The M-18 was designed in co-operation with Rockwell International in the USA to FAR Part 23 standards. It uses several components of the then Rockwell S2R Thrush, including the outer wing panels. The cockpit is a sealed unit and has a similar layout to the Snow S2D-600. With a requirement for a crew seat, the rear canopy was later redesigned with a hatch on the port side for entry to a rear facing seat. The earlier M-18 models that were converted and new production aircraft were designated M-18A.

Described as a low wing agricultural mono¬plane with fixed landing gear, the unswept cantilever wings are of constant chord, with 2o 30’ dihedral on the centre section and 6o on the outer panels. The wing sections are NACA4416 at the root and NACM412 at the tip. The aircraftis fitted with a steel-capped wing spar with all-metal, two section, trailing-edge flaps, actuated hydraulically. Metal slotted ailerons and metal wing tips complete the 58’ wing span and 430.56 sq ft wing area.

The fuselage is of all-metal tubular construc¬tion and incorporates an all-metal tailplane. It stretches 31 feet long and in a flying attitude stands at 15’01”. The hopper is made from glass fibre and has a capacity of 2,500 litres, or 660 US gallons. The aircraft’s empty weight is 5,445 lbs with a maximum take-off weight of 11,684 lbs. It has a maximum speed of 138 knots and a stalling speed, with flaps extended, of 59 knots. The pilot being accommodated in a cockpit stressed to survive an impact of 40g. Special materials and treatment limit airframe corrosion to a minimum.

PZL-Mielec built three prototype aircraft powered by the uprated P.Z.L. ASz-621R engine. The first, for testing, was non-flying, but the second aircraft, SP-PBW, and the third aircraft, SP-PBZ, first flew on 27 August 1976 and 2 October 1976 respectively. From April 1978, a batch of ten pre-production aircraft were built, of which two were non-flying test aircraft. Five of them used for operational trials, in Eastern Europe and and two were used in trials in Egypt during the summer of 1978. Another was test flown (on 11 November 1978) as a firefighter to test the concept. The Polish type certificate was issued on 27 September 1978 and two aircraft from this batch were sold to Yugoslavia the following year.

Deliveries of the second batch of five air¬craft began in 1980, with four going to Canada. Canadian certification of the fire-fighting version was awarded on 10 March 1980. Another batch of ten aircraft was built in 1980, six of which went to Canada.

Production of the M-18 began following the receipt of Polish certification on 27 September 1978, but came to an end in 1984, shortly after the M-18A two-seat version was certificated by the Polish authorities. A dedicated two-seat agricultural trainer, designated the M-18AS, was constructed with a smaller hopper to allow an instructor to sit behind the pilot, and flew for the first time on 21 March 1988. Five were built by 1992.

In common with most East European air¬craft, Dromaders are built in batches. This is evident in the constructor number sequences. In the Soviet Union series of numbers are used, however, PZL-Mielec used an alphabetical and numerical sequence. The prototype Dromaders used 1ZP and the production Dromader 1ZO.
Mielec has produced a two-seat trainer Dromader, the M-18BS, first flying in November 1997.

The fifth batch to come out of Poland saw the first aircraft, 1ZO05-01, being delivered to the USA as N42255. Of the fifteen aircraft built, nine were sold to the United States, three to Hungary and two to Cuba. The fifteenth airframe was used for spares. In 1981 the Polish com¬pany had two new customers. Turkey purchased four aircraft and South Africa two. Hungary, Cuba and the USA were the main buyers until 1982, when Bulgaria purchased four aircraft and followed with another fourteen by the end of that year. From December 1983, the Greek Air Force took delivery of eighteen aircraft for use as fire bombers. As mentioned above, Cuba took delivery of their first M-18 in January 1981 and by October1988, forty-six aircraft had been reg¬istered in that country.

The nine-cylinder, supercharged radial engine, the AS-621z, which drives the four-blade PZL-Warszawa SP.00 propeller, has been the only power plant supplied by the factory. Operators in the United States have taken advantage of this large airframe with some replacing the PZL radial with turbine power. Turbine Conversion of Nunica, MI, converted some M-18/M-18A aircraft by installing P&WPT-6A-45 and -65 series engines and 800 US gallon hoppers. Delta Turbines have also converted a number of Dromaders to turbine power, fitting a TPF-33-10UA. One of the most unusual conversion was the installation of a 1000 shp Lycoming T53-L-3 from a Grumman OV-1 Mowhawk.

By the end of 1997, six hundred and eighty-three aircraft had been registered and more air¬craft were awaiting assembly.

The M-18B Dromader is certified under European Aviation Safety Agency EASA A.056.

Gallery

PZL Mielec M-18a
Engine: 1 x P.Z.L. Kalisz ASz-62IR radial, 746kW
Max take-off weight: 4700 kg / 10362 lb
Empty weight: 2470 kg / 5445 lb
Wingspan: 17.7 m / 58 ft 1 in
Length: 9.47 m / 31 ft 1 in
Height: 3.7 m / 12 ft 2 in
Wing area: 40.0 sq.m / 430.56 sq ft
Max. speed: 237 km/h / 147 mph
Cruise speed: 185 km/h / 115 mph
Range: 520 km / 323 miles

M18A
Engine: ASz-621RM, 967 hp
Prop: AW-2-30, 4 blade
Wing span: 58 ft
Wing area: 430.56 sq.ft
Length: 31 ft
Hopper cap: 2500 lt (660 USG)
Empty wt: 5445 lb
MTOW: 11,684 lb
Max speed: 138 kts
Stall: 59 kts

M18AS
Seats: 2