Oct 062017
 

Interesting:

Boeing-backed, hybrid-electric commuter plane to hit market in 2022

 

It’s a small plane, seating only 12, designed to go about 700 miles at an airspeed of about 340 miles per hour. It is to use two electric motors running off batteries, with a backup jet fuel powered generator to extend range and keep the craft airborne when the batteries run dry. Improvements in battery technology would allow the plane to be fully electric and to eventually extend range. As a small aircraft it is meant to operate from smaller non-hub airports, theoretically shaving hours off actual trip time due to avoiding the nightmare that is modern airport security theater.

 

 Posted by at 10:40 pm
  • gormanao gormanao

    Is this actually a “jet” or just a ducted fan? Like a Kort Nozzle or a submarine propulsor in the sky?

    • Peter Hanely

      At the listed flight speed, almost certainly a ducted fan.

  • Peter Hanely

    The point of a hybrid electric vehicle is to operate the combustion engine near max efficiency or not at all. My understanding is aircraft already routinely operate their engines in that band of best efficiency, which defeats the purpose of the hybrid electric.

    • Scottlowther

      If an electric jet aircraft is actually a functional and practical device, having a jet fuel turbogenerator on board would be just for backup and range extension. The claim is that with exiting battery technology the aircraft already has better dollars per seat-mile than a conventional aircraft; as the battery tech improves, the need for the turbogenerator would decrease.

      Assuming it all works, of course.

      • publiusr

        And electric planes will be just as heavy when they land as when they take off–for whatever that’s worth.

    • Paul451

      My understanding is aircraft already routinely operate their engines in that band of best efficiency, which defeats the purpose of the hybrid electric.

      Not necessarily. During take-off and climb (and by extension landing), the engines have to be over-powered compared to during cruise. That means you need larger engines than is strictly required for cruise, even if you optimise their fuel efficiency for cruise. Electric motors give roughly the same efficiency during all modes and should be lighter than twin jets for the same maximum power.

      OTOH, batteries seem like the killer to me. AIUI, energy storage per kilogram hasn’t improved as much as energy storage per volume.

      I would think it would be better to have a turbine-generator that supplies power for the entire trip, with just a small battery/supercapacitor pack to supply power during take-off. The generator can be smaller since it only has to supply power for cruising speed, not take-off/climb.

  • markus baur

    if that drawing is halfway accurate it looks a lot like they are planing to use a learjet 55 as demonstrator hull .. there is a marked family resemblance