|Bell Model 222|
In March 1974, in view of the rapidly growing market for business and utility helicopters (especially in the oil related work), Bell decided to commit its own resources to the development of a new twin-turbine, ten-seat helicopter. This helicopter was evolved from studies begun in the late 1960s which had led, in 1973, to the Design D-306, a twin-turboshaft helicopter. The engines were to be either the 500shp Allison 250-C28, the 590shp Lycoming LTS-101 or the 650shp Pratt & Whitney Canada PT7B driving the Bell classic two-blade main rotor. The D-306 could accommodate two pilots and eight passengers (four passengers in executive configuration).
In January 1974, a full-scale mock-up of the D-306 was displayed at the Helicopter Association of America (HAA) convention in order to study the market potential and to gather the would-be customers remarks in order to upgrade the project.
The reactions were so promising that, on 20 April, 1974, Bell announced its decision to go ahead. This gave birth to the Model 222, five prototypes of which were to be built and which were quite similar to the D-306 (the windscreen was improved and the fuselage lengthened by a few inches). The Model 222 was the first completely new Bell design to reach production status since the JetRanger and the Model 222 was described then as 'the first American made light twin-turbine helicopter'. It had a semi-monocoque light alloy fuselage with a hydraulically retractable tricycle undercarriage. The two Avco Lycoming turboshafts drove a two-blade main rotor through a gearbox with two spiral bevel reductions and one planetary reduction.
The maiden flight of the prototype was expected by the end of 1975 but, in fact, the first prototype (c/n 47001, N9988K) got into the air on Friday 13 August, 1976, with Donald Bloom at the controls. Certification by the FAA under FAR Part 29 was received on 16 August, 1979, followed by approval for VFR operation on 20 December of the same year. On 15 May, 1980, the Model 222 received FAA approval for single-pilot IFR operation.
During flight tests several improvements were introduced on the prototypes, the most discernible of these being a completely new tail configuration. With the fourth prototype (c/n 47004, N680L) a new tail layout was adopted: the T tail was replaced by tailplanes and end-plate fins fixed forward of the rear fuselage. The fifth prototype (c/n 47005, N222BX), representative of the production aircraft, was presented at the Paris Air Show in June 1978. In fourteen months, the five prototypes logged more than 600 flying hours and by December, 1977, the figure of 700 hours was reached.
Production was launched with a backlog of orders for some 140 aircraft and Bell had to boost its planned production from 125 machines the first year to 137. On 16 January 1980, Petroleum Helicopters Inc (New Orleans) received the first of its sixteen machines soon followed by Schiavone Construction which received an aircraft in executive configuration. Heliflight Systems (Houston), Aerogulf Sales Co (Dubai), Bemor Agencies (Bermudas), CSE Aviation Ltd (UK) and Astra Helicopters (South Africa) were among the main customers. On 18 January 1981, Bell Helicopters delivered its 25.000th helicopter, a Model 222, to Omniflight Helicopters. Several versions have been developed:
Model 222 and 222A: first production variants powered by two 592shp Avco-Lycoming LTS 101-650C-3 engines.
Model 222B: this was the second main production variant with accommodation for seven to nine passengers. The Model 222B incorporates numerous improvements such as a taller main rotor mast, increased diameter narrow-chord blades, larger tail rotor and lengthened tail boom. The powerplant consists of two 684shp Textron Lycoming LTS 101-750C-1 turboshafts. The fuel is contained in five crash resistant tanks located in the fuselage as well as in the sponsons, with a total capacity of 710 litres.
The Model 222B Executive is the luxury variant for five or six people with complete systems and avionics such as IFR, Sperry coupled automatic flight control system and VOR/LOC. Luxury equipment includes automatic temperature control, fluorescent and reading lights and window curtains. A stereo system and refreshment cabinet are optional.
In 1982, the Model 222B became the first transport category helicopter to be certificated by the FAA for single-pilot IFR flight without stability augmentation. Model 222U and 222UT: the Model 222UT (UT for Utility Twin) variant is externally recognisible by its tubular skid undercarriage in place of the usual retractable wheels. It can accommodate up to eight passengers and could have a fuselage mounted flotation system. The powerplant is the same as for the Model 222B but fuel capacity has been increased to 930 litres. This variant received VFR and single-pilot IFR certification during the spring of 1983.
