Читать книгу The Immortal Beaver - Sean Rossiter - Страница 6

Facing page: Smiling test pilot Russ Bannock climbs out of Beaver prototype CF-FHB-X early in the afternoon of August 16, 1947, after the second takeoff and landing of its two-part first flight. He tells chief engineer Doug Hunter (grey hair), chief designer jaki JakimiuK (jacket) and aerodynamicist Dick Miscodes that the airplane is a delight to fly. DHC

No matter how much metal working finesse goes into the construction of a prototype airplane, there is a roughness around the edges, a dimpled aluminum skin and a general lack of finish chat is the mark of a handbuilt machine. Details come later. The esthetics can watt. No need for a racy paint job yet. Let’s see if this thing; will fly.

Still, the de Havilland Canada DHC-2 Beaver prototype that Wing Commander Russ Bannock climbed into shortly before 10 A.M. on August 16, 1947, was a handsome airplane in its own way: a sturdy-looking, squared-off, pug-nosed fuselage, fronted with a big, flat, non-nonsense radial engine, with its bulk set on thick land inggear struts that gave it the look of a heads-up bulldog ready to leap off the ground.

To the eyes of the engineers who had designed and built it, though, this first Beaver looked distinctly odd on wheels. The Beaver had been intended from the beginning to operate from water, a more demanding medium to leave and return to than concrete or grass. It looked better on floats. Still does.

In fact this prototype had, until a few weeks before, been mounted on floats in Bill Burlison’s experimental shop. Its reserve of power in operating from water would be the Beaver’s competitive advantage over other single-engine bush planes, including the one that looked to be the Beaver’s main competition in the postwar market, the Fairchild Husky (which had flown for the first time more than a year before near Montreal). The Husky was a bigger plane powered by the same engine, giving the Beaver a performance edge.

It is part of the lore of the Beaver that only during those last few weeks before its first flight did it occur to someone in the shop that the de Havilland Aircraft of Canada (DHC) factory at Downsview is totally landlocked. The city of Toronto lay between the factory and the Lake Ontario waterfront. The Beaver was on floats.

“In our preoccupation with the floatplane the design and construction of a wheeled undercarriage had been postponed,” the Beaver’s aerodynamicist, Dick Hiscocks, dryly recalls.¹ By July the Beaver was photographed with a wheel landing gear while undergoing its fuselage stress tests.

Its landing gear was not the Beaver’s only improvised feature, but it was one of the most successful. In a matter of hours “a block of rubber in a sort of nutcracker arrangement,” as Hiscocks characterizes it, “was pressed into service.”² With more time, a more conventional oleo, or combined air-and-oil type of shock strut arrangement, might have been used. No doubt such a mechanism would have given trouble in the north, where oleo seals froze solid and then leaked.³ In fact, the use of rubber as a shock-absorbing device was an old engineering ploy of the English de Havilland company of Hatfield. It was used, in a different way, on the company’s wartime Mosquito fighter-bomber.

Nevertheless, from that time on, a Beaver on wheels has always looked odd and somehow incomplete, like Ginger Rogers in a wheelchair. Ernest Krahulec, who would be the Beaver prototype’s mechanic when it went into service with Russ Baker’s Central British Columbia Airways and later Pacific Western Airlines, always took care to save that particular set of wheeled landing gear for that unique aircraft. Only that set of landing gear would fit that airplane.

The first Beaver was singular in other ways. The valleys and wrinkles on the aluminum fuselage skin, where hand-formed panels were riveted to the interior structure, were emphasized by seemingly random reflections off the polished metal on the sunny morning of its first flight. A crew in the experimental shop had stayed up all night polishing the Beaver, while Charlie Smith manned the stores-department desk in case they needed any last-minute parts. A matte black anti-glare panel in front of the windshield was the only paint on the Beaver’s gleaming fuselage.

Most of the markings an aircraft carries are meant to identify it. If anyone from outside the DHC plant—or most of the workers inside it, for that matter—wondered what the strange, angular was, no clue was offered by the white lettering on a horizontal black stipe running across the prototype’s vertical tail: CF-FHB-X. CF. made it a Canadian-registered airplane, which revealed very little. The Letters FHB said a lot to anyone who knew what they stood for.

Those letters were a tribute to the Beaver’s chief design engineer, a low-key, can-do, problem-solving wizard named Frederick Howard Buller. The x was for Experimental.

