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Trener
Z-126 Trener II
Role	Training aircraft
Manufacturer	Moravan Otrokovice
Designer	Karel Tomáš, František Novotný
First flight	October 20, 1947
Produced	1949-1977

Zlin Trener is a family of aircraft that was based on a basic training aircraft, the Z-26.

The original Z-26 was designed in late 1940s and produced in 1946 by the Czechoslovakian company, Moravan to meet a requirement for a basic trainer to replace the Bücker Jungmann and Bestmann (Czechoslovak military designation C-104 and C-106/C-206). It was a low-winged monoplane of mixed construction, with wooden wings and a welded metal tube fuselage, powered by a single four-cylinder piston engine, the Walter Minor 4-III producing 77kw (105 hp). It first flew in early 1947, proving superior to the competing Praga E-112, and was declared the winner, entering production in 1949. Later Z-26 variants were optimised to participate in aerobatic competitions, training and glider towing with both twin and single seat versions. The design was adapted to all-metal wing and tail shortly after the production started and also more powerful six-cylinder engines were used since 1955.

Variants

Z-26 Trener (military code C-5)

Development of a new training aircraft started in Moravan Otrokovice (then Zlínavion) in 1946 based on a requirement issued by the Czechoslovak Ministry of Defence. The requirement asked for a basic military and civil training aircraft capable of aerobatic figures, reaching speed of 200 km/h with two seats in tandem and powered by the Walter Minor 4-III engine with a fixed wooden propeller.

163 were delivered since 1949 but many of them were later converted to Z-126 replacing the wooden wing and tail stabilizers with the all-metal version. Trener was exported to Romania (3) and Poland (37).

Z-126 Trener II (C-105)

Trener II was produced 1954-1956 as a successor of the original version implementing required changes identified during the first years of the Z-26 operation. More reliable all-metal wing replaced the original wooden one which was depreciated due to a low-grade glue used on the original Z-26. The tail was metal with modified rudder shape. Also the fuel instalation in wings had to be modified, oil installation was changed and brakes were simple mechanical instead of hydraulic. Modifications were intended to stimulate export to souther countries with more demanding climate.

• Z-126T version was in fact modification of the later Z-226T or B airframe using Walter Minor 4-III due to shortage of the new six-cylinder Minor 6-III.
• Z-126M represents models with later Avia M-332 engine (103 kW/140 hp) and metal electric-driven Avia V-410 variable propeller.

169 were delivered in total of which 32 were exported, mainly to East Germany (19), Yemen (10), Germany (7) and Austria (6).

Z-226 Bohatyr (C-205)

Z-226 was a next generation of Trener family originally designed as a glider towing aircraft requested by a National Aeroclub (SVAZARM). Conversion of the proven Trener design was chosen to reduce development costs and time. Its fuselage was lightened, having only one rear pilot seat as the front one was only kept for a passenger and electric flaps operation were replaced with a simple mechanical lever. This reduced the weight by 50 kg. The main improvement was a new six-cylinder Walter Minor 6-III engine giving 118 kW so the total empty weight increase was only 15 kg. Oil tank had to be moved to the wing to keep the center of gravity. Fixed wooden propeller was designed especially for towing. This type was designated Z-226B Bohatýr.

It was found durinng the tests of the new type that the modifications had a very positive impact on its aerobatic performance compared to the Z-126. It resulted in a new Z-226T Trener 6 version again having both seats equipped with pilot controls which aimed on advanced aerobatics training. This version was also delivered to the army as C-205.

Special one-seat versions were additionally designed for the national aerobatics team which then defined the new category of high performance aerobatics specials. Z-226A Akrobat was the first one in 1956. It was a single seat version based on the original Trener with front seat removed and only a small canopy in place of the rear seat. As first world championship tool place in 1960, first three places were occupied by Czechoslovak pilots on the Z-226A.

Z-226AS Akrobat Special was developed in 1963 with a new hydraulic V-500 or later with an automatic constant-speed metal propeller V-503. This upgrade had a significant effect on the performance and as this modification came after the Z-326, it led to the Z-526 combining the benefits of both in a new type.

Many Z-226s were later converted and some of these changes received its specific name:

• Z-226M with a new Avia M-137 engine and Z.42 propeller in two versions – standard and tow. Conversion was an answer to a shortage of the Minor 6-III production.
• Z-226MS is a tow variant equipped with the automatic V-503A propeller attached to the M-137 engine.
• Z-226SL was a late (1987) modification for a high performance glider tow aircraft. Engine was Lycoming AEIO-540-D4B5 / 190kw with three-bladed Hoffmann propeller and modified engine cowling.

