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I saw an article from the BBC about the Eviation Alice this morning that left me puzzled. The design is a tail wheel tri-motor with the power plants located in a pusher configuration at the wing tips and tail.

Eviation Alice prototype on the ground

The article describes the aircraft thusly:

"Alice is an unconventional-looking craft: powered by three rear-facing pusher-propellers, one in the tail and two counter-rotating props at the wingtips to counter the effects of drag."

I'm wondering about what drives the configuration of the Alice? What compelling benefits does the configuration offer to balance the challenges it poses:

  • Controllability in the case of the failure of one of the wing tip power plants - even with the ability to fly (and presumably continue a worst case take off) on only the rear motor - why wouldn't you move the wing mounted engines inboard and have even better "engine" out performance?
  • Ground clearance and crosswind problems for the tail gear.
  • Designing a light and efficient wing with tip mounted power plants.

Obviously Eviation thinks that their configuration makes sense, has anybody heard or seen their arguments?

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  • $\begingroup$ That design looks to be more aesthetic than practical. A tailwheel configuration is much more limited in crosswind operations. $\endgroup$
    – GdD
    Jun 21, 2019 at 15:08
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    $\begingroup$ I doubt this aircraft will ever fly, or be certified. There is no way to control the yaw of 350 horsepower at the end of a 25’ wing if the other engine should quit. Even with a nose wheel, crosswind landings will be a challenge since the wing can not be lowered into the wind. $\endgroup$
    – Mike Sowsun
    Jun 21, 2019 at 15:28
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    $\begingroup$ @GdD -- "That design looks to be more aesthetic than practical. A tailwheel configuration is much more limited in crosswind operations." -- a tailwheel configuration is no problem as long as you can do a nice wing-low slip to cancel drift -- oops, never mind! $\endgroup$
    – quiet flyer
    Jun 21, 2019 at 19:32
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    $\begingroup$ I suppose the intended benefits have something to do with the propwash cancelling the wingtip vortices. Maybe they could have better gone with a tricycle gear configuration with an extra rear gear to protect against prop strike. $\endgroup$
    – quiet flyer
    Jun 21, 2019 at 19:37
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    $\begingroup$ @quietflyer Just keep lengthening the gear until the props stop hitting :-) $\endgroup$
    – dlu
    Jun 21, 2019 at 19:40

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According to a recent article from the travel blog The Points Guy (whose reporters were at the Paris Air Show and toured the aircraft,)

[W]hile it has three motors, the aircraft can continue to fly with just the rear motor engaged. If one wing-mounted motor fails, the other will be disabled to maintain stability, and additional electric power can be diverted to the rear motor so the plane can continue its flight.

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Multiengine aircraft date back to 1913, when Igor Sikorsky's Russky Vityaz first flew. Darn thing was huge, had a balcony, of all things, and could only do 55 kts, but it was impressive.

All multiengine pilots have to pass training on what to do if an engine fails, including what happens if airspeed falls below Vmc (minimum controllable airspeed) and how to keep the airplane flying reasonably straight until you can land. This aircraft is no different. It's also possible this aircraft can at least maintain straight and level flight on just the rear engine after shutting down the function wing engine if needed.

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  • $\begingroup$ Perhaps I should revise my question - even if the design is certifiable, it seems like they’re taking on unnecessary control problems. I’m wondering what the compelling benefits might be. $\endgroup$
    – dlu
    Jun 21, 2019 at 15:25

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