MOHAWK - First Conceived As A tactical Reconnaissance Machine With 
STOL Capabilities, Grumman's OV-1 Soon Showed The Way Toward Improved Tactical 
Air Support By Armed Fixed-Wing Specialty Aircraft Of The Future!

by: Frank Colucci

Photos from the authors collection except where noted

Credits

From, the time of military balloonists, battlefield commanders have known the value of aerial reconnaissance, and the continuing need to look "over the next hill" has spawned many airborne observation platforms. The Grumman OV-1 is, however; unique among modern military aircraft in having been designed from the outset for battlefield surveillance. Strong, powerful, and purposefully ugly, the Mohawk has given the U.S. Army a versatile eye in the sky for twenty years, and it promises to have an important future.

Grumman undertook development of the Mohawk in an unusual joint program sponsored by the U.S. Army and Marine Corps. The two services shared broadly similar requirements for an observation aircraft with Short Takeoff and Landing (STOL) performance and the ability to operate under spartan conditions along-side frontline troops. Grumman and Lycoming were the unanimous choice of a joint service selection board for airframe and engine manufacturers, and the aircraft was designated OF-1 in Marine markings and AO-1 with the Army.

As unveiled late in 1957, the Grumman G-134 Mohawk mockup had a round, insect-like nose, twin engines, and high T-tail. The roomy cockpit featured a large windshield that gave pilot and observer good downward visibility over the nose. Bulged side windows made it possible for the crew to look down at any spot on the ground, even directly beneath the aircraft, from any altitude greater than 37 ft.

The mid-wing layout gave the Mohawk a short, incredibly strong landing gear, and the overwing engine installation kept the 10 ft. diameter propeller well clear of the ground while affording the power plants some protection from groundfire. The OF-1/AO-1 also represented the first fixed wing application for the Lycoming T-53 turboshaft, the engine then flying in the prototype Huey helicopter.

Marine requirements contributed an unusual feature to the design. As originally proposed, the OF-1 could be fitted with water skis that would allow the aircraft to land at sea and taxi to island beaches at 20 kts. Since the Marines were authorized to operate fixed wing aircraft in the close support role, the mockup also spored underwing pylons for rockets, bombs, and other stores.

Soon after the detailed wooden mockup was displayed, the Marines withdrew from the Mohawk program for economy reasons, but in April 1958, the Army gave Grumman the go-ahead for nine YAO-1 prototypes. The joint service roots of the Mohawk did, however, result in the aircraft being evaluated by the U.S. Navy, and all early contracts were placed through the Navy on the behalf of the Army.

By the time the first YAO-1 rolled out, the single T-tail of the mockup had given way to the distinctive three-tailed layout. Grumman engineers found the T-tail would have provided inadequate control with one engine out, and to overcome this, the aircraft would have required a hydraulically boosted rudder, an unwanted complexity in an aircraft intended for operation from rudimentary frontline bases.

Twin tails would have given the Mohawk sufficient single-engine control but poor directional stability in conventional flight due to propwash. The triple tail layout proved best, and in an unexpected example of early "stealth" technology, it created a smaller overall radar return than the original T-tail layout.

Grumman test pilot Ralph Donnell made the first flight in the YAO-1 on April 14, 1959, at the company's Peconic River test facility. The aircraft handled well, and the last of nine prototypes under the original $22 million contract was flying by the end of the year.

With its short, broad-chord wing, hydraulically operated flaps, leading edge slats and hydraulic speedbrakes, the Mohawk was very much a STOL flying machine. More than half the wing span was bathed in the wash of the big, reversible pitch propellers, and the wing incorporated a pair of hydraulically operated auxiliary ailerons that worked only when the flaps were down, for better low-speed control. Even loaded with test gear heavier than its intended reconnaissance fit, the YAO-1 could take off over a 50 ft. obstacle in about 900 ft. of runway and stop in just 300 ft.

