Independent aerospace technology innovator Conseil et Technique hopes that 2021 will be the year it finds backers for its radical reboot of the traditional airliner powerplant configuration. The French company’s Integrated Propeller Plane (IP2) concept involves completely removing the standard turbofans from the wings and replacing them with a pair of counter-rotating, ducted fans driven by brushless electric motors and solenoid valves coiled around the rear of the fuselage just in front of low-profile V-shaped tail.
Observers looking at a concept loosely based on a standard narrowbody aircraft like the ubiquitous Airbus A320 family will immediately wonder how current battery-electric power could possibly drive an aircraft of that size, with standard payloads and routes. Conseil et Technique proposes to strip out as much as 30,000 kg (66,000 pounds) of weight, allowing it to carry enough batteries to fly an A320 for 78 minutes based on current average energy density assessed at 0.15 kWh/kg.
Engineers project that flight time to increase to 323 minutes within five years, assuming that available energy density reaches 0.4 kWh/kg. The company has not yet indicated what cruise speeds the configuration might deliver, but some aspects of its presentation seem to imply that they would lag current air transport speed norms.
Batteries would be packed in containers similar to those already used for electric cars and trucks. The company envisions the ability to quickly change batteries during turnarounds at airports in what it describes as a “plug and fly” approach. Mechanics could move the position of the battery containers between flights to take account of overall payloads and ensure the right center of gravity.
Beyond batteries, Conseil et Technique believes its new propulsion concept could also work with hydrogen power. It has not yet defined how performance projections might differ for this approach.
The company claims that losing the standard wing-mounted turbofans and pylons cuts 8,000 kg in weight and that the replacement fans and electric motors add only 3,000 kg to the weight equation. It assesses the weight of the jet-A fuel no longer required at 20,000 kg, and a further 1,000 kg from the lack of fuel pumps and pipes. The removal of a traditional horizontal stabilizer cuts 3,000 kg, the new wing design is expected to be 1,000 kg lighter, and the same weight again is saved because the fuselage no longer needs to be reinforced to protect against possible damage from an exploding engine.
According to Conseil et Technique sales director Slim Tarkhani, the overall aerodynamic flow around the aircraft will be cleaner, resulting in reduced energy consumption. “The two ‘engines’ at the rear of the fuselage suck the boundary layer, promoting a more laminar flow around the fuselage,” he told FutureFlight. He claimed the design of its fixed-blade fans avoids torque and any disruptive airflow around the tail.
Conseil et Technique has yet to publish a proposed timeline for the implementation of its IP2 concept, which has been in the works since 2019. According to Tarkhani, the company already has held some discussions with Airbus, having helped to design the composite propellers for the CityAirbus eVTOL aircraft technology demonstrator under evaluation by Airbus Helicopters. He said it also aims to propose the technology to airframers including Boeing, Embraer, and Dassault Aviation, as well as to engine makers like Pratt & Whitney and GE Aviation. It aims mainly to partner with, or license its intellectual property to companies seeking to develop new-design aircraft around IP2, but it also believes retrofitting existing designs would work.