De Havilland Canada DHC-2 Beaver


The de Havilland Canada DHC-2 Beaver is a single-engined high-wing propeller-driven short takeoff and landing aircraft developed and manufactured by de Havilland Canada. It has been primarily operated as a bush plane and has been used for a wide variety of utility roles, such as cargo and passenger hauling, aerial application, and civil aviation duties.
Shortly after the end of the Second World War, de Havilland Canada decided to orient itself towards civilian operators. Based on feedback from pilots, the company decided that the envisioned aircraft should have excellent STOL performance, all-metal construction, and accommodate many features sought by the operators of bush planes. On 16 August 1947, the maiden flight of the aircraft, which had received the designation DHC-2 Beaver, took place. In April 1948, the first production aircraft was delivered to the Ontario Department of Lands and Forests. A Royal New Zealand Air Force Beaver played a supporting role in Sir Edmund Hillary's famous 1958 Commonwealth Trans-Antarctic Expedition to the South Pole.
In addition to its use in civilian operations, the Beaver has been widely adopted by armed forces as a utility aircraft. The United States Army purchased several hundred aircraft; nine DHC-2s are still in service with the U.S. Air Force Auxiliary for search and rescue. By 1967, over 1,600 Beavers had been constructed prior to the closure of the original assembly line. Various aircraft have been remanufactured and upgraded. Additionally, various proposals have been made to return the Beaver to production.
The Beaver's versatility and performance led to it being the preferred aircraft of bush pilots servicing remote locations in the Canadian north, and it is considered by aviation historians to be a Canadian icon. In 1987, the Canadian Engineering Centennial Board named the DHC-2 one of the top ten Canadian engineering achievements of the 20th century. The Royal Canadian Mint honoured the aircraft on a special edition Canadian quarter in November 1999, and on a 50-cent commemorative gold coin in 2008. Large numbers continue to be operational into the 21st century, while the tooling and type certificate for the Beaver have been acquired by Viking Air who continue to produce replacement components and refurbish examples of the type.

Development

Origins

Following the end of the Second World War, de Havilland Canada's management team, recognising that there were would be a corresponding downturn in military orders in the immediate post-war climate, decided to focus the company's energies upon finding work within the civilian sector. The company had recently hired Punch Dickins as Director of Sales; Dickins carried out an extensive market research program in the form of requesting and collecting feedback from other pilots, to understand what they needed in a new aircraft. It was on the basis of this information from the prospective operators themselves, as opposed to aerodynamic research or fiscal data, that the future aircraft has its origins.
In response, almost without exception, these pilots specified their desire for tremendous extra power and STOL performance, in a design that could be easily fitted with wheels, skis or floats. When de Havilland engineers noted this would result in poor cruise performance, one pilot replied, "You only have to be faster than a dog sled to be a winner". Other suggestions that were seemingly mundane, but important in the bush plane world, included the installation of full-sized doors on both sides of the aircraft, which meant that it could be readily loaded no matter which side of a dock it tied up on; the doors were also made wide enough to allow for a 44 Imperial gallon drum to be rolled up into the aircraft.
On 17 September 1946, de Havilland officially put together a design team consisting of Fred Buller, Dick Hiscocks, Jim Houston and W. Jakimiuk, led by Phil Garratt. The new aircraft was designed to be all-metal, using "steel from the engine to the firewall, heavy aluminum truss frames with panels and doors throughout the front seat area, lighter trusses toward the rear and all monocoque construction aft". At the time, de Havilland Canada was still a British-owned company and there were plans to fit the evolving design with the British de Havilland Gipsy engine. As a result of its comparatively limited power, the wing area was greatly increased in order to maintain STOL performance. When Pratt & Whitney Canada offered to supply war-surplus Wasp Junior radial engines at a low price, the aircraft ended up with extra power as well as the original long wing. The result was unbeatable STOL performance for an aircraft of its size.
In line with the convention for aircraft produced by de Havilland Canada being named after animals, it was decided that the new bush plane would be named after the beaver, which was known for its hard-working nature. On 16 August 1947, the maiden flight of the DHC-2 Beaver was in Downsview, Ontario; it was flown by Second World War flying ace Russell Bannock. After completing its flight test programme, the prototype received several adjustments and improvements in order for it to serve as a flying demonstration model ready for the sales circuit. The prototype was ultimately sold to Central British Columbia Airways, as a routine day-to-day working air-taxi airplane and continued to fly as such with various until 1980, after which it was retired and preserved. In April 1948, the first production aircraft was delivered to the Ontario Department of Lands and Forests, who had been a design partner.