First deliveries of the Model 222UT were in September 1983. Among the main operators are the New York City Police Department, the Port Authority of New York, Michigan State Police, West Virginia State Police and Lloyd Helicopters.
From 1982, the fourth prototype (N680L) served as test bed for the Model 680 four-blade composite bearingless rotor system, designed to improve performance and reduce noise. On 10 November, 1987, this Model 222 flew with a digital control system developed by Bell and Lucas Aerospace which gave the engine the ability to adapt its characteristics in flight.
To date, one hundred and fifty-six Model 222Bs and seventy-two 222UTs have been delivered, mainly on the civil market. Only two aircraft are known to have been taken on charge by military customers: one by the Uruguayan Air Force and the other by the Uruguayan Navy.
Model 222X: at the end of 1988, a multi-mission variant of the Model 222, called Model 222X, was proposed among several contenders in order to replace the CH-136 and CH-139 of the Canadian Armed Forces but no decision had been taken by early 1991.
A.J.Pelletier "Bell Aircraft since 1935", 1992
Bell began developing a twin turbine light helicopter in the late sixties, but it was not until January 1974 that a mock-up of what was to become the Bell 222 was exhibited at the annual convention of the Helicopter Association of America. Towards the end of 1975 Bell announced that the Model 222 was passing from the design to the construction stage. The first prototype flew on 13 August 1976 — considerably later than originally planned owing to the decision to investigate thoroughly the market and operators' requirements before building the new aircraft. The second prototype followed in October 1976, and by March 1977 all five prototypes were operational. The final development stages for these aircraft also took longer and were less straightforward than the targets fixed in 1974 had suggested. The specifications of the Bell 222 were in fact considerably modified in the light of results from test flights. Necessary modifications included both structural elements such as the tail plane and endplate fins, and flight controls.
The Bell 222 is a classic design with a light alloy structure, and a fuselage built around a large cabin which can seat two pilots and five or six passengers in the executive trim. In all configurations, there is a bench seat at the back for three, which fits into the L-shape of the fuel tank behind it. The executive Bell 222 is sold with full IFR capability. One alternative is the offshore configuration for ferrying eight passengers to offshore oil platforms.
The large main rotor with two wide blades is of steel with a honeycomb core. The blades are held to the rotor hub by standard Bell elastomeric bearings. The tail rotor is also metal with two blades. The twin Lycoming LTS-101-650 engines are mounted side-by-side above the fuselage and have integral particle separators. The fuel is contained in three tanks, one in the fuselage and two in the sponsons into which the main landing gear members retract.
A few dozen Bell 222s have already been sold to operators in Europe, Latin America and the Far East. The first customers included the Metropolitan Police in London and the Japanese National Police. The Bell 222B is one of two current production versions: it too has IFR capability, but has more powerful turbines and a 135kg bigger payload. The other is the 222UT utility variant, with a skid undercarriage and other weight and cost saving changes.
G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984
Bell Helicopters first announced in April 1974 the company's intention to develop a new commercial helicopter which would be the first light twin-turbine commercial helicopter to be built in the USA. This was no blind decision for, shrewdly, a mock-up of the company's design proposal had been exhibited at the annual convention of the Helicopter Association of America at the beginning of the year, giving potential customers an opportunity of making constructive suggestions for product improvement. The resulting interest was sufficient to warrant a decision to proceed with the construction of five prototypes, and the first of these flew on 13 August 1976.
Allocated the company designation Bell Model 222, these prototypes were used to complete the development and certification programme as quickly as possible, with FAA certification in VFR configuration being gained on 20 December 1979. The Model 222 benefits from new-technology features developed at an earlier date for both civil and military helicopters, and includes the nodal suspension system described for the Model 214ST, a no-lubricant elastomeric bearing main rotor hub, and glassfibre/stainless steel main rotor blades.