In flight, the Mohawk had a design ceiling of 22,000 ft. and a top speed of about 320 mph. The big fuselage speedbrakes helped the aircraft make ultra-short landings, and they enabled the Mohawk to drop quickly from moderate cruising altitudes to escape enemy fighters. Drawing from a Grumman Ironworks heritage, based on the 20 year production of dependable, robust fighter planes, the sturdy AO-1 was rated plus 5g and minus 1 1/2g, and could reportedly pull up to 7g without structural damage.

Ralph Donnell's masterful demonstration routines with the snappy Mohawk often included a near hover in a stiff wind. The new aircraft had a stalling speed of just 60 kt., and with flaps down a minimum turning radius of only 355 ft. at 1.6g. Flight testing of the YAO-1 turned up some slight flutter, quickly cured by smoothing the skin of the vertical tail. The successful test program led to a second $22 million contract for 35 production AO-1AFs, the first of which were delivered to the U.S. Army Aviation School at Ft. Rucker, Alabama, in mid 1960.

1. Wooden mockup of Grumman G-134 Mohawk in 1957 sports Marine markings and shows original T-tail. Note "eyebrow" windows over windshield and open overhead canopy panels. Joint Army-Marine design program made Mohawk a more sophisticated, more capable, and more expensive aircraft than Army originally envisioned. Ironically, after the Marine Corps dropped out, aircraft was developed solely for Army use.

2. Another view of the AO-1/OF-1 mockup shows Army markings and Marine water skis. Skis would have enabled OF-1 to land at sea and taxi to shore at about 20 kts. Underwing weapons resulted from Marine emphasis on close air support capability, which proved very effective in Vietnam.

3. First of nine YAO-1 prototypes flew April 14, 1959, with distinctive triple tail. Prototypes and initial production models had Lycoming T-53-L3 engine rated 1,005 equivalent shaft horsepower (total thrust from propeller and jet exhaust). Note aft side windows in line with prop warning stripes. Together with "eyebrow" windows. they were deleted from production Mohawks. First Mohawk was heavily instrumented for flight testing and carried long air data sensing probe. Designed to be maintained and repaired in the field. aircraft had interchangeable left-right stabilizers, elevators, and outboard fins. Wings could be removed inboard of engines to ship Mohawk by truck or train. (U.S. Army)

From inception, the AO-1 had been designed to accommodate three different reconnaissance systems: conventional cameras, side- looking airborne radar, and infrared sensors. The early AO-1AF carried a single camera amidships that could take pictures vertically, or tilt 15 or 30 degrees to either side under the control of pilot or observer.

While the Army's first turboprop aircraft entered the inventory successfully, the Mohawk proved very much a "hot" ship to service aviators coming from slow, piston-engined airplanes. Its power and responsiveness tempted pilots to show off and resulted in more than a few fatal accidents. The two-seat cockpit could be fitted with dual controls for training, but operational Mohawks were most often flown by a pilot and reconnaissance systems operator. The right- hand observer's seat might have had the linkages for control stick and rudder panels, but the controls themselves were rarely in place.

With the big propellers so close to the cockpit, and with the Mohawk destined to spend much of its time at low altitudes, conventional crew bail-outs were impossible. Grumman therefore provided the AO-1 with twin Martin-Baker ejection seats that could propel pilot and observer to safety from zero altitude at any air- speed greater than 100 kts. The transparent overhead panels also could be jettisoned, but normal ejection sequence blasted the crew right through the canopy. It took some time for Army ground and flight crews to learn how to maintain and use the new seats properly, but once procedures were established, the notoriously hard seats proved themselves lifesavers.

The second of the Mohawk recon systems spawned a new model, the AO-1BF (later OV-1B). First unveiled in 1960, the B model had its Side-Looking Airborne Radar (SLAR) in an 18 ft. long fiberglass pod suspended from the right side of the fuselage. To save weight, the fuselage speedbrakes and wing leading edge slats were deleted, but the wings themselves were extended 6 ft. for additional lift. The B also incorporated an autopilot that helped fly uniform radar mapping patterns.