Production

Initial sales were slow, perhaps two or three a month but as the plane was demonstrated sales started to improve. A key event in the Beaver's history occurred the next year, when the US Army commenced its search for a new utility aircraft to replace their fleet of Cessnas. The competition quickly boiled down to the Beaver and the Cessna 195; however, the Beaver proved itself to outperform the 195 and, as a consequence of the outbreak of the Korean War, this led to orders for hundreds of aircraft being placed. The US Army would ultimately order 970 Beavers, more than half of the overall production run for the type.
Soon, the Beaver grew to become an export success as orders for the type increased from customers around the world. Individual military services of more than 30 different nations would ultimately be included amongst its operators. In later life, as the type was gradually phased out of military service, many examples underwent conversion work so that they could continue to be operated as civilian aircraft instead. During the 1960s, de Havilland developed an improved model of the Beaver, the Mk.III Turbo Beaver, which was equipped with a Pratt & Whitney Canada PT6 turboprop engine. A total of sixty aircraft were built during the late 1960s. In 1967, when production of the type finally ceased, a total of 1,657 DHC-2 Beavers had been constructed.
The Beaver was designed for flight in rugged and remote areas of the world. Its STOL capability made it ideal for areas normally only accessible by canoe or foot. Because the aircraft often flies to remote locations and in cold climates, its oil reservoir filler is located in the cockpit and oil can be filled in flight. A series of upgrades to the basic design were incorporated. One major customer introduced the use of flat steps replacing the earlier tubes, a feature now almost universal. In 1987, the Canadian Engineering Centennial Board named the DHC-2 as one of the top ten Canadian engineering achievements of the 20th century.

Recent developments

At one point in its production, plans to license-build the Beaver in New Zealand were proposed. The remaining tooling was purchased by Viking Air of Victoria, British Columbia, Canada, which manufactures replacement parts for most of the early de Havilland line. The company markets and sells the remanufactured DHC-2T Turbo Beaver, an improved variant of the aircraft which has been upgraded with a PT6A-34, which enables an increased maximum gross takeoff weight of and the carriage of up to of freight, a roughly 25 per cent increase in usable payload. By August 1995, Viking completed its 30th Turbo Beaver conversion. The firm has also developed and marketed other improvements for the type, such as an advanced wing and modified floats. Other manufacturers have also offered aftermarket upgrades and modifications for the type, such as re-engining programmes by Orenda Aerospace and Wipaire.
On 24 February 2006, Viking purchased the type certificates from Bombardier Aerospace for all the original de Havilland designs, including the Beaver. The ownership of the certificates gives the company the exclusive right to manufacture new aircraft. Viking has stated its interest in the potential restart of production of the Beaver, and commented that, dependent upon market demand, the firm may offer two separate models of the Beaver, one intended to be close to the design of the original batch, and another incorporating various improvements such as new avionics, engines, and doors, as well as likely being stretched to provide increased internal space. However, Viking's Turbo Beavers are currently only produced as rebuilds from existing air frames, and have not been manufactured as new-builds, unlike Viking's own DHC-6 Series 400 Twin Otter, which is manufactured using a completely new airframe.
Stolairus Aviation of Kelowna, British Columbia has developed several modifications for the DHC-2 including a STOL Kit which modifies the wing with a contoured leading edge, flap-gap seals, wing fences and drooped wingtips for increased performance. Stolairus has also developed a Wing Angle Kit which changes the incidence of the wing.
Advanced Wing Technologies of Vancouver, British Columbia has developed and certified a new wing for the DHC-2. The FAA Supplemental Type Certificate also raises the aircraft's gross weight to. So far, at least two Beavers have been modified in such a manner.
In September 2017 the Transportation Safety Board of Canada recommended stall warning devices be mandated for commercial Beaver operators.
In March 2019, Harbour Air announced plans to convert a DHC-2 Beaver to an electric aircraft and eventually to convert its entire fleet of aircraft. The first test flight of the aircraft took place in Vancouver in December 2019.

Design

The de Havilland Canada DHC-2 Beaver is a single-engined high-wing propeller-driven STOL aircraft, principally operated as a bush plane and other utility roles, such as cargo and passenger hauling, aerial application, and general civil aviation purposes; aviation publication Plane & Pilot described the type as being "arguably the best bush plane ever built". The Beaver was designed to operate in all seasons and the majority of weather conditions; a large proportion were also equipped with floats for buoyancy in water; it reportedly possesses favourable performance characteristics for a floatplane. As a result of its favourable characteristics as a hard working and productive aircraft, the Beaver has had a lengthy service life and many examples have been remanufactured or have otherwise received life extension modifications.
The Beaver is typically powered by a single Pratt & Whitney R-985 Wasp Junior radial engine. In order to provide the necessary weight balance for optimal loading flexibility, the engine was mounted as far rearwards as possible, resulting in elements intruding into the cockpit space, such as the oil tank being positioned within the center console between the pilot and copilot's feet and the main fuel tank within the forward belly of the aircraft, which also improves accessibility for replenishment. Many Beavers have had wingtip tanks also installed; careful fuel management between the various fuel tanks is required throughout flights in order to maintain the aircraft's center of gravity. The remanufactured DHC-2T Turbo Beaver is equipped with a PT6A-34 turboprop engine.
The Beaver is functionally shaped in order to accommodate a useful and sizable payload, typically close to, even when equipped with floats. While the front doors are narrow, the aft doors are wider, having been designed to facilitate the loading of 55-gallon barrels, either upright or on their sides. The Beaver is considered a 'working' aircraft, which was designed for vigorous use. In addition to cargo, passengers can also be carried; when appropriately fitted out, the Beaver Mk.I can accommodate up to seven passengers while the more spacious Beaver Mk.III can hold a maximum of 11. Various alterations have been approved, including alternative seating arrangements, enlarged cargo doors, larger windows and smaller batteries have been approved for use.
During takeoff, both the ailerons and flaps are lowered, which is a relatively uncommon design approach but results in substantially elevated STOL performance. The flaps can be deployed to an extreme range, extending out at full to a 58-degree position; the flight manual notes that the full setting is recommended only for performing emergency landings. In the skies, the Beaver is relatively easy to handle, having been described as possessing light and comfortable controls; however, effective application of the rudder is necessitated in order to counteract adverse yaw. It should be flown with a relatively nose-low pitch attitude to maintain airspeed. Reportedly, the aircraft is very easy to land, even upon less than calm water conditions.