Total production of all Z-226 was 366 during 1954-1959. 283 were Z-226T which were broadly exported to the Soviet Union (72), Egypt (50), East Germany (45) and also Hungary, Romania and Vietnam.

Z-226 Twin Trener – was an Easter egg created at Bratislava Vajnory airfield. Two airframes missing one wing each were put together reminding of the US F-82 Twin Mustang or German Bf 109Z "Zwilling". It was never intended to be airworthy as the central section was only imitated using cardboard. http://gonzoaviation.blogspot.cz/2011/06/twin-trener-v-bratislave-clanok-fera.html

Z-326 Trener Master (C-305)

Introduced in 1959, Z-326 came with a major upgrade of a partially retractable main gear but there were more upgrades - larger wing, canopy with less frames and more complex cabin capable of basic instrument flying. Main pilot seat was again the front one. External fuel tanks could be attached on the wing tips extending the fuel capacity by 2x35 l). Walter Minor 6-III was later replaced with Avia M-137 133kw. The new type was capable of aerobatics even on maximum take off weight of 900 kg.

• Z-326A Akrobat was designed on request of foreign customers in 1960 as a single seat aerobatic aircraft with the Avia V-503 automatic propeller. 15 were produced, 10 exported to Soviet Union and East Germany.
• Z-326M (1977) – Avia M-137 engine

420 were produced 1959-1968 and was exported to 25 countries, for example Soviet Union (259), Cuba (40), France (38).

Z-526 Trener Master

The new type was a combination of the Z-326 and the new automatic metal propeller Avia V-503. Main pilot seat had to be moved to the rear one again due to its higher weight. Instrument panel and engine cowling were also modified. 61 were produced between 1966 and 1969 being again exported to 16 countries including USA.

• Z-526A "Akrobat" Aerobatic one-seater derived from the 526 fuselage. One prototype and 20 produced, mostly exported.
• Z-526AS "Akrobat Special" was build on request of the Czechoslovak team which asked for better G-load limits then +6g / -3g which were standard for Trener series so far given one seat operation. The new "Akrobat Special" was certified for +7g / -4.5g including US FAR Part 23 for Special category. In order to improve its performance mainly in vertical figures the weight was again reduced having the flaps removed and new strutless canopy. 5 were produced in 1968 (OK-WXA - OK-WXE).
• Z-526F Significant change came in 1969 when the engine was replaced with a new type Avia M-137A 134 kW / 180 hp which was an unsupercharger aerobatic version of the M337 engine used in Zlin Z-142, Z-43 or Let L-200 Morava. The M137A was shared with Zlin Z-42. Other modifications were related, for example new oil and fuel installation and a new V-503A propeller with bigger diameter (+5 cm). Z-526F is usually considered as the most versatile and universal version of the Trener family as it was used for elementary and advanced training, aerobatics and glider towing. It allowed full aerobatics (+6g / -3g) with maximum take off weight including two pilots which was so far only possible with single-seat versions or with only one pilot in the cabin.
• Z-526L
• Z-526AF
• Z-526AFS Akrobat Special, AS-V (1970) – last single seat aerobatic special version of Trener line. Shorter wing and fuselage, reduced fuel tank. Maximum permitted G-loads for aerobatics are +7/-4.5. Contemporary competitors were Pits S-2A or Yak-18.
• Z-526AS-V – Conversion of the AFS into a glider tow aircraft after the aerobatic end of life.
• Z-526AFM Condor – another high performance glider tow aircraft. Based on Z-526AS fuselage and tail, Z-326 wing and wing tip fuel tanks from Z-526AFS. Avia M-337 155kw engine, its cowling and V-410 propeller are based on Z-726K. This type could be also equipped with high altitude kit with oxygen system and altitude record logger.

Z-726 Universal

This is the lates series of the TRENER type. Its goal was to provide advanced aerobatics training aircraft combining Z-526AFS (shorter) wing and fuselage, Z-526F cabin and M-137AZ engine.

• Z-726K is the latest version with even more powerful Avia M-337 155kw engine, variable propeller (not automatic like V-503) and hydraulic brakes.

32 built AERO Hobby 2011/1 pp. 71–72. ISSN 1214-4975 http://www.aeroweb.cz/clanek.asp?ID=3405&kategorie=3

Zlin Trener is a family of aircraft that was based on a basic training aircraft, the Z-26.