Despite its ungainly appearance, the SLAR-toting B handled quite well. In 1971, a single example was loaned by the Army to the US, Geological Survey for geologic and hydrologic studies under the direction of Herbert Skibitzke. Over the next four years, systems specialist and pilot Mary Lou Brown was to fly the USGS Mohawk on survey missions all over the United States.

4. Wearing olive drab, second Mohawk prototype takes off in July 1959. STOL AO-1 had landing gear stressed for sink rates to 17 fpm and low pressure tires for soft, unprepared surfaces. Landings could be made in 300 to 500 ft.: takeoffs in 900 to 1,000 ft. (U.S. Army)

5. Fifth YAO-1 prototype shows Naval Air Test Center Markings at Ft. Eustis, Virginia, 1961. Even though Marines dropped out of Mohawk development before first flight, aircraft was evaluated by Navy, and early contracts placed by Naval Bureau of Aeronautics.

6. Clean production Mohawk in flight. AO-1AF (OV-1A) carried single KA-30 camera in fuselage. Camera could take pictures vertically or swivel 15 to 30 degrees, to either side, under control or pilot or observer. Production totaled 64 OV-1As.

1. Prototype OV-1D carries large, more-easily removable SLAR pod. It can also be fitted with radiation sensors for nuclear attack assessment, and it has a sophisticated data annotation system that codes all photos, radar maps and infrared imagery with precise location, altitude, and other information. (Grumman)

2. OV-1A sports overwing flare dispensers. Each box-like dispenser contained 52 upward-firing flares. Accidents with these eventually led to development of underwing strobe pod. OV-1A measured 41 ft. long with 42 ft. wingspan. Normal takeoff weight was 12,700 lbs.

As she recalls: "The Mohawk was a delightful plane to fly. Perhaps I should quality that statement. The B model had a longer wingspan...and it was considered to be the safest model. We had no experience with the A or C models; however, we knew of several accidents with those models that were attributed to the shorter wingspan.


"Our pilot checkout procedure was informal and abbreviated. First, we read the manual. Then, Skibitzke rode in the right seat observing while a qualified Army instructor flew the plane. They then traded places, and Skibitzke piloted the plane with the instructor in the right seat. The process was repeated twice with Skibitzke being the check pilot for Ruby Sheldon and me. After several takeoffs and landings, we felt quite confident in the Mohawk."

The radar imaging capability of the Mohawk was to prove a significant advance in both peace and war. The SLAR could look through foliage and map terrain, presenting the observer with a film image of the earth below only minutes after the area was scanned. In military operations, the image was split in two parts - - one showing fixed terrain features, the other spotting moving targets.

In mid-1961, the first Mohawks to serve with U.S. forces overseas were delivered to the 7th Army at Sandhoffen airfield near Manheim, Germany. Before its formal acceptance, the camera-carrying AO-1AF was flown by Ralph Donnell on a tour of 29 European airfields to show it off before the U.S. Army field commanders and potential European customers.

Germany and France had shown early interest in the Mohawk, and Grumman actually signed a license production agreement with the French manufacturer Breguet in exchange for American rights to the Atlantic maritime patrol aircraft.

3. Down on the deck, second production A model shows its form. Mohawk had excellent handling characteristics but proved tricky, particularly if pushed to extremes of flight envelope at low altitude.

4. Mohawk in "Short Takeoff" mode shows full-span leading edge slats, large flaps just outboard of engines, and auxiliary ailerons between laps and ailerons. Mohawk wing has aspect ratio of 5:3, and one British test pilot compared its handling characteristics and performance to the Gloster Meteor jet fighter, with exception that Mohawk had better rate of roll.

5. First production Mohawk is shown with air-drop supply pod -- this time without stabilizing fin. Production AO-1AF had de-icer boots on wing and tail leading edges. Note aft portion of side blister window has been faired over.

