At the beginning of the 1970s, Bell was still busy improving the performance of its workhorse, the UH-1. A more powerful variant of the Model 205 (UH-1H) had been studied in which a 1,900shp Lycoming T53-L-702 turboshaft had replaced the standard 1,400shp T-53-L13 unit. The newcomer, designated Model 214 HueyPlus also retained the main rotor and tail rotor drive systems and the larger two-blade rotor of the Model 309 KingCobra, these offering better high speed and weight performance as well as reduced noise. The airframe was also strengthened including the pylon structure and fuselage.

The Model 214 prototype flew for the first time at Arlington in October 1970. Development of the HueyPlus progressed steadily until 1972 when Iran approached Bell for the design of a UH-1 derivative which could be operated in hot and high conditions. Several hundreds of this new type of helicopter would be delivered together with some two hundred AH-1J Cobras. A $500 million contract for 287 machines was signed on 22 December, 1972. by the US Army, acting on Iran's behalf.

During the first phase of this programme, Bell built three additional prototypes of the Model 214. These were powered by 2,050shp Avco Lycoming T55-L-7C turbo-shafts, and in August 1972, one of them was shipped to Iran for evaluation. The tests were considered successful and Bell moved on to the Model 214A which was the production model. On this variant, power was increased further by the installation of a 2,930shp Avco Lycoming LTC4B-8D turboshaft which permitted operation at a greater gross weight. Three prototypes of the Model 214A were prepared by Bell (c/n 27001/27003), the first of them (N214J) making its maiden flight on 13 March, 1974. The second prototype flew in April 1974 and the third in May. Flight testing and certification were resumed in the following year.

The first production Model 214A (c/n 27004) was taken in charge by the Iran Imperial Army Aviation (IIAA) on 26 April, 1975. Three days later, on 29 April, this aircraft with Maj-Gen Manouchehr Khosrowdad, commander of the IIAA, and Clem A Bailey, Bell's assistant chief production test pilot, at the controls, established five new world records in the FAI Class E-1e. The helicopter reached a maximum altitude of 9070m and sustained a horizontal altitude of 9010m for 30 seconds. It also climbed to 3000m in 1min 58sec; to 6000m in 5min 13.2sec and to 9000m in 15min 05sec.

The last Model 214A of the first batch was completed on 19 December, 1975. A second batch comprising thirty-nine examples of a modified variant tailored specifically to SAR missions (Model 214C) was ordered in February 1976, and delivered between January 1977 and March 1978. A third batch of six Model 214As was ordered in March 1977 and this order was completed by the autumn of 1978.

The whole contract was so huge that a separate division of Textron Inc had to be founded to handle the programme with Maj-Gen Delk M Oden as president. The partnership between Bell and Iran would have led to the building of a factory in Isfahan for the production of a further 400 helicopters (Model 214As and 214STs), but all the contracts were cancelled because of the Islamic revolution in December 1978.

Today, Model 214s are still operated by the Iran Islamic Revolutionary Air Force, but the actual numbers of aircraft in service are not known. Limited stocks of spares, and quality of maintenance are likely to ground a large number of aircraft.

As for the majority of its products, Bell also prepared a commercial derivative of the Model 214A (with Avco Lycoming T5508D turboshaft with the same ratings as LTC4B). Known as Model 214B BigLifter, this helicopter received FAA type certification on 27 January, 1976, but saw limited success and no more than seventy were produced. The Model 214B was externally similar to the Model 214A with the exception of an additional window in the side sliding door. Other differences included a fire-fighting system and new avionics. The Model 214B-1 variant was certificated under a different weight specification.

A.J.Pelletier "Bell Aircraft since 1935", 1992

The company developed a Model 214A utility helicopter of which a total of 293 was delivered for service with Iranian Army Aviation, which gave them the name Isfahan. Subsequently, 39 generally similar aircraft, but with specific equipment for SAR operations, were delivered to the Iranian Air Force under the designation Bell Model 214C. Testing of these military helicopters convinced Bell that there should be a significant market for a civil variant, for it would have a lifting capability better than any contemporary helicopter within the medium category range. Accordingly, the company announced in early 1974 its intention to develop such an aircraft under the designation Bell Model 214B BigLifter. Generally similar in configuration to the military helicopter, retaining the same airframe, rotor/transmission systems, and powerplant, the BigLifter differs by having emergency escape windows in the cargo doors, an engine fire extinguishing system; and avionics suited to civil rather than military operation.

Two versions were available, and the standard Model 214B was intended for a variety of purposes. They included operation as a 14-passenger transport with a crew of two; as a cargo lifter, with an external cargo hook certificated to carry a maximum load of 3629kg; in an agricultural role, carrying a very similar chemical load; or as a firefighter able to drop a total 2725 litres of fire retardant, carried in cabin and under-fuselage tanks. The alternative Model 214B-1 was certificated to different standards that allowed for operation at a lower gross weight with an internal load. The Model 214B was available to commercial operators from the receipt of certification on 27 January 1976 until production ceased in 1981.

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

This development of the UH-1, known as the Model 214 Huey Plus, was first announced in 1970. The prototype was a scaled-up, strengthened and improved Model 205, powered by a 1,415kW Lycoming engine, and this was followed by a 214A demonstration aircraft, which was shipped to Iran for evaluation. This resulted in an order for 287 aircraft, announced by Bell on 22 December 1972. The first 214A flew on 13 March 1974 and deliveries began on 26 April 1975. A further 50 214As and 350 twin-engined 214ST’s were to be built in Iran, but the fall of the Shah put an end to these plans.

