In 1966, the United States Air Force (USAF) realised it needed a replacement for its O-1 Bird Dogs in Vietnam. The Cessna 337 was selected and, with relatively minor modifications to incorporate four under wing weapons mounts and weapon release systems, was sent to war in Vietnam designated O-2A. The Cessna O-2A is an all metal, high wing, retractable gear aircraft incorporating twin tail booms and an engine mounted at the front and rear of its fuselage pod.
501 were supplied to the USAF designated O-2A. In addition, a version equipped for psychological warfare missions entered USAF service under the designation O-2B This carried an air-to-ground broadcasting system using three 600-watt amplifiers and a battery of highly directional speakers. Total procurement of O-2B aircraft amounted to 31. The first Cessna 0-2A was delivered to the 20th Tactical Air Support Squadron at Da Nang on 2 July 1967.
Twelve O-2As were supplied to the Imperial Iranian air force in early 1970.
A twin-turboprop O-2T/O-2TT did not proceed beyond USAF evaluation.
Detail improvements continued each year, and a turbocharged version, the Model T337 Super Skymaster, was introduced in 1970, but the prototype of a pressurised T337G Skymaster, powered by 168kW Continental TSIO-360 engines, flew in July 1971 (the word Super had then been dropped), and deliveries began in 1973.
Only 356 were produced by 1980, when production ceased.
In 1969, Reims Aviation in France began licence assembly of the Model 337, with primary structures supplied by Cessna and Continental engines built in the UK under licence by Rolls-Royce. The US and French production lines continued in parallel, the French versions being classified Reims F337. The name Milirole was applied to the basic unpressurised F337 for a short time. Since 1974 Reims have developed a special unpressurised STOL version, designated FTB337, which can be provided with a wide range of equipment to make it suitable for such duties as maritime or overland patrol and rescue, and the military FTMA Milirole with wing strongpoints and enlarged flaps.
Production of the Model 337 series by Cessna ended in mid-1980 by which time 1,821 Model 337s, 313 pressurised Model 337s and 544 military O-2s had been delivered. French production by Reims Aviation totalled 66 Model F337s, 27 F337Ps and 61 FTB337s.
US Basler Flight Servic modified a CE-337 with a P&W PT6 at the rear, replacing both piston engines, and stretched the fuselage 2.1m to accommodate 10 passengers or freight.
The Summit Aviation Sentry O-2-337 Sentry is a military conversion of the Cessna T337 push-pull twin-piston-engined light aircraft with uprated 225 hp Continental TSI0-360 engines, similar in config-uration and role to the O-2. Four underwing Nato-standard pylons can carry up to 160kg of stores including gun and rocket pods, and a combined search radar and speaker system pod. The Royal Thai Navy has taken delivery of ten O-2-337s.
Groen Hawk 6 / Revcon 6G / Cessna Skymaster
Engine: 2 x Continental IO-360-GB, 157kW, 210 hp
Max Take-off weight: 2100 kg / 4630 lb
Empty weight: 1264 kg / 2787 lb
Wingspan: 11.63 m / 38 ft 2 in
Length: 9.07 m / 29 ft 9 in
Height: 2.79 m / 9 ft 2 in
Wing area: 18.81 sq.m / 202.47 sq ft
Max. speed: 332 km/h / 206 mph
Cruise speed: 315 km/h / 196 mph
Ceiling: 5485 m / 18000 ft
Range: 1235 nm / 2288 km / 1422 miles
Crew : 2 + 4
Engines: 2 x Continental IO-360, 210 hp.
Fuel consumption: 70 lts total/hr.
Cessna 337 Super Skymaster
Engines: 2 x Continental IO-360-C, 310 hp
Length: 29 ft 9 in.
Wingspan: 38 ft 2 in.
Speed: 199 mph.
Ceiling: 18,000 ft.
Range: 755 mls.
Landing speed: 63 mph.
Landing dist: 575 ft.
Pax cap: 6.
Payload: 1,610 lb.
1977 CE-337 Skymaster
Engines: 2 x Continental IO-360-G, 210 hp.
Wing loading: 22.9 lb/sq.ft.
Pwr loading: 11 lb/hp.
Gross wt: 4630 lb.
Empty wt: 2786 lb.
Equipped useful load: 1730 lb.
Payload max fuel: 842 lb.
Range max fuel/75% pwr: 986 nm/5.8 hr.
Range max fuel / 55% pwr: 1199 nm/ 8.1 hr.
Service ceiling: 18,000 ft.
