The AC-21 powered sailplane is an evolution of AL-12 design that was developed in Ukraine during 2000 – 2005 as a joint project by Aeros and Aerola. In 2006 it was decided to make a next step in the development of the sailplane, splitting the project and leaving production of AL-12 (now Alatus) in Aerola. AC-21 joins unique features of AL-12 incorporated in the new design.
The AC-21 is all about maximum enjoyment of free flight. Sweet handling, slow flight capabilities and low sink rate allows exploring “microlift” conditions, when most other gliders are unable to stay in the air. AC-21 can turn really tight.
AC-21 structural capacity has been increased keeping an aim to meet actual sailplane standards (+5.3 -2.65 G load factors). It gives us a chance of wider margin over current DULV and DAeC requirements for ultra light aircraft (+4/-2 G).
Specifically the wing leading edge D-spar had to get stronger by 25%; the ribs structural capacity and rigidity was greatly increased and the ribs are now made of carbon.
Powered by a Hirth F33 BS delivering 28 hp, it has a factory recommended TBO of 1000 hours at 75 % power.
A newly designed fuselage insures laminar flow over its front, makes room for the engine and allows full enclosure of the propeller when in glider mode. There has also been an increase in the transparent part of the canopy, improving forward visibility.
Engine: Hirth F33 BS, 28 hp
Empty weight: 135 kg
Мах. takeoff weight: 264 kg
Wing span: 13.3 m
Sail area: 13.5 sq.m
Pilot weight: 60-110 kg
Stall speed: 52-56 km/h
Vne: 140 km/h
Best glide ratio: 27 at 70 km/h
Min. sink rate: 0.6 m/s at 67 km/h
Climb w. Engine: 2.5 m/s