Robinson — the smallest production two-seater
So favourable was the response from readers to our comparison, published last October, of an Enstrom light helicopter and certain upper price bracket cars that this month we describe an even smaller aircraft, the diminutive Robinson R22, the nearest thing to a personal helicopter that any manufacturer has put into volume production.
When we journeyed through the fog to Cranfield in Bedfordshire, where the British importers, Sloane Helicopters, have their operational base, we could not help but remember the words of an American friend who dislikes Robinsons so much that he considers R22 time on a pilot's log to be worse than having antisocial diseases on his medical record. However, he is a regular flier of much bigger machines and is inclined to be biased against anything small, so we reserved judgement until we experienced for ourselves what the Robinson had to offer.
During that experience we were pleasantly surprised to discover that it was not at all what we had been led to believe, but an extremely agile, comfortable, good handling aircraft with none of the twitchiness we had expected of such a light machine.
Part of our friend's poor opinion of the Robinson undoubtedly stems from accidents involving early models, caused by in-flight delamination of rotor blades, but this defect has long since been remedied and the present blades are certified for 2,000 hours. The gyroscopic inertia of the rotor has also been increased by the addition of blade tip weights, slowing the response rate slightly but resulting in more docile handling than before and better autorotation characteristics.
Nearly ten years have passed since Frank Robinson formed his company in California, after which it took him just two years to get his first prototype into the air. Certification was granted in March, 1979, and in the four following years the company has grown to employ a staff of 180 producing some four completed aircraft each week, and to capture an estimated 57% of the piston-engined helicopter market.
Robinson's aim was to produce a "personal" helicopter as convenient transport for two people. It was never intended that the aircraft should be a working machine, but some 80% of the 400 or so now flying are in use as trainers rather than personal transport, partly due to low running costs and partly to excellent handling characteristics.
The first thing that impressed us was the way that one man could clip the aircraft's ground handling wheels to the brackets on the skids and wheel the aircraft out of the hangar to the start-up point without much effort. This feature, plus its dimensions (8' 9" high and 28' 8" long including the two-blade rotor) makes it ideal for operation from a garage-cum-hangar on the edge of a lawn-cum-helipad. What is more, its fixed and direct operating costs total only 42 dollars per hour in the USA, and if we assume that one air mile is the equivalent of one and a half road miles, a cruising speed of 108 m.p.h. can be achieved at an average cost of less than 26 cents per mile. Servicing, incidentally, is minimised by the use of greaseless bearings.
The R22 is by no means a bulk carrier, for with its 20 gallon tanks full a margin of only 384 lb. is left for pilot, passenger and baggage, that figure being reduced by the installation of any optional extras. Two eleven-stoners, therefore, will be allowed no more than 5½ lb. of baggage between them. However, the same two men can be carried for 240 air miles at 108 m.p.h. with none of the inconvenience of traffic jams or airport formalities. Its 6,500 feet hover ceiling in ground effect, and 4,500 feet out of it, present no problems in the UK save perhaps to Scottish Highlanders, whilst the service ceiling is way up at 14,000 feet.
Our day at Cranfield was so foggy that we saw no fixed-wing activity whatsoever, but the versatility of the helicopter is such that we were able to fly without difficulty. But it was rather a pity that we could not achieve the height for a decent autorotation, that engine-off landing which reveals much of not only the helicopter's handling properties but also the skill (or otherwise) of its pilot.
From the outside, the R22 looks crowded when two people sit in it, but there is really ample room and we experienced no in-flight elbowing. What is more, engine noise was so moderate that we were able to converse even without headsets.
Start-up and rotor engagement procedures were pretty standard, though it was our first experience of a clutch engaged by an electric motor which moves pulleys to take up the slack in the main drive belt. The tachometer, too, was new to us, for in place of the usual concentric scales with two needles (one engine, one rotor) sharing the same central pivot, they were quite separate and full engagement was indicated when the two needles, pivoted on opposite sides of the outer rim of the instrument, pointed to the same mark on the vertical scale down the centre.
The feature which stood out most was the one, centrally mounted cyclic stick doing the job of two. This had a T-bar across the top, with a vertical handgrip at each end, centrally pivoted so that either end could be brought down by whoever was going to do the flying. The extra articulation was disconcerting at first, particularly as a slight, unfamiliar torque had to be overcome for fore / aft movement, but one soon got used to it. It could even be seen as an advantage, for access to the seat was possible without cocking any legs, whilst the action of bringing down the cyclic handle on the pilot's side to comfortable, wrist-on-knee level hoisted the opposite handle out of harm's way, an important feature when carrying a non-pilot passenger with a tendency to grab at things.
Another point which we liked was its certification for solo flight from the right hand seat, so that instruments, radio etc. can be reached without changing hands on the cyclic or crossing arms. This is a matter of personal preference, of course, but we always find it none too easy to reach out for things when flying solo from the left seat, a point which probably never occurs to fixed-wing pilots.
After some hovering, air-taxying, moderate climbs and a few turns, all at low level over the otherwise deserted, mist-covered airfield, we progressed to quick stops and much tighter turns, pulling an impressive amount of G in steep banks. Even more impressive was the very little adjustment needed to relate engine r.p.m. to various load (rotor blade pitch) settings. This is always difficult for students on piston-engined aircraft, and nothing like as easy as knowing when to change up and down a gear when driving a car on steeply undulating roads.
The R22 has a throttle mechanism which is partly synchronised with collective pitch control, so that from cruise setting (22 inches manifold pressure) down to autorotation entry (13 inches) and back up to power climb (25 inches) the r.p.m. varies by no more than 2% even with no twist-grip movement at all, thus greatly reducing the work load on pilots. Indeed, we were at ease in this aircraft in a very short time, although some of that was due to the presence in the left seat of former Fleet Air Arm pilot David Dixon.
On the safety side there are warning devices in excess of authority requirements, even a low r. p.m. horn which blasts out if the collective lever is raised to increase blade pitch beyond the degree corresponding to r.p.m.
An unfamiliar aircraft always takes some getting used to, far more than a strange car, but we got the hang of the Robinson fairly quickly and found it far easier to fly than some other piston-engined helicopters. Its cruise speed is higher than some bigger aircraft, and even though it is no heavy lifter it provides fast, convenient, exhilarating, traffic-beating transport for a most reasonable outlay. What is more, it has a very pleasing appearance, weighs no more than 930 lb. with full tanks and turns in a fuel consumpuon of about 12 air miles per gallon.
In January, the fly-away price at the Torrance factory was just under 76,000 US dollars, and Sloane Helicopters will be able to quote the current UK price. The address is 45 Seagrave Road, London SW6 1SA. — G.P.