The North American Rockwell OV-10 Bronco is an American twin-turboprop light attack and observation aircraft.
It was developed in the 1960s as a special aircraft for counterinsurgency (COIN) combat, and one of its primary missions was as a forward air control (FAC) aircraft.
It can carry up to 3,200 lb (1,450 kg) of external munitions, internal loads such as paratroopers or stretchers, and loiter for three or more hours.
The OV-10 has a central nacelle containing pilots and cargo, and twin booms containing twin turboprop engines.
The visually distinctive feature of the aircraft is the combination of the twin booms, with the horizontal stabilizer that connects them.
The aircraft’s design supported effective operations from forward bases.
The OV-10 can perform short take-offs and landings, including on aircraft carriers and large-deck amphibious assault ships without using catapults or arresting wires.
Further, the OV-10 was designed to take off and land on unimproved sites.
Repairs could be made with ordinary tools.
No ground equipment was required to start the engines.
If necessary, the engines could operate on high-octane automobile fuel with only a slight loss of power.
The aircraft had responsive handling and could fly for 5Â 1/2 hours with external fuel tanks.
The cockpit had extremely good visibility for a tandem pilot and co-pilot, provided by a wrap-around “greenhouse” that was wider than the fuselage.
North American Rockwell custom ejection seats were standard, with many successful ejections during service.
With the second seat removed, it can carry 3,200 pounds (1,500 kg) of cargo, five paratroopers, or two litter patients and an attendant.
Empty weight was 6,969 pounds (3,161 kg).
Normal operating fuelled weight with two crew was 9,908 pounds (4,494 kg).
Maximum take-off weight was 14,446 pounds (6,553 kg).
The bottom of the fuselage bore sponsons or “stub wings” that improved flight performance by decreasing aerodynamic drag underneath the fuselage.
The sponsons were mounted horizontally on the prototype.
Testing caused them to be redesigned for production aircraft; the downward angle of the sponsons on production models ensured that stores carried on the sponsons jettisoned cleanly.
Normally, four 7.62 mm (.308 in) M60C machine guns were carried on the sponsons with the M60Cs accessed through a large forward-opening hatch on the top of each sponson.
The sponsons also had four racks to carry bombs, pods, or fuel.
The wings outboard of the engines contain two additional racks, one per side.
Racked armament in the Vietnam War was usually seven-shot 2.75 in (70 mm) rocket pods with white phosphorus marker rounds or high-explosive rockets, or 5 in (127 mm) four-shot Zuni rocket pods.Â
Bombs, ADSIDS air-delivered/para-dropped unattended seismic sensors, Mk-6 battlefield illumination flares, and other stores were also carried.
Operational experience showed some weaknesses in the OV-10’s design.
It was significantly underpowered, which contributed to crashes in Vietnam in sloping terrain because the pilots could not climb fast enough.
While specifications state that the aircraft could reach 26,000 feet (7,900Â m), in Vietnam the aircraft could reach only 18,000 feet (5,500Â m).
Also, no OV-10 pilot survived ditching the aircraft.
Variants
YOV-10A
Seven prototype NA-300s with two 600 shp T76-G-6/8 engines, last one was flown with YT74-P-1 engines.
OV-10A
Original production version with enlarged wing and 715 shp T76-G-10/12 engines.
Distinguished by a long-wire HF antenna between the centre rear stabilizer and the central nacelle, 114 for the United States Marine Corps and 157 for the United States Air Force.
OV-10B
Target towing variant for Germany, with a target towing pod mounted beneath the fuselage.
A clear dome replaced the rear cargo door.
The rear seat was moved to the cargo bay to look backwards out the dome, 18 built; known as the OV-10B(Z) when fitted with an additional J85-GE-4 turbojet.
OV-10B (Z)
A variation of the German target tug, with one J85-GE-4 turbojet mounted in a nacelle above the fuselage.
A total of 18 aircraft were supplied to the Germans.
OV-10C
Export version for Thailand; based on the OV-10A, 32 built.
YOV-10D (NOGS)
The prototype Night Observation Gunship System variant developed as the YOV-10D.
OV-10D
Second generation Bronco developed under the NOGS program.
The D-model was an extensively modified OV-10A airframe, adding a forward-looking infrared night-vision system with a turret-mounted camera under an extended nose, visually distinct from the short, rounded nose of the A-model.
The D also has bigger engines and larger fiberglass propellers.
Other noticeable external differences are the chaff dispensers installed midway down the booms and infrared-suppressive exhaust stacks (which mix the exhaust with colder air to reduce the aircraft’s heat signature).
17 modified from OV-10A.
OV-10D+
The next USMC upgrade, consisting of A and D aircraft being extensively reworked at MCAS Cherry Point Naval Air Rework Facility with new wiring and strengthened wings.
Engine instrumentation was changed from round dials to tape readouts.
OV-10E
Export version for Venezuela; based on the OV-10A, 16 built.
OV-10F
Export version for Indonesia; based on the OV-10A, 16 built.
OV-10G+
Designation given to OV-10s loaned from NASA to the United States Special Operations Command for evaluation under the Combat Dragon II as a counter-insurgency aircraft, featuring new Hartzell four-bladed props and an off-the-shelf sensor suite.
3 modified from OV-10D+.
OV-10M (modified)
A four-bladed version of OV-10A; modified to accommodate bigger engines with larger fiberglass props.
Equipped with square chaff dispensers midway down the booms and with new wiring and strengthened wings.
Engine instrumentation was changed from round dials to tape readouts by Marsh Aviation for the Philippine Air Force.
OV-10T
Proposed cargo version of the OV-10, capable of carrying 8–12 troops or 4,500 pounds (2,000 kg) of cargo, studied during the Vietnam War but not developed.
Specifications
Crew
2
Capacity
Cargo compartment for personnel (no seats) or 3,200 lb (1,451 kg) of freight
Length
44 ft 0 in (13.41 m)
Wingspan
40 ft 0 in (12.19 m)
Height
15 ft 2 in (4.62 m)
Wing area
291.0 sq ft (27.03 m2)
Airfoil
NACA 64A315
Empty weight
6,893 lb (3,127 kg)
Gross weight
9,908 lb (4,494 kg)
Max take-off weight
14,444 lb (6,552 kg) (overload)
Fuel capacity
252 US gal (210 imp gal; 950 L) internal
Powerplant
2 × Garrett T76-G-420/421 turboprop engines,
1,040 shp (780 kW) each equivalent
Propellers
3-bladed Hamilton Standard,
8 ft 6 in (2.59 m) diameter constant-speed fully feathering propellers
Performance
Maximum speed
250 kn (290 mph, 460 km/h) at sea level
Combat range
198 nmi (228 mi, 367 km)
Ferry range
1,200 nmi (1,400 mi, 2,200 km) with auxiliary fuel
Service ceiling
30,000 ft (9,100 m)
Rate of climb
3,020 ft/min (15.3 m/s)
Take-off run
740 ft (226 m)
Take-off distance to 50 ft (15 m)
1,120 ft (341 m)
Take-off distance to 50 ft (15 m)
2,800 ft (853 m) at MTOW
Landing run
740 ft (226 m)
Landing run
1,250 ft (381 m) at MTOW
Landing distance from 50 ft (15 m)
1,220 ft (372 m)
Armament
Guns
1 × 20 mm (0.79 in) M197 electric cannon (YOV-10D)
Or
4 × 7.62×51 mm M60C machine guns (OV-10D/D+)
Hardpoints
5 fuselage and 2 under wing with provisions to carry combinations of:
Rockets
7 or 19 tube launchers for 2.75 in FFARs/2.75 in WAFARs
