Developed as a competitor to aircraft like the Aerospatiale/Eurocopter Super Puma on the civil market, the Sikorsky S-92 is a derivative of the S-70 family. The S-70's low-height cabin, inherited from the military Black Hawk, was a major drawback for potential civil customers, so the new design combined the proven transmission, rotor system and power train from various military S-70 sub-types with an all new fuselage.
The fuselage is of conventional construction, but with a 1.83m square cross-section and a length of 5.89m and provision for an optional rear loading ramp. Up to 19 passengers can be seated. The undercarriage is retractable, with aft-retracting twin nosewheels and with twin mainwheels, retracting into huge sponsons, which also accommodate crash-resistant fuel tanks. The rotor head is derived from that fitted to the UH-60L, while the transmission system is the 2500kW unit from the SH-60B. The rotor itself is redesigned with graphite spars, broader-chord blades and anhedral tips. Also new is the cockpit, which features colour multi-function flight and engine displays, cockpit voice recorders and extensive monitoring systems. General Electric CT-7 and Rolls-Royce RTM 322 turboshafts have been proposed for the new aircraft.
A military derivative, the S-92M, has also reached mock-up form, this featuring automatic main rotor and tailboom folding, semi-retractable inflight-refuelling probe, and a rear loading ramp and floor-mounted freight rollers. Sponsons are further enlarged to house larger fuel tanks. With a cabin volume more than double that of an MH-60G, able to accommodate up to 24 troops or 16 litter patients, the S-92M has been proposed as a replacement for USAF Special Operations MH-53 and Marine Corps CH-46. It is proposed to fit General Electric T701-GE-401X engines, which should give a cruising speed of 276km/h) and a range in excess of 740km.
Both the S-92 and S-92M have been shelved because market research has shown an insufficiently large market to justify a full-scale launch.
D.Donald "The Complete Encyclopedia of World Aircraft", 1997
Announced March 1992; originally envisaged as S-92C 'Growth Hawk' development of S-70; market evaluation coordinated with Mitsubishi Corporation and Mitsubishi Heavy Industries. Launched at Paris Air Show, June 1995 as S-92A Helibus and military S-92IU (international utility). Risk-sharing partners Mitsubishi Heavy Industries (7.5%), Jingdezhen Helicopter Group of China (2%) and Gamesa of Spain (7%), with Taiwan Aerospace (6.5%) and Embraer (4%) as additional fixed-price supplier/partners; Russia's Mil is associated with programme, but not yet a full partner; other suppliers include Aerazur (fuel cells), Goodrich (health and usage monitoring system), Dunlop (engine inlet), Eaton (emergency flotation bag electro-optical sensors); Hamilton Sundstrand (automatic flight control system and active vibration computers), Honeywell (radar and APU), Lucas-Western (rescue hoist), Martin-Baker (crew seats), Messier-Bugatti (wheels and brakes), Moog (active vibration controls), Parker Bertea (servos), Rockwell Collins (multifunction displays and nav/com suite); Universal (FMS) and Vickers (hydraulic pumps). Programme rationalisation resulted in discontinuation of S-92IU and adoption of standard civil/military configuration with new designation S/H-92 applied in 2002; designations S-92 and H-92 Superhawk adopted in 2003 for civilian and military variants respectively.
Design changes announced in July 2000 in response to customer requests include a 0.41m increase in cabin length to permit installation of a 1.27m wide cabin door to improve hoisting capability and to accommodate a Stokes litter during SAR operations; reduction in height of tail rotor pylon by about 1.02m to offset additional weight of cabin extension; and relocation of the horizontal stabiliser. These changes will provide additional benefits in creating an improved fold configuration for shipboard operations, increased birdstrike protection deriving from the relocation of tail rotor drive shaft and controls aft of the tail spar, and a flatter hover attitude arising from a forward shift of the helicopter's centre of gravity, improving visibility for confined space and shipboard landing, and increasing aft fuselage ground clearance. The revised configuration has been incorporated from the third prototype and on all production aircraft.
Test programme comprises one ground test vehicle (PA1/GTV; first airframe built, first, ground run 4 September 1998 and completed 200-hour FAA certification endurance run in September 1999) and four flying prototypes, of which first (PA2/N292SA) completed maiden flight at Sikorsky's Development Flight Center in Florida on 23 December 1998 and was subsequently modified to the revised configuration described above. GTV and first flying prototype have 1,305kW CT7-6D engines; remaining three flying prototypes have production-standard CT7-8 and APUs. PA3/N392SA (second flying) joined the test programme in May 1999, flew in October, and is devoted principally to engine and AFCS development; subsequently upgraded to production configuration with extended main rotor shaft; new main rotor servos; redesigned electrical system to maintain rotor ice protection after a generator failure; new tail rotor pylon; and state-of-the-art cockpit displays. Flown again in this configuration on 22 March 2002. PA4/N492SA delayed during assemhly to incorporate airframe changes described above and final avionics updates and first new in definitive production configuration on 5 October 2001. PA5/N592SA, exhibited unflown at the Paris Air Show in June 1999, is in utility configuration with MIL-STD-1553 databus, rear loading ramp, folding seats for 22 troops, sliding windows, cargo hook and provision for 7.62mm machine gun pintle mounts; was later modified to revised configuration as described above, and made its first flight on 8 February 2001.
