Questions tagged [aeroelasticity]

The interaction between elastic aircraft parts and the air they pass through, which can cause the structural failure of said parts.

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How are control surface problems in wings having high bending dealt with?

In some aircraft which have large wing deflection due to bending, do ailerons or flaps not get stuck or bent themselves? In the case where hinging axis is also bent how do ailerons operate?
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Can a normally poorly handling airframe with high moments of inertia actually have superior flight dynamics under autonomous control? [closed]

I’m not a pilot but know a thing or two about flight dynamics. As you know there are currently quite a few aircraft under development designed for low-and-slow and (eventually) autonomous flight. ...
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2 votes
1 answer
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Combating flutter with mass distribution?

Considering aeroelastic flutter, when an eigenfrequency of the wing meets with an aerodynamic frequency, the commonly mentioned solutions make sense: avoid the convergence zone by limiting speed, or ...
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Do/why don't spaceplanes suffer from flutter?

Spaceplanes tend to have beefier, stiffer parts than normal aircraft, at least partly due to drag-reduction being less of a concern. But they also experience far higher airspeeds during reentry. Yet I'...
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5 votes
1 answer
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Does flutter disappear above the flutter speed?

Okay, lets assume we have an airplane with some sort of superstrong wing, but otherwise conventional configuration. We accelerate it gradually. Eventually, it will reach flutter speed, at which the ...
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2 votes
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What is the relationship between aspect ratio and divergence speed?

Why do longer wings with higher aspect ratios have lower divergence speeds?
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1 answer
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What is the difference between flutter and vortex induced vibration?

During flutter, the airfoil oscillates with a large amplitude, which generates vortices at the wake. In vortex induced vibration (VIV) the oscillations of the airfoil are caused by the shedding of ...
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How do airliners with engines mounted on places other than wings suppress wing flutter?

Assuming airliners typically have high aspect ratio flexible wings, how are wing flutter suppressed when engines are not available on forward-reaching pylons as weights?
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How do we choose a frequency range of interest for flutter prediction?

I'm trying to perform some flutter and dynamical (gust etc.) calculations with Nastran. It has been told to use a range up to 30 Hz for an aircraft I'm working with, but why the upper limit is so ...
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Can a large aspect ratio wing be actively controlled using distributed electric propulsion to avoid getting ripped apart in wind shear?

This question is related to the recent possibility of solar aircraft becoming flyable. Solar Impulse, the NASA Helios, and the Titan Aerospace/Ascenta Aerospace solar drones have all have issues with ...
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How do active blades work on helicopters?

Can someone throw some light on 'active blades' as used in helicopters? I'm mostly interested in the use of piezoelectric material and actuators. How are the actuators able to sense the change of ...
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9 votes
3 answers
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How can engine positioning affect flutter tendency?

I understand that moving the engines towards the wingtips would increase flutter tendency, but are there any other positioning options which could affect flutter? How about moving the engine ...
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How to define pitch angle for a passive variable pitch propeller?

This question is a continuation of the question How to calculate variable pitch propeller parameters? mentioned before. Actually, the theory described as an answer on the question above is the exact ...
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2 answers
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What is the reason for the poor low-speed characteristics of sweptback wings?

I know there are advantages of swept-back wings delaying shock-wave allowing a aircraft to fly faster. However, what are the disadvantages. I know one of them is that they have very poor low speed ...
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5 votes
4 answers
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Is Fluid Structure Interaction considered in aircraft design?

Fluid Structure Interaction (FSI) causes an aeroplane’s geometry to change and hence the forces on the different surfaces of an aeroplane become different than the forces expected according to ...
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5 votes
1 answer
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Why can not two modes coincide perfectly for some cases in Flutter phenomena?

I have a question about flutter phenomena. As you know, flutter occurs when two modes (for example, first mode and second mode) coincide (that is, after a specific velocity, the frequencies of two ...
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Is flutter speed always smaller than divergence speed for aircraft?

In aeroelasticity, there are three main phenomena that one should take care of: divergence, aileron reversal and flutter. Each of them has an associated speed at which the phenomenon might start to ...
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