We know how, achievement of the high tech from Slovenia.

C11, the big and complex airplane prototype, with the MTOM of 1050 kg, was delivered to its customer.

C11 is the cruising motorglider and a highly efficient long endurance airplane platform with the endurance over 50 hours.

We worked on it a year and a half. Complete: concept, design, engineering, application, tooling, testing and prototyping were very successfully made from our extended team.

Six of engineers worked on the task. Chief engineer was Ales Cebavs which has, among others, also twenty years of experience from the development and construction of airplane. Standard used was CS23 in category normal.

We had new developed all three retractable undercarriages. Shock absorbers are of oil-gas system (nitrogen under 280 psi and 120 psi). In the wings they are two integral composite fuel tanks, in each of the wing can be filled with 165 liters of fuel. In the fuselage is the central – compensatory fuel tank with a volume of 70 liters. Insides of the tanks are protected with a special epoxy resin paint which protects the composite structure from the impact of aggressive petrol additives. In to the airplane was mounted the ballistic parachute. And so on.

C11 has remarkable flying abilities and capacities. It was developed and built from a base of two-seater glider with 22 m wing span with ailerons and flaps. Air brakes remained in use also at C11.

Operation of C11 systems is largely automated, thus working systems as indications and their Interactions.

C11, among others, reaches more characteristics and some exceeds (payload, service ceiling, endurance) regarding the performances of airplanes: Hermes 900, Heron, Predator and Eagle 1. But C11 is also a glider and because of its high glider ratio of 1:40, it has added specialty – C11 can also be a well usable airplane with the engine switched off and using such the flight mode its endurance and service ceiling can be even increased, additionally when C11 can positive use air thermals.

Some typical points are presented hereinafter together with propeller efficiencies.

Best glide ratio is 1:40 at 120 km/h IAS with the propeller with zero thrust. This gives sink speed 0.89 m/s. In 8000 m this is 1,36 m/s@195 kmh TAS. Power to fly horizontal is 24 kW. Fuel flow is between 9.5 and 10 l /h. Out from this a 40 hours endurance is possible.

Minimum sink speed at 85 km/h with MTOW is 0.65 m/s. In altitude 8000 m this corresponds to 0,93m/s @130 km/h TAS. Out from this the endurance over 50 hours with the fuel of 400 l capacity is resulted.

Sink speed at 180 km/h IAS at MTOW is 2 m/s.  In the altitude of 8000 m this is 3.06 m/s @275 km/h TAS. Endurance resulted is 25 h.

Best climb speed with MTOW is about 3.1 m/s at maximum continuous power in low altitude and 2.9 m/s in 4900 m altitude. At altitudes higher than 4900 m the available power begins to be reduced.

For now, C11 is available for orders only on request, each piece as single airplane and own project – on customer demand. Powerful core platform enables a large number of possible uses of the C11. C11 successors would be C12, C13, and so on.


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