Photo: Bára Nahodilová Bártová

HISTORY

TEXT: RICHARD NOXA, RICHARD PLOS

The Z 526 AFS represents the peak of the development of

aerobatic versions of this type originally designed as a training two-seater. The successful concept had a lot of potential, which was fully exploited with the “Kraťas” (translates

as “Shorty”), as the Z 526 AFS is called. A total of 45 of them

were produced, 16 of which originally remained in Czechoslovakia, while the rest were exported.

The history of the Z 526 AFS begins with the

single-seat aerobatic variant Z 526 A, flown

on April 16, 1966. However, the first aerobatic Trainers, apart of Polish specials Super

Kasper Akrobat and Beskid I (both originating from early Z-26 version), appeared earlier and were based on the Z 226, the first

production version with a six-cylinder Walter Minor 6-III engine. The Z 226 A was a simple adjustment, as only the front cockpit was

removed and covered, while the rear one got

shortened and received a not so elegant canopy.

At the very beginning of the Z-226 version

production, four units of this aerobatic aircraft were built (OK-KMA, KMB, KMC, KMD)

with three more Z 226 T later converted to

the Z 226 A standard. From these seven Z 226

A, six Z 226 AS were made by fitting the variable-pitch propeller V-500 ( later V-503) in

the mid-1960s. This change was also associated with the modification of the front engine

cowling. There was also a change of the cabin canopy, which was reworked from sliding

to hinged, opening to the right. The Z 226 AS

was used by the Czechoslovak aerobatic na-

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INFO Eduard

tional team until the second half of the 1960s

and after the aerobatic hours were over ,

they were either scrapped or converted back

to Z 226 two seater standard. There is only

one exception, OK-MHC owned and operated

by the Wallachian Aeroclub Slavičín.

An aerobatic version of the Z 326 was also

produced, but all fifteen Z 326 A were exported to the GDR and the USSR. These aircraft received also a single-seat cabin , now

with a lengthened canopy compared to Z 226

A and AS versions. No turbulators were installed on the wings and the elevator received aerodynamic balancing to reduce steering forces. At the same time, the fuselage

structure was strengthened. Some Z 326

A received a V-503 autonomously variable-pitch propeller.

First time special

After the introduction of the Z 526 in 1965,

another aerobatic version was created, again

in the same proven and relatively simple

way, i.e., by removing the front cockpit and

installing a right-hand opening hinged canopy. The canopy was the same as on Z 326 A.

In total, twenty Z 526 As were produced, most

of them for export to a total of eight countries. One of these was Great Britain, where,

amongst others, aircraft factory number

1036 registered G-AWAR was flown. During

training at Hullavington prior to the forthcoming World Aerobatic Championships, this

aircraft, with British national team member

Neil Williams at controls, suffered failure in

the centre-section lower spar boom on June

3, 1970. As a result, the dihedral of the left

wing increased considerably and the aircraft

started rotation to the left. The experienced

pilot kept his wits, turned the aircraft onto its

back and subsequently managed to land, after he conducted a flip over the ground at the

very last moment. He had no choice, as he

had no parachute... As it turned out, the aircraft exceeded the limit of flight hours with

high-g maneuvers, which was the cause of

the fatigue failure. Subsequently, a measure

was taken to equip all Trenér series aircraft

with a pressure gauge to check the pressure

of the nitrogen-filled main spar. This is located on the floor in front of the pilot.

Aerobatic versions of Trenér were still very

popular in top aerobatic competitions during

the first half of the sixties. This was true for

both domestic and foreign pilots, but by the

mid-1960s their star began to fade. The pilots of Czechoslovak national team had also

higher demands than what the five Z 526

As produced for them were capable of. The

pilots' calling for a more agile aircraft was

heard and resulted in the Z 526 AS "Acrobat Special" version. On March 29, 1968 the

new type made its maiden flight in order to

March 2022