By February 2002, PA2 had flown more than 380 hours, and ÐÀÇ 221 hours, including flights at maximum take-off weight of 13,998kg, demonstrating a range of 1,482km wilh mid-mission hover; PA4 had flown 60 hours; and PA5 more than 260 hours. PA2 was withdrawn from use in May 2002. FAA FAR Pt 29 certification achieved in December 2002 after 1,570-hour flight test programme; JAA certification expected in late 2003; first customer deliveries in first quarter of 2004.
CUSTOMERS: Launch customer Cougar Helicopter of Eastern Canada announced intent to order up to five for delivery in 2002; following programme delays, reaffirmed requirement for three at February 2003 Heli-Expo, Dallas, Texas. Other announced customers include Helijet of Vancouver, Aircontactgruppen AS of Norway (six for delivery between 2004 and 2007), Copterline of Finland, Norsk Helikopter (two for Stratoil contract, agreed February 2003), Era Aviation Inc, which ordered three in August 2001 for offshore operations in the Gulf of Mexico, East Asia Airlines/HeliHongKong which ordered one at the Asian Aerospace Show at Singapore in February 2002 for passenger service on the Hong Kong-Macau route, and Petroleum Helicopters Inc (PHI), which ordered two in August 2003 for delivery in 2004 for offshore support operations in the Gulf of Mexico.
COSTS: Programme US$600 million; unit cost US$13 million to US$14 million. Direct operating cost US$2,381 per hour, comprising $1,194 fixed and $1,175 variable costs (2002).
DESIGN FEATURES: Design, manufacture and assembly use CATIA database system; modular design simplifies customised configurations. Standard medium helicopter conliguration, with engines above cabin; raised tailboom to permit rear loading via ramp; high-set, strut-braced tailplane to port. Prominent sponsons accommodate main landing gear and fuel.
Dynamic components based on proven Sikorsky technology to reduce development risks, including: titanium yoke-type infinite-life main rotor head with elastomeric bearings; four-blade, quick-release, all-composites main rotor with swept, tapered anhedral tips based on scaled-up version of blades tested on Black Hawk in 1995-96; blade chord increased 12% compared with Black Hawk; damping masses at mid-span of each blade, new transmission based on upgraded four-stage version of Black Hawk's three-stage main gearbox; rotor brake; new intermediate tail rotor gearbox; and new four-blade, fully articulated, birdstrike-tolerant tail rotor with individually removable blades to starboard, meeting FAR/JAR 29 birdstrike requirements. Manual rotor blade folding (two forward; two aft). New-style bifiliar vibration absorber, with Hamilton Sundstrand computer and Moog actuators, on top of rotor hub comprises metal drum enclosing five composites springs allowing absorber to move in opposition to in-plane forces. Target ÒÂO for rotor head is 50,000 hours. Gearbox TBO 6,000 hours.
FLYING CONTROLS: Similar, but not identical, to Black Hawk; dual digital AFCS with autopilot and dual independent, triple-axis stability augmentation features Hamilton Sundstrand primary processor based on that of RAH-66 Comanche, and is expected to have 8,000 hour MTBF. ÂAÅ Systems contracted in 2003 to design FBW control system.
STRUCTURE: Modular structure of aluminium and composites (about 40% of structure is of composites, though mostly non-structural to reduce costs) designed to be highly crack-resistant, with extensive lightning/HIRF protection; composites main rotor blades (including spars); structure optimised for minimum parts count.
Sikorsky responsible for rotor and transmission systems, final assembly and flight test. Airframe largely designed and manufactured by "Team S-92" partners, as follows: Mitsubishi (main cabin), ÀIDÑ of Taiwan (flight deck), Embraer (sponson front halves, landing gear and incorporation of Aerazur/Intertechnique fuel system), Gamesa (cabin interior, aft fuselage, tail boom and upper fuselage transmission housing), and Jingdezhen (vertical tail including horizontal stabiliser).