6. Triple-tailed Mohawk had flaps inboard of engines and auxiliary ailerons between engines and ailerons. All primary flight controls (ailerons, rudders, elevators) were manually operated through rods, cranks, and cables. Auxiliary ailerons. speed brakes, and flaps were hydraulic.

Projected European versions of the Mohawk were to have had the more powerful DeHavilland Gnome turboprops, but orders never materialized. Two radar-equipped OV-1Bs were, however, evaluated in both German and French markings in 1963.

The Berlin Crisis led President Kennedy to bolster U.S. forces in Europe and, as a result, eleven OA-1s were hurriedly cocooned for shipment to Germany in November 1961.

Stateside test work with the AO-1 continued. The aircraft performed well at temperatures down to -50 degrees F during a deployment to Fort Greely, Alaska, and in February 1962, two AO-1As maintained near perfect availability during the arduous Alaskan winter exercise Operation Great Bear at Fort Richardson.

When the Department of Defense reorganized American military aircraft designations in 1962, the Mohawk models were tagged OV-1A for the visual recon/photographic version, OV-1B for the SLAR toting variant, and OV-1C for the infrared reconnaissance bird.

That same year also marked the debut of the Mohawk in the Far East when the first OV-1s were delivered to U.S. Army training units in Japan.

The OV-1 was soon to take part in one of the earliest elements of American involvement in Vietnam, In July 1962, the 23rd Special Warfare Aviation Detachment (Surveillance) was formed. The unit arrived in the Republic of Vietnam in September with six OV-1As to provide reconnaissance capability for the South Vietnamese Army (ARVN). They were flown by American pilots and South Vietnamese observers.

The ordnance-carrying potential of the OV-1 soon generated a long- running feud between the Army and the Air Force, and among factions of the Army aviation community itself. Tested with a varied collection of bombs, rockets, gunpods, and other stores, the OV-1 proved itself a nimble and potent weapons platform. It did, however, venture into what was considered the operational realm of the Air Force by providing fixed-wing air support for Army ground forces. The running battle over who should be responsible for such missions became so heated that at one point the Air Force demanded Grumman suppress company brochures stressing the attack potential of the OV-1.

Mohawk armament in the early stages of the Vietnam war was specifically restricted to 0.50 caliber gunpods, and pilots were ordered not to fire unless fired upon by guerilla forces. Nevertheless, the OV-1s did provide important information to field commanders on Viet Cong movements, and their usefulness was to result in additional deployment as the American presence in southeast Asia grew.

The photo reconnaissance OV-1As were joined in 1963 by specially modified JOV-1Cs of the 11th Air Assault Division Based on the more powerful C version of the Mohawk, the armed reconnaissance JOV was stripped of the sophisticated infrared sensing gear that distinguished the C model and equipped with gunsight, dual controls, and two additional stores pylons. (All Mohawks had six wing hard-points but normally operated with only two or four pylons in place.) The aircraft represented the Army's attempt to exploit the attack capability of the OV-1, specifically in support of troop-carrying helicopters. It was to prove a successful and highly controversial experiment.

More Mohawks appeared in Vietnam in the fall of 1964 when the 4th Aerial Surveillance and Target Acquisition (ASTA) Detachment arrived with a mix of radar-equipped OV-1Bs and infrared recon Cs. By spring, 1965, the thirty Mohawks in Vietnam had been combined in the 73rd Aerial Surveillance Company based at the former seaside resort of Vung Tau, 35 miles southeast of Saigon.

Despite the value of the OV-1s in providing American and South Vietnamese field commanders with their own, responsive reconnaissance capability, the U.S. Army remained unsure of the value of the Mohawk. The very nature of the joint Army/Marine program had forced design compromises that made the aircraft an expensive and, sometimes, openly resisted item in Army budgets. Orders for the OV-1 stopped in Fiscal 1964, and the controversy in the Pentagon over the armed Mohawk peaked with a 1965 directive that prohibited the Army from operating armed fixed wing aircraft.

