Aerocopter / Aerokopter ZA-6 San’ka / AK1
The Ukraine State Border Committee sought a light helicopter for border patrol from a Ukrainian-based company and selected Aerokopter. Founded on 14 December 1999 by I.V.Polituchy, A.N.Zapishny and A.I.Polituchy, the Politava-based Aerokopter design team began with Aviampex of Kiev to co-develop and manufacture the AK1-3. This coopertion ended within months and as of 3 May 2000 Aerokopter worked independently. One month later the chief designer, Zapishniy Alexander Nikolayevich was killed in a motor hang glider accident and the team carried on under Slava Sherbak. Much of the experimental research was done in co-operation with the Kharkov National Aeronautical University. The whole helicopter was designed using CAD.
Two-stage development of ZA-6: initially involving one of the latter (registered GL-0478, shown at Manufacturing & Security Exhibition, Kiev, September 2002), designated AK-1-5 (five-blade main rotor). At the same event, the uncompleted AK-1-3 prototype was shown with the definitive three blade rotor, starboard side tail rotor and twin vertical fins mounted on horizontal tail surfaces.
The first AK1-5 Sanka helicopter was flown on October 12, 2001. This helicopter was used for many ground and factory tests so that constructional elements could be improved and engineering processes for units and parts could be worked through. Production of this model was stopped. This had a five blade rotor and was tested with different Subaru engines including the 3.0 lt flat six, the 2.0 lt turbo and 2.5 lt had normally aspirated power plants.
The second AK1-3 was flown in July 2003. Aerokopter AK1-3 is a light helicopter, which can be used for a range of practical purposes. The design makes it comply with the FAR 27 Regulations, and with the requirements of JAR 27 and international noise abatement requirements.
The AK1-3 helicopter conforms to international airworthiness regulations (FAR, Pt.27) for normal category rotorcraft and international noise abatement regulations. The AK1-3 is certified under the State Administration of Ukraine for Aviation Safety Oversight and bears the Type Certificate Number TII 0008.
A conventional, two seat pod-and-boom helicopter, with five-blade main rotor and two-blade tail rotor mounted on the left side. The structure is of metal and composites and all flying flying controls are manual. The landing gear is of Twin skids.
The AK1-3 is designed with a skid landing gear, a tubular chassis, composite cabin, and empty weighs 390kg, making it possible to transport it on a small car trailer. The two seat cabin has a shoulder height width of 1200mm (Elbow height – 1353mm). Instrumentation is for daytime VFR only.
The three rotor blades are made of composite material with non-linear construction. Powered by a Subaru EJ-25, with belt drive reduction, the minimum fuel is 95 octane. The composite floor with its lower triangulated aluminium sub-frame are the main structural elements. The floor is made of a 16mm plywood with machined out pockets filled with foam inserts, with a skin of composites on both sides. The lower Duralumin frame is riveted together CNC machined elements which are atached to the rest of the airframe.
The seat frames are made from titanium tubing, have a riveted aluminium sheet base, with leather covered cushion. Each seat has a four point harness. The upper body of the cabin is made of coposite material with four separate tinted polycarbonate windscreens bonded into place.
The lower composite belly-panel is screwed in to allow access to control linkages, wiring loom, and “Red-Top” racing battery. The doors can be removed, limiting the Vne to 150 kph / 80 kt at sea level. The single electronic ignition system is toally waterproof.
In the AK1-3 with the rotors turning at 595 rpm (105.5% - top of the green band), the engine turns at 5600 rpm so full power is available for takeoff and landing. Bottom of green ban equals 5000 rpm and sea level flight cruise with governor set to middle of green (100%) equtes to 5300 rpm. The engine redline is 6200 rpm. Engine power transmission uses primary engine speed reduction via pulleys and V-belts, driving a seconsary main rotor gearbox on one side and shaft drive to the tail rotor gearbox on the other. To disengage the rotors for startup, the six untensioned V-belts are used as a clutch. The rotor head uses a laminated torsion bar system with sixteen Y-shaped steel plates. The three main blades operate from 465-600 rpm.
The composite main rotor blades have a non-linear -9.5 degree twist and a variable profile NACA 63012 / 63015. Each finished blade weighs approximately 7.5 kg. The tail rotor blades are also made of composite material and Rohacell foam with a leading edge wear strip. Both the main and tail rotor blades have no time life and are only replaced “on condition”.
The collective and cyclic cntrol inputs are transmitted to the rotor system via duralumin tube control rods and levers.The designed MAUW is 650 kg.
The tail boom is made up of four rolled aluminium sheet sections.
The AK1-3CX helicopter is a further development of the basic model and is designed for aerial spraying of crops with chemicals using 1-40 liters per hectare. The helicopter’s general dimensions and construction are similar to those of the basic model. The helicopter is equipped with a unit of quick-detachable equipment for spraying liquid chemicals, including the ULV technique. The unit of equipment consists of two tanks (140 liters each), which are mounted on either side of the cockpit, spray booms with struts, a rotary pump, connection hoses, and a control unit. The whole unit weighs 34kg.