LANDING GEAR: Retractable tricycle; main units retract rearwards into sponsons; nosewheel retracts forwards under flight deck. Wheels and brakes supplied by Messier-Bugatti. Optional inflatable emergency flotation bags, usable up to Sea State 5, activated by Eaton electro-optical sensors.
POWER PLANT: TWO GE CT7-8A turboshafts, each rated at 1,879kW for T-O, 1,742kW for 30 minutes, and 1,523kW maximum continuous; 2,043kW OEI 30 seconds; 1,881kW OEI 2 minutes: and 1,863kW OEI continuous. Hamilton Sundstrand dual-channel FADEC with autostart, power assurance and OEI training modes. Rolls-Royce Turbomeca RTM322 will be offered as alternative engine if demand is forthcoming. Transmission via modular compound planetary gearbox with 30 minute run-dry capability, and 140% overtorque certification, rating 3,117kW.
Single-point pressure refuelling/defuelling. Standard fuel in sponsons, each with optional gravity fuelling port, combined capacity 2,877 litres. Standard auxiliary fuel option of 1,400 litres comprising two 700 litre tanks in cabin. Other fuel options include two external tanks, each 871 litres; or single or dual 322 litre bench-type tanks in cabin. Crash-resistant fuel system standard, In-flight refuelling probe optional.
ACCOMODATION: Two-pilot crew on separate flight deck on FAA/JAA 16g crashworthy seats, 19 to 24 passengers, with baggage on rear ramp; 10 executive passengers; or up to three LD-3 cargo containers in civil version. Main door, starboard side, front in three options: (a) split horizontally in upward- and downward-hinged sections, latter including steps; (b) lower airstair section with inward/backward-sliding upper portion (allowing installation of external SAR winch) and (c) full-height sliding door incorporating Type IV emergency exit. Further three FAA/JAA Type IV cabin emergency exits, plus pop-out windows at each seat row, for rapid emergency evacuation. Total of 22 combat-ready troops on sideways seats in military version; both versions have rear-loading ramp and 366 kg/m2 minimum floor rating (optionally 976 kg/m2). Military version has sliding cabin windows and weapons mounts. Martin-Baker crew and passenger seats. Accommodation is heated and ventilated with independent cockpit and cabin zones; air conditioning optional. Active noise suppression system under consideration.
SYSTEMS: Goodrich IMD-HUMS health and usage monitoring system standard, with cockpit displays and downloading facility to enable ground crew to access system via hand-held diagnostic equipment; active noise control system reduces cabin noise by 3 to 4 dB; active vibration control may be employed in key airframe areas.
Honeywell 36-150 (S92) APU with in-flight start and continuous run capability. Electrical system comprising two 75kVA, 115V, 400Hz, three-phase main gearbox-driven AC generators, two 400A AC/ 28V DC converters and one 35kVA APU-driven back-up generator with 100A AC/ DC backup converter. Battery 28V, 15Ah. Three hydraulic systems, supplied by main gearbox-driven pumps, two serving main and tail rotor and stability augmentation system, while third serves utilities and acts as back-up; all 276 bar. Anti-icing system for engine inlets, windscreen and pitot head; main and tail rotor de-icing optional. Automatically deployed emergency flotation system meets or exceeds FAR/JAR stability requirements and has demonstrated Sea State 5 capability; externally mounted 14-person liferaft in forward end of each sponson, with 50% overload capability.
AVIONICS: Open architecture avionics system accommodating ARINC 429 and MIL-STD-1553 interfaces with Collins Pro Line 4 as core system.
EQUIPMENT: Optional, single or dual, hydraulically powered, electrically controlled SAR rescue hoist, maximum capacity 272kg, with cable viewing window and spotlight. Windscreen wiper/washer system. Optional cargo handling system, which is compatible with 1.07 x 1.22m pallets, includes 1,814kg capacity centreline winch with 28V DC winch motor, easy on/off cabin rollers, and 16g cargo tiedowns at all major frames.
Jane's All the World's Aircraft, 2004-2005
Technical data for S-92
Main rotor diameter: 17.71m, tail rotor diameter: 3.35m, overall length, rotors turning: 20.88m, fuselage length: 17.12m, height to top of rotorhead: 4.70m, empty weight (offshore oil): 7,212kg, max external load: 4,536kg, max internal fuel weight: 2,327kg, max take-off weight (civil, internal load): 11,861kg, max take-off weight (civil, external load): 12,836kg, max level speed (without radar): 324km/h, max level speed (with radar): 307km/h, never-exceed speed: 305km/h, max cruising speed: 283km/h, econ cruising speed: 257km/h, service ceiling: 4,575m, hovering ceiling OGE: 2,170m, hovering ceiling IGE: 3,450m, range, offshore configuration (19 passengers): 800-1000km, range with standard internal auxiliary fuel: 1344km