VERSIONS

214A: Powered by a 2,185kW (2,930 shp) Lycoming LTC4B-8D turboshaft engine, an improved version of the T55-L-7C fitted to the original Model 214A demonstrator when it went to Iran. It has the 1,528kW (2,050 shp) transmission and rotor drive system developed for the KingCobra experimental gunship helicopter and embodies Bell's NodaMatic nodalised beam concept to minimise vibration. 296 delivered to the Iranian Imperial forces.

214B BigLifter: Commercial version of the 214A, announced on 4 January 1974, providing better lift capability than any commercial helicopter then in production. Powered by a 2,183kW (2,930 shp) Lycoming T5508D turboshaft, it has the same rotor drive and transmission system as the 214A. The engine is flat-rated at a maximum 1,677kW (2,250 shp) and the transmission at 1,528kW (2,050 shp) for take-off, with a maximum continuous power output of 1,379kW (1,850 shp). Advanced rotor hub with elastomeric bearings on the flapping axis; raked tips to main and tail rotors. Other features include an automatic flight control system with stability augmentation and attitude retention; nodalised suspension; separate dual-hydraulic systems; a large engine deck which serves as a maintenance platform; addition of an engine fire extinguishing system; push-out escape windows in the cargo doors, and commercial avionics.

214B-1: As 214B, but with restricted internal gross weight of 5,669kg (12,500 lb).

214C: Search and rescue variant of 214A. Total of 39 delivered to Iran.

214ST: Stretched twin-engined military version originally developed for production and service in Iran; but later transformed into commercial transport (described separately).

POWER PLANT: One 2,183kW Lycoming T5508D turboshaft engine. Standard fuel capacity 772 litres; maximum with auxiliary tank is 1,434 litres.

ACCOMMODATION: One or two pilots and 14 to 15 passengers.

Jane's Helicopter Markets and Systems

The Bell 214B BigLifter is the civil version of the Model 214A utility helicopter produced for the Iranian army, itself developed in 1972 and 1973 from the Model 214 Huey Plus. The BigLifter was announced on January 4, 1974 for delivery beginning 1975. Unfortunately, US Federal Aviation Administration Type Approval of the 214B was not received until January 27, 1976.

The 214B BigLifter is derived essentially from the 204 and 205, and was specifically designed to better the lift capacity of any contemporary civil helicopter of the same power. The key to the type's considerable lifting ability is the use of a 2930shp Lycoming T5508D turboshaft (the civil version of the T55-LTC4B-8D turboshaft powering the 214A and its search-and-rescue derivative, the 214C), flat-rated to 2250shp maximum output. The rotor and transmission are identical with those of the 214A, the transmission being capable of accepting up to 2050shp at take-off and 1850shp for continuous running.

The rotor system is of an advanced type, the blades having swept tips and the hub featuring elastomeric bearings on the flapping axis. The twin-blade tail rotor has a hub which needs no lubrication. Other advanced features of the type are the use of an automatic flight-control system, with the capability of altitude maintenance and augmented stability; dual hydraulic systems; a nodalized suspension (Bell's patented 'Noda- Matic' concept of 1972, by which the fuselage is suspended from points of no relative motion in the engine mounting) to reduce fuselage vibration by about 80%; and an engine decking that is also used as a maintenance platform for the engine, transmission and rotor hub.

The 214B BigLifter carries to an extreme the Bell design philosophy of a twin-blade wide-chord main rotor, each of the blades having a chord of no less than 88.9cm. The transmission and rotor-drive systems are well proved by earlier use in the 214A, after development in the experimental KingCobra gunship helicopter.

Although it is intended mainly as a weight-lifter, the 214B can carry up to 14 passengers in addition to its crew of two. As a weight-lifter, however, the 214B can carry up to 1814kg internally, or up to 3175kg externally on its cargo hook, which is cleared for flight with loads weighing up to 3629kg. This weight-lifting capacity is also useful in the agricultural role, in which up to 3629kg of chemicals or 3023 litres of liquid can be uplifted. The considerable liquid-carrying capability of the 214B is also useful for fire-fighting.

The only current version of the Bell 214B is the Model 214B-1, which is intended for different certification standards, and is thus limited in the internal load-carrying role to a maximum take-off weight of 5670kg.

The Bell 214A is the military version supplied to the Iranian army as the Isfahan, while the Model 214C is the search-and-rescue variant operated by the Iranian air force.

On April 29, 1975, three days after delivery to Iran of the first production 214A, this machine was used to set up five records for altitude and time-to-height. The records were for a maximum altitude of 9071m, maximum sustained altitude in horizontal flight also of 9071m and times of 1 min 58 sec to 3000m, 5 min 13.2 sec to 6000m and 15 min 5 sec to 9000m.

Before the overthrow of the Iranian royal dynasty, an agreement was signed for Bell and Iranian Helicopter Industry (IHI) to co-produce the 214A, after which IHI was to have built some 350 of an improved variant, the Model 214ST (Stretched Twin), with a coupled turboshaft powerplant and greater size. This scheme has now been abandoned, and with it has been lost the short-term chance of Bell producing a civil model based on it.

Bill Gunston "The Illustrated Encyclopedia of Commercial Aircraft", 1980

- Iran's Bell 214s were operational in the war with Iraq, flying alongside CH-47Cs.