CF-FHB-X, the handbuilt and polished Beaver prototype, undergoing engine runups and control surface tests shortly before its two-part first flight the morning of August 16, 1947. DHC VIA PETER M. BOWERS

There was almost nothing experimental or tentative about the Beaver that morning, aside from the fact that it had not yet flown. All successful aircraft are designed with specific missions in mind, but few have succeeded so spectacularly and for so long in such demanding circumstances as the Beaver. In conditions where arrival and departure involve dangerous terrain or capricious weather, there is no substitute for a Beaver. Unlike most fixed-wing aircraft, the Beaver can get out of pretty much any situation it can get itself into. The demand for Beavers is such that they are being rebuilt better than new. More Beavers are flying today than ten years ago—not just as millionaires’ restorations, but as hard-working commercial aircraft flying in the most unpredictable weather conditions in the world along the foggy and mountainous North Pacific coast from Portland to Anchorage.

Histories of flight are usually organized to show the advances in speed, ceiling, range and payload—the categories in which aviation records are set. But it is also possible to see the history of aviation as a quest for the most important goal, safety aloft, with the Beaver as its outcome. As early as 1929, with the Guggenheim safe aircraft competition that offered $150,000, a lot of money in the twenties, the search had begun for an aircraft that could meet such stringent conditions as a requirement that it be controllable in flight at only 35 mph.⁴

The Fairchild F-II Husky first flew more than a year before the Beaver, and was its competition for a 25-30-plane order from the Ontario Provincial Air Service. The Beaver’s performance edge won it the OPAS contract. About a dozen Huskies were built. PETER BOWERS

Hiscocks, who formulated the Beaver’s wing and its high-lift devices, makes his own claim for the Beaver when he calls it “the first serious short takeoff and landing (STOL) airplane.”⁵ By this he means that, while there were STOL aircraft, such as the Guggenheim competitors and Germany’s wartime Fieseler Storch, that offered short-field performance even better than the Beaver’s, not until the Beaver appeared did such an aircraft carry useful commercial payloads. And, while some subsequent turboprop STOL aircraft (including the Turbo Beaver) exceed the Wasp Junior-powered Beaver’s takeoff and landing performance because of their greater power, the turboprop engine is not at its best in the kind of short-haul, low-level, island-hopping work that is the Beaver’s forte.

Following the Beaver’s success came a line of de Havilland Canada aircraft that continued to embody the single most critical element of flight safety: the ability to fly slowly and under control, and thereby take off and land in as short a distance as possible.

Russ Bannock was hired as much for his organizational abilities as for his talent as a pilot. He was taken on by DHC managing director Phil Garratt, firstly as operations manager and second as chief test pilot. Bannock eventually became president of the company during the mid-1970s—a difficult period in the company’s history when spiralling developmental costs on the Dash-7 commuter airliner series led to a government takeover.

As a test pilot, Bannock had more in common with the future breed of scientific evaluators than the daredevils of the past who had flown the wings off new types in terminal-velocity dives. He had made it his business to be present when most of the important engineering decisions about the Beaver were made. The prototype was no stranger to him when it was rolled out of Bill Burlison’s experimental shop that August 16 morning.

Although Bannock was no engineer, he had worked closely with the engineering department to resolve the difficult issue of what engine should power the Beaver. Once that was decided, Bannock stayed in touch with the changes mandated by the new engine, changes that extended from nose to tail. His preparation for the first flight would be to work out and review “a test program to develop handling characteristics, performance criteria, and all the data required to take the aircraft up to certification by the Department of Transport.”⁶

Inside the cockpit of this outwardly spartan prototype, there were touches of something close to the exotic. Four doors on a small airplane! Having doors for both pilot and co-pilot verged on the luxurious, but was pure practicality for an airplane expected to be so fully loaded the rear doors would be blocked, an airplane that would normally park on one side or another of a dock. In time, two more hatches, in the roof and floor, would be added.

The instrument panel was as streamlined as anything else on the aircraft. It curved back and down from the base of the windshield with its three vertical slots down the upper middle for the throttle, propeller pitch and fuel mixture levers—equally accessible to pilot and co-pilot—and was neatly finished at the bottom of the slots with a chrome strip on which black paint outlined the shiny capital letters DE HAVILLAND. There were no seats in the prototype except for the pilot’s.