Fast, quiet, and rugged, the 'Hawks in Vietnam proved their worth time and again. At the full-scale battle of laDrang in 1965, and later in the Bong Son campaign, the few Mohawks available provided the ground forces with important visual reconnaissance reports, and the growing usefulness of SLAR and IR imagery became increasingly apparent to the other American services. The Air Force used precision targeting data from OV-1s to direct B-52 strikes. Navy coastal patrol forces were directed to infiltration points discovered by Mohawk radar; and the Marines made good use of Mohawk night recon data in the conduct of Operation Starlight in August 1965.

Operational success led to additional Mohawk orders in 1966, and by 1968, five surveillance companies were operating in Southeast Asia.

Regardless of official policy, OV-1s in Southeast Asia often flew armed with a mix of rocket and gun pods. The rugged constitution of the aircraft proved a blessing for flightcrews, particularly when Viet Cong forces were equipped with heavier weapons and learned how to use them against low-flying aircraft. One Mohawk returned to base with more than 90 holes in one wing, another with its empennage nearly severed by an anti-aircraft hit. One, nicknamed "Old Yeller" for all the zinc chromate dabbed over its battle patches, was mortally wounded after 900 combat hours. Unable to lower or shake one landing gear down, the pilot ordered the observer to eject, then followed himself. A Grumman technical representative later confirmed that the abandoned Mohawk obligingly crashed in a nearby scrapyard.

By night, photo reconnaissance OV-1s flew with two box-like dispensers mounted over the aft wing roots, each with 52 upward firing flares. Catastrophic accidents in which improperly loaded flares fired down and detonated the entire package led to the introduction of a more effective strobe light pod that could generate up to 300 powerful flashes a flight, one every 3 seconds.

Of far greater value was the radar and infrared imagery provided by OV-1Bs and Cs. Day or night, in any weather, the Mohawks could paint details of enemy movement and disposition on continuous film strip maps of the terrain below. The SLAR system could look to the left or right of the flight path, or scan both sides at once. The "Red Haze" infrared system painted a picture of the earth directly under the aircraft, detecting telltale heat traces of truck engines, campfires, or other disturbances ordinarily hidden by darkness, camouflage, or the density of the natural jungle canopy.

The Viet Cong developed a fearful respect of the all-seeing Mohawk. They reportedly dubbed the quiet OV-1 "Whispering Death," and they offered a standing reward of 50,000 piastres (then, 118 piastres to the dollar) to any gunner downing a Mohawk.

From the first American presence in Vietnam to the final withdrawal, the OV-1 provided an important dimension in intelligence gathering.

Last of the principal Mohawk versions to enter production was the versatile OV-1D with more powerful T53-701 engines, improved avionics, and interchangeable mission pallets that make it possible to switch the aircraft from infrared to SLAR configuration in about an hour. The first four OV-1Ds were prototypes converted from earlier production airframes, and the first flew in 1969. These were followed by 37 new-build aircraft, the last of which was delivered in December 1970.

While the OV-1 was never the subject of heavy export sales, two olive drab D models were transferred to Israel direct from U.S.Army stocks in 1974, and their delivery was kept a closely guarded secret for more than a year. Despite the Israeli penchant for secrecy, the aircraft were flown out of Lod International Airport. A Pan Am copilot reportedly photographed one from the cockpit of his waiting jet and was met in Rome by Israeli agents demanding the film! The aircraft are evidently still in Israeli service, conducting classified surveillance operations.

Grumman also demonstrated the OV-1 to the Philippines Air Force in 1974, again stressing the counterinsurgency potential of the armed Mohawk. No sale resulted.

In the score of years since the OV-1 entered Army service, this powerful, versatile machine has set its share of performance records. On June 16, 1966, test pilot Jim Peters flew an OV-1 to 3,000 m (9,842 ft.) in 3 min., 41 sec., and to 6,000 m (19,685 ft.) in 9 min., 9 sec. He also held the OV-1 at 32,000 ft. sustained altitude, all world records for a turboprop aircraft in the Mohawk's weight class. A month later, Army Colonel Edward Nielson flew an OV-1 to a new turboprop speed record when he covered a 100 km closed course in 12 min., 48.8 sec. at an average speed of 292 mph.

