In The E-plane From Mannheim To Berlin

2023 Author : Hannah Pearcy | [email protected] . Last modified: 2023-06-05 23:50

Today, around 3,000 Commuter-class aircraft are in use worldwide, with only a little more than a dozen 19-seaters being delivered in the civil sector in recent years. The German Aerospace Center (DLR), together with Bauhaus Luftfahrt, analyzed in the CoCoRe (Cooperation for Commuter Research) project what possibilities and potential there are for hybrid-electric 19-seaters . Using the 19-seater Do-228 and Jetstream 31 flying today, they examined an example of a configuration.

What is the commuter class?

A feeder aircraft, in English "Commuter Aircraft", is a smaller short-haul airliner for a maximum of 19 passengers and a maximum takeoff weight of 8,618 kg. Internationally, however, some types with larger capacity and starting mass are used in this role. Likewise, smaller machines are used as feeder aircraft, which have only 6 to 10 seats depending on the type.

The next largest class of commercial aircraft for use on short-haul routes is the regional commercial aircraft, also known as the regional aircraft.

The researchers modified the chassis nacelles in their design. These sit on the wings and have been expanded to accommodate quickly replaceable battery blocks. “This means that we have the weight of the comparatively heavy batteries exactly where it is most conveniently located on the plane during takeoff and landing - directly above the landing gear. Empty batteries can be changed quickly and easily at an airport”, project manager Wolfgang Grimme from the DLR Institute of Airport Management and Air Transport summarizes the advantages.

Fly 200 km fully electric

The batteries weigh about 2 tons. About 8.6 tonnes of mass have to be moved on departure. In their concept, the researchers therefore assume a fully electric range of 200 km . Depending on requirements, this range can be extended to over 1000 km with two range extenders in the form of a gas turbine, which can be coupled and decoupled with the respective propeller.

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According to our research, 19-seaters fly 56% of the distances under 200 km and 83% under 350 km worldwide, so that this combination of fully electric flight, supplemented by a range extender, already accounts for a large part of the CO ₂ emissions in the area of commuter aircraft would avoid,”explains Dr. Annika Paul from Bauhaus Luftfahrt.

In this case, the range extender also serves as an emergency reserve if, for example, a distant alternate airport would have to be controlled in bad weather conditions. "The range extender therefore enables a longer fully electric flight because the battery does not have to be used for reserves," adds Georgi Atanasov from the DLR Institute of System Architecture in aviation.

Range up to 400 km in the future?

If the storage capacity of batteries is further improved in the future, a purely electrical range over 200 km with the same battery weight is also conceivable, according to the DLR. To do this, the aircraft would have to be redesigned. For example, numerous distributed electric propellers on the wings in combination with a modern, lighter aircraft construction would also extend the range of fully electric flight. For these reasons, fully electric flights of over 400 km are conceivable in the future.

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Regional air taxi service in Germany

In a market analysis, the researchers identified possible fields of application for electric commuter aircraft. So far, these small feeder planes have been used in remote regions with little passenger traffic, such as in Canada. There is also a need for medium-sized cities in Europe that have inadequate direct connections to large metropolitan areas, among others.

An economically viable regional air taxi service from smaller airports would be conceivable for these cities. For Germany, such routes are, for example, Mannheim-Berlin, Bremen-Berlin or Münster-Leipzig. So far, the low number of approximately 1000 charge cycles of the batteries and the comparatively low CO ₂ prices have been economically challenging compared to conventionally operated commuter aircraft. If these factors increase in the future, the economic prospects of electric aircraft will also increase.