That morning Bannock looked like the fighter ace he was, in the same Royal Canadian Air Force sunglasses and blue-grey flight suit he had worn on Mosquito operations. Not a hair was out of place. His flight suit, besides fitting well, had plenty of pockets for the pencils, pens, notebooks, maps and calculated data he would carry on the flight. The trousers, rather short to give him freedom in operating the rudder and brake pedals, were crisply ironed. Thick, off-white parachute straps converged from his shoulders and crotch at a quick-release latch on his lower midriff.

Although most test pilots would say that flying a wide variety of aircraft is the best preparation for test flying, very few could claim to have flown every type in the RCAF wartime inventory, with the British Commonwealth Air Training Plan and then overseas, or that their logbooks had recorded recent post-overhaul test flights in PBY Canso and Catalina flying-boats, DC-3 transports “and even Lancasters”—four-engine wartime bombers converted by DHC for peacetime mapping survey and maritime patrol missions.

For the finishing touch to his preparations, Bannock had recently flown with George Phillips, chief pilot of the Ontario Department of Lands and Forests, in one of the government’s Stinson Reliants, which had the Beaver’s high-wing layout, a less powerful engine than the Beaver’s Wasp Junior, and was also mounted on floats, Bannock was killing two birds with one stone by getting to know Phillips. Lands and Forests, on behalf of the Ontario Provincial Air Service, was dangling an order for twenty-five airplanes to replace the prewar Stinsons, one of which had shed its wing in flight, before the eager design teams at Fairchild in Montreal and DHC in Downsview. Lands and Forests was a major influence on the Beaver’s preliminary design, encouraging DHC’S engineering director, Doug Hunter, a wartime expatriate from the English parent company, to give it a design load factor of 5.25—that is, the Beaver is theoretically capable of carrying five times its gross weight.

The first flight of a new airplane in 1947 was a much less complicated affair than it is today. No special instrumentation was carried in the Beaver, and no computer-generated schedule governed Bannock’s actions in the air. He was pretty much on his own. He recalls his first-flight agenda for the Beaver. It was simplicity itself.

Plans for the first flight included the following:

Ground handling checks, including taxi tests.

High-speed taxi tests on the main runway to check directional control and rudder forces.

High-speed taxi tests to liftoff with and without flaps to check all control forces. Takeoff and climb to approximately 3,000 feet and carry out general handling and engine performance [tests] and obtain a general impression of speeds at different power-settings.

One strong memory Bannock retains after fifty years is the group of people whose labours had produced the creation he would now subject to a thorough investigation. They were bunched together on the concrete apron outside the experimental shop at the north end of Runway 33.

“I recall seeing Philip Garratt, managing director; Doug Hunter, engineering director; Jaki Jakimiuk, chief designer; Fred Buller, chief design engineer; Dick Hiscocks, chief aerodynamicist, and Jim Houston, power plant engineer.”

All six were wearing white shirts, in the formal style of their wartime generation of professionals, four of them with ties. The Beaver’s design team, the next day’s Globe and Mail photo caption stated, “consists of three young Canadians and an expert from Poland and England.”

Young Canadians Hiscocks and Buller, the two with the most intimate understanding of the airplane’s outline and inner workings, had their sleeves rolled up, looking businesslike and technical in their spectacles. Buller, of course, had just become aware that CF-FHB-X was named after him. Houston, the engine man, was tieless and in a short-sleeved shirt that acknowledged the impossibility of the man responsible for the overall powerplant installation wearing a white shirt with long sleeves. Hunter, the quite British production overseer from Hatfield, had turned his cuffs up only one turn.

The Beaver prototype during flight tests later in 1947, after it had earned the nose-to-tail speed line that characterized most civil production Beavers, DHC

Among the five men most responsible for the Beaver that morning, only their supervisor, the aristocratic Pole known to his colleagues as Jaki Jakimiuk, continued to wear his suit under the hot mid-morning August sun. It was heavily wrinkled at the elbows and knees. None of them wore sunglasses. Sunglasses were for pilots.

Garratt, also in shirtsleeves, was photographed later that day with a distinguished group that included Punch Dickins and Frank MacDougall, Ontario’s Deputy Minister of Lands and Forests. MacDougall would soon effectively decide, with his initial twenty-five-aircraft order, whether the Beaver or the Husky would be the bush plane to go into production.

“With full fuel (79 Imperial gallons) and a single pilot,” Bannock recalls, “we were well within the calculated centre-of-gravity range, so there was no ballast on-board.

