be ready for the national team at the time of
the fifth World Aerobatic Championship in
Magdeburg. The Zlin Z 526 AS did not get the
word "Special" in its name for nothing, it was
indeed special, because it met the requirements of the FAR Part 23 regulations for
the Special category with the allowable loads of +7/-4.5g, while the existing aerobatic
Trainers had to fit into the “envelope” of the
The engine mount of Z 526 AS was strengthened for higher loads. In addition, it received a completely new, lighter and sleeker rearward-sliding canopy. The Z 526 AS
was also the first of the Z 26 series aircraft
without flaps, which were removed to save
weight. However, the Walter 6-III carburetor engine with a maximum output of 160 hp
continued to serve as the powerplant.
All of Z 526 ASs prepared for the Czechoslovak representation received a very spectacular livery, which was uniform for all machines except for the lower surfaces, which
were of a different color for each aircraft.
Photo: Stanislav Trnka
Aircraft standing and ready to fly at the aerobatics nationals, which were held in Kunovice, Czechoslovakia in 1969.
In the front, two examples of the „Shorty“ predecessor, the Z 526 AS.
OK-ZRB was the first “Shorty” converted to the towing version AFS-V. It was later sold to Germany, where it kept flying
with Czech matriculation. It was destroyed in a crash near the Eberswalde Finow airfield during the Roadrunner's
Paradise Race 61 event on June 26, 2013.
The M 337 engine was modified in 1969 to
create the 180 hp M 137A. The oil system of
this engine was modified to fully aerobatic
operation with non-restricted reversed flying and snap roll aerobatic figures. The engine also got a modified crankshaft and was
equipped with an injection system to ensure
trouble-free operation even under negative
loads. This was the main problem of the Minor series carburetor engines, where it was
kind of art to tune them for such flight modes. Apart of the Z 526 two-seater, this engine was, of course, also used for the aerobatics specials. These aircraft received their
new engine prior to the 1970 World Championships held at RAF Hullavington, England.
All five Z 526 ASs of Czechoslovak national
team were converted to Z 526 AFs, while the
aircraft received new redesigned fuselage
that incorporated the M 137A engine with
new engine covers. Unlike the exhaust system of the Minor 6-III engine, which had exhaust pipes on the right side leading directly
from each cylinder, the new exhausts were
routed to two exhausts protruding from the
engine cover relatively far apart.
For the needs of the Czechoslovak national team, a Z 526 AFM registered OK-KZA
was later created. The airframe of this version basically corresponded to the Z 526 AF
design, but the wing received landing flaps.
A M 337 engine and a modified V-410 propeller (with propeller blades from the V-503)
were installed. The cowling was taken from
the Z 726 version and its cooling air inlet received louvers . The aircraft had permanently mounted auxiliary wingtip tanks. Due to
the purpose (special towing aircraft), special
equipment such as an oxygen breathing apparatus, two Becker communication radios,
etc. were also installed. This aircraft was
subsequently converted to the Z 526 ASM
(OK-WXA) and sold to Germany, where it is
still flying today as D-EWXA. Later OK-WXB
aircraft gave rise to another Z 526 ASM re-
With an aerobatics engine
OK-ERS parked at the Nitra airfield. This one was manufactured in 1974 and is still airworthy. More to it, the aircraft
keeps the original red-white coloring of all the Z 526 AFS. It is based at the Boleráz airfield, where Aero Club Bratislava is operating it, now as OM-ERS.