The original Z-26 was designed in late 1940s and produced in 1946 by the Czechoslovakian company, Moravan to meet a requirement for a basic trainer to replace the Bücker Jungmann and Bestmann. It was a low-winged monoplane of mixed construction, with wooden wings and a welded metal tube fuselage, powered by a single four-cylinder piston engine, the Walter Minor 4-III. It first flew in early 1947, proving superior to the competing Praga 112, and was declared the winner, entering production in 1948.

Later Z-26 variants were optimised to participate in aerobatic competitions and many were owned by private pilot owners.

Variants

Zlin Z-226T Trener 6 exhibited at the 1957 Paris Air Show

The following variants were progressive improvements on the Z-26:

Z-26

two-seat primary trainer aircraft. 163 built.

Z-126

all-metal wing instead of original wooden wing

Z-226

more powerful Walter Minor 6-III six-cylinder engine, A.K.A. C-205

Z-226A - single-seat aerobatic aircraft

Z-226B - glider tug aircraft

Z-226T - basic training version

Z-326

160 hp model with an electrically retractable undercarriage

Z 526

with the Walter 6-III carburettor's six-cylinder engine

Z-526A - single-seat aerobatic aircraft

Z-526F - Improved version. Avia M-137 Engine with fuel injector.

Z-726

shorter wing, shorter fuselage. Avia M-137 Engine with fuel injector.

Z-726K - Avia M 337 Engine with a compressor (210 HP). Not in serial production

Many sub-variants were also produced, for example the Z-526A and Z-526AFS were aerobatic specials. The production of the family was terminated in the 1970s with Z-726.

Trener production timeline

{{Horizontal timeline}}

Production Timeline

Engines introduced

• 1946 - Walter Minor 4-III 77 kW
• 1956 - Walter Minor 6-III 118 kW
• 1969 - Avia/LOM M-137A 133 kW
• 1973 - Avia/LOM M-337A 154 kW

Operators

Military Operators

Austria

Austrian Air Force

Bosnia and Herzegovina

• Air Force and Anti-Aircraft Defence of Bosnia and Herzegovina - One civil aircraft impressed into service in 1995.

Cuba

Cuban Air Force

Czechoslovakia

Czechoslovakian Air Force

East Germany

East German Air Force

Egypt

Egyptian Air Force

Mozambique

Air Force of Mozambique

Republika Srpska

Republika Srpska Air Force - One civil aircraft impressed into service in 1995.

Romania

Romanian Air Force ^ Aeroclubul Romaniei /Romanian Airclub

Vietnam

Vietnam People's Air Force

Yugoslavia

SFR Yugoslav Air Force

Specifications (Z-726)

Data from Jane's All The World's Aircraft 1976-77

General characteristics

• Crew: 2
• Length: 7.975 m (26 ft 2 in)
• Wingspan: 9.875 m (32 ft 5 in)
• Height: 2.06 m (6 ft 9 in)
• Wing area: 14.89 m² (160.3 sq ft)
• Airfoil: NACA 2418 / NACA 4412
• Empty weight: 700 kg (1,543 lb)
• Max takeoff weight: 1,000 kg (2,205 lb)
• Powerplant: 1 × Avia M137AZ 6-cyl. inverted air-cooled in-line piston engine, 134 kW (180 hp)

Performance

• Maximum speed: 236 km/h (147 mph, 127 kn)
• Cruise speed: 216 km/h (134 mph, 117 kn)
• Stall speed: 98 km/h (61 mph, 53 kn)
• Range: 440 km (270 mi, 240 nmi)
• Service ceiling: 4,500 m (14,800 ft)
• Rate of climb: 5 m/s (980 ft/min)

See also

• Podesva Trener, a reproduction of the Zlín 126

References

• Mourik, Dick van. "A to Zlin: An Illustrated History of a Light Aircraft Dynasty". Air Enthusiast, No. 93, May/June 2001. Stamford, UK:Key Publishing. ISSN 0143 5450. pp. 59–65.
• Taylor, John W R. (editor). Jane's All The World's Aircraft 1976-77. London: Jane's Yearbooks, 1976. ISBN 0-354-00538-3.
• Taylor, Michael J.H. (editor). Jane's Encyclopedia of Aviation. London:Bracken Books, 1989. ISBN 1-85170-324-1.
• Volejník, Jiří. Zlínské letectví, Ilustrovaná historie 1924-2004, Zlín, 2009. ISBN 978-80-87130-10-0.
• Němeček Václav. Československá letadla [1918-1945], Naše Vojsko, Praha, 1983. 28-108-83.05/112

External links

Media related to Zlín Z-26 at Wikimedia Commons

• Zlin Trener history on aeroweb.cz

Category:Aerobatic aircraft Category:Czechoslovakian military trainer aircraft 1950–1959 Category:Zlín aircraft