Agricultural

Zlin Z-137

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The Zlin Z-137T Agro Turbos are essentially an updated turbine version of the piston engine Z-37 Cmelak, first flown in 1981. Modifications included strengthening the centre section of the wing, alterations to the tail surfaces and the installation of a rudder trim.

The first Z-137T was #029 and registered OK-UJM in July 1989.

The aircraft were built in batches. The first batch totalled six and from 1960 they were built in batches of 20 or 30, with production reaching its height in 1972 when some 65 aircraft were produced. Along with the agricultural aircraft, some two-seat trainers were built, with a second cockpit replacing the hopper. Production ceased in 1977 but in 1981 the production line was reopened at Kunovice, and a further 40 aircraft were built. Production ceased in 1995 with #053, which was sold to Hungary as HA-MFR. The constructor numbers are in batches — 00-01 through 00-06, then 01-01 to 01-20, 02-xx and so on depending on the number in the batch.

A modernized Z-137 Agro Turbo light aircraft equipped with air-to-air missiles was spotted in the Ukrainian sky in August 2025. The Czechoslovakian-made Z-137 civilian turboprop aircraft was converted to perform air defense missions. Its tail section was marked with a typical army aviation insignia of two white transverse stripes.

Two AKU-73 pylons were mounted under the wings of the aircraft, which made it possible to use R-73 short-range air-to-air missiles. The use of R-73 missiles from non-designated aircraft is possible due to its complete autonomy as it does not require complex integration with the radar or central radar of the aircraft. It uses an infrared guidance system to track the target. The missile head itself ‘captures’ a heat-contrasting object. Given the type of weaponry and the aircraft’s ability to reach speeds of 200-250 km/h, the tasks of such a combat unit could include intercepting Russian attack drones and tactical reconnaissance UAVs.

An R-73 missile on the wing pylon of MiG-29 and Z-137 Agro Turbo.

The use of turboprop aircraft for such tasks can significantly increase the capabilities of the Air Force, as well as unload full-fledged fighters for higher priority tasks.

137T Agro Turbo
Engine: Motorlet M601Z turboprop (520 hp)
Wing span: 44 ft 8.5 in
Length: 34 ft 4 in
Height: 11 ft 6 in
Empty wt: 2756 lb
MTOW: 5566 lb

Zlin Z-37 Cmelak / OK-60 / Bumble Bee / Z-237

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The XZ-37 was first flown as OK-60 on 29 June 1963. Powered by a 310 hp Ivchenko Al-14VF, the aircraft went into production as a joint venture between Moravan and SPP at Kunovice in 1966. The Zlin Z-37 Cmelak was fitted with a 315 hp Walter M-462RF radial, a licence-built version of the Ivchenko AI-14.

Zlin Z-37 Brochure

Z-37

In 1967, the first Z-37s were exported to East Germany and Yugoslavia. The Z-37A was an improved version from 1971 with stronger and more corrosion-resistant airframe and other changes. Both featured an auxiliary seat behind the hopper.

As in the West, the swing to turbines was noticed by Moravan and a new aircraft, the XZ-37T, was built at Otrokovice and made its maiden flight on 6 September 1981. It was powered by a 691-shp Walter M-60lB. Two more prototypes were completed in 1983, these powered by a 483-shp M-601Z turbine. Certification under BCAR (British Civil Air Regulations) was received in 1984 and production was started in 1985 as the Z-37T Agro Turbo. Two Z-37T-2 two-seat trainers were completed in 1987. An upgrade of the Z-37 with increased engine power followed and, although the aircraft was designated the Z-137T, the same type certificate is used. A total of 713 piston engined aircraft were built with the last being 25-40.

Z-37
Engine: M 462 RF, 315 hp
Span: 40’ 01” / 12.22 m
Length: 28’ 0.5” / 8.55 m
Height: 9’ 10”
Wing area, 256 sq.ft
Empty weight 2,295 lb / 1043 kg
MTOW normal: 3,855 lb / 1750 kg
Cruise 4920 ft / 1500 m: 99 kt / 114 mph / 183 kph
ROC SL: 925 fpm / 282 m/min
Service ceiling: 13,125 ft / 4000 m
Range w/1 hr +10% res: 345 nm / 398 mi / 640 km
Seats: 1 crew + 1 pax

