North American Rockwell OV-10 Bronco

https://en.wikipedia.org/wiki/North_...l_OV-10_Bronco

see also:
https://www.thedrive.com/the-war-zon...ir-controllers

The aircraft was initially conceived in the early 1960s through an informal
collaboration between WH Beckett and Colonel KP Rice, U.S. Marine Corps, who met
at Naval Air Weapons Station China Lake, California, and who also happened to
live near each other. The original concept was for a rugged, simple, close air
support aircraft integrated with forward ground operations. At the time, the
U.S. Army was still experimenting with armed helicopters, and the U.S. Air Force
was not interested in close air support.

The concept aircraft was to operate from expedient forward air bases using roads
as runways. Speed was to be from very slow to medium subsonic, with much longer
loiter times than a pure jet. Efficient turboprop engines would give better
performance than piston engines. Weapons were to be mounted on the centerline to
get efficient unranged aiming like the Lockheed P-38 Lightning and North
American F-86 Sabre aircraft. The inventors favored strafing weapons such as
self-loading recoilless rifles, which could deliver aimed explosive shells with
less recoil than cannons, and a lower per-round weight than rockets. The
airframe was to be designed to avoid the back blast.

Beckett and Rice developed a basic platform meeting these requirements, then
attempted to build a fiberglass prototype in a garage. The effort produced
enthusiastic supporters and an informal pamphlet describing the concept. WH
Beckett, who had retired from the Marine Corps, went to work at North American
Aviation to sell the aircraft.

Rice states:

"The military definition of STOL (500 ft to a 50 ft obstacle) allows takeoff and
landing in most of the areas in which limited war might be fought. In addition,
the airplane was designed to use roads so that operation would even be possible
in jungle areas where clearings are few and far between. As a result the
wingspan was to be limited to twenty feet and a heavy trailing arm type landing
gear with a tread of 6.5 ft was provided for operation from roads. Float
operation was to be feasible ...it is quite feasible to design the various
components so that it can be disassembled easily and stored in a box that would
fit in a 6×6 truck bed together with the equipment needed for re-assembly in the
field. It could thus be transported by amphibious shipping and either
heli-lifted or driven ashore by a 6×6 truck.

Design

The OV-10 had 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 takeoffs 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. And, if necessary, the engines would operate on high-octane
automobile fuel with only a slight loss of power.

The aircraft had responsive handling and could fly for 5 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 fueled
weight with two crew was 9,908 pounds (4,494 kg). Maximum takeoff 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.

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 (7,900 m), in Vietnam the
aircraft could reach only 18,000 feet (5,500 m). Also, no OV-10 pilot survived
ditching the aircraft.


Role
Light attack and observation aircraft

National origin
United States

Manufacturer
North American Rockwell

First flight
16 July 1965

Introduction
October 1969

Retired
US (1995)

Status
In limited service (2015–present)

Primary users
United States Marine Corps (historical)
United States Air Force (historical)
United States Navy (historical)
Philippine Air Force

Produced
1965–1986

Number built
360

The OV-10 served in the U.S. Air Force, U.S. Marine Corps, and U.S. Navy, as
well as in the service of a number of other countries. A total of 81 OV-10
Broncos were ultimately lost to all causes during the course of the Vietnam War,
with the Air Force losing 64, the Navy 7, and the Marines 10.

U.S. Marine Corps

The OV-10 was first acquired by the U.S. Marine Corps. Each of the Marine
Corps's two observation squadrons (designated VMO) had 18 aircraft – nine
OV-10As and nine OV-10Ds night observation aircraft. A Marine Air Reserve
observation squadron was also established. The OV-10 operated as a forward air
controller and was finally phased out of the Marine Corps in 1995 following its
employment during Operation Desert Storm, which also saw the final combat losses
of OV-10s by U.S. forces. Among these losses were two USMC OV-10s being shot
down due to a lack of effective infrared countermeasures. It was also thought
that the slow speed made it more vulnerable to anti-aircraft weapons. Forward
air control passed mostly to ground units with laser designators and digital
radios (GFACs) and the twin-seat F/A-18D Hornet (FAC(A)s). Most operational
Broncos were reassigned to civil government agencies in the U.S., while some
were sold to other countries.

The U.S. Marine Corps YOV-10D Night Observation Gunship System (NOGS) program
modified two OV-10As (BuNo 155395 and BuNo 155396) to include a turreted forward
looking infrared (FLIR) sensor, laser target designator and turreted 20 mm (.79
in) XM197 gun slaved to the FLIR aimpoint. NOGS succeeded in Vietnam, but funds
to convert more aircraft were not approved. NOGS evolved into the NOS OV-10D,
which included a laser designator, but no gun.

