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Tamsin, the pilot, was joined for this journey by the headmaster of Leckhampton Church of England Primary School, Peter Gardner, who was marking his retirement. Peter's wife Christine, who organised the flight as a surprise, accompanied him over Leckhampton, where the primary school children spelt out his initials on the playground, Hartpury, where Peter had formerly been headmaster, and their home in Tibberton.
Although a larger R66 gas turbine powered model is being planned and built, the current Robinson range of two-seat R22 and the four-seat R44 are both represented in the Rise fleet and both use Lycoming piston engines almost identical to those found in such small fixed-wing aircraft as the Cessna 172 - like N3540U seen in the background of the pictures above.
The R22's four-cylinder prime mover is horizontally mounted and - like the Rolls Royce Merlin but unlike its BMW equivalent in the Messerschmitt Bf 109 - is carburettor-equipped. Running on 100LL grade aviation gasoline, the normally-aspirated Lycoming is air cooled through a direct drive squirrel-cage blower.
The R22's basic structure is welded chrome moly tubing with a forward fuselage made of fibreglass and aluminum. The vertical and horizontal stabilizers are aluminium and the R22 has an cabin enclosed by a Plexiglas canopy with side-by-side seating for a pilot and passenger. The doors may be removed for photographic flights, interior cooling at high temperatures or for a 10.4 lb weight saving.
Instead of a floor-mounted cyclic stick between the pilot's knees, the R22 uses a unique teetering "T-Bar" control connected to a stick that emerges from the console between the seats. This makes it easier for occupants to enter and exit the cabin and reduces chances of injury in the event of a hard landing. The teeter bar has a hand grip on both sides that hangs down between the pilots' legs. Thus, if teetered to the right, the right side pilot would be flying and the left grip would be about 12 inches above the left pilot's lap. The left part of the bar, left collective control, and left tail rotor pedals can be removed if the left seat occupant is not certificated to fly the R22 or needs the room for technical or observer duties.
Collective and cyclic pitch inputs to the main rotor are transmitted through pushrods and a conventional swashplate mechanism. Control inputs to the tail rotor are transmitted through a single pushrod inside the aluminium tail cone.
To ease the pilot's workload, a mechanical throttle correlator adjusts the throttle as the collective pitch control is raised or lowered. The pilot only needs to make small adjustments by twisting the throttle grip on the collective throughout the flight regime. Later models such as the R-22B are also equipped with an electronic governor which works to maintain RPM within normal operating limits (between 97 and 104% RPM) The governor is only active when the engine is running above 80% RPM and is effective in normal flight conditions.
Although the Mariner version has floats, the normal production R22 has skid landing gear and so requires either detachable wheels or an hydraulic jacking trolley for unpowered movement on the ground.
Compared with the original R-22 they have the slightly nose-down ground attitude and rear-extending skids introduced on the R-22A. As discussed above, the R-22B added an engine speed governor along with rotor brake and auxiliary fuel tank. It has been offered as an instrument trainer version, with optional fixed floats as the R22 Mariner, and other special configurations for police work and electronic news gathering. The R22 BII - only available in basic skid format - added a Lycoming 0-360 engine, remade of lightweight materials and derated for sea level operation. It allows greater altitudes for hovering in and out of ground effect (HIGE/HOGE).
The lightweight Lycoming 0-360 engine had to be derated - that is, optimised to run at less than maximum power- to ensure maximum engine and transmission life because at "full chat" at sea level it was capable of producing more power than the transmission and rotor system could safely handle.
However, as the air becomes thinner with increasing altitude, maximum available horse power decreases, reaching a point where the throttle can be completely open and rotor RPM is controlled by collective position. By derating the engine at sea level, the R22 BII achieves acceptable high-altitude performance without use of super ot turbo charging, thus saving the weight, complexity, unreliability, and shortened engine life of a forced induction system.
Unlike fuel injected engines, those with carburettors to mix air with fuel are susceptible to carburettor icing, which can lead to loss of engine power, and if not corrected, total shutdown of the engine. However, although heated air supplied to the carburettor can prevent or cure icing, it also causes a reduction in engine power output because hot air is less dense.