The airframe structure is primarily of light alloy, the fuselage having a short-span cantilever sponson mounted on each side. Of aerofoil section, these provide some lift in forward flight and thus supplement the main rotor; in addition, they provide a housing for the main units of the tricycle-type landing gear when retracted. The design includes more tail unit than seen on most helicopters, with both upper and lower sweptback fins and mounted further forward on the aft fuselage, a tailplane with endplate fins. Maximum high-density seating capacity is for 10 occupants, comprising one or two crew, and nine or eight passengers respectively, but production aircraft are available in three versions. These comprise the basic Model 222 with a standard seating configuration for a pilot and seven passengers. Optionally, there is the Model 222 Executive, fully equipped for IFR flight with a crew, of one or two, and luxury accommodation for six or five passengers respectively; and the Model 222UT (Utility Twin) equipped for IFR operation with a crew of two, and with an emergency flotation system and auxiliary fuel tanks as standard while the wheeled undercarriage is replaced by tubular skids.
The twin turbine powerplant selected for the Model 222 consists of two Avco-Lycoming LTS 101-650C-2 turboshafts, their dry weight of only 110kg each providing a maximum power/ weight ratio of 4.58kW/kg at maximum rating. The current Model 222B production version introduced uprated LTS 101-750C-1 engines, with other minor improvements.
Initial deliveries of VFR certificated Model 222s were made to Petroleum Helicopters and Schiavone Construction in January 1980. A Model 222 delivered to Omniflight Helicopters, on 25 January 1981, was the 25,000th helicopter to be built by Bell. By January 1989, 176 Model 222s had been built.
D.Donald "The Complete Encyclopedia of World Aircraft", 1997
The first of five prototypes of the Model 222, described as the first commercial light twin-engined helicopter to be built in the USA, flew for the first time on 13 August 1976. FAA certification for a Model 222 in preproduction configuration was received on 16 August 1979. The production 222 received approval for VFR operation on 20 December, and the first delivery, to Petroleum Helicopters Inc, was made on 16 January 1980. FAA certification for single-pilot IFR operations in Category I weather conditions was granted on 15 May 1980. A Model 222 delivered to Omniflight Helicopters on 18 January 1981 was the 25,000th Bell helicopter built. Another became a flying testbed for Bell's Model 680 rotor system. Production ceased in 1989.
222A: Initial production model powered by twin 462kW Lycoming LTS 101 650C-3 turboshaft engines. Replaced from late 1982 by the Model 222B. Total 82 built.
222B: Standard production model from late 1982. More powerful, 510kW Lycoming LTS 101 750C-1 engines; fuselage increased by 0.43m and main rotor diameter 0.69m larger. Strakes added to sponsons. First flight 1 August 1981; FAA certification 30 June 1982. On 29 July 1982, the 222B became the first transport category helicopter to be certified by the FAA for single-pilot IFR flight without stability augmentation. Total of 26 produced between 1982 and 1987.
222B Executive: Fully equipped for both single- and dual-pilot IFR flight. Honeywell coupled automatic flight control system to provide stability augmentation and automatic hold for attitude, altitude, heading and airspeed, plus VOR/LOC course and glide slope hold during approach. Collins Pro Line avionics include dual VHF com, dual VOR nav with glide slope. ADF, marker beacon receiver, transponder, DME and area navigation. Luxury accommodation for five or six passengers, with automatic temperature control, fluorescent and reading lights, window curtains and ceiling speakers. Optional stereo system and refreshment cabinet.
222UT (Utility Twin): Utility version, incorporating the improvements and power plant detailed for the Model 222B. Retractable tricycle landing gear replaced by tubular skid gear with lock-on ground handling wheels. Fuselage-mounted flotation system optional. Standard seating for a pilot and six or seven passengers. Optional layout for a pilot and eight passengers. First flight 7 September 1982. VFR and single-pilot IFR certification received in Spring 1983; customer deliveries began in September 1983. Total of 80 built up to 1989.
The following description refers to the basic Model 222B, except where indicated:
ROTOR SYSTEM: Two-blade main rotor. Blade section Wortmann 090. Thickness chord ratio 8 per cent. Each blade has a stainless steel spar with bonded glass fibre safety straps to retard crack propagation and offer secondary load path; replaceable stainless steel leading-edge; and afterbody of Nomex honeycomb covered with glass fibre skin. Each blade is attached to the rotor head by two chordwise bolts. Small trim tab on each blade. Completely dry titanium main rotor hub has conical elastomeric bearings. Two-blade tail rotor of stainless steel construction, with preconing, underslung feathering axis and skewed flapping axis. Rotor blades do not fold. A rotor brake is standard.
