|AD & D Hummingbird|
Aero-Design & Development (Israel)
AD & D Hummingbird
TYPE: Lifting vehicle.
PROGRAMME: Launched as private venture, reviving concept explored by US Hiller VZ-1 in the 1950s but incorporating new features. First (tethered) hovering flight 28 August 1997; first free (untethered) flight (4X-BEB) 4 October 1998. Availability in kit form originally planned for 2000, but has been delayed; no new date reported bу mid-2003.
COSTS: Estimated US$30,000 (1998).
DESIGN FEATURES: Naturally stable VTOL platform which can be flown by persons with limited piloting experience. Has full engine redundancy, and can continue flying safely throughout full flight envelope after a single engine failure (initial hovering flights used approximately half of total available power). Air duct has outwards-curved lip on upper surface and diameter:length ratio of approximately 2.75:1. Quoted build time approximately 250 hours.
FLYING CONTROLS: Vertical speed (rise/descent) is controlled by pilot increasing or reducing rotor rpm via a twist-grip throttle with the left hand. Lateral (sideways) and longitudinal (fore/aft) motion is achieved simply by the pilot tilting his body slightly in desired direction. Maximum allowable speed is attained when pilot's body reaches limit imposed by circular railing at waist height. 'Nose' of vehicle can be turned by a small lever at pilot's right hand.
STRUCTURE: Engines are mounted on four sides of a square gearbox which also serves as pedestal supporting occupant. Rotors extend from lower end of gearbox. Engines and propellers are basically off-the-shelf ultralight components. Circular outer duct is of graphite/epoxy construction.
LANDING GEAR: Four non-retractable, free-castoring single wheels, each with shock-absorbing oleo. Can withstand vertical impacts of up to 3.7m/s without injuring pilot or damaging airframe.
POWER PLANT: Four 16.4kW Hirth F33-15A single-cylinder piston engines, each with dual ignition, own carburettor and own fuel line. Engines are coupled through torsional dampers and one-way clutches. These drive, via an AD & D gearbox equipped with a chip detector, two three-blade contrarotating propellers/rotors which are synchronised to obtain practically zero yawing moment at all throttle settings. Alternative engines under consideration. Standard fuel capacity 19 litres.
ACCOMODATION: Pilot only, standing inside tubular metal frame.
AVIONICS: Instrumentation: Battery voltage meter; rotor tachometer; four CHT gauges with an ignition kill switch for each engine; four warning lights (engine out, transmission chips, engine temperature and low battery); master switch; emergency parachute activation handle (optional); and mode selector button for yaw stabilisation augmentation system.
EQUIPMENT: Ballistic parachute recovery system optional.
Jane's All the World's Aircraft, 2004-2005