Unusual in that it marked one of the few world record attempts to be made by an Army tactical unit, an OV-1C of the 293rd Aviation Company based at Fort Hood, Texas, set three new time-to-climb records in June 1971. The unpressurized Mohawk with uprated T53-L15 engines also climbed to 39,880 ft. peak altitude and sustained 36,352 ft. Before their flight, CW2 Thomas Yoha and Capt. Richard Steinbock had to pre-breathe pure oxygen to eliminate nitrogen from the blood-stream and prevent decompression sickness at high altitude.

The specialized sensing capabilities of the Mohawk have proven useful to several civilian government agencies. With its radar modified for the survey role, the single OV-1B of the U.S. Geological Survey participated in a series of geologic and hydrologic studies, mapping fractured rock formations, limestone sink holes, and other phenomena to help document water resources.

1. OV-1B inflight with APS-94 Side-Looking Air-borne Radar pod (SLAR). B model had an auto-pilot and could fly 4 1/2 hours with two 150 gal. drop tanks. With same T-53-L3 engines as OV-1A, heavier B was slower and did not have A model's snappy handling characteristics.

2. The first AO-1BF (later OV-1B) shown in 1960 with its distinctive Side-Looking Airborne Radar pod. B model Mohawk retained KA-30 camera in fuselage but had wing slats and speed brakes deleted to save weight. Wingspan was extended to 48 ft. to generate more lift.

3. Older OV-1A during tests or snow/mud skis in 1963. If skis were fitted, nosewheel doors were removed. Nosewheel well was plugged by ski itself after retraction. Main gear skis rotated 94 degrees for retraction. Stripes on fuselage were for photographic record of aircraft motion and fuselage flexing, a procedure that is widely followed throughout industry.

4. Mohawk in German markings was one of two 0V-1Bs evaluated by Heersflieger (West German Army Aviation) in 1963. The aircraft flew 366 demonstration flight hours with both American and German pilots and maintained near 95% availability. They were later painted with French roundels for another series or tests but no sales resulted.

5. SLAR-carrying OV-1B at Ft. Greely. Alaska, in February 1965. Note 10 ft. diameter Hamilton Standard propellers were normally feathered on ground to keep them from turning freely in wind. Grumman built 101 OV-IBs. (U.S. Army)

1. More powerful OV-1C gave birth to armed JOV-1C variant with dual controls and gunsight. Aircraft were sent to Vietnam with 11th Air Assault Division, later absorbed by 1st Air Cavalry.

2. Third Mohawk variant to enter service, OV-1C, incorporated UAS-4 "Red Haze" infrared sensor in fuselage and had 1,150 eshp T53-L7 engines. Wing leading edge slats were deleted, but fuselage speed brakes restored. Short-winged C could be distinguished from camera- carrying OV-1A only by slight ventral bulge over infrared scanner. Production totaled 81 OV-1Cs. In-flight view shows bug-eyed cockpit canopy. which made for good vision, but large amount of glass area made Mohawk uncomfortably hot. Enough to sweat off three lbs. during an average mission. Top speed in level flight was nearly 300 mph.

3. Designed to take punishment and shoot back, Mohawk had 246 Ibs. of crew armor including 1/4 in. thick aluminum cockpit floor and flak curtains. Photo shows .50 cal. machine gun pod being loaded on outboard wing pylon. This OV-1A also has experimental terrain following radar antenna on nose.

4. Armed OV-1As taxi out during exercise at Ft. Stewart, Georgia, February 1967 -- two years after Dept. of Defense officially prohibited Army from operating armed, fixed-wing aircraft. Mohawk has 19-round rocket pod on outboard pylons and .50 caliber machine gun pods on intermediate stations. (U.S. Army)

5. Firepower: OV-1 with gun and rocket pods pulls up after firing pass on gunnery range. Nimble Mohawk proved to be an excellent gun platform, but its speed and control touchiness were the cause of frequent accidents early in its operational career. More than one was lost on gun passes when one engine failed and the immediate resulting roll flipped the aircraft into the ground.

