- Aircraft History, Specification and Information -
de Havilland Canada DHC-3 Otter
De Havilland DHC-3 Turbine Otter - N50KA - Kenmore Air
1956 De Havilland DHC-3 Turbine Otter
N50KA (sn 221) Kenmore Air
This seaplane is flying for Kenmore Air in a "King 5 Evening Magazine" livery. "King 5" is a local TV station in Seattle.
Photo taken July 09, 2006 @ Kenmore Air Harbor Inc Seaplane Base - Kenmore, WA - USA (KEH / S60)
Photo © Marcel Siegenthaler

The de Havilland Canada DHC-3 Otter is a single-engined, high-wing, propeller-driven, STOL aircraft developed by de Havilland Canada. It was conceived to be capable of performing the same roles as the earlier and highly successful Beaver, but was overall a larger aircraft.

DeHavilland DHC-3 Turbine Otter - Harbour Air - C-GHAR
1954 DeHavilland DHC-3 Turbine Otter C-GHAR (sn 42)
Harbour Air Turbo Otter Taxiing For Take-Off At The Vancouver Harbour Seaplane Base.
Photo taken July 13, 2004
Vancouver Harbour Seaplane Base, BC Canada (CXH / CYHC)
Photo © Marcel Siegenthaler

Design and development

When de Havilland Canada began design work on the "King Beaver" (the Otter's original name) in January 1951, it was trying to extend the company's line of rugged STOL utility transports that had begun with the Beaver. The single-engined, high-wing, propeller-driven DHC-3 Otter was conceived to be capable of performing the same roles as the Beaver, but was considerably larger, the veritable "one-ton truck" (in company parlance, the Beaver was the "half-ton truck").

Using the same overall configuration of the earlier and highly successful DHC2 Beaver, the new design incorporated a longer fuselage, greater-span wings, and was much heavier. Seating in the main cabin is for 10 or 11, whereas the Beaver could seat six. Power is supplied by a 450-kW (600 hp) Pratt & Whitney Wasp radial. Like the Beaver, the Otter can be fitted with skis or floats. The Otter served as the basis for the very successful Twin Otter, which featured two wing-mounted Pratt & Whitney Canada PT6 turboprops.

The Otter received Canadian certification in November 1952 and entered production shortly after.

Operational use

The DHC-3/CSR-123 Otter was used until 1980 by the Royal Canadian Air Force and its successor, the Air Command of the Canadian Forces. It was used in Search and Rescue, as the "CSR" denotes Canadian Search (and) Rescue (type 123). The engine is a Pratt & Whitney R-1340 (1,340 cubic inches) geared engine. The version used in the Otter was geared for lower prop revs and consequently lower airspeed. The electrics were 28 volts D.C. It was also operated on EDO floats on water and skis for winter operations on snow. The EDO floats also had wheels for use on runways (amphibious). It was used as army support dropping supplies on parachutes, and also non-parachute low-speed, low-altitude air drops, to support the Canadian Army on maneuvers. In the end it was operated by the Primary Air Reserve in Montreal, Toronto and Winnipeg, with approximately 10 aircraft at each base, as well as by the RSU (Regular (Forces) Support Units) at those bases. It was usually flown with a single pilot (Commissioned Officer) in the left seat and a Technical Air Crewman (NCO) in the right seat. It was stood down, and the Kiowa helicopter replaced it in Air Reserve squadrons.

Although the Otter found ready acceptance in bush airlines, as in a similar scenario to the DHC-2 Beaver, the United States Army soon became the largest operator of the aircraft (184 delivered as the U-1A Otter). Other military users included Australia, Canada, and India, but the primary role of the aircraft as a rugged bush plane continues to this day.

An Otter crossed the South Pole in 1957 (see Commonwealth Trans-Antarctic Expedition). The Otter is also popular in the skydiving community and can be found in many dropzones throughout the world.

Modifications
Some aircraft were converted to turbine power using a PT6A, Walter 601 (manufactured in the Czech Republic),, or Garrett/Honeywell TPE331-10, by Texas Turbine Conversions. A Polish Pezetel radial engine has also been fitted. Re-engined aircraft have been offered since the 1980s by Airtech Canada as the DHC-3/1000 using current-production 1,000 hp (745 kW) PZL ASz-62IR radials.

Variants

  • DHC-3 Otter: Single-engined STOL utility transport aircraft.
  • CSR-123 Otter: STOL utility transport aircraft for the Royal Canadian Air Force.
  • YU-1 Otter: Six test and evaluation aircraft for the U.S. Army.
  • U-1A Otter: STOL utility transport aircraft for the US Army.
  • UC-1 Otter: STOL utility transport aircraft for the United States Navy. Later redesignated U-1B Otter in 1962.
  • DHC-3-T Turbo-Otter: Otter fitted with a 494-kW (662-hp) PT6A-27 turboprop engine.

Military operators

  • Argentina
  • Australia
    Royal Australian Air Force - Two Otters (RAAF serial A100-1 and 2) were in service with the RAAF from 1961 to 1967. The aircraft were used for passenger and freight transport duties at the Weapons Research Establishment, Woomera, South Australia. No. 1 Air Trials Uni.t
  • Bangladesh
  • Burma
  • Cambodia
  • Canada
    Royal Canadian Air Force
  • Chile
    Chilean Air Force
  • Colombia
  • Costa Rica
  • Ethiopia
  • Ghana
    Ghana Air Force
  • India
    Indian Air Force
  • Indonesia
  • New Zealand
    Royal New Zealand Air Force
  • Nicaragua
  • Nigeria
  • Norway
    Royal Norwegian Air Force
  • Panama
  • Paraguay
    Paraguayan Air Force 1 DHC-3 donated by Argentina.
  • Philippines
  • United Kingdom
    Royal Air Force
    United States
    United States Army
    United States Navy

Accidents

On 9 August 2010, a DHC-3T registered to Anchorage-based GCI crashed about 17 miles (27 km) north of Dillingham, Alaska, while en route to a private fishing lodge. Five of the nine people on board were killed, including former Alaska Senator Ted Stevens. Surviving passengers included former NASA administrator Sean O'Keefe and his teenage son, both of whom sustained injuries.

Specifications (DHC-3 Landplane)

General characteristics
Crew: 1
Capacity: 9 -10 passengers
Length: 41 ft 10 in (12.80 m)
Wingspan: 58 ft 0 in (17.69 m)
Height: 12 ft 7 in (3.83 m)
Wing area: 375 sq ft (34.84 m²)
Empty weight: 4,431 lb (2,010 kg)
Max takeoff weight: 8,000 lb (3,629 kg)
Powerplant: 1× Pratt & Whitney R-1340-S1H1-G Wasp 9-cylinder air-cooled radial engine, 600 hp (448 kW)

Performance
Maximum speed: 160 mph (139 knots, 257 km/h)
Cruise speed: 121 mph (105 knots, 195 km/h) at sea level (econ cruise)
Stall speed: 58 mph (50 knots, 93 km/h)
Range: 945 mi (822 nmi, 1,520 km)
Service ceiling: 18,800 ft (5,730 m)
Rate of climb: 850 ft/min (4.3 m/s)

Last updated November 19, 2010
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "de Havilland Canada DHC-3 Otter".
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