Advanced powertrain developer Dovetail Electric Aviation and Netherlands-based Zeusch Aviation are to collaborate on a hybrid-electric retrofit solution for the latter’s fleet of Beechcraft King Air twin-turboprops.
This foresees the replacement of the King Air’s two Pratt & Whitney Canada PT6 engines with Dovetail’s battery and electric propulsion units, with a turbogenerator serving as a range extender.
However, the partners will initially “assess the technical and commercial viability” of such a serial hybrid system under their agreement, signed at June’s Paris air show.
Lelystad-based Zeusch operates a fleet of B200 and C90A King Air variants for private charter, medevac, aerial mapping, and surveillance missions.
Those aircraft are powered by different versions of the PT6 engine, with output ranging from 550shp (410kW) to 1,050shp.
Dovetail’s own DovePower electric propulsion system includes a 671kW direct-drive electric motor.
A supplier for the turbogenerator has yet to be confirmed, but Dovetail says it is looking at several options, with output ranging from 600-900kW and is “in advanced discussions with a large OEM about this”.
The developer has long harboured plans for the King Air, although had recently appeared to be leaning towards the De Havilland Canada DHC-6 Twin Otter as its second conversion project after the battery-electric modification of the Cessna Caravan.
Dovetail chief executive David Doral says customer interest in the Twin Otter relates to a pure-electric powertrain for very short-duration flights and would involve “a straightforward application of the Caravan powertrain”.
But he says Dovetail sees “significant interest” in the range extender-equipped King Air, noting that the around 7,000 units built represent a “massive opportunity”, although this is likely to be confined to the 200- and 300-series versions of the aircraft.
“The discussions we are having with developers of turbogenerators make the integration of our electric powerplant and batteries with a range extender more than feasible, even easy,” he says.
Equipped with the electric powertrain and turbogenerator, range will be about 215-270nm (400-500km), carrying at least eight passengers.
Dovetail aims to perform a first demonstration flight of a modified King Air within around two years, with another 12-24 months required for certification.
Ironically, Dovetail was previously in possession of a King Air – donated by investor Rex, the Australian regional airline – but recently completed the sale of this asset to fund its ongoing development work.
