de Havilland Canada C-7B (DHC-4) Caribou, Twin-engine High-wing STOL Cargo Military Aircraft, Canada (2024)

de Havilland Canada DHC-4A (CV-2B, C-7B) Caribou
Twin-engine High-wing STOL Cargo Military Aircraft, Canada

Archive Photos ¹

de Havilland Canada C-7B Caribou (AF 63-9757, c/n 220, CV-2B) on display (1/20/2001) at the Hill Aerospace Museum, Hill AFB, Roy, Utah (Photos by John Shupek)

Overview ²

• de Havilland Canada DHC-4 Caribou
• Role: STOL Transport
• Manufacturer: de Havilland Canada
• First flight: 30 July 1958
• Introduction: 1961
• Retired: Royal Australian Air Force (2009), United States Army, United States Air Force
• Status: Retired from military operators, limited service. Some turboprop conversions in active service.
• Produced: 1958-1968
• Number built: 307
• Developed into: de Havilland Canada DHC-5 Buffalo

The de Havilland Canada DHC-4 Caribou (designated by the United States military as the CV-2 and later C-7 Caribou) is a Canadian-designed and produced specialized cargo aircraft with short takeoff and landing (STOL) capability. The Caribou was first flown in 1958 and although mainly retired from military operations, is still in use in small numbers as a rugged bush aircraft.

Design and Development ²

The de Havilland Canada company’s third STOL design was a big step up in size compared to its earlier DHC Beaver and DHC Otter, and was the first DHC design powered by two engines. The Caribou, however, was similar in concept in that it was designed as a rugged STOL utility aircraft. The Caribou was primarily a military tactical transport that in commercial service found itself a small niche in cargo hauling. The United States Army ordered 173 in 1959 and took delivery in 1961 under the designation AC-1, which was changed to CV-2 Caribou in 1962.

The majority of Caribou production was destined for military operators, but the type’s ruggedness and excellent STOL capabilities requiring runway lengths of only 1,200 ft (365 meters) also appealed to some commercial users. U.S. certification was awarded on 23 December 1960. Ansett-MAL, which operated a single example in the New Guinea highlands, and AMOCO Ecuador were early customers, as was Air America (a CIA front in South East Asia during the Vietnam War era for covert operations). Other civil Caribou aircraft entered commercial service after being retired from their military users.

Today only a handful are in civil use.

The Turbo Caribou Program ²

PEN Turbo Aviation of Cape May, NJ, has undertaken the re-engineering of the DHC-4A Caribou to a turbine powered variant, designated DHC-4A Turbo Caribou. The conversion utilizes the PT6A-67T engines and Harzell 5 Bladed HC-B5MA-3M Constant Speed/Reversing propellers. Overall performance has improved and new basic weight is reduced while maximum normal take-off weight remained at 28,500 lbs. Maximum payload is 10,000 lbs. Both Transport Canada (11/14/00) and Federal Aviation Administration (2/27/01) have issued Supplemental Type Certificates for the Turbo Caribou. As of Sept 17, 2014, only 3 air frames have gone through the conversion process. PEN Turbo has stockpiled dozens of air frames at their facility in NJ for possible future conversion. . PEN Turbo Aviation named their company after Perry E. Niforos, who died in the 1992 crash of an earlier turboprop Caribou converted by a different firm, NewCal Aviation.

Operational History ²

In response to a U.S. Army requirement for a tactical airlifter to supply the battlefront with troops and supplies and evacuate casualties on the return journey, de Havilland Canada designed the DHC-4. With assistance from Canada’s Department of Defence Production, DHC built a prototype demonstrator that flew for the first time on 30 July 1958.

Impressed with the DHC-4’s STOL capabilities and potential, the U.S. Army ordered five for evaluation as YAC-1s and went on to become the largest Caribou operator. The AC-1 designation was changed in 1962 to CV-2, and then C-7 when the U.S. Army’s CV-2s were transferred to the U.S. Air Force in 1967. U.S. and Australian Caribou saw extensive service during the Vietnam War.

The U.S. Army purchased 159 of the aircraft and they served their purpose well as a tactical transport during the Vietnam War, where larger cargo aircraft such as the Fairchild C-123 Provider and the Lockheed C-130 Hercules could not land on the shorter landing strips. The aircraft could carry 32 troops or two Jeeps or similar light vehicles. The rear loading ramp could also be used for parachute dropping (also, see Air America).