75% cruise: 169 kt.
55% cruise: 149 kt.
Stall: 61-69 kt.
1.3 Vso: 79 kt.
ROC: 1100 fpm.
SE ROC: 320 fpm @ 88 kt.
SE Service ceiling: 7100 ft.
Min field length: 1675 ft.
Fuel cap: 528/888 lb.
Engine: 2 x Continental IO-360-G, 210 hp.
Max speed: 171 kts.
Max cruise speed: 169 kts.
Max range: 1155 nm.
Max usable fuel: 148 USG.
ROC: 925 fpm.
ROC SE: 300 fpm.
Service Ceiling: 16,100ft.
Service ceiling SE: 6900 ft.
Takeoff dist 50 ft obstacle: 1,675 ft.
Landing dist 50 ft obstacle: 1,650 ft.
Max ramp wt: 4648 lb.
Max useful load: 1848 lbs.
Engine: 2 x 225 hp Continental TSIO-360-C, 210 hp.
Vne: 197 kts.
Max cruise: 205 kts.
Econ cruise: 147 kts.
ROC: 1100 fpm @ 110 kts.
SE ROC (87kts): (Front eng.) 400 fpm, (rear eng) 500 fpm.
Operational ceiling: 20,000 ft.
Range, no res @ 16,000ft: 1308 nm.
Empty wt: 3184 lbs.
MTOW: 4700 lbs.
Wing span: 38 ft 2 in.
Length: 29 ft 9 in.
Height: 9 ft 4 in.
Wing area: 202.5 sq.ft.
Stall: clean: 57 kts, Flap, u/c dn: 50 kts.
Engines: 2 x Continental TSIO-360-C, 225 hp.
TBO: 1,400 hrs.
Propellers: constant-speed, full-feathering, two-blade.
Length: 29 ft. 10 in.
Height: 9 ft. 2 in.
Wingspan: 38 ft. 2 in.
Wing area: 202.5 sq.ft.
Wing loading: 23.2 lb/sq.ft.
Power loading: 10.4 lb/hp.
Gross weight: 4,700 lbs.
Empty weight: 3,311 lbs.
Useful load: 1,389 lbs.
Max ramp wt: 4,724 lbs.
Payload with full fuel: 511 lbs.
Rate of climb: 1,250 fpm.
Single-engine rate of climb: 375 fpm.
Single-engine climb gradient at 89 knots (Vyse): 253 ft./nm.
Service ceiling: 20,000 ft.
Single-engine service ceiling: 18,700 ft.
Certificated ceiling: 20,000 ft.
Max speed: 217 kts.
Maximum cruise (75 % @ 20,000 ft.): 205 knots.
Intermediate cruise (75% @ 10,000ft): 186 knots.
Duration @ maximum cruise: 5.8 hrs.
Maneuvering speed: 139 knots.
Stall speed (clean): 70 knots.
Stall speed (gear, flaps down): 62 knots.
Pressurization differential: 3.35 psi.
10,000-foot cabin at 20,000 ft.
Usable fuel capacity: 148 USG/888 lbs.
Maximum takeoff weight: 4,700 lbs.
Maximum landing weight: 4,465 lbs.
Takeoff dist 50 ft obstacle: 1,500 ft.
Landing dist 50 ft obstacle: 1,675 ft.
Max range: 1,155 nm.
Reims Cessna FT.337G Turbo Super Skymaster
Engine: Two Continental IO-360-D, 210HP (158 kW)
Propeller: Two McCauley Constant Speed, Full Feathering 2 blade
Prop Diameter: 6 ft 6 in (1.95m)
Fuel: Aviation Gasoline 100 Octane
Wing Tank Capacity: 37 Imperial Gallons / 167 Litres / 44 U.S. Gallons
Reserve Tank Capacity (2): 15 Imperial Gallons / 68 Litres / 18 U.S. Gallons
Wingspan: 38 ft 0 in / 11.58 m
Length: 29 ft 2 in / 8.90 m
Wing Area: 201 sq. ft / 18.67 sq. m
Height: 9 ft 5 in / 2.87 m
Empty: 3,226 lb / 1,463 kg
Maximum Takeoff weight: 4,850 lb / 2,200 kg
Maximum Speed: 192 knots / 221 mph / 356 km/h
Cruise Speed: 140 knots / 161 mph / 261 km/h
Engines: 2 x 225 hp Continental TSI0-360
Hardpoints: Four underwing
Hardpoint load: 160kg
Engine: 1 x P&W PT6.
Pax cap: 10.