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In this article, the author raises doubts about the viability of this aircraft:

Sadly for the Flying-V, it will probably fail like the blended wing body designs we've seen down the years. It's for the same reason, too: airplanes bank as they turn. That's not much of a problem in a conventional airliner design, where passengers are never that far from the plane's central axis. But as you move further out from that central axis the effect becomes a lot more pronounced.

A rendering of the Flying-V wearing KLM's livery. credit: Edwin Wallet, Studio OSO

I don't really understand how banking is a problem. The angle for the passenger remains the same, the only difference being an increased of vertical acceleration when the airplane is initiating / retracting the bank.

An apparent simple solution would be to... bank more slowly...

Is there something I'm missing? Would the vertical acceleration really be a concern for passengers?

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    $\begingroup$ Maybe it's the amount of movement that would be felt as up & down motion. So instead of maybe a foot or two around a central axis, it could be tens of feet as you move farther away from the centerline. $\endgroup$
    – CrossRoads
    Jun 5, 2019 at 1:28
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    $\begingroup$ @CrossRoads that's the vertical acceleration I'm talking about yes $\endgroup$
    – Antzi
    Jun 5, 2019 at 2:04
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    $\begingroup$ I mean no disrespect to the author, but the blurb underneath the article says "[Author] is the automotive editor at Ars Technica, covering all things car-related." As far as I'm concerned, he does not actually know what he's talking about. Other answers on Aviation.SE about BWB designs will point you to much greater and fundamental challenges. $\endgroup$
    – Sanchises
    Jun 5, 2019 at 12:31
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    $\begingroup$ @jamesqf Sure, but passenger comfort isn't really considered for this emergency edge case. $\endgroup$
    – Antzi
    Jun 6, 2019 at 6:28
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    $\begingroup$ The author over at Ars is right with being concerned about this concept, but for the wrong reasons. $\endgroup$
    – Peter Kämpf
    Jun 12, 2019 at 18:22

2 Answers 2

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There are two possible sources of discomfort for passengers sitting farther away from the aircraft's longitudinal axis during a roll manoeuvre:

  1. At the start and end of the roll manoeuvre, the angular acceleration will be felt as a stronger vertical acceleration, as you pointed out (vertical as in perpendicular to the cabin's floor).
  2. Between the start and the end, the aircraft will be rolling at constant angular speed (or roll rate), so the angular acceleration will be zero, but the passengers will still be moving along a circular trajectory (around the aircraft's longitudinal axis) and therefore will also be subject to a centrifugal force (parallel to the cabin's floor) that grows proportionally with the distance from the longitudinal axis.

The roll manoeuvre itself may only last a few seconds, but if the above effects are strong enough, it could be enough to make some passengers feel properly queasy, especially if it's repeated a few times as during departure and arrival procedures.

As you suggest, rolling more gently and more slowly would limit these effects. However, instrument flight procedures always involve standard rate turns, with turn radii expected to remain within certain limits, depending on the aircraft's speed. Rolling more slowly would increase the aircraft's overall turn radius and could make it harder or impossible to comply with currently published procedures.

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  • $\begingroup$ In this case, standard rate turns would be unaffected: rolling more slowly would just add a small delay to the beginning of the turn. $\endgroup$
    – Antzi
    Jun 12, 2019 at 0:24
  • $\begingroup$ Yes, which means that the aircraft would take up more space to achieve the same change of heading - that's what I meant with 'overall turn radius' $\endgroup$
    – Deeday-UK
    Jun 12, 2019 at 0:53
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    $\begingroup$ It's not that bad. A normal roll might take 3s and peak at 15°/s. For a total 30° bank it follows the angular acceleration would peak at 15°/s². From the picture I'll guess the outer passengers may sit around 15m off the axis, which yields maximum vertical acceleration ~0.4G and lateral acceleration ~0.1G. Noticeable, but not too bad. Would be worse for bigger aircraft, of course. $\endgroup$
    – Jan Hudec
    Jun 12, 2019 at 20:42
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I have a doubt if the question addresses and actual problem. Banking in airplanes is supposed to match centrifugal forces, same as roads and rail tracks are not horizontal in turns. A lateral pull of gravity, or of the force towards airplane floor, when turning around the main fuselage axis won't be noticeable for passengers, as otherwise, structural loads on airplane would be too high, an airplane is not a rollercoaster, an airliner is not an aerobatics machine, not a combat airplane in a dogfight, but perhaps the inertia, momentum forces in having the lot of weight passengers and airplane structure turning will impose an slow banking rate, a regular airliner has most weight close to center, a 'V' shaped machine, or other lifting bodies, do have an important width in weight distribution; ordinary airplanes have just the light wings quite apart from center line. Is this a reasonable answer to issue? Thanks. Salut +

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