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Questions tagged [flutter]

A type of uncontrolled divergent oscillations in an aircraft's structure, typically encountered at excessively-high speeds or if the airframe's stiffness has been reduced by previous damage. Flutter is extremely dangerous, and can rapidly cause an aircraft to break apart in flight; it has caused many fatal accidents over the years.

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State of the art in aircraft industry for flutter analysis

I'm an aerospace engineering PhD student and for my research I'm investigating how to come up with a way to pick the most critical flight conditions for flutter. The main idea is to understand how it ...
user9870949's user avatar
4 votes
1 answer
154 views

Are flaps regulated as balanced control surfaces?

I was talking about flutter the other day and how it occurs with the ailerons able to flap out of sync with the wing. I realized that the flaps, could in theory, move in a similar way. However, the ...
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1 answer
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How can I calculate torsional stiffness of a wing when the dimensions of the cross section vary?

I am working on a project and we need to calculate the torsional stiffness of a wing in order to analyze flutter and divergence. However, the dimensions of the cross section vary along the semi-span, ...
Pedro Andrade's user avatar
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0 answers
36 views

does ice accumulation of wing affect its flutter speed

I am trying to find a possible link between wing icing and flutter. I want to know if ice accretion mass will change aeroelastic properties of the wing. Does wing icing affect the flutter speed of ...
user66458's user avatar
2 votes
1 answer
80 views

At which stage of Aircraft Part 23 Type Certification needs flutter test / Vne 1.3x top speed?

Hello AviationExperts, Recently Joby #eVTOL went down after trying to do extreme stress tests. Tracking websites have shown Joby Flying at 270 Miles per hour where as top speed of Joby S4 is 200 MPH ...
JobyResearcher's user avatar
12 votes
1 answer
2k views

Why do flying wires hum louder in a sideslip?

Page 50 of the Feb. 2021 issue of the EAA's magazine Sport Aviation reports that Like any good vintage airplane, the Sea Bird likes to fly coordinated, and the flying wires will sing out loud if the ...
Camille Goudeseune's user avatar
2 votes
2 answers
462 views

What limits high altitude powered paragliders other than the engine?

Due to their extremely low wing loading, powered paragliders stall at very low indicated airspeeds compared to other airplanes. A typical paraglider can continue flying all the way down to 10-15 ...
Thorondor's user avatar
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2 votes
1 answer
267 views

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 ...
GZoltan's user avatar
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2 votes
2 answers
315 views

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'...
Abdullah is not an Amalekite's user avatar
4 votes
1 answer
275 views

Why this inertial regulator of dragonfly wing pitch reduces self-excited coupled flapping and feathering vibrations and improves gliding flight speed

The pterostigma of insect wings an inertial regulator of wing pitch is linked in this answer to Why do dragonflies have these special little spots on their wings? (open access copy here) The Summary ...
uhoh's user avatar
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5 votes
1 answer
353 views

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 ...
Abdullah is not an Amalekite's user avatar
3 votes
2 answers
727 views

Does every control surface need to have a counterweight?

Is it not a good idea to balance all control surfaces, no matter what they weigh? I am building a small plane, with small control surfaces. There are many of the same type of plane flying. Most have ...
Kevin Curtis's user avatar
3 votes
2 answers
4k views

Why was the Electra uniquely vulnerable to whirl-mode flutter?

The Lockheed L-188 Electra, notoriously, suffered from early problems with whirl-mode flutter, which caused two Electras to break apart in flight in 1959 and 1960, forcing an expensive redesign of the ...
Vikki's user avatar
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4 votes
1 answer
2k views

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 ...
Upid's user avatar
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1 vote
1 answer
465 views

Is aerodynamic flutter speed dependent?

Is it possible for control surface flutter to occur at low Reynolds and low speed? If yes,why don't Ultralights have counter weights or tail sting mass to immune the control surfaces against flutter ...
David Teahay's user avatar
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0 votes
1 answer
201 views

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 ...
Jean-Philippe Landais's user avatar
9 votes
3 answers
1k views

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 ...
Guha.Gubin's user avatar
12 votes
4 answers
14k views

How are aircraft wings protected against flutter - aerodynamic oscillations that can break bridges?

A wing and a bridge are both exposed to flutter, a transverse wind distorting them by resonance. Aircraft flutter: Aircraft flutter, source (video) Bridge flutter: US Tacoma-Narrows bridge collapse ...
mins's user avatar
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3 votes
1 answer
481 views

What are the factors that determine the speed flutter appears on wings?

I'm doing a study on the flutter phenomenon of airplane wings. I'm interested in factors that influence wing stability, and how one can increase the speed where flutter starts. What are the ...
saud's user avatar
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1 vote
1 answer
142 views

May someone please suggest EHA design procedures for AFS?

Are usual electro-hydraulic actuator designs for aileron control employable for aeroelastic flutter suppression? If not, where can I find design procedures for this specific case?
Mirko Aveta's user avatar
17 votes
3 answers
2k views

How was flutter mitigated in jets such as the F-15 and F-16?

As I understand it flutter was a serious problem for early jets, like the XF-104. Flutter can affect any of the extended members of an aircraft during high-speed flight, including the wings and the ...
Tyler Durden's user avatar
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5 votes
1 answer
3k views

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 ...
Shellp's user avatar
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8 votes
1 answer
333 views

Where can I find nice animations of flutter? [closed]

Where can I find nice flutter animations/videos (other than YouTube) to add to a presentation without violating Copyright regulations ? It can either be for wings as well as blade arrays. Are you ...
Nicolas's user avatar
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18 votes
2 answers
10k views

What causes aileron and elevator flutter?

This video shows a Hawker jet with the wing fluttering up and down like it's about to break. What can cause flutter like that? Can it actually cause a wing or stabilizer failure? How can flutter be ...
xpda's user avatar
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