The PZL-106 Kruk was developed by engineer Andrzej Frydrychewicz as a successor to the PZL-101 Gawron. The new aircraft was a light, single-engine, single-seat agricultural machine of all-metal construction in a low-wing layout. Work on the project was carried out during a period when the Polish aviation industry was engaged in building the unsuccessful M-15 jet agricultural aircraft. The first Kruk prototype was flown in April 1973. After further testing, production of a pre-production series began — 7 units were built.
The last two aircraft of this series became prototypes of the PZL-106A version. Simultaneously, tests were conducted with various agricultural equipment. Serial production of the PZL-106A began at the Panstwowe Zaklady Lotnicze in 1976. Between 1979 and 1983, tests were conducted with different powerplants. The PZL-106A was developed based on experience from trials of the prototype PZL-106 with a T-tail, which was abandoned due to significant vibrations in the tail section of the truss fuselage. The Kruk was produced in series from 1976. It was operated by the Aerial Application Services Plant domestically and particularly in Egypt and Sudan, where it replaced the less safe and less efficient PZL-101 Gawron aircraft, which were withdrawn from service.
A considerable number of these aircraft were also purchased by the GDR, whose “Agrarflug” enterprise cooperated in refining their agricultural equipment. Serial production was interrupted in the late 1980s and resumed in 1995. In total, between 1976 and 2002, 147 aircraft of the A, AR and AS versions and 126 of the BR, BS and BT versions were produced, including 32 BT units. 102 units went to the GDR, 72 to the Aerial Application Services Plant, and the remainder operated in South and Central American countries. Currently, no PZL-106 aircraft remain in service in Poland.
The aircraft’s construction was similar to the SP-PBK prototype. In serial-production aircraft, the fuselage sides were removable sheet-metal panels, facilitating the installation of agricultural equipment inside the fuselage during longer ferry flights. During these flights, the chemical tank, after fitting an appropriate bottom plate, was used as an auxiliary fuel tank (900 l). The Kruk was produced in the following variants: PZL-106A with a PZL-3S engine and US 132000 propeller, PZL-106AR with a PZL-3SR engine and US 133000 propeller, PZL-106AS with an Asz-62IR engine (1,000 HP/736 kW) and AW-2-30 propeller. In 1981, a new B wing was developed featuring a different airfoil, shorter teardrop-profile struts, electrically actuated flaps and an integral fuel tank.
Aircraft equipped with this wing were produced from 1982 with the PZL-3SR engine as the PZL-106BR, and with the Asz-62IR engine as the PZL-106BS. A version with a Czech-made Walter M-601 turbine engine (600 HP/442 kW) was also developed and produced from 1989 as the PZL-106BT-601 (the first Polish turbine-powered aircraft). In 1981, a firefighting version was prepared, equipped with an appropriate bottom plate and a foam concentrate tank. A unique solution was the training version, where a unit was installed in place of the standard chemical tank: its upper part contained an instructor’s cabin, and its lower part a 300-litre liquid chemical tank. This arrangement allowed pilot training and pilot checks to be conducted during normal working flights. After training was completed, the standard tank was reinstalled and the aircraft “returned” to its working configuration. In the 1980s, using the main structural assemblies, engineer Andrzej Frydrychewicz developed a multi-purpose aircraft family. An armed version was even created, intended for operations against Colombian drug cartels.
[…] in the days of the GDR many people tried to escape to the West […] One desperate mechanic […] packed his family into the chemical tank and flew off. After crossing the border between the two German states seven times (!), due to poor navigation, he safely landed in West Germany and was granted asylum […] — Andrzej Kardymowicz*
The serial-production PZL-106AR, factory number 07810131, from the 7th series, was built in 1981 at PZL Warszawa-Okecie as the 131st unit. It is equipped with a PZL-3SR engine manufactured by PZL Rzeszow and a US 133000 propeller manufactured by PZL Okecie. Until 1992, this aircraft was operated by WSK PZL-Rzeszow under the registration SP-KFB for flight testing of PZL-3S and -3SR engines. It was donated to the Museum collection by WSK PZL-Rzeszow in 1992.
| year of production | 1981 |
| wingspan | 14.92 m |
| length | 9.10 m |
| height | 3.32 m |
| wing area | 28.4 m2 |
| empty weight | 1670 kg |
| take-off weight | 3000 kg |
| cruise speed | 180 km/h |
| working speed | 150 km/h |
| max speed | 211 km/h |
| service ceiling | 4000 m |
| range | 680 km |
| take-off/landing run | 200/200 m |
| spraying working width | 30–35 m |
| fertilising working width | 10–25 m |
| powerplant | 7-cylinder radial piston engine with reduction gear PZL-3SR rated at 600 HP (442 kW); 4-blade US 133000 propeller |