ROTOR DRIVE: Rotors shaft driven through gearbox with two spiral bevel reductions and one planetary reduction. Transmission rating (two engines) 690kW. Single-engine rating 548kW. Main rotor engine rpm ratio 1:27.4; tail rotor engine rpm ratio 1:5.08.
SPONSONS: Short-span cantilever sponson set low on each side of fuselage, serving as main landing gear housings, fuel tanks and work platforms. Section NACA 0035. Dihedral 3° 12'. Incidence 5°. Sweepback at quarter-chord 3° 30'. All-metal structure of light-alloy sheet and honeycomb. No movable surfaces.
FUSELAGE: Semi-monocoque structure of light alloy, with limited use of light-alloy honeycomb panels. Fail-safe structure in critical areas. One-piece nosecone tilts forward and down for access to avionics and equipment bay.
TAIL UNIT: Cantilever structure of light alloy. Fixed vertical fin in sweptback upper and lower sections. Tailplane, with slotted leading-edge and endplate fins, mounted midway along rear fuselage. Small skid below ventral fin for protection in tail-down landing.
LANDING GEAR: Hydraulically retractable tricycle type. All units retract forward, mainwheels into sponsons. Free-fall extension in emergency. Oleo-pneumatic shock-absorbers, with scissored yoke. Self-centring nosewheel, swivelling through 360°. Single wheel and tyre on each unit. Mainwheel tyres size 6.00-6, pressure 5.18 bars. Nosewheel tyre size 5.00-5, pressure 4.14 bars. Hydraulic disc brakes. New-type water-activated emergency pop-out floats optional. Model 222UT has skid-type landing gear and lock-on ground handling wheels, with fuselage-mounted flotation system optional.
POWER PLANT: Two Textron Lycoming LTS 101-750C-1 turboshafts, each rated at 510kW for take-off, mounted in a streamline housing above the cabin and aft of the rotor pylon. Bell focused pylon with nodalisation. Fuel contained in five crash-resistant internal bladders, in fuselage and sponsons, with total capacity of 710 litres in Model 222B. Model 222UT has maximum fuel capacity of 931 litres. Rear seat fuel tank, capacity 246 litres, and parcel shelf fuel tank, capacity 181 litres, optional on both models. Single-point refuelling on starboard side of fuselage. Oil capacity 6.5 litres per engine.
ACCOMMODATION: Pilot and seven passengers in standard 2-3-3 layout, alternatively pilot, co-pilot and six passengers. Two additional passengers can be accommodated in a high-density 2-2-3-3 arrangement. Energy attenuating seats, all with shoulder harness in Model 222B. Crew door at forward end of cabin on each side; cabin door on each side immediately forward of wing. Space for 1.05m3 of baggage aft of cabin, with external door on starboard side. Ventilation standard; air conditioning and heating optional.
SYSTEMS: Dual hydraulic systems, pressure 103.5 bars. Maximum flow rate 15.1 litres/min. Open reservoir. Electrical system of Model 222B supplied by dual 150A DC generators, dual 250VA AC inverters and 17Ah Ni/Cd storage battery. Dual inverters deleted in Model 222UT, and 17Ah battery replaced by one of 34Ah capacity.
AVIONICS AND EQUIPMENT: Standard avionics in 222B comprise VHF transceiver and intercom system. Collins Pro Line and AlliedSignal Gold Crown Series III avionics optional. Honeywell SPZ-7000 digital automatic flight control system approved for single-pilot IFR operation in 222UT. Other avionics, blind-flying instrumentation and equipment, including Honeywell Helipilot system. AlliedSignal RDR-1400 weather radar and 1,270kg capacity cargo hook kit, to customer's requirements. Bristol Aerospace/Aeronautical Accessories Inc wire strike protection system optional.
Jane's Helicopter Markets and Systems
Technical data for Bell Model 222
Engine: 2 x Avco Lycoming LTS 101-650C-2 turboshaft, rated at 446kW, main rotor diameter: 12.12m, fuselage length: 10.98m, height: 3.51m, take-off weight: 3650kg, loaded weight: 2204kg, cruising speed: 241km/h, service ceiling: 6095m, range with max fuel: 523km