Under the Johnson-McConnell agreement of 1966, the Army relinquished the fixed wing Caribou to the United States Air Force in exchange for an end to restrictions on Army rotary wing operations. On 1 January 1967, the 17th, 57th, 61st, 92nd, 134th, and 135th Aviation Companies of the U.S. Army were inactivated and their aircraft transferred respectively to the newly activated 537th, 535th, 536th, 459th, 457th, and 458th Troop Carrier Squadrons of the USAF (This was Operation Red Leaf). On 1 August 1967 the troop carrier designations were changed to tactical airlift.

Some U.S. Caribou were captured by North Vietnamese forces and remained in service with that country through to the late 1970s. Following the war in Vietnam, all USAF Caribou were transferred to Air Force Reserve and Air National Guard airlift units pending their replacement by the C-130 Hercules in the 1980s.

All C-7s have now been phased out of U.S. military service, with the last example serving again under U.S. Army control through 1985 in support of the U.S. Army’s Golden Knights parachute demonstration team. Other notable military operators included Australia, Canada, India, Malaysia and Spain.

The Royal Australian Air Force retired its last Caribou, A4-140, on 27 November 2009. The aircraft, which was manufactured in 1964, was donated to the Australian War Memorial, Canberra.

Variants ²

• DHC-4 Caribou: STOL tactical transport, utility transport aircraft.
• CC-108: Royal Canadian Air Force designation for the DHC-4 Caribou.
• YAC-1: This designation was given to five DHC-4 Caribou, sold to the United States Army for evaluation.
• AC-1: United States Army designation for the first production run of 56 DHC-4 Caribou. Later redesignated CV-2A in 1962.
• CV-2A: United States Army AC-1 redesignated in 1962.
• CV-2B: This designation was given to a second production run of 103 DHC-4 Caribou, which were sold to the U.S. Army, with reinforced internal ribbing.
• C-7A/B: These designations were applied to all 144 Caribou transferred to the U.S. Air Force by the U.S. Army.
• DHC-4A Caribou: Similar to the DHC-4, but this version had an increased takeoff weight.
• DHC-4T Turbo Caribou: A conversion of the baseline DHC-4 Caribou powered by the PWC PT6A-67T turboprop engines designed, test flown and certified by the Pen Turbo Aviation company.

Operators ²

Military Operators

• Abu Dhabi/United Arab Emirates: Abu Dhabi Defence Forces Air Wing - Abu Dhabi operated five Caribou; United Arab Emirates Air Force.
• Australia: Royal Australian Air Force - 18 ordered in 1963, with further orders for seven in 1964 and four more aircraft ordered individually between 1968 and 1971. Retired 2009.
• Canada: Royal Canadian Air Force - nine delivered; retired from Canadian Forces in 1971.
• Cameroon: Cameroon Air Force - two delivered in 1971. The surviving Caribou was sold in 1987.
• Costa Rica: Air Surveillance Service - Two ex-USAF C-7As delivered in the 1980s. Refurbished in July 2010 for the Fuerza Publica.
• Ghana: Ghana Air Force - Ghana acquired eight new-build Caribou in 1963, which were operated until replaced by Fokker F.27-400Ms in 1975.
• India: Indian Air Force - India received 20 new build Caribou, supplementing them with four ex-Ghanaian Caribou in 1975.
• Iran: Imperial Iranian Air Force - One aircraft delivered to Iran. It was retired after Iran-Iraq War.
• Kenya: Kenya Air Force - received six DHC-4As, operating the type from 1966-1987.
• Kuwait: Kuwait Air Force - received two aircraft in 1963.
• Liberia: Liberian Army - Two refurbished aircraft were delivered to the Air Reconnaissance Unit in 1989. The aircraft were destroyed during the civil war.
• Malaysia: Malaysian Air Force - retired their Caribou from active service.
• Oman: Sultanate of Oman Air Force
• Spain: Spanish Air Force - received 12 new Caribou later supplemented by 24 former United States Air Force C-7As. Final retirement 12 June 1991.
• South Vietnam: Republic of Vietnam Air Force
• Sweden: Swedish Air Force - operated one DHC-4 Caribou designated Tp.55 between 1962 and 1965 for evaluation purposes at Skaraborg Air Force Wing).
• Tanzania: Tanzanian Air Force
• Thailand: Royal Thai Police - used three DHC-4A from 1966 to 2005.
• Uganda: Uganda Police Force Air Wing
• United States: United States Army, United States Air Force
• Vietnam: Vietnam People’s Air Force - captured several ex-VNAF airplanes.
• Zambia: Zambian Air Force - operated four Caribou.