U.S. Air Force

The USAF acquired the Bronco primarily as an FAC aircraft. The first combat USAF
OV-10As arrived in Vietnam on 31 July 1968 as part of "Operation Combat Bronco",
an operational testing and evaluation of the aircraft. These test aircraft were
attached to the 19th Tactical Air Support Squadron, 504th Tactical Air Support
Group at Bien Hoa Air Base in South Vietnam. The test roles included the full
range of missions then assigned to FAC aircraft, including day and night strike
direction, gunship direction, bomb damage assessment, visual reconnaissance,
aerial artillery direction, and as escorts for aircraft engaged in Operation
Ranch Hand. The aircraft's ability to generate smoke internally was utilized for
strike direction and "in four specific instances under conditions of reduced
visibility, the smoke was seen by strike aircrews before the [OV-10A] [was]
detected." Operation Combat Bronco ended on 30 October 1968.

After the end of Combat Bronco, the USAF began to deploy larger numbers to the
19th TASS (Bien Hoa), 20th TASS (Da Nang Air Base), and for out-of-country
missions to the 23d TASS (Nakhom Phanom in Thailand). The 23d TASS conducted
Operation Igloo White, Operation Prairie Fire/Daniel Boone, and other special
operations missions.

U.S. Navy

The U.S. Navy formed Light Attack Squadron Four (VAL-4), the "Black Ponies", on
3 January 1969, and operated in Vietnam from April 1969 to April 1972. The Navy
used the Bronco OV-10A as a light ground attack aircraft, for interdiction of
enemy logistics, and fire-support of Marines, SEALs and naval riverine force
vessels. It succeeded in this role, although the U.S. Navy did lose seven OV-10s
during the Vietnam War to various causes. Other than OV-10 Fleet replacement
training done in cooperation with Air Antisubmarine Squadron Forty-One (VS-41)
at NAS North Island, California, VAL-4 was the only squadron in the U.S. Navy to
ever employ the OV-10 and it was decommissioned shortly following the end of the
Vietnam War. VAL-4's surviving OV-10s were subsequently transferred to the
Marine Corps.

NASA

NASA has used a number of Broncos for various research programs, including
studies of low speed flight carried out with the third prototype in the 1970s,
and studies on noise and wake turbulence. One OV-10 remained in use at NASA's
Langley base in 2009 with three additional aircraft obtained from the Department
of State formerly used in drug eradication efforts.

California Department of Forestry and Fire Protection

The California Department of Forestry and Fire Protection (CALFIRE) has acquired
a number of OV-10As, including the six surviving aircraft from the BLM and 13
former U.S. Marine Corps aircraft in 1993 to replace their existing Cessna O-2
Skymasters as air attack aircraft. The CAL FIRE Broncos fly with a crew of two,
a contract pilot and the CAL FIRE ATGS or Air Tactical Group Supervisor, whose
job it is to coordinate all aerial assets on a fire with the Incident Commander
on the ground. Thus, besides serving as a tanker lead-in aircraft, the OV-10A is
also the aerial platform from which the entire air operation is coordinated.

Specifications (OV-10D)

General characteristics
Crew: 2
Capacity: cargo compartment for personnel (no seats) or 1,452 kg (3,201 lb) of
freight
Length: 44 ft (13 m)
Wingspan: 40 ft (12 m)
Height: 15 ft 2 in (4.62 m)
Wing area: 290.95 sq ft (27.030 m2)
Airfoil: NACA 64A315
Empty weight: 6,893 lb (3,127 kg)
Gross weight: 9,908 lb (4,494 kg)
Max takeoff weight: 14,444 lb (6,552 kg)
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 reversible propellers with metal hub and
composite blades

Performance
Maximum speed: 250 kn (290 mph, 460 km/h)
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)

12,500 ft (3,810 m) on one engineRate of climb: 15.33 ft/min (0.0779 m/s)

550 ft/min (2.79 m/s) on one engine, clean
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 cannon (YOV-10D) or 4 × 7.62×51 mm M60C machine
guns (OV-10D/D+)
Hardpoints: 5 fuselage and 2 underwing with provisions to carry combinations of:
Rockets: 7- or 19-tube launchers for 2.75 in FFARs/2.75 in WAFARs or 2- or
4-tube launchers for 5 in FFARs or WAFARs
Missiles: AIM-9 Sidewinder on wings only
Bombs: up to 500 lb (227 kg)




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