Where can I place an engine in a twist morphing wing?

Question

I am designing an electric aircraft with a wing that is completely based on the idea of biomimicry, whereas the wing has multiple winglets and can also morph by twisting. It is more like an experiment to check about the possibilities of a commercial aircraft with the ability to morph.

Where could I possibly place the engine if my wing is going to be able to twist?

I don't want to be on the nose about it, but how about on the nose? :) — Sanchises, Aug 20 '19 at 10:17

score 1 · Answer 1 · answered Jul 20 '21 at 19:17

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Don't

Twist, morphing sounds torsionally flexible. Add mass to a soft spring and you get all kinds of resonances and eigenmodes. Better put the engine mass to a stiff and strong structure that can deal with its mass and forces.

answered Jul 20 '21 at 19:17

Peter Kämpf

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I suppose one could implement digital augmented damping, similar to the fly-by-wire damping of phugoid aerodynamic oscillations. But, as the pioneers discovered, as soon as you start flying at any speed, the warp control forces become horrendous. One of them described it as the controls flying the pilot. – Guy Inchbald Jul 21 '21 at 06:50
@GuyInchbald I agree, and then it remains to be proven that the benefits of the warping wing with all additional controls and the redundancy this requires added will still exist. – Peter Kämpf Jul 21 '21 at 06:55

score 0 · Answer 2 · answered Jul 19 '21 at 20:43

Maybe within the wing towards the root, like in the concept of the Eather One (or de Havilland Comet).

Otherwise, if it's a X-57-like concept, with distributed electric propulsion, I don't see why it couldn't work.

Feather-tipped wings have made their way to Airbus' Bird of Prey conceptual proposal, although I don't know if that's the kind of biomimicry you refer to.

I'm also not sure whether there was a lot of technology maturity/consolidation from the flight testing campaign using a Gulfstream with morphing wings.

Distributed propulsion with twisting would likely lead to distributed thrust vectors and unpredictable vibration modes. I would not recommend it here. — Guy Inchbald, Jul 20 '21 at 19:07

Guy Inchbald · Answer 3 · 2021-07-21T06:41:11.153

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The Wright brothers offset the engine to one side and the pilot to the other. The engine drove twin pusher props via bicycle chains. Outboard of that rigid centre section, control was by wing warping. Don't knock it, the plane flew on only 12 hp. But maybe you could improve on the bicycle chains.

Another approach is to place the engines at the tail. In the 1960s and 70s airliners such as the Sud Aviation Caravelle and BAC One-Eleven and Trident were quite successful, and a lot of bizjets have them tail-mounted too.

edited Jul 21 '21 at 06:41

answered Jul 20 '21 at 19:06

Guy Inchbald

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The Caravelle is from the Fifties (first flight 1955) and all tail-engined airliners are from the early to mid-Sixties. The last one was the Tu-154 (first flight 1968). After that the designers had learnt their lesson. – Peter Kämpf Jul 20 '21 at 19:22
@PeterKämpf The Caravelle did not enter service until 1959. But I'll grant you the swinging sixties. How good an idea is and how successful are not the same thing, and neither is the same as how possible it is. – Guy Inchbald Jul 21 '21 at 06:40
Once the difficulties of wing aerodynamics with an engine attached are solved, the wing mounted engine really is the better solution. For a multitude of reasons. But the wing should not be wobbly. – Peter Kämpf Jul 21 '21 at 06:52

Where can I place an engine in a twist morphing wing?

3 Answers3