Flexrotor Long-Endurance VTOL Aircraft Transitions to Wing-Borne Flight

[Someoneforyou]

Flexrotor Long-Endurance VTOL Aircraft Transitions to Wing-Borne Flight
UNITED STATES - 12 AUGUST 2011

Husum, Washington - On Friday Aerovel's Flexrotor demonstrated transition between hover and wing-borne cruise, capabilities which allow it to combine VTOL with range of more than 3000 km and endurance exceeding a day and a half. Aerovel's president, Tad McGeer, explains that "transition requires a climb, pitch-over, dive, and zoom, so we entered the new regime with a roller-coaster thrill. But after a few seconds the ride turns sedate, with the engine ticking over for long-endurance cruise at 50-60 kt, and the big rotor hardly making a sound."

Flexrotor's first wing-borne flight included autopilot and performance checks, followed by transition back to hover. The technique, says McGeer, "involves a 3g pull-up from 70 kt to nose-vertical, climbing over 100 metres in about 3 seconds. The autopilot managed the transition maneuvers nicely, and was crisp and precise in both wing- and thrust-borne regimes." Pandora then hovered into a docking station, which is itself a key component of the Flexrotor system.

McGeer explains that "Flexrotor is designed to be autonomous not only in the air, but also on the ground. We've designed a rig which assembles in a few minutes out of a duffel bag, and then handles the aircraft automatically through the full cycle of launch, retrieval, docking, fueling, checkout, and back to launch." The rig uses a pair of widely-spaced parallel bars to support the wings, which McGeer says "offers a practical, forgiving target for use on something like a small boat on a windswept sea."

The overall objective, says McGeer, is "to make operating costs low enough for civil applications, such as offshore weather reconnaissance and geological survey. We aim to get there through small size, long range, light footprint, basing flexibility, and autonomy throughout the operations cycle."

Source : Aerovel Corporation

 

[Someoneforyou]

FLEXROTOR:

Flexrotor is a tabletop-sized robotic aircraft which offers an unprecedented combination of long range and endurance together with vertical takeoff and landing (VTOL). Exceptional performance is enabled by:

"¢a "tailsitter" layout roughly comparable to that of experimental VTOL fighters of the 1950s, and likewise somewhat akin to the "helicopter airplane" proposed by Prince (1952);

"¢a large, geared-down tractor rotor/propellor having low disc loading, offering reasonable propulsive efficiency over a flight envelope stretching from hover to long-range cruise to high-speed dash;

"¢thrust-borne launch, with fuselage and rotor axis vertical;

"¢wing-borne cruise, with fuselage and rotor axis horizontal;

"¢standard aerodynamic surfaces for control in wing-borne flight, and a combination of rotor cyclic and stowable wing-tip thrusters for control in thrust-borne flight.

VTOL is exploited to allow the aircraft to operate autonomously from sites having restricted access, including small boats in rough conditions. Automation encompasses the full ground-handling cycle, from retrieval through to parking, fueling, and launch, which will be possible from an unattended and portable base station. The system is designed for low logistics costs, high flight-hours per man-hour, and wide-ranging operations over oceans and remote areas. Prospective applications include weather and environmental monitoring, geological survey, and land- and ship-based imaging reconnaissance (McGeer 2007). The accompanying table lists salient features of the aircraft.

Source : Aerovel Corporation