Niki Lightning  The Niki Lightning is a fully enclosed two-seater tricycle autogyro of composite construction, designed and built by Niki Rotor Aviation in Bulgaria. It was introduced in 2009  The Lightning's cockpit pod accommodates a pilot and passenger in tandem. The main rotor is two-bladed, with a pre-rotator. Unconventionally the tail boom is mounted though the centre of the propeller shaft. The boom may be unbolted and removed to aid access to the engine and prop. There is a choice of two very compact D-Motor engines (both liquid-cooled horizontally-opposed side-valve four-strokes): either the 4-cylinder LF26 or the 6-cylinder LF39. The engine is sited behind the cockpit, driving a 3- or 4-bladed ground-adjustable pusher propeller which is coaxial with the tail boom. Although D-Motor engines are direct-drive units with no gearbox, the Lightning has a multi-belt-drive reduction system of about 3:2 ratio, resulting in a maximum propeller speed of some 2,000 rpm. This arrangement avoids the necessity of a tailboom beneath the propeller, thereby reducing drag. The empenage has a spring-steel tail drag to inhibit propeller strikes. Consuming some of avgas per hour, the autogyro has an endurance of 4 hours, with 30 minutes reserve. Its cruise speed of gives the autogyro a range of over . It has a take-off roll of , and a landing roll of . The Lightning may be flown with its side doors removed. An alternative engine for the Niki Lightning is the Rotax 914UL.