The first survey mission flown by the USGS was to detect surface water in the jungles of Panama as part of the Inter-American Geodetic Survey. In September 1971, project head Herbert Skibitzke was on the way to the Canal Zone when bad weather diverted him to Tapachula, Chiapas, Mexico, Low on fuel, he found the runway covered with slick, rain-soaked volcanic ash. Ordinary braking would have caused any conventional aircraft to swerve dangerously on landing, but the reverse thrust of the twin-engined Mohawk brought it to a safe stop.

In 1974, the USGS OV-1 surveyed the route of the Alaskan oil pipeline, and later that year, it helped study pack ice in the Beaufort Sea off the north coast of Alaska. In the frozen Arctic, using an ejection seat to abandon a crippled aircraft meant almost certain death by exposure. The OV-1B was consequently equipped with underwing pods packed with emergency flotation gear that would let survey crews ditch and survive. Fortunately, the situation never arose.

Supporting the lone Mohawk posed its own problems. "Maintenance was a nightmare," according to Mary Lou Brown, "especially in the Arctic. The aircraft and all its components were highly specialized. Parts could be procured only from the Army, and special tools were required for all the special parts. The hydraulic system was particularly vulnerable to the extremely cold temperatures of the Arctic; but then a main gear collapsed on landing at Phoenix Sky Harbor where the temperature was more than 100 degrees. The SLAR antenna made an excellent skid... On one memorable Arctic flight, Skibitzke had departed Fort Wainwright, in Fairbanks, after the plane had been in for maintenance, to return to our base at Point Barrow. As he approached the Yukon River, there was a resounding thud as first one gear and then the other dropped out of the wells and dangled beneath the plane. Attempts at recycling were ineffective. With about 400 miles of frozen tundra and the Brooks range between him and Point Barrow, he turned back to Fort Wainwright for another maintenance session."

The Mohawk continued its valuable survey work until 1975 when the aircraft was turned over to the Naval Air Test Center at Patuxent River, Maryland.

Another "renegade" OV-1 served with the Environmental Protection Agency in the early seventies. EPA bailed an OV-1C from the Department of Defense and used the panoramic nose camera and infrared sensing system to document oil spills, strip mine land damage, industrial waste flows, and other phenomena. The aircraft was flown from the EPA facility near Las Vegas, and returned to the Army in 1976.

After more than eight years of service, four OV-1Cs still fly with the U.S. Customs Service, hunting for drug smugglers with a non- standard, nose-mounted infrared system.

NASA too has found some uses for the Mohawk. An OV-1B was modified by Grumman to carry a small jet engine under the right wing. With it, carefully controlled flight profiles are flown over a test range to measure aircraft noise characteristics.

Additional early-model Mohawks have been brought up to the latest OV-1D standard, and if service longevity is a measure of design success, the OV-1 is undoubtedly a successful airplane. By the end of 1980, the Army still had 25 OV-1Bs, 26 Cs, and 84 Ds in active and reserve units. Starting in 1972, the Army National Guard began to receive the Mohawk, and today, the Guard has 13 OV-1Bs, 24 Cs, and 16 Ds serving with three units in Georgia and Oregon.

Grumman at one time proposed a single-seat attack version of the Mohawk with powerful T-55 engines and 30mm cannon in response to the Air Force AX competition. The production contract eventually went to the Fairchild Republic A-1O. Another Mohawk derivative with an extended nose for extra seats and special electronics never advanced past the drawing board.

There is, however, a specialized, little publicized Mohawk in service. The RV-1D performs classified electronic intelligence duties and is distinguished by two large underwing pods.

Grumman continues to update Mohawks at the company's Stuart, Florida facility. And with new avionics and nap-of-the-earth flying tactics, Grumman's bug-eyed, multi-sensor bird is expected to serve with the Army well into the nineties.