Z-37 Ag
Engine: M 462 RF, 315 hp
Span: 40’ 01” / 12.22 m
Length: 28’ 0.5” / 8.55 m
Height: 9’ 10”
Wing area, 256 sq.ft
Empty weight 2,295 lb / 1043 kg
MTOW: 4089 lb / 1850 kg
Cruise 4920 ft / 1500 m: 92 kt / 106 mph / 170 kph
ROC SL: 728 fpm / 222 m/min
Hopper capacity: 143 Imp.Gal / 650 lt / 1323 lb / 600 kg
Hopper / cargo volume: 63.5 cu.ft / 1.8 cu.m

Let Z 37 A Cmelak
Engine : Avia M 462 RF, 306 hp
Length : 28.215 ft / 8.6 m
Height : 9.514 ft / 2.9 m
Wingspan : 40.026 ft / 12.2 m
Wing area : 256.183 sqft / 23.800 sq.m
Max take off weight : 4079.3 lb / 1850.0 kg
Max. speed : 108 kts / 200 km/h
Cruising speed : 100 kts / 185 km/h
Initial climb rate : 787.40 ft/min / 4.00 m/s
Service ceiling : 13287 ft / 4050 m
Wing load : 15.99 lb/sq.ft / 78.00 kg/sq.m
Range : 346 nm / 640 km
Crew : 1-2

Z-37T
Engine : Walter M 601 Z, 360-483 shp
Length: 34.449 ft / 10.5 m
Height: 11.483 ft / 3.5 m
Wingspan : 44.619 ft / 13.6 m
Wing area : 287.399 sqft / 26.7 qm
Max take off weight : 5567.6 lb / 2525.0 kg
Weight empty : 2756.3 lb / 1250.0 kg
Max. weight carried : 2811.4 lbs / 1275.0 kg
Max. speed : 118 kts / 218 km/h
Landing speed : 42 kts / 77 km/h
Cruising speed : 103 kts / 190 km/h
Initial climb rate : 826.77 ft/min / 4.20 m/s
Wing load : 19.48 lb/sq.ft / 95.00 kg/sq.m
Range : 189 nm / 350 km
Crew : 1

Z-37T-2
Seats: 2

Z-237

Yeoman YA-1 Cropmaster 250 / KS.3 Cropmaster 250 / Fieldmaster 285

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YA-1

Australian designed and built, based on the CAC CA-6 Wackett trainer. A new wing, tail, and engine were fitted and twenty-one were built between 1959 and 1967. The first flying in February 1960.

Production versions were the KS.3 Cropmaster 250 and Fieldmaster 285.

Yeoman Cropmaster YA 1 250R

At least one was converted to three seats and, as a Yeoman Hanes 250, fitted with an extended glazed canopy to cover all seats.

Gallery

White Aircraft D-25B

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The 1940 White Aircraft D-25B (108 2-557) was New Standard D-25 production, bought from Jones Co, and repowered with a 285hp Wright J-6 for use as a crop duster.

Five were built, of which two were destroyed in a 1940 hangar fire at Monroeville AL, NR25317 and NR25318, and two went to the Dept of Agriculture in 1941 (NR25319, NR25320). The fifth, actually a D-25A airframe, was delivered to White Co in 1942 as NR25313.

Weatherly W620 / W620TP

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W620B

Built in Hollister, California and first built and certified in 1979 (TC A26WE). The 620, the first of which, N9245W, first flew in 1979 and was powered by the 450-hp R-985. The next aircraft, N9259W, was fitted with a PT6A-11AG. One similar aircraft was manufactured in 1960 but Weatherly remained faithful to the radial.

Production waned in the mid-eighties but with the introduction of the model 620A sales picked up again. The 620A wingspan was further extended another five feet to 40 ft 8 in (the wing is now 277 sq.ft) with longer ailerons and a new wingtip design but still retaining the vanes. The 620A also featured a new tail. The empty weight of the 620A is 2,840 lbs and the maximum all-up weight is 5,900 lbs, the hopper capacity being 335 US gallons.

In 1991 the 620A was upgraded to the 620B with major improvements to the cockpit and the addition of two auxiliary fuel tanks providing extra range on ferry flights. Put into production in 1992, this has by far been the most popular model with over one hundred been built and sales not only in the United States but Canada, Central and South America and Australia.

The 620B was then offered with a turbine, this time an Allied Signal TPE331-1, which Weatherly Aviation market as the 620BTG.