Operational history

Despite the fact that production ceased in 1967, hundreds of Beavers are still flying—many of them heavily modified to adapt to changes in technology and needs. Kenmore Air of Kenmore, Washington provides Beaver and Otter airframes with zero-hour fatigue-life ratings, and owns dozens of supplemental type certificates for aircraft modifications. These modifications are so well known and desirable in the aviation community, rebuilt Beavers are often called "Kenmore Beavers" or listed as having "Kenmore mods" installed.
The original Wasp Jr radial engine of the Beaver is long out of production, so repair parts are getting harder to find. Some aircraft conversion stations have addressed this problem by replacing the piston engine with a turboprop engine such as the PT6. The added power and lighter installed weight, together with greater availability of kerosene fuel instead of high-octane aviation gasoline, make this a desirable modification, but at a high financial cost.
The Beaver was deployed by the British Army Air Corps during the Troubles, at least until 1979, for photo-reconnaissance missions. One of them was hit seven times by machine gun fire in South County Armagh, near the border with the Republic of Ireland in November 1979, while taking valuable photos of an IRA checkpoint. The border crossing where the action took place has been known to the British Army as "Beaver Junction" since then.
Operators of significant numbers of piston-Beavers in early 2008 include Air Saguenay and Harbour Air in Canada and Kenmore Air in the USA.
American actor Harrison Ford owns a DHC-2 Beaver; he is known for referring to it as being his favourite among his entire fleet of private aircraft.
The Civil Air Patrol operated the larger numbers of the DHC-2 Beaver, where it was commonly used for conducting search and rescue missions. For some decades, the United States military has operate a pair of DHC-2s at the United States Naval Test Pilot School, where they are used to instruct students in the evaluation of lateral-directional flying qualities and for the towing of gliders.
In recent years, growing numbers of the type have been used within the leisure industry, being used for pleasure flight and as lifting platforms for skydiving and aerial film activities. The DHC-2 Beaver has been sometimes used by skydiving operators due to its good climb rate. When fitted with a roller door that can be opened in flight, it can quickly ferry eight skydivers to.

Variants

;: Single-engined STOL utility transport aircraft.
;Beaver AL Mk 1: STOL utility transport aircraft for the British Army.
;C-127: original designation for DHC-2 aircraft used by the U.S. military, redesignated L-20.
;YL-20: Test and evaluation aircraft for the US military.
;L-20A Beaver: STOL utility transport aircraft for the U.S. Army, later redesignated U-6A in 1962, 968 built.
;L-20B Beaver: Basically similar to the L-20A, but with minor equipment changes. Six were sold to the US Army. Later redesignated U-6B in 1962.
;U-6A:US Army L-20A aircraft re-designated
;U-6B:US Army L-20B aircraft re-designated
;Beaver II: One aircraft was fitted with an Alvis Leonides radial piston engine.
;Wipaire Super Beaver: Conversion of surplus US Army and USAF L-20 Beavers.
;Wipaire Boss Turbo-Beaver: Turbo conversion fitted with PT-6 but retaining the original lower curved fin shape
;: Powered by a 431 kW Pratt & Whitney PT6A-6 or -20 turboprop engine.
;Airtech Canada DHC-2/PZL-3S: After-market conversion by Airtech Canada in the 1980s, using current-production PZL-3S radial engines of 600 hp.
;Volpar Model 4000: A 1970s conversion by Volpar, first flown in April 1972 with a modified nose fitted with an AiResearch TPE331-2U-203 turboprop with a three-bladed propeller. Other changes included a new fin and rudder.
; Turbo Beaver: Remanufactured Beavers by Viking Air, upgraded with a Pratt & Whitney Canada PT6A-34 turboprop engine.

Operators

Civil

The DHC-2 is popular with air charter companies, police forces and small air taxi operators as well as private individuals and companies. Both the Royal Canadian Mounted Police and Finnish Border Guard operate the aircraft.

Military operators

; Federation of South Arabia
As of May 2019, there have been 313 incidents involving the DHC-2 and 663 deaths. Listed below are a select few of the most notable ones.

Citations