Peter wrote:
Putting it another way, if there is no G loading (straight and level flight in smooth air) and there is no flutter, what will be the first to break and why?
How long is a piece of string? It it’s not the first thing to break, it will be the second!
If there is no G loading and no flutter, in straight and level flight, exceeding Vne… how…? By strapping a couple of rockets to the airframe.
Actually, thinking about huv’s response regarding tail structure. To achieve straight & level above Vne, you’d need buckets of nose down trim, meaning the tailplane would generate huge amounts of upforce, which it may not be designed to take. (In huv’s scenario of spiral dive the trim would be in the normal position by the way.)
@LeSving: there is nothing wrong with feeling (or even being 
) (a bit) nerdy, and posting accordingly. But, even if I might sound like a broken vinyl record, please abstain from abbreviations and acronyms unless really common. By Re-number I reckon you mean the Reynolds number – a measure of the smoothness of the airflow, iow how much turbulence there is or isn’t, mostly about a wing; but what do you mean by the St-number?
I am sure the incredible details expressed here are most interesting to some, I am equally sure that it is way over the head for most of us. I do a pre-flight inspection on my own aircraft which no one else flies or even touches (except my well trusted engineer) and then do all the desired cockpit checks before departing. Having done that and seeing the instruments telling me all is well, I never think of anything listed above. Let’s face it I do not even understand most of it. Are most pilots of a like mind? Do you “worry” about what might go wrong? Please tell me I am not alone in this.
Jan_Olieslagers wrote:
but what do you mean by the St-number?
Strouhal number. (I didn’t know either until I searched for it.)
This compendium of flutter events makes you respect aerodynamic engineers.
https://m.facebook.com/story.php?story_fbid=1181612781888292&id=1126867284029509
…and an excellent article on the subject (thank you supercub.org as the source)
http://www.airspacemag.com/military-aviation/the-hammer-1873980/
Fenland Flyer, aircraft are built by engineers so that they are safe to fly by pilots. Being ignorant of engineering detail is quite probably something that allows you to enjoy your flying more than those who fret about engineering detail.
Personally I’m somewhere in the middle as I am an engineer but not in aircraft so I like to read these technical posts in the hope that I might accumulate more useless (to me) facts. It’s the curse of an enquiring mind.
the Mooney wing was tested to 9G (pilot neck break first) but it can’t fly more than 200KIAS due to low wing load & flutter
In a recent loss of spatial orientation in IMC event in Canada a M20 F has been clocked up to 242 kts IAS (70kts above Vne) with no wing structural damage.
T28 wrote:
In a recent loss of spatial orientation in IMC event in Canada a M20 F has been clocked up to 242 kts IAS (70kts above Vne) with no wing structural damage.
Thanks for that reference, but I think we already have a winner 245kts on fiberglass !
https://www.euroga.org/forums/flying/12331-pipistrel-virus-i-b939-doing-245kt?page=1
VNE certfification for CS23 aircraft will only show you have no flutter beyond VD (VD approx 50*SQRT(Wing Load in lbs/ft2) ) in turbulent conditions and set VNE = 0.8*VD, some can push VNE higher by diving beyond VD untill flutter happen or the wings breaks
I fly Pilatus B4-PC11, it has 5lbs/ft2 with VD at 120kias and VNE at 130kias, I am happy to dive it up +120kias then loop/barrel in calm evening aerobatics but when doing aerobatics midday in turbulent thermals, I tend to chiken out at 110kts due to asynchronous hand & teeth mouvements even when wearing parchute (it’s metal structure does start singing like organ piano and I was never comfortable, most of my glider flying was on fiberglass with air whistling only)
Thanks for that reference, but I think we already have a winner 245kts on fiberglass !
this conditions, 220 kts (405 km/h) and over 10 G, load the aircraft wings structures separated from the airframe
Not sure how 245 kts without wings is exactly a “winner” in this context?
T28 wrote:
Not sure how 245 kts without wings is exactly a “winner” in this context?
How far you can go beyond VNE before wings are pulled? it lost it’s wings somewhere 40%-50% more than VNE?
