRB2) with a projected service life of 15,000 hours.

LANDING GEAR: Tailwheel type, with forward retracting twin mainwheels and non-retractable tailwheel. Liquid spring shock-absorbers in main gear legs; oleo-pneumatic shock-absorber in tailwheel unit, which is fully castoring for taxying but locked fore and aft for T-O and landing. Mainwheels have 8-ply tubeless tyres size 17.5 x 6.25-11, pressure 17.25 bars; tailwheel 10-ply tube-type tyre size 5.00-5, pressure 11.04 bars.

POWER PLANT: Two 1,285kW General Electric T700-GE-401/401C turboshafts, one on each side of rotor pylon structure. Thirty-minute maximum rating 1,259kW; maximum continuous 1,070kW. Basic fuel capacity of 1,802 litres, including up to two external auxiliary tanks with a combined capacity of 1,516 litres. Ship-to-air Helicopter In-Flight Refuelling (HIFR).

ACCOMMODATION: Crew of three, consisting of pilot, co-pilot/tactical co-ordinator, and sensor operator. SH-2G(A) and SH-2G(NZ) have crew of two, pilot and TACCO. One passenger with LAMPS equipment installed; four passengers or two litters with sonobuoy launcher removed. Provision for transportation of internal or external cargo. Space for additional troop seats.

SYSTEMS: Include dual 30kVA electrical system and Turbomach T-62 gas-turbine APU.

AVIONICS: LAMPS Mk I mission equipment includes Canadian Marconi LN-66HP surveillance radar; General Instruments AN/ALR-66A(V)1 radar warning/ESM; Teledyne Systems AN/ASN-150 tactical management system; dual Collins AN/ARC-159(V)1 UHF radios; Texas Instruments AN/ASQ-81(V)2 magnetic anomaly detector; Computing Devices AN/UYS-503 acoustic processor; Flightline Electronics AN/ARR-84 sonobuoy receiver and AN/ARN-146 on-top position indicator; Tele-Dynamics AN/AKT-22(V)6 sonobuoy datalink; Kaman Magic Lantern laser-based minehunting system; 15 DIFAR and DICASS sonobuoys; AN/ALE-39 chaff/flare dispensers; AN/ASQ-188 torpedo presetter. The US Navy plans to retrofit additional self-defence equipment in fleet SH-2Gs, consisting of Hughes AN/AAQ-16 FLIR, Sanders AN/ALQ-144 IR jammers, Loral AN/AAR-47 missile warning and Collins AN/ARC-182 VHF/UHF secure radio. Integrated Tactical Avionics System (ITAS) being proposed for Royal Australian Navy. Mission equipment package includes Telephonics APS-143 search radar with optional Inverse Synthetic Aperture Radar capability; Hughes AAQ-16 FLIR (Raytheon AAQ-27 for Australia); and Litton ALR-93 Electronic Protection Measures (Elisra ESM for Australia). Comms/nav suite incorporates dual Litton LN100G INS/GPS, Link 11 datalink and Rockwell Collins radios.

EQUIPMENT: Cargo hook for external loads, capacity 1,814kg; and folding rescue hoist, capacity 272kg.

ARMAMENT: Two Mk 46 or Mk 50 torpedoes; two Penguin, Maverick or Sea Skua missiles in ASUW role; eight Mk 25 marine smoke markers. Provision for pintle-mounted 7.62mm machine gun in both cabin doorways. Penguin missile capability for SH-2G(A).

Jane's Helicopter Markets and Systems

- Early Seasprite models were rebuilt in Connecticut to become advanced SH-2Fs and SH-2Gs.

- The Seasprite helicopter known as HU2K- 1 first flew on 2 July 1959.

- Egypt bought the SH-2F, and the SH-2G has been selected by the Australian navy.

- Kaman is flying an SH-2F with the company's Magic Lantern anti-ship mine detector housed in a pod.

- The first flight of the new SH-2G took place on 28 December 1989.

- Turkey received 14 surplus SH-2Fs under an agreement proposed in 1994.