Overshadowed by sleek spyplanes and all-seeing satellites, the OV-1 remains a potent, responsive reconnaissance platform -- one that will stay in the frontlines of aerial intelligence gathering for some time to come.

Acknowledgement -- The author wished to express special thanks to the following people for their help in the preparation of this article: Mr. Allen Cobrin, Mr. Herman Schoenburg, Ms. Lois Lovisolo, and Mr. Joel DiMaggio of Grumman Corp.; Ms. Mary Lou Brown of Hydro-Data, Inc.: Mr. Steve Miller and Mr. Donald Weinstein

1. Radar-podded OV-1B and infrared-sensing OV-1C fly formation. Together, the two Mohawk variants gave American forces in Southeast Asia round-the-clock battlefield surveillance capability. Both types retained optical camera to supplement their sophisticated reconnaissance systems. OV-1C also had message-dropping chute.

2. Mohawk tested with terrain avoidance radar is checked out at Fort Huachuca, Arizona, in 1966. Two-seat OV-1 had Martin Baker ejection seats that could carry crew to safety at speeds greater than 100 kts. from any altitude. These were later upgraded to permit safe ejection at speeds down to 60 kts.

3. Prototype OV-1D incorporated most of the many changes found in 37 production D models. Powered by 1,400 eshp T-53-L-701 engines, OV-1D has a strengthened airframe with the 48 ft. wingspan or the OV-1B and fuselage speedbrakes of OV-1A and C. It carries camera, SLAR, or IR reconnaissance systems in interchangeable pallets that let field commanders quickly configure aircraft for job at hand.

4. OV-1B modified for air-to-air refueling tests. Jury-rigged probe mates with drogue trailing from C-7 Caribou tanker. Arrangement worked well but was never used operationally.

5. OV-1B of the 1st Air Cavalry Division at Loading Zone "Two Bits" in Vietnam, 1967. Mohawk represented odd mix of easy-to-maintain airframe with sophisticated avionics. SLAR system could map terrain to left or right of aircraft, or on both sides at once, letting airborne observer view the continuous film strip three minutes after exposure. (U.S. Army)

6. Ordnanceman of the 73rd Aviation Company, 272nd Aviation Battalion, 12th Combat Aviation Group, loads 2.75 in. rocket on Mohawk at Vung Tau, Vietnam, June 1967.

7. OV-1B of 1st Air Cavalry Aerial Surveillance and Target Acquisition Platoon displays its 18 ft. long SLAR pod. Scene is near An Khe, 1967. Bulged cockpit canopy of Mohawk affords excellent downward view, and 1 in. thick, bullet-resistant (not bullet proof) windshield gave pilot and observer 22 degrees downward visibility over nose. (U.S. Army)

8. Among the stores combinations tested on Mohawk were 250 and 500 lb. bombs and rockets, as well as guns. Inboard pylons could carry 1,370 lbs.; out-board 500 Ibs. each. Grumman planned to test 20mm cannon pods, Bullpup air-to-surface missiles, and other heavier ordnance on Mohawk, but Air Force protests put end to effort.

9. Ready to taxi out at Landing Zone "English" in Vietnam, radar- equipped OV-1B carries 150 gal. underwing tanks. Missions were typically flown with an officer pilot and enlisted observer. SLAR imagery proved particularly effective in locating enemy movements in any weather. OV-1B retained KA-30 vertical camera in fuselage. and some Mohawks were field-modified with a panoramic camera in the nose. Notice modern variant of WW II PSP (Pierced Steel Plank) landing strip. Here it is made up of grooved panels linked together.



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AIRPOWER

The proceeding story has been retracted, in its entirety, from "AIRPOWER" Magazine - NOVEMBER 1981, VOLUME 11, NO. 6, PAGES 24-37, (33 pictures, 1 illustration). "AIRPOWER" is published bi-monthly by Sentry Books, Inc., 10718 White Oak Ave, Granada Hills, California 91344.

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