Nevertheless, the Carburettor Air Temperature (CAT) indicator does not read correctly below 18" of intake manifold pressure, so icing conditions require applying full carburetor heat in that instance.
Power is transmitted from the engine to the rotor system through a drive belt. Originally, the R22 used separate v-belts but this system proved problematic, as belt length variations due to manufacturing tolerances caused some belts to overstress and break. The problem was solved by replacing the individual belts with a single multi-v belt, running on matching multi-groove sheaves. The upper driven sheave is mounted on the tail rotor drive shaft next to a flexible coupling and is raised and lowered relative to the engine-mounted driving sheave by means of a small electric gear motor. During shutdown, the gear motor is used to lower the top sheave to loosen the drive belts. For startup, the engine is started with the belts loose, allowing the engine to run without spinning the rotor system. Immediately after engine start, the clutch switch located in the cockpit is closed by the pilot, powering the gear motor to slowly move the top sheave up to flight position which tightens the belts. The gear motor is thereafter controlled by a pressure-sensing switch, automatically maintaining proper belt tension during flight as the belts warm up and stretch. The tail rotor drive shaft also turns the main transmission, delivering power to the main rotor shaft through a pair of spiral bevel gears.
The top sheave has an over-running clutch built in to the middle to allow the rotor system to continue to rotate in the event that the engine stops. This allows the R22 to enter auto rotation and land in a controlled manner after loss of engine power. Because the main rotor has very little mass and resulting inertia, auto rotations in an R22 are exciting at best and require careful and proper execution to assure a successful outcome. Much time is spent in training practising various types of autorotation awith a target speed of 120 km/h and a glide angle of approximately 4:1.
After 2 200 hours of flight time every R22 must undergo an extensive overhaul either at the Robinson factory or at a factory authorised service centre. An even more extensive component part replacement is scheduled for every 4 400 hours during which the helicopter is virtually rebuilt as new.
In 1997, Jennifer Murray became the first woman to circumnavigate the world in a helicopter, covering a distance of 36,000 miles in 97 days in her Robinson R44.
Like the R22, the R44 is a single-engined helicopter with a semi-rigid two-bladed main rotor, a two-bladed tail rotor and skid landing gear. It has an enclosed cabin with two rows of side-by-side seating for a pilot and three passengers and tail rotor direction is reversed compared to the R22 for improved yaw control authority. On the R44 the advancing blade is on the bottom.
In January 2000, Robinson introduced the Raven with hydraulically-assisted controls and adjustable pedals followed in July 2002 by the Raven II featuring a more powerful 245 bhp, fuel injected Lycoming flat six engine and wider blades, allowing a higher gross weight and improved altitude performance.
However, it started out by losing the race to fill a 1964 US Army requirement for a light obervation helicopter to the Hughes OH-6. Undeterred, Bell draughtsmen modified their product for civilian use with a larger more streamlined fuselage that is so well known today. Capable of carrying five people and their baggage, the Bell JetRanger changed the public perception of rotary winged flight.
With a cruise speed of around 125 mph and the ability to land on small lawns and helipads alike, the JetRanger is comfortable and roomy for passengers and visibility is excellent, even from the back of the cockpit. The single gas turbine machine is also one of the world’s safest helicopters.
As well as a chic corporate transport, the JetRanger has also been used for scenic flights, photography, police surveillance work, crop spraying and as a training machine - often used by pilots graduating from piston engined helicopters.
Flying a helicopter has been described as like balancing five broomsticks on the fingers of one hand but the JetRanger is one of the most inherently stable helicopters, even for low hours trainee pilots, and is enjoyable to fly.
The first three flights round the world by helicopter were all made in Bell 206s (two JetRangers and one LongRanger), and each set a new record. Dick Smith’s 35, 257 mile solo flight took place in 1982. He was followed by Ross Perot Jr, whose record stood for twelve years, until Ron Bower managed to beat it, covering 24,800 miles. Since then Bower’s record has been beaten, but in other helicopter types.
