LWD Junak

LWD Junak
275px
Junak 3
Type	Trainer aircraft
Manufacturer	WSK-Okęcie
Maiden flight	22 February 1948
Introduced	1952
Retired	1972
Primary user	Polish military and civilian aviation
Produced	1951-1956
Number built	252

The Junak is a Polish trainer aircraft, designed in the LWD bureau and produced in the WSK factory. It was used from 1952 to 1961 by the Polish Air Force and to 1972 by Polish civil aviation.

Design and development

The aircraft was designed in response to a Polish Air Force requirement of 1946 for a trainer plane to replace the Soviet UT-2, which was obsolete and difficult to handle. The new plane was designed in 1947 in the LWD (Lotnicze Warsztaty Doświadczalne, Aircraft Experimental Workshops), the first Polish post-war construction bureau. The chief designer was Tadeusz Sołtyk. A prototype named LWD Junak ("brave young man", later Junak 1) was flown on February 22, 1948. The whole design was Polish, except for a licence-built 93 kW (125 hp) Soviet Shvetsov M-11D radial.

After tests, an improved Junak 2 was flown on July 12, 1949. The most notable changes were: cabin moved forward, bigger tailfin, more powerful 118 kW (160 hp) M-11FR, and lack of wheel pants. The plane's handling improved. In a meantime, the LWD team was disbanded in 1950 and the Junak 2 was further developed by the CSS workshops in Warsaw. After some improvements the prototype was designated Junak-2bis, but finally entered production in 1951 as Junak-2. Tadeusz Sołtyk was given a State Award in 1952 for the design. From 1951 to 1954, 105 Junak 2s were produced in the WSK-Okęcie in Warsaw (the first 3 in the WSK-Mielec).

Tadeusz Sołtyk, then working in the Aviation Institute (Instytut Lotnictwa, IL) in Warsaw, proposed next a Junak development with bubble canopy, retractable landing gear and other improvements, designated TS-7 Chwat, but it was not accepted by the authorities and remained in sketches. Instead, after the Polish Air Force was equipped with first jet fighters (Yak-23, MiG-15), there appeared a need of a trainer plane with a tricycle landing gear. Then, Sołtyk designed a modified Junak with a fixed tricycle landing gear and minor improvements. This plane was accepted for a production as TS-9 Junak 3 ("TS" for Tadeusz Sołtyk). It was first flown on 7 August 1953. The new plane was heavier, and the maximum speed was reduced from 223 km/h (139 mph) to 205 km/h (128 mph). Between 1953 and 1956, 146 Junak 3s were produced.

Along with the Junak 1, the LWD developed its civilian trainer and aerobatics variant LWD Zuch. Only a short series of 5 Zuch 2s was built in 1950, powered with the 116 hp Bramo Sh 14 radial engine.

The Junak was the first aircraft built in a big series in Poland after the World War II, which annihilated the Polish aviation industry. Despite being not very modern, it was a stable and good handling aircraft, one of its few flaws being an uncomfortable cabin. All models of Junak are often called LWD Junak or WSK Junak; the designation TS-9 is not commonly used. IL Junak 3 is also encountered.

Operational history

File:LWD-Junak-3 PICT0033.JPG

Junak-3 in the Polish Aviation Museum

Junak 2s were used in the Polish military trainer aviation from 1952. When their replacement with Junak 3s started in 1954-1955, Junak 2s were withdrawn and handed over to civil aero clubs.

Junak 3s were used in the Polish military aviation from 1954 until 1961, when they were finally replaced with TS-8 Bies. Starting from 1956, they were handed over to civil aviation as well.

In the civilian aviation, 71 Junak 2s and 93 Junak 3s were distributed among aero clubs in the country, suffering lack of aircraft after the war. They were used there for pilots' training and glider towing through the 1960s. The last Junak 2s and Junak 3s ended service in 1972.

Variants

Junak 1

Prototype.

Junak 2

First serial produced variant, 105 aircraft built.

TS-9 Junak 3

Fixed tricycle landing gear version, 146 aircraft built.

Operators

Template:POL

• Polish Air Force
• Polish Aero Club (APRL)

Specifications (Junak 3)

Description

File:LWS JUNAK.JPG

Junak 3 in Polish Aviation Museum in Kraków

Mixed construction (steel and wood) trainer plane, conventional in layout, low-wing monoplane. Fuselage of steel frame, covered with canvas, in front with metal sheet. Two-spar wings of wooden construction and trapezoid shape, canvas and plywood covered, fitted with split flaps. Two-seat tandem cabin (front: instructor, rear: student) with a common closed canopy (front section opening to the right, rear section sliding). Fixed tailwheel (Junak 2) or tricycle (Junak 3) landing gear. 5 cylinder radial engine M-11FR with 119 kW (160 hp) maximum power and 104 kW (140 hp) normal power. Cylinders have individual hats, often removed. Two-blade fixed pitch wooden propeller. Fuel: 80 l (Junak 2) or 100 l (Junak 3). The plane had no armament. Junak 3 was fitted with radio.

General characteristics

• Crew: two - student and instructor
• Length: 7.75 m (25 ft 5 in)
• Wingspan: 9.92 m (32 ft 6 in)
• Height: 2.5 m (8 ft 2 in)
• Wing area: 17.50 m² (188 ft²)
• Empty weight: 818 kg (1,800 lb)
• Loaded weight: 1,080 kg (2,376 lb)
• Powerplant: 1× Shvetsov M-11FR air-cooled 5-cylinder radial, 160 hp (118 kW)

Performance

• Maximum speed: 205 km/h (128 mph)
• Range: 450 km (281 miles)
• Service ceiling: 4,100 m (13,448 ft)
• Rate of climb: 180 m/min (590 ft/min)
• Wing loading: 62 kg/m² (12.6 lb/ft²)
• Power/mass: 0.11 kW/kg (0.07 hp/lb)
• Take-off run: 155 m
• Landing run: 140 m

References

• Kempski, Benedykt. Samolot szkolno-treningowy Junak, TBiU #110, Wydawnictwo MON, Warsaw 1986, ISBN 83-11-07341-4

External links

• Photos at Ugolok Neba site

See also

Related development
LWD Zuch Comparable aircraft
Yak-18 - Zlin Z-26 Trener - De Havilland Chipmunk - Percival Prentice Designation sequence
LWD Szpak - LWD Żak - LWD Junak - LWD Zuch - LWD Miś - LWD Żuraw
TS-7 - TS-8 - TS-9 - TS-11 - TS-15 - TS-16

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "LWD Junak".