Motor-glider AC-7K is a lightweight, cruise aircraft.
This model is designed for training and recreational flights. There is a two-man cabin with a crew arrangement under the scheme side by side. The specific feature of AC-7K is a fuselage-stowed propeller-driven installation. The engine Rotax 912 UL DCDI is located inside the fuselage, behind the cockpit. Developing 100hp power enables the motor to aerotow a single motor-glider.
The wing is trapezoidal with 18 meter span clearance. The wing has 24 elongation point. Standard AN lot profile FX60-157 is used for the wing fabricating. It’s an NLF airfoil which is characterized by a high rate of ascentional force. They submit high claims to the wing surface waviness to the NLF airfoil. By the American standard AC-7K’s waviness along the airfoil is less than 0.1 mm.
Specific wing load is 49 -53 kg / sq.m. depending on the take-off weight. Due to the selected wing elongation, at the speed of 90 km / h it takes the glider no more than 3 seconds to bank rolls from +45˚ to -45˚ during the spiral.
The connection in the steering system centre of speed brakes and ailerons is realized with lateral control rods system.
Motor-glider AC-7К’s got a contractile quadricycle landing gear. The aircraft is in constant resting contact upon 3 wheels: 2 transversal tubed rims with a diameter of 360х160 mm and a nose gear with a diameter of 310х12 mm. The tailwheel with a diameter of 200×80 mm is secondary one. It’s used only during the motor-glider touchdown on the air-strip.
A rubber bag is used as a Shock Absorber damping. Ball bearings are applied in a wheel design. Mainwheels are supplied with drum type brakes that are controlled with Bowden cable system. Decelerating is made with a handle.
Cockpit canopy is opened up. For canopy emergency release it’s necessary to use two red handles that are located on both bottom sides of the canopy line. The cockpit has got a side by side seating arrangement that allows a comfortable embarkation of two athletically built pilots up to 190 cm tall. Cabin visibility is not less than 300 degrees.
Directional control pedals are set up to length.
The cockpit panel’s got a complete list of standard flight navigation instruments. There is some more space for component devices. VHF antenna is set up in a tail fin.
There is a standard four-point harness.
- Power generator Rotax ® 912 UL DCDI, four-stroke, spark-ignition
- Peak thrust is 73.5 kW / 100 hp at 5800 rev/ min
- Power at cruise speed is 69 kW / 95 hp at 1400 rev/ min
- A compound cooling system. The cylinders are cooled by air and the cylinder head – by liquid cooling system.
- Propellant is a general gasoline motor fuel not lower than EUR -3 with an octane number not less than 95.
- Starting from the electric starter.
- Electric network potential difference is 12 volts.
- The reservoir is located in a fore part of the propulsion section.
Two-bladed adjustable pitch propeller. Wooden. Propeller diameter is 1180 mm.