Thread: The largest plane ever built, but will it fly?

Fascinating, the parallels. Not many things got in Howard Hughes' way. Not a lot different here, really. Spruce Goose flew. Why not this? Love the adventure, unattached to the money.

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Originally Posted by rick130

I remember talking to a bloke I knew many years ago who was an ex-RAF fighter pilot and test pilot.
He really didn't like Bert Rutan's early designs, the Vari-eze and Long-eze

Thinking about that, I suspect that the reason for this is likely to be the bad taste left by the most celebrated previous home build canard design, the 'Pou de Ciel', which gained a reputation for killing owner-builders.

The problem with a canard design is that unlike a conventional design, it does not invariably inherently recover automatically from a stall.

In a conventional design, the tail plane pushes down rather than up, as does the main lifting wing, so that if speed drops to where the tailplane stalls, with the centre of gravity ahead of the mainplane centre of lift, the nose drops, so airspeed increases, and similarly, if the mainplane stalls first the, nose drops and airspeed increases, so that in both cases, control is regained.

With a canard design, since the canard is lifting normally, if it stalls, the nose drops. But if the mainplane stalls first, the nose lifts, and things can get very interesting. Canard designs always take great care to make sure that the canard always stalls first. The advantage of a canard design is that both wings are lifting, increasing efficiency - i.e. faster, everything else being equal.

(And the Pou de Ciel was not, strictly speaking a canard design, but rather had two equal wings, close coupled, with vertical control by tilting the front wing. Air tunnel tests on a full scale one showed that the issue was that the short distance between the two wings resulted in interference between airflow over the wings under landing conditions, which could result in loss of control. Later versions increased the wing spacing to (allegedly) correct the issue. But this gave all canard designs a bad reputation.)