Definitive prototypes of the Ka-25 incorporated mission equipment and corrosion protection for the structure. The rotor system introduced aluminium alloy blades pressurised with nitrogen for crack detection, lubricated hinges, hydraulic powered controls, alcohol de-icing and automatic blade folding. Power was supplied by two free-turbine engines sat atop the cabin, with electrically de-iced inlets, plain lateral exhausts with no infrared countermeasures, driving the main gearbox directly and a cooling fan for the gearbox and hydraulic oil coolers aft of the main gearbox. Construction was of stressed skin duralumin throughout with flush-riveting, as well as some bonding and honeycomb sandwich panels. The 1.5m × 1.25m × 3.94m cabin had a sliding door to port flight deck forward of the cabin and fuel tanks underfloor filled using a pressure refueling nozzle on the port side. A short boom at the rear of the cabin had a central fin and twin toed-in fins at the ends of the tailplane mainly for use during auto-rotation. The undercarriage consisted of two noncastoring mainwheels with sprag brakes attached to the fuselage by parallel 'V' struts with a single angled shock absorber to dissipate landing loads, and two castoring nosewheels on straight shock absorbing legs attached directly to the fuselage either side of the cockpit which folded rearwards to reduce interference with the RADAR, all wheels were fitted with emergency rapid inflation flotation collars. Flying controls all act on the co-axial rotors with pitch, roll and collective similar to a conventional single rotor helicopter. Yaw was through differential collective which has a secondary effect of torque, an automatic mixer box ensured that total lift on the rotors remained constant during yaw maneuvers, to improve handling during deck landings. Optional extras included fold up seats for 12 passengers, rescue hoist, external auxiliary fuel tanks or containers for cameras, flares, smoke floats or beacons.
Definitive prototypes of the Ka-25 incorporated mission equipment and corrosion protection for the structure The rotor system introduced aluminium alloy blades pressurised with nitrogen for crack detection lubricated hinges hydraulic powered controls alcohol de-icing and automatic blade folding Power was supplied by two free-turbine engines sat atop the cabin with electrically de-iced inlets plain lateral exhausts with no infrared countermeasures driving the main gearbox directly and a cooling fan for the gearbox and hydraulic oil coolers aft of the main gearbox Construction was of stressed skin duralumin throughout with flush-riveting as well as some bonding and honeycomb sandwich panels The 15m × 125m × 394m cabin had a sliding door to port flight deck forward of the cabin and fuel tanks underfloor filled using a pressure refueling nozzle on the port side A short boom at the rear of the cabin had a central fin and twin toed-in fins at the ends of the tailplane mainly for use during auto-rotation The undercarriage consisted of two noncastoring mainwheels with sprag brakes attached to the fuselage by parallel 'V' struts with a single angled shock absorber to dissipate landing loads and two castoring nosewheels on straight shock absorbing legs attached directly to the fuselage either side of the cockpit which folded rearwards to reduce interference with the RADAR all wheels were fitted with emergency rapid inflation flotation collars Flying controls all act on the co-axial rotors with pitch roll and collective similar to a conventional single rotor helicopter Yaw was through differential collective which has a secondary effect of torque an automatic mixer box ensured that total lift on the rotors remained constant during yaw maneuvers to improve handling during deck landings Optional extras included fold up seats for 12 passengers rescue hoist external auxiliary fuel tanks or containers for cameras flares smoke floats or beacons