RED Aircraft is to supply its A03 engine for the powertrain Ampaire is developing to convert Cessna Grand Caravan aircraft to hybrid-electric propulsion. The compression ignition engine will be rated to 405 kW (550 hp) as part of Ampaire’s integral parallel configuration with the electric motors and battery packs, with the A03 providing base power and peak power coming from the electrical system.
Under the terms of a memorandum of understanding signed by the companies on the first day of this week’s EAA AirVenture show in Oshkosh, Wisconsin, the partners intend to jointly commercialize the hybrid-electric version of the utility aircraft under the brand name Eco Caravan. Ampaire is developing a family of propulsion systems for applications requiring power ratings of up to 800 hp. RED will develop, certify, and supply a range of engines that can run on both jet-A and sustainable aviation fuel.
According to Ampaire, the converted Grand Caravans, which can be used for a variety of passenger- and freight-carrying services, will consume 70 percent less fuel on shorter trips and 50 percent less on longer flights with corresponding reductions in CO2 emissions. It also said that the A03 engine will deliver twice the thermodynamic efficiency of a comparable turboprop engine and that the Eco Caravan should cut operating costs by 25 to 40 percent.
Over the past couple of years, Ampaire has conducted extensive flight testing with its in-development powertrain using its Electric EEL technology demonstrator platform. The company flew the converted Cessna Skymaster to the Oshkosh show from its headquarters near Los Angeles. The trip included a 1,135-mile sector that it said was the longest-ever nonstop flight by a hybrid-electric aircraft, from Mojave in California to Hays in Kansas.
According to Susan Ying, Ampaire’s senior vice president of global partnerships, the EEL aircraft will have flown more than 15,000 miles by the time it returns from Oshkosh. It has conducted flight trials in Hawaii and also in the UK, where Ampaire partnered with regional airlines to evaluate the potential to serve remote communities.
The Eco Caravan is expected to be able to carry 11 passengers or 2,500 pounds of cargo on flights of up to 1,100 nm. By comparison, the current production version of Textron’s Grand Caravan seats 10 to 13 passengers and has a useful load of 3,692 pounds, with a slightly shorter range of 962 nm.
In April, Ampaire started ground runs with the latest version of the powertrain, and it aims to start flight testing of the first converted Eco Caravan prototype in the second half of this year. Its objective is to secure an FAA supplemental type certificate for the conversion program by 2024.
“The modern, powerful, and ultra-fuel-efficient RED engines have exactly the right characteristics for the Eco Caravan’s hybrid-electric propulsion system and for many other upgrades or all-new designs we may pursue,” said Ampaire CEO Kevin Noertker. “We are very pleased to take this first step in collaboration with a company that shares our goal to decarbonize aviation while reducing costs for aircraft operators and their passengers.”
RED Aircraft is part of Raikhlin Engine Developments, which is based at Adenau in Germany. The company produces engines for motorsport and aviation applications, including small commercial aircraft and UAVs.
“RED Aircraft sees enormous potential for hybrid-electric aircraft and believes the Eco Caravan is just the first step to bringing a new level of efficiency and vastly lower emissions to a large swath of aviation,” commented CEO Jürgen Schwarz. “We are thrilled to be pursuing these opportunities hand-in-hand with Ampaire.”