A2-Cal Aptos Blue (concept design)

Aptos Blue (concept design)
A2-Cal
Berkeley, California, USA
www.a2-cal.com

Jean-Francois Clavreul is an aircraft designer based in Berkeley, California, USA, who has been part of the teams designing the AKOYA seaplane by LISA Airplanes, the Joby S4 eVTOL by Joby Aviation and cargo UAVs by 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 based in 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."

Aptos Blue air ambulance eVTOL concept design aircraft
The Aptos Blue is an air ambulance eVTOL concept design aircraft that 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 has an estimated range of over 280 miles (450 km). The aircraft has eight propellers, eight electric motors and is powered by batteries. All eight are used for VTOL flight and two rear propellers tilt for forward flight. Six of the VTOL propellers are foldable which fit into two booms during forward flight to reduce drag.

The maximum takeoff weight of the aircraft is calculated to be 4,409 lb (2,000 kg). The aircraft has one high main wing to maximize the long range capability of the aircraft. There are two T-tails for stabilizing and optimizing forward flight. The aircraft can land conventionally on a runway or street, or can land like a helicopter.

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 long range ability of this aircraft is crucial for several reasons. The aircraft will need to have enough power to fly long-range round trip missions without recharging to complete critical emergency medical flights. Its long-range capability will be useful for both city and rural travel. 

Design Experience
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.

Specifications:

• 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: 1 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.

Related Aircraft:

• A2-Cal Aptos Mini (concept design)

Resources:

• A2-Cal website
• A2-Cal YouTube Channel
• Jean-Francois Clavreul LinkedIn
• Video: Aptos Blue, A2-Cal, Nov. 15, 2020
• Article: Meet the Teams: Team A2-CAL, GoAERO, Mar. 20, 2025