Civil Operators

After retirement from military use, several examples of the Caribou have been purchased by civilian operators for deployment in areas with small airfields located in rugged country with few or poor surface transport links.

• Australia: Ansett-MAL - operated one aircraft in the New Guinea highlands.
• Canada: La Sarre Air Services, acquired C-GVGX in 1977 (delivered 1961) and unknown status after 1981 when Propair formed from merger of La Sarre Air Services (used in El Salvador to Nicaragua 1986).
• Costa Rica: Air Vigillance Service.
• Ecuador: AMOCO Ecuador, Anglo-Ecuador Oilfields, Aerolíneas Cóndor of SA.
• Gabon: Air Inter Gabon.
• Indonesia: Puncak Regency, Trigana Air.
• Malta: New Cal Aviation.
• Papua New Guinea: Garamut Exploration Services, Vanimo Trading.
• Taiwan: Air Asia.
• United States: Air America, Bannock Aerospace, Chieftain Air, Deutsche Aviation, Environmental Research Institute of Michigan, Fowler Aeronautical Service, H A T Aviation Inc., John Woods Inc., New Cal Aviation, Pen Turbo Aviation.

de Havilland Canada DHC-4A (CV-2B, C-7B) Caribou ³

Type

• Twin-engine all-weather STOL, utility transport.

Wings

• Cantilever high-wing monoplane.
• Wing section NACA 64₃A417-5 throughout one-piece center-section, varying to NACA 63₂A615 near tips of outer panels.
• Aspect ratio: 10.
• Chord: 11 ft 10 in (3.60 m) at root, 5 ft 7.8 in (1.72 m) the tip.
• Dihedral on outer panels: 5°.
• Incidence: 3° inboard, 0° outboard.
• Sweptback at quarter-cord: 0°.
• All-metal two-spar fail-save structure.
• Full-span double-slotted slot flaps, outer trailing portions operated independently as ailerons.
• Trim-tabs on ailerons.
• Goodrich flush-mounted inflatable de-icing boots and four sections.

Fuselage

• All-metal fail-safe semi-monocoque structure.
• Rear portion is upswept aft of wings, with upward and inward hingeing door forming underside of rear fuselage.

Tail Unit

• Cantilever all-metal structure.
• Variable-incidence tailplane.
• Glass-fibre fairings at top and bottom of rudder.
• Spring tabs on rudder and elevators.
• Goodrich inflatable de-icer boots.

Landing Gear

• Retractable tricycle type.
• Hydraulic retraction, main units forward, nose unit rearward.
• Main gear, produced by Jarry Hydraulics, shortens as it retracts.
• Dual wheels on all units.
• Hydraulically-steerable nosewheel.
• Goodyear wheels and tires, size 11.00×12 on main units, 7.50×10 on nose unit.
• Tire pressure (nominal) 40 psi (2.81 kg/cm²).
• Goodyear four-cylinder single-disc brakes.

Power Plant

• Two 1,450 hp Pratt & Whitney R-2000-7M2 fourteen-cylinder two-row radial air-cooled engines, driving Hamilton Standard type 43D50-7107A three-blade fully-feathering Hydromatic propellers.
• Fuel in two wing tanks, each of 10 cells, with total capacity of 690 Imp. gallons (3,137 L).
• Refueling point in upper surface of each wing.
• Oil capacity 50 Imp. gallons (227 L).

Accommodation

• Flight compartment seats two side-by-side.
• Civil version accommodates 30 passengers, who enter by two doors, at rear of cabin on each side (an air-stair type can be provided) or via the large rear loading ramp, formed by lowering electrically the sloping under-surface of the rear fuselage.
• The military version carries 32 troops inward-facing folding seats or 26 fully-equipped paratroops, or, in an ambulance role, up to 22 litter patients, four sitting casualties and four attendants.
• Typical freight loads are three tons of cargo or two fully-loaded jeeps.
• The floor is stressed to support distributed loads of 200 lbs/ft² (975 kg/m²) and has tie-down fittings on a 20 in (0.50 m) grid pattern over the entire area.
• Tie-down rings can be fitted at 36 points on the side walls.

