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What 2 parts of the airframe are the first to have structural failure after exceeding maximum speed?

Sorry. I just thought there might be a part that usually failed first.

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    $\begingroup$ This is very specific to each aircraft design, and will vary from airplane to airplane... It would also depend on the configuration of the airplane. $\endgroup$
    – Lnafziger
    Jan 14, 2014 at 19:51
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    $\begingroup$ As Lnafziger points out it's hard to really answer this generically. If you exceed Vfe we can presume you're going to damage the flap mechanism. If you exceed Vne you could lose a control surface to flutter, oilcan/damage wing skins, overstress a wing spar (or attach bolt), or any number of other things - where the weak link is depends on the aircraft... $\endgroup$
    – voretaq7
    Jan 14, 2014 at 20:19
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    $\begingroup$ This is a very broad question and can not be answered specifically. It also depends on the attitude / configuration when exceeding Vne, including other factors as mass / balance, age of components and already existing damages. Obviously there is a safety margin, but in certain cases (eg when having a load factor) this is not enough. It is very common to have nearly invisible cracks in the structure after reaching various limits, but especially at the very high speed flutter can happen. As said above, this question cannot really be answered, as it is quite broad. $\endgroup$
    – Force
    Jan 14, 2014 at 21:11
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    $\begingroup$ No need to be sorry ptgflyer. You got your answer this way, it just wasn't what you were expecting! :) $\endgroup$
    – Lnafziger
    Jan 14, 2014 at 22:56

2 Answers 2

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Q: Which link of a chain will fail first when you exceed the maximum design tension?

A: The weakest link.

It could be any link since none is designed as the weakest link.

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  • $\begingroup$ or you just crash when the plane reaches transonic speeds and control is lost $\endgroup$ Jan 15, 2014 at 10:56
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Unfortunately it's impossible to answer your question. No part of any aircraft design will simply fail because the 'speed' is to high. You need to consider the airspeed (in this particular case the equivalent airspeed) as a force acting on the airframe and as Force stated correctly it's not the only factor, which needs to be considered. Mass, existing weakening of the structure and the attitude as well as the surface design, which obviously varies between different aircraft, need to be taken into account.

Now tell a Pilot that he is not allowed to bank more than x1 degrees, if the aircrafts mass is bigger than x2 or even lighter than x3, if the aircrafts last overhaul was more than x4 month ago, at a higer airspeed then x5 KEAS. He will refuse it - by the way the aircraft won't be certified because of its manual - as well as he would refuse to calculate the load factor while flying. Thats why maximum speeds are calculated or even set up during flight testing. VNE, VA, VFE, VLO... all expressed in KIAS. By the way 2 different aircraft flying the same KEAS will most probably don't have the same indicated airspeed.

In general you can say that at maybe 70 percent of all aircraft either the parts which carry the heaviest loads or those parts which are not reinforced to withstand high loads, because they don't have to during normal operation plus safety margins, fail first when exceeding VNE and the safety margin in straight and level flight.

The never exceed speed can also be set as the aircraft becomes only very hard to control above it, there were no further tests and calculations made or for sure also some other reasons.

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  • $\begingroup$ I'm not sure I understand - you say it's impossible to answer, but your actual reply seems to try anyway. If you think this question is too broad, you should vote to close it and leave a comment as to why. $\endgroup$
    – egid
    Jan 21, 2014 at 5:07

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