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)
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.
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.
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
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
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
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
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.
|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|
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
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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.
Reprinted with "written permission" from Publisher.
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