Systems

• Flaps, brakes, landing gear retraction and nose-wheel steering actuated by 3,000 psi (210 kg/cm²) hydraulic system.
• No pneumatic system.
• Two engine-driven generators, 24V 300A DC/115V 400-c/s AC.

Electronics and Equipment

• To customer’s requirements.
• Blind-flying instrumentation standard.

Dimensions, External

• Wing span: 95 ft 7½ in (29.15 m)
• Length overall: 72 ft 7 in (22.13 m)
• Height over tail: 31 ft 9 in (9.70 m)
• Tailplane span: 36 ft 0 in (11.00 m)
• Wheel track: 23 ft 1½ in (7.05 m)
• Wheelbase: 25 ft 8 in (7.82 m)
• Passenger door height (each side): 4 ft 7 in (1.40 m)
• Passenger door width (each side): 2 ft 6 in (7.68 m)
• Main cargo door height (rear fuselage): 6 ft 3 in (1.90 m)
• Main cargo door with (rear fuselage): 6 ft 1½ in (1.86 m)
• Main cargo door height to sill (rear fuselage): 3 ft 9½ in (1.16 m)

Dimensions, Internal (Cabin, excluding flight deck)

• Length: 28 ft 9 in (8.76 m)
• Maximum width: 7 ft 3 in (2.21 m)
• Maximum height: 6 ft 3 in (1.90 m)
• Floor area: 176 ft² (16.35 m²)
• Volume: 1,150 ft³ (32.57 m³)

Areas

• Wings, gross: 912 ft² (84.72 m²)
• Ailerons (total): 91 ft² (8.45 m²)
• Trailing-edge flaps (total): 285 ft² (26.47 m²)
• Fin: 127 ft² (11.80 m²)
• Rudder, including tab: 84 ft² (7.8 m²)
• Tailplane: 144 ft² (13.37 m²)
• Elevators, including tab: 86 ft² (7.99 m²)

Weights and Loadings

• Basic operating weight (including 2 crew): 18,260 lbs (8,283 kg)
• maximum payload: 8,740 lbs (3,965 kg)
• Normal maximum T-O weight: 28,500 lbs (12,928 kg)
• Maximum permissible weight for ferry missions: 31,300 lbs (14,197 kg)
• Maximum zero-fuel weight: 27,000 lbs (12,250 kg)
• Maximum landing weight: 28,500 lbs (12,928 kg)
• Normal maximum wing loading: 31.2 lbs/ft² (152.3 kg/m²)
• Normal maximum power loading: 9.83 lbs/hp (4.45 kg/hp)

Performance (at normal maximum T-O weight)

• Maximum level speed at 6,500 ft (1,980 m): 216 mph (347 kmh)
• Maximum diving speed: 240 mph (386 kmh)
• Maximum cruising speed at 7,500 ft (2,285 m): 182 mph (293 kmh)
• Econ cruising speed at 7,500 ft (2,285 m): 182 mph (293 kmh)
• Stalling speed: 68 mph (109 kmh)
• Rate of climb at S/L: 1,355 ft/min (413 m/min)
• Service ceiling: 24,800 ft (7,560 m)
• T-O run: 725 ft (221 m)
• T-O 250 ft (15 m): 1,235 ft (376 m)
• Landing run: 670 ft (204 m)
• Range with maximum fuel: 1,307 miles (2,103 km)
• Range with maximum payload: 242 miles (390 km)
• Note: Ranges are for long-range cruising speed at 7,500 ft (2,285 m), with allowances for warm-up, taxi, take-off, climb, descent, landing and 45 minute reserve.

References

1. Shupek, John. The Skytamer Photo Archive, photos by John Shupek, copyright © 2001 Skytamer Images (Skytamer.com)
2. Wikipedia, the free encyclopedia. de Havilland Canada DHC-4 Caribou
3. Taylor, John W. R. Jane’s All the World’s Aircraft 1965-66, New York: McGraw-Hill Book Company, 1965, pgs. 20-21.