Pedro, OffShoreIgor,
" Doing Vertical Take-offs and Landings with an UNPOWERED Rotor "
Does this explanation from Carter Copters' website make sense to a pilot, or are they
just 'blowing smoke' as we say here in USA?
The CarterCopter rotor is a high-inertia rotor. This means it stores rotational energy because of its weight & design. The 110 lb. of depleted uranium (55lbs in each blade tip) allows the rotor to hold sufficient rotational energy when spun at approx. 500 RPM to lift the aircraft (weighs approx. 2600 lb.) up to 50' height & forward distance of 75' at 50 mph.
In slow speed flight the rotor spins at approx. 300 RPM. During high-speed flight above 100 mph the rotor will spin at between 75-150 RPM as it gets unloaded. But when landing or taking off the speed should be between 400-500 RPM. Jump take-offs are performed at about 500 RPM main rotor speed.
To commence vertical take-off the pilot uses a prerotatror set for slipping mode, to firstly spin the rotor up to 150 RPM which takes about 45 seconds. At that speed the prerotator clutch is switched to non-slip mode & full engine power is applied. Then it takes another 45 seconds to spin the rotor up to pre take-off speed (currently 500 RPM).
The pilot pulls collective steadily, taking pitch to a max of 10 degrees over about 4 seconds, then eases back to about 4 degrees - which is the normal forward flight pitch setting. The rotor by this time will have dropped back to near normal flight rotation speed (300 RPM).
additional info:
CarterCopter is a VTOL gyroplane projected to cruise at 400 MPH at 50,000 feet. It uses a rotor for vertical takeoff and landing and a small wing for high speed cruise. The rotor is powered only prior to takeoff and is always in autorotation during flight, like an autogyro. During high speed flight, the rotor is basically unloaded so there is no retreating blade stall and the rotor RPM is low to reduce drag. This offers the speed & efficiency of a fixed wing aircraft plus the off-airport abilities of a helicopter, all with much less complexity than tilt rotor aircraft and other vectored thrust aircraft such as the Harrier.