A2-Cal Aptos Blue
Berkeley, California, USA
Jean-Francois Clavreul is an aircraft designer based in Berkeley (California, USA), who has been part of the teams designing the AKOYA seaplane (LISA Airplanes), the Joby S4 eVTOL (Joby Aviation) and cargo UAVs (Camp6). Clavreul has designed his own aircraft, the Aptos Blue electric vertical takeoff and landing (eVTOL) aircraft for air ambulance service, and won the first place at the Royal Aeronautical Society General Aviation Design Competition in 2020.
The name Aptos Blue plays homage to the AKOYA seaplane aircraft made by the LISA Airplanes (France). A2-Cal is not a company at this time but will be the name Clavreul will choose once his company is officially a business. The company name translates to "Aerial Ambulances of California."
The Aptos Blue is a concept design eVTOL aircraft is an air ambulance which holds three passengers. One pilot, one emergency medical technician (EMT) and one patient. The patient is loaded in the rear of the aircraft and the front canopy slides open for the pilot and EMT crew. The aircraft has an estimated cruise speed of 137 mph (220 km/h) and an estimated range of over 280 m (450 km).
The long range ability of this aircraft is crucial for several reasons. The aircraft will need to have enough power to fly roundtrip missions without recharging. Therefore, the air ambulance needs a long range capability to fly long distances for city to city travel, city to rural travel and rural travel. There are a total of eight propellers on the aircraft. All eight are used for VTOL flight and two rear propellers tilt for forward flight.
The aircraft has a long range due to its long high wing and six foldable VTOL propellers which fit into two booms, reducing drag, during forward flight. The aircraft can land conventionally on a runway or street, or can land like a helicopter. There are two T-tails for stabilizing and optimizing forward flight.
Two emergency inflatable floats are stored in the landing gear compartment and can be deployed in the event of a water landing. The airbags can also be deployed in the event of an anticipated hard VTOL landing. If up to two VTOL propellers fail to work during landing, the remaining VTOL propellers can land the aircraft safely.
The design of the aircraft is built on years of experience from other effective aircraft designs such as the Rutan Voyager and the ETA glider. A2-Cal is working on making a sub-scale demonstrator to validate the aircraft and demonstrator will have the option to be crewed or uncrewed.
- Aircraft type: eVTOL air ambulance aircraft
- Piloting: 1 pilot
- Capacity: 3 people (including the pilot)
- Estimated Cruise Speed: 137 mph (220 km/h)
- Estimated Range: 280 miles (450 km)
- Maximum takeoff weight: 4,409 lb (2,000 kg)
- Propellers: 8 propellers
- Electric motors: 8 electric motors
- Power source: 8 Lithium-ion batteries
- Fuselage: Carbon fiber composite
- Wingspan: 52-1/2 ft (16 m)
- Windows: The entire nose of the aircraft is clear allowing forward, left, right and top visibility, for an excellent view by the pilot
- Wings: One high long main wing
- Tail: 2 T-tails attached to the rear of two booms, the booms are connected to the main high wing.
- Landing gear: Tricycle wheeled retractable landing gear
- Safety Features: Distributed Electric Propulsion (DEP), provides safety through redundancy for its passengers and/or cargo. DEP means having multiple propellers and motors on the aircraft. If up to two motors or propellers fail, the other working motors and propellers can safely land the aircraft. Two emergency inflatable floats are stored in the landing gear compartment and can be deployed in the event of a water landing. The airbags can also be deployed in the event of an anticipated hard VTOL landing. The aircraft can also land like a conventional aircraft if the VTOL propellers fail to deploy or are not working.
- A2-Cal website
- A2-Cal YouTube Channel
- Jean-Francois Clavreul LinkedIn
- Video: Aptos Blue, A2 Cal, Nov. 15, 2020
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