No matter how well an engine is designed it has the potential to malfunction at some point during its lifetime. The possibility also exists that something outside the pilot's control, like bird ingestion, could cause an engine or lift fan to fail. If the proposed VTOL aircraft is to be a practical size, it must use a propulsion system with fairly high fan or disc loading, which is also necessary for good cruise efficiency. A more highly loaded fan (>30 LB/ft.) is not capable of auto-rotation. Therefore, any aircraft using higher disc loading will need a back-up system or systems to ensure passenger survival in case of a critical component failure. Great care was taken developing a production model volantor which would provide safety and comfort as well.
The most important issue in aviation is safety. So, the following safety features were designed into our volantor to help provide a safe alternative to ground transportation:
-- In the unlikely event of an engine failure sufficient power remains to ensure a safe and comfortable landing. Since the M400 has eight engines, one or more can fail and the Skycar will still operate safely. Unlike any light helicopter or airplane, the M400 Skycar has four engine nacelles; each with two Rotapower engines. These computer-controlled engines operate independently and allow for a vertical controlled landing should one engine fail. Top
| • Redundant Computer Stabilization Systems |
-- The Skycar has redundant, independent computer systems for flight management, stability and control. Should a computer problem occur backup systems would take over seamlessly. M400 has multiple independent computers for flight management and the design prevents a single-point failure from adversely effecting the performance of the aircraft. Top
| • Redundant Fuel Monitoring |
-- Multiple systems check fuel for quality and quantity and provide appropriat warnings. Top
-- In the unlikely event that insufficient power is available to hover, the Skycar's aerodynamic stability and good glide slope allows the pilot to maneuver to a safe area before using the airframe parachutes. Top
| • Automated Stabilization |
-- Since computers control the Skycar flight during hover and transition, the only pilot input is speed and direction. Undesirable movement of the Skycar due to wind gusts is automatically prevented. Top
| • Inherent Simplicity of the Engines |
-- Rotary engines have very few moving parts and therefore require very little maintenance and have little opportunity for breakdown and wear. Top
-- Each nacelle fully encloses the engines and fans, greatly reducing the possibility of injury to individuals near the aircraft. The volantor's VTOL lift is obtained via airflow through the four ducted fan propulsion nacelles which is redirected downward by deflection vanes during vertical takeoff. Top
-- Even in the instance of complete power loss you and your passengers are protected. The two airframe parachutes, front and rear, will guide the volantor safely and comfortably to the ground without incidence and can be deployed in the event of a critical failure of the aircraft. With the parachutes, the pilot, passengers and the Skycar can be recovered safely. Parachutes developed for the ultra-light aircraft industry, that are ballistically ejected, have demonstrated reliable vehicle recovery above 150 feet. Recovery is possible at a much lower altitude if the aircraft has a modest forward velocity or if a spreader gun is used to spread the parachute canopy. The best primary system should use the minimum number of engines necessary together with sufficient power to hover after the failure of one engine. A multi-engine system also interfaces well with a back-up parachute system since the time between consecutive engine failures should allow sufficient opportunity for the parachute to be deployed. A single engine failure in a VTOL aircraft with eight independent ducts and one engine per duct would require 54% reserve power in order to continue to hover. The same number of engines arranged in four nacelles with two engines per nacelle requires 36% reserve power to accommodate an engine failure. The safe operation of a VTOL aircraft requires that during hover it operate as close to the ground as possible (<25 ft.) and that transition to forward flight occur as quickly as possible. With the loss of an engine at 25-ft altitude the vehicle could be landed very quickly without incident. Above 25 ft altitude one can assume that the vehicle is moving forward and generating some aerodynamic lift so that a second engine failure should not be as critical. In the case where a critical number of engines fail and transition is not complete, aerodynamic lift can extend the flight time in the critical period before the parachute is fully deployed. Thus, deployment could occur at relatively low altitudes (<25 ft.) particularly if a spreader gun is used. In any case, a new concept aircraft can be expected to undergo the unexpected. Thus, overlapping systems to ensure passenger safety would be appropriate and should be mandatory. Top
-- The Skycar can land almost anywhere, and therefore avoid dangerous situations created by a sudden weather change or equipment failure.
By emphasizing simplicity, durability and redundancy, Moller is making safety an inherent attribute of this revolutionary aircraft. Top
