AS 13,5 m FES (FAI Class)

The International Air Sports Federation announced the conditions for building a new type of sailplane to enable more pilots to fly and take part in gliding competitions. The sailplane should have a wing span of 13.5 m and should be suitable for training and recreational flying. It should also be affordable and have good flight characteristics.

In 2014, FAI will start organizing competitions for sailplanes in the 13.5 m FAI class. Because of that, our company Albastar decided to develop a sailplane that would meet all the conditions. We carried out market research and determined that there were no such planes on the market. Autonomy was our main concern when designing the sailplane. Even though it is an ultra-light sailplane with an auxiliary engine, it meets the ULF and CS 22 certification standards. The sailplane has an FES (Front Electric Selflaunch) electric motor, a swivelling tail wheel that can be operated using the rudder pedals and wheels on the wing ends that enable the pilot to manoeuvre on land. It uses its electric motor to take off and does not need a tow plane. There is no additional resistance on the propeller mast, because the motor and the propeller are placed in the nose, which results in a better propulsive efficiency. The plane will have retractable landing gear and BRS-Ballistic Recovery System (as option). Tow hook for aerotow is standard equipment.

Our AS 13.5 FES took off for the first time in April 2013. Currently, it is in the final flight-testing phase and we expect the extensive test programme to be finished by the middle of June 2013:

  • The sailplane needs a 170 m run to take off and climbs to 15 m in 260 m after the start of the run
  • The highest climb speed is 2.6 m/s at a speed of 80 km/h
  • The batteries allow the plane to reach an altitude of 1800 m
  • The sailplane can operate autonomously for more than 60 minutes when flying horizontally at a speed of 90–100 km/h
  • The system is operated by an FCU (FES Control Unit, instrument with 57 mm diameter, produced by LX NAV), which is easy to use and reliable
  • The weight of the sailplane is low (approx. 200 kg), even with the electric motor that allows the plane to take off and climb
  • When using the electric motor, the aerodynamics of the sailplane changes only slightly
  • During motor operation, there are no unwanted motor and propeller moments
  • Low cost operation and maintenance
  • Environmentally friendly


The electric motor and the propeller are positioned in the nose—FES (Front Electric Selflaunch) is designed and produced by LZ design. The energy consumption is smaller and the system is lighter and cheaper. The motor was specially designed for the FES: an outrunner BLDC brushless synchronous magnet motor with electronically controlled commutation system and 3 phases;

It does not need to be warmed up, it allows full power immediately and it is quiet, clean and does not produce any odour or vibrations; The electric motor is smaller and lighter than a gasoline-fuelled engine, it is easy to use and maintain.

23 kW, peak power;

Length: 100 mm;

Diameter: 180 mm;

Weight: only 7,3 kg

FCU (FES Control Unit)

Standard size 57 mm;

High-resolution colour screen, sunlight readable;

Shows important information: RPM, power, voltage, current,

battery capacity, motor run time, remaining run time and

battery, motor and controller temperature

Alarms with an audible signal

Battery Packs

28 LiPo (Lithium Polymer) high power cells;

Single cell capacity: 43 Ah;

Total available energy in Battery packs: 4.2 kWh (2,1 kWh each Battery pack);

2 boxes with batteries, weight per box 15.5 kg;

The batteries are in a battery rack behind the wings, where the body is reinforced;

Life expectancy: more than 10 years (1,500 charging cycles);

Easy removal when you want to recharge;

Charger: separate LiPo with active BMS (Battery Management System);

Charging time: less than 3 hours;

Enough energy for all the measurement instruments in the cockpit