W620
Engine: 1 x P&W R-985, 450 hp
TBO: 1000 hrs
Prop: Hartzell, 3 blade, constant speed 95.5 in
Seats: 1
Length: 27.2 ft
Height: 8.1 ft
Wingspan: 41 ft (with wingtip vanes 47’0″)
Wing area: 264 sq.ft
Wing aspect ratio: 6.1
Max take off wt: 5600 lbs
Standard empty wt: 2760 lbs
Max useful load: 2840 lbs
Max landing wt: 4000 lbs
Wing loading: 21.2 lbs/sq.ft
Power loading: 12.4 lbs/hp
Max useable fuel: 390 lbs
Hopper capacity: 335 USG
Max climb rate: 700 fpm
Service ceiling; 15,000 ft
Max speed: 130 kts
Working speed: 78-100 kts
Stall speed flaps down: 57 kts
Turbulent air penetration speed: 122 kts
Fixed tail wheel undercarriage

W620A

W620B

W620TP
Engine: 1 x P&W PT6-11AG, 500 hp turboprop
TBO: 3500 hrs
Prop: Hartzell 3 blade constant speed 96 in
Seats: 1
Length: 30.5 ft
Height: 8.3 ft
Wingspan: 41 ft
Wing area: 264 sq.ft
Wing aspect ratio: 6.1
Max take off wt: 5600 lbs
Standard empty wt: 2700 lbs
Max useful load: 2900 lbs
Max landing wt: 4000 lbs
Wing loading: 21.2 lbs/sq.ft
Power loading: 11.2 lbs/hp
Hopper capacity: 340 USG
Service ceiling; 15,000 ft
Max speed: 153 kts
Working speed: 78-122 kts
Stall speed flaps down: 57 kts
Turbulent air penetration speed: 122 kts
Fixed tail wheel undercarriage

Weatherly W201

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When the supply of Fairchild aircraft ran out, John Weatherly started to build the complete aircraft. Two model W201s were built in 1966/67, N86686 and M86687. Powered by a 450-hp R-985 Pratt & Whitney, these aircraft had an improved wing design with the span increased to 39 ft.

The 1970 production aircraft, the W201A, were built between 1968 and 1971. These can be identified by a triangular shaped fin and rudder. More than 100 were built at $22,800.

Weatherly 201A N2930W

The W201B model commenced production in 1971 and 45 aircraft were built at $31,500 in 1974.

Another version followed in 1975, the W201C, and this was the Weatherly that introduced the wingtip vanes which diffuse the normal formation of the wingtip vortex. The 201, 201A, and 201C models were under TC A10WE.

201 / 201A / 201C
Engines: P&W R-985, 450 hp
Wingspan: 39’6″
Length: 26’7″
Max TO wt: 4800 lb
Empty wt: 2580 lb
Equipped useful load: 2169 lb
Payload max fuel: 1769 lb
Hopper cap: 270 USG
Wing loading: 19.2 lb/sq.ft
Pwr loading: 10.6 lb/hp
Max speed: 128 mph
Cruise speed: 105 mph
Stall: 58 mph / 60 kt
Working speed: 95 kt
Working endurance: 3 hr
ROC: 980 fpm
Min field length: 1500 ft
Fuel cap: 400 lb
Seats: 1

210B
Engine: P&W R-1340, 450hp
Wing span: 39’0″
Length: 26’7″
Useful load: 2260 lb
Max speed: 130 mph
Cruise speed: 108 mph
Stall: 53 mph
Seats: 1

Weatherly WM62C

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WM62C

Weatherly Aviation’s first aircraft was the WM-62C, N3775G. This was followed by at least 18 aircraft 1961-1965 which were conversions of the PT-19/-23 aircraft. They can be identified by their rounded Fairchild fin and rudders. The first were open cockpit with a roll-over frame but later versions were fitted with an enclosed cockpit.

Weatherly WM-62C N51239

Single place aircraft, power was from a Continental W-670 or P&W R-985.

UTVA UTVA-65 Privrednik

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Super Privrednik-350

The UTVA-65 agricultural aircraft first flew in 1965.

The Privrednik-GO initial version was powered by a 295 hp Lycoming GO-480-G1A6 engine with a constant speed propeller.

The Privrednik-IO is the export version of the -GO with a softer landing gear. Power was a Lycoming IO-540-K1A5 with fixed pitch or constant speed propeller.

The Super Privrednik-350 is a more powerful version.

UTVA-65 Privrednik Article

Super Privrednik-350
Engine: Lycoming IGO-540-A1C, 350 hp
Wingspan: 44 ft 0.5in / 13.42 m
Length: 27 ft 9 in / 8.46 m
Payload: 1455 lb / 660 kg
MTOW w/spray equip: 4409 lb / 2000 kg
Seats: 1

Privrednik-GO