“It was a lovely summer day, with a slight northwest wind, so I taxied out onto Runway 33 at approximately 10 A.M. and commenced the high-speed taxi tests, a series of skip-hops, checking brakes, checking rudder control—directional control.

“At the south end of Runway 33 (which gave me 6,000 feet of paved runway), I went through the takeoff checks that we had established. Runway 33 faces northwest, into the prevailing wind. I was hoping there would be no crosswinds.

“I commenced a series of high-speed taxi tests doing a short liftoff for the last two or three. I remember thinking I didn’t have enough brake-pedal travel for directional control on the ground. Later we installed pads on the brake pedals, which gave me greater leverage on the brakes. The next time I would taxi back and open up and just get airborne at the end of the run. I probably did that four or five times, checking longitudinal control, lateral control, just general handling, before deciding to take off.

“Using about 10 degrees of flap I opened up the engine to takeoff power (36 MP at 2,300 rpm) and was surprised how quickly the aircraft became airborne [in 15 seconds, according to the Globe and Mail’s story⁷]. A climbing speed of 74 mph was established with power reduced to 30 MP [manifold pressure, a measure of power derived from the amount of air being pumped into the engine] at 2,000 rpm. I levelled out at about 3,000 feet, staying within gliding distance of the field in case I had any powerplant problems. Cruise power was set at 28 MP at 1,800 rpm.

“After doing some gentle turns, climbs and descents, my first reaction was how pleasant the Beaver was to fly. It had good pilot visibility, good aileron response, and I had the feeling of lots of power up front.”

It was at just this moment, with Bannock warmed by the midsummer sun shining through a windshield that, on the prototype alone, was faired back overhead and into the wing’s leading edge, and the satisfaction of knowing the Beaver could fly and fly well, that the crisis struck.

Experimental shop and engineering staff peer at the pool of engine oil dripping from FHB’s powerplant after the abbreviated first flight. Access panels to the engine’s equipment bay are open. DHC

For most of the flight so far, barely more than ten minutes, Bannock had been preoccupied with the flight controls. He now paused to look out over the farmland that is now North York and Richmond Hill. Thornhill was a separate village. surrounded by fields, Dufferin Street was still a rural two-lane road which, during the war, had been interrupted by a liftgate at the end of Runway 27 whenever a newly built Mosquito fighter-bomber was being flight-tested.

Bannock, reassured by the big Wasp Junior’s steady throb on the climbout and the upward spiral he had maintained to stay over the airfield in case of trouble, had glanced at the engine instruments only a couple of times, and then very quickly. Now he looked again.

The oil-pressure gauge on the prototype was located on a three-in-one dial near the middle of the instrument panel. The all-important cylinder-head temperature gauge took up the top half, with the oil-and fuel-pressure gauges side-by-side below.

When Bannock glanced at it, the oil pressure was reading 35 pounds per square inch. The ideal figure is 60 psi. That concerned him, but his first reaction was to assume there was some problem with the instrument rather than the engine, which sounded normal. If the engine was losing oil, he knew, that oil would be streaming along the underside of the fuselage, out of sight.

That small, inconspicuous instrument now had Bannock’s full attention. His eyes returned to it in a matter of seconds. It read 10 psi.

It no longer mattered whether the problem was with the engine or the gauge. Damaging the engine would put the Beaver program that much further behind Fairchild’s Husky.

Bannock reached up toward the centre of the instrument panel and pulled the throttle lever back to the bottom of its slot, leaving the engine to idle. He trimmed the Beaver’s nose down, noting that the response from the elevators was not quite what he would have liked.

As he began a gliding circuit to the left with the engine barely ticking over, he could hear the fuselage skin popping in and out in the slipstream. The Beaver’s thick wing had been formulated to provide the maximum possible lift with the less-powerful engine it was originally designed around, so it was all the more effective when the Wasp Junior was adopted. This wing also made the Beaver a pretty good glider. So much so, in fact, that Bannock regards his dead-stick, or power-off, landing as no more than “reasonable.”

To the knots of white-shirted men who anxiously watched Bannock approach in near-silence, flying an airplane whose engine tests had been characterized by an unholy racket, this landing was impressive airmanship. Happy to see it on the ground and in one piece, they gathered around the Beaver, asking questions of Bannock as his door opened, then crouched down as the propeller ceased its desultory windmilling and, duckwalking underneath, looked up.

Ugly streaks of oil defiled the carefully-polished aluminum underside of the Beaver. Some of it began to drip on the concrete apron.