The Bell 47G2 manufactured by the Bell Aircraft Corporation is the successor of the Bell 47G. The two models are very similar, but the G2, which obtained the type certificate on the 20th of January 1955, is powered by a more powerful Lycoming VO-435-A1 engine.
There are several versions of this engine known with the designation –A1A, A1B, A1D, A1E and A1F, but all have a max power of 194/260 kW/hp.
However on this model the engine is derated to a maximum continuous rating of 149/200 kW/hp at 3’100 rpm, from sea level up to an altitude of 1’523 m (5’000 feet).
This mean that the pilot must strictly observe the placard with the manifold pressure limits.

Compared to the Bell 47G the G2 offers a higher max take-off weight of 1’111 kg (2’450 lbs) instead of 1’065 kg (2’350 lbs). However the payload is slightly lower because the Lycoming engine is heavier (177 kg instead of 141 kg of the Franklin 6V4-200-C32) and the G2 is equipped with more accessories (such as for example hydraulic power control).
The G2 is equipped with an electric starter initially installed on the center console with a turn-key. Later this was replaced with a button located on the top of the collective pitch lever.
The G2 was furnished with standard hydraulic boost servos (cyclic control). The system includes push-pull tubes, bell cranks, a hydraulic system, and provision for dual controls.
On the Bell 47G hydraulic boost servos were available as an optional.

Landing on the Mont Blanc

There is a feat related with the Bell 47G2 which has passed into legend. It is the historical landing which made on June 6, 1955 on the summit of the Mont Blanc (4’807 m – 15’776 ft) the French pilot Jean Moine (1915-2000).
The helicopter registered F-BHGJ (serial number 1342) was the first G2 manufactured by Bell. To establish this record the helicopter was lightened as much as possible. Some non vital parts such as for example the battery, alternator, second fuel tank, were taken down.
According to Moine, who was accompaigned by the mountain guide André Contamine, the historical landing was made without particular difficulty.

Engine

The helicopter is powered by a six-cylinder horizontally-opposed air-cooled Lycoming VO-435-A1 with a maximum power of 194/260 kW/hp at 3'100 rpm. The helicopter has a two-stage planetary transmission with a 9:1 reduction ratio.
The two interconnected gravity fuel tanks located on the centre of gravity have a total capacity of 162 litres. A selector permits to separately read the quantity of fuel in each tank. 
The electrical system incorporates a 50 ampere 28 volt generator, and a heavy-duty battery for quick, dependable engine start. There is obviously also an external power receptacle.

Performance data

With a gross weight of 1'111 kg (2'450 lbs) the Bell 47G2 with metal rotor blades has a max. cruising speed (at sea level) of about 136 km/h. The never exceed airspeed from sea level up to an altitude of 430 meters is 161 km/h. From this altitude up the cruising speed must be decreased of 1.84 km/h (1 knt) for each additional 100 meters (305 ft) of climb. A sea level the maximum rate of climb at 72 km/h (45 mph) is 245 m/min (800 ft/min).
At its maximum gross weight the helicopter has a service ceiling of 4'022 meters, while the hovering ceiling in ground effect (IGE) is theoretically possible at an altitude of approximately 3'047 meters (10’000 ft), or 975 meters (3’200 ft) out of ground effect (OGE). The maximum range is 383 km.
These performance data are based on operation in still air (zero wind) under NACA standard atmospheric conditions.

Rotor and engine limitations

During normal operations in flight the main rotor rpm must be kept between 294 and 360 rpm, while the engine rpm must be kept between 2'900 and 3'100 rpm (oil pressure 40-60 psi and cylinders head temperature 100 to 224°C).

Dimensions, weights and payload

The main rotor of the Bell 47G2 has a diameter of 10.72 m, while the tail rotor has a diameter of 1.72 m. The fuselage has a total length of 8.33 m. The max height of the helicopter is 2.85 m.
The empty weight of the helicopter fitted with a skid-type landing gear is of approximately 725 kg (1'600 lbs), while its max take-off weight (MTOW) is 1'111 kg. Deduced the std weight of the pilot (77 kg/170 lbs), and with a fuel and oil reserve for one hour of flight the payload is approximately 273 kg (600 lbs).

Autorotation

In case of engine or tail rotor failure the pilot must immediately execute an autorotation maintaining an indicated airspeed of at least 64 km/h (40 mph). At an altitude of 15 metres (50 feet) over the landing place he must decelerate constantly. At 3 metres (9-10 feet) over the ground the pilot must apply collective pitch as necessary in order to cushion the landing.
However in the event of an engine failure hydraulic control is lost. So in addition to correctly entering and executing the autoration to "flare, level, and cushion", the pilot as the additional workload of managing the cyclic without hydraulics. A later version, the Bell 47G3-B2A, used the 900 series transmission that supported the hydraulic pump allowing the hydraulics to operate after an engine failure and during autorotation.

