WOW, THAT was Expensive

Insufficient data to formulate a proven scientific answer.

 

Without the weight of a pilot and/or passenger I'd bet all it takes is 55-60ish mph wind maybe even less, this is a really light weight kit plane.

 

I was guessing about the same thing but without knowing what kind of A/P and what it weighed I couldn't offer an estimate.

It only takes one GUST.

 

Flaps up too.

She was born to fly

 

IIRC, normal rotation speed for that plane (looks to be a CZAW Sportcruiser to me) is about 47 MPH using 10 degrees of flaps. Stall is very low at about 34 or so MPH. The thing only weighs around 750 lbs. empty.

Quick aside -- CZAWs are also rated to +6 G's, again IIRC. We used to have great fun holding it in ground effect and making quick pull-ups. I say "used to" because, unfortunately, a student let a power-off stall get away from him at 2,500ft and the thing ended up in a spin. Despite the best efforts of the instructor, the plane refused to fly out of the spin, and they spun right into the Dismal Swamp. Both occupants made it, IMO most likely due to the incredibly low stall speed and the fact that they somehow hit the trees tail first. There are pictures on here somewhere in an old post of mine.

 

LOL ha ha ha, yea... Sounds like the poor guy needed the insurance money, kit plane/sport cruiser sales aren't what they use to be.

 

so this is possible at anytime with just a strong gust,,thanks,

 

I thought pilots were supposed to have good vision?

I can clearly see tie downs in that video being stressed to the point of failure. If they weren't there the plane would have moved off a lot earlier on in the clip.

>8^)
ER

 

IF the gust is strong enough, especially if the wind is coming from the front of the A/P.
The wind speed (or gust) has to equal what the airplane would be subjected to at takeoff, (with the weight being a factor)
The wings are just doing what they were designed to do.

 

Without knowing the gust speeds in the video (and the weight of the airplane) nobody can predict when that airplane would have left the ground.

I see no tie downs.
I do see an aero stand in the foreground partially blocking the view of the RH wing.

I also see multiple antenna sticking down from the bottom of the fuselage inline with a view of the LH wing.

 

Maybe this helps?

Watch the video full-screen and you can see them flapping in the winds from the start. The left one breaks first and then the right one holds on another second or so before snapping - its right at that point in my second screenshot. All I did was enhance contrast in the bubble.

>8^)
ER
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Wow, they were there. Good eye, I would have never seen that on my iPhone.

This is a good article and there are facts in it that I did not know, it's worth the read to prevent this in the future.

http://www.airventure.org/planning/tying_down.html

Sufficient tensile forces and effective tiedowns also depend on the quality of the rope. The best ropes are UV-resistant braided nylon or dacron. Manila ropes are not recommended because they shrink when wet, are subject to mildew and rot, and have considerably less strength. All ropes should be regularly checked for damage due to chafing.

I feel really bad about my previous attempt at humor.

 

What was the official wind speed that day?

 

Remember too, this is a low wing airplane close to the ground. The wing is in ground effect and the speed at which it will lift off with nobody aboard is a lot lower than the published stall speed that assumes the aircraft is at full gross weight. While it will take some more lift to break the ropes, 50 knots would probably do it.

The real cause is the position in which the elevator was locked. It's not uncommon to lock the controls with a seat belt, we've all seen it done. While this provides an effective lock that prevents the controls from being slammed around, it locks the elevator in a nose upward position. For a tricycle airplane that's a really bad thing, since the tail can (and will) drop down and drastically increase the angle of attack of the wing. Since the main gear of a tricycle aircraft are further aft, you are going to get more angle of attack than a tail dragger before the tail hits the ground. Had the controls been locked in a nose down position this wouldn't have happened. With the controls properly locked the nose wouldn't have gotten so high and the lift forces wouldn't have been enough to break the ropes.

 

Thank you. That's what I get for watching on a cheap monitor

 

Hey now, wait a second... Was that plane tied down with shoe laces?

PDF's for the FAA Tie Down - Advisory Circular
http://www1.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/ACNumber/3121C979AF8A048C862569D60074B3B3?OpenDocument