Accessories

A number of accessory kits were available for installation on the Bell 47G2 which multiplied its versatility. Among them there were dual controls, night flight equipment (which included position light, landing light, instrument panel illumination and cabin interior light), floats for operation from land, water, marsh, ice or snow, external litters attached to the cross tubes of the landing gear, spraying, dusting or fogging equipment, kit for the transportation of sling loads, snow shoes, external cargo carriers, radio (there were several radios available such as for example Lear LTR-6, Lear LTRA-6, ARC-12 with variable prices ranging from 860 to over 1’375 US $), cockpit heater and defroster, rotor brake, fire extinguisher, first aid kit and a shoulder harness kit.

The Bell 47G2 in Switzerland

The Bell 47G2 was presented in Switzerland for the first time on June 30, 1955, by French pilot Jean Moine (1915–2000), one of Europe’s foremost pioneers in the use of helicopters in mountainous terrain. For this demonstration, Moine flew the aircraft registered F-BHGJ—the same helicopter that had successfully landed on the summit of Mont Blanc only a few weeks earlier.
To captivate the audience, Moine performed a spectacular vertical climb immediately after takeoff, ascending straight upward like an elevator to an altitude of approximately 1,000 meters (3,000 feet).
Pilatus Air Service became the first Swiss company to acquire a 47G2. This particular helicopter was historically significant as the first G2 manufactured under license in Italy by Costruzioni Aeronautiche Giovanni Agusta. Registered as HB-XAP (serial number 65, built in 1955), it was ferried from Cascina Costa, Italy, to Kloten, Switzerland, by pilot Oswald Matti on December 28, 1955.
Between 1956 and 1957, the helicopter saw only limited use, accumulating a total of just 282 flight hours. 
From June 1 to June 4, 1957, HB-XAP was flown by Sepp Bauer to complete the helicopter training of Hermann Geiger, the renowned Swiss alpine rescue pilot. Geiger had begun his helicopter training in France at the Fenwick School, where Jean Moine served as chief pilot.
From March 1958 onward, HB-XAP was based in Germany, where it was used extensively for the training of Bundeswehr pilots, logging several hundred flight hours within a few months.
The helicopter’s operational career ended on November 19, 1958, when it was damaged during an autorotation training exercise. Although neither the instructor nor the student pilot was injured, the aircraft caught fire and was completely destroyed.

Heliswiss Bell 47G2 fleet

Heliswiss immediately realised that the G2 better suited its need and decided to replace the Bell 47G HB-XAE with the Agusta-Bell 47G2 HB-XAO (s/n 116 b/y 1956).
The new aircraft was ordered on the 16th of August 1955 and delivered on the 20th of March 1956. It was purchased for a price of about 210’000 Sfr. and was equipped with dual controls, night lighting equipment, and barycentric hook.
The service life of this helicopter was quite limited. On the 24th of September 1956 it was damagaed at Innertkirchen (Berne Alps) during a series of transportation flights. The helicopter was repaired and since March 1957 it was again used. One year later, on the 10th of March 1958, during a series of ski flights the helicopter was newly damaged in Gstaad/BE. It was repaired and then sold as YU-HAO.
To replace the HB-XAO Heliswiss purchased HB-XAT (s/n 1632 b/y 1956), a second hand machine previously registered N2808D, which entered in service on March 20, 1957.

In the course of 1958 two more aircraft were purchased: HB-XAW (s/n 2180 b/y 1958) and HB-XAX (s/n 2195 b/y 1958). For a short period Heliswiss also rent the Agusta-Bell 47G2 F-BDVL usually in service with Briand SA, an aerial company based in Paris.
The helicopters mentioned were mainly used for the transportation of people and goods the Swiss Alps. 
In the role of aerial cranes the G2 were able to lift a payload of 200 kg (445 lbs) up to an altitude of about 3'000 meters (9'850 ft).
Moreover they were used for other tasks such as for example pilot training, spray flights, advertising, photographic and search and rescue flights on behalf of the Swiss Air Rescue Guard.
With its (Agusta-)Bell 47G2 fleet Heliswiss during the Winter 1957 begun a new kind of activity: the heli-skiing.
Until this moment during the long Winter months helicopters were not in fact often used. For this reason Heliswiss decided to deploy its aircraft in the most known Swiss ski resorts, such as for example St. Moritz/GR and Gstaad/BE.
In the Grison Alps the helicopter transported the skiers on the top of the most famous mountains such as for example Corviglia (2'486 m/sm – 8'158 ft), Piz Rosatsch (2'950 m/sm – 9'680 ft), Piz Kaesch (3'100 m/sm – 10'175 ft) or Piz Corvatsch (3'250 m/sm – 10'666 ft).
For information the transportation on the Piz Corvatsch required about 15 minutes and cost 140.— Sfr., a lot of money at that time! It is no coincidence that the main customers which used the helicopter were the rich families such as for example the Onassis and Niarchos.
"To control the helicopter at these altitudes with two passengers on board required great attention" told Walter Demuth, one of the first helicopter pilots in Switzerland.
"The place in cabin was quite limited and the passengers were not confortably seated next to the pilot. In return they had an exceptional visual in all directions, which is probably the characteristic most appreciated of this helicopter".
Among the most important feats related to the Bell 47G2 in Switzerland to mention the landing made on the 3rd of March 1957 by Leonard Kunz and Demuth on the Piz Zupo/GR at an elevation of 3'912 m (12’840 ft).