The insurance company won't pay out on this: not tied down properly.
*promote

Promoting this video and sending it back into the queue for one more try; last queued Friday, November 18th, 2011 12:44pm PST - promote requested by Boise_Lib.

The takeoff looked fine... not too sure about the landing.

Awe - I wanted to see the SPLAT!

I know I parked it RIGHT HERE...

"Dude, have you seen my plane?"

*science

Adding video to channels (Science) - requested by BoneRemake.

*Nature

*WTF

^Upvoted^

Adding video to channels (Nature, Wtf) - requested by Barseps.

ah yes, aerodynamics and the laws of physics are not science. the wind picking up hundred of pounds without mechanical power is not science. Good call.




Not.

When I was a kid, my dad told me about take-off speeds of airplanes. He said the plane's ground speed plus headwind speed must add up to at least the minimum take-off speed, or the plane won't leave the ground. I then saw that a plane could then take off with headwind alone. Dad agreed. What we both didn't see in our heads is that once the plane leaves the ground, if the propulsion system isn't engaged, the plane will be pushed backwards, lose speed, and crash again.

>> ^messenger:

What we both didn't see in our heads is that once the plane leaves the ground, if the propulsion system isn't engaged, the plane will be pushed backwards, lose speed, and crash again.


I foresee a one word critical flaw in your argument.

Glider.

I don't. Gliders cannot take off from the ground without a tether, and can only stay airborne by riding up thermals or other updrafts. This is a form of propulsion. Without updrafts and untethered, a glider will eventually fall to the ground.>> ^sirex:

>> ^messenger:
What we both didn't see in our heads is that once the plane leaves the ground, if the propulsion system isn't engaged, the plane will be pushed backwards, lose speed, and crash again.

I foresee a one word critical flaw in your argument.
Glider.

They can take off without a teather, in exactly the same way as the plane in this video takes off. It's not at all safe, which is why it isnt done that way. You can even throw a glider directly off a cliff to gain the airspeed if you have a deathwish.

The way you need to look at it is that the thermals increase the height of the glider which increases its potential energy. The pilot converts this into forward momentum by pushing forwards on the stick, and in turn losing height. With fast enough winds (and we're talking 70-80mph, not great flying weather), a light aircraft will fly regardless of the updraft.

Also, its perfectly possible for aircraft to be flying either under propulsion or unaided and have a negative groundspeed (i.e, be going backwards). As long as the wind over the wing provides the needed lift, the aircraft *will* fly.

That said, landing with a negative ground speed is going to be interesting. However you can land with a tail wind as long as the overall air speed still provides the lift needed.


>> ^messenger:

I don't. Gliders cannot take off from the ground without a tether, and can only stay airborne by riding up thermals or other updrafts. This is a form of propulsion. Without updrafts and untethered, a glider will eventually fall to the ground.>> ^sirex:
>> ^messenger:
What we both didn't see in our heads is that once the plane leaves the ground, if the propulsion system isn't engaged, the plane will be pushed backwards, lose speed, and crash again.

I foresee a one word critical flaw in your argument.
Glider.

@sirex

Lift is dependent upon a plane's relative speed to the wind. Without brakes or chocks to hold the plane in place, the plane begins to travel with the wind as soon as it lifts off, lowering its relative speed. It loses lift and drops. A glider (which is what this plane effectively is, with its prop idle) would do the same thing, as its "propulsion" system is gravity. That close to the ground, there isn't anywhere near the altitude it would require to maintain lift.

Check out the elevators on the tail. Someone wanted this to happen. I think this is some sort of test.

I'd have to ask one of my flight-nut friends, but I'm fairly sure you're supposed to park with the yoke forward to prevent exactly this...

The wind would be picking up the tail first, causing the wind to press down on the wings. It would cause damage to your plane, but at least it would stop it from slamming into other things.

>> ^Fletch:

@sirex
Lift is dependent upon a plane's relative speed to the wind. Without brakes or chocks to hold the plane in place, the plane begins to travel with the wind as soon as it lifts off, lowering its relative speed. It loses lift and drops. A glider (which is what this plane effectively is, with its prop idle) would do the same thing, as its "propulsion" system is gravity. That close to the ground, there isn't anywhere near the altitude it would require to maintain lift.


That's all well and good, but downvoting his comment seems a bit harsh?

A downvote is harsh? My god, are you people really this fragile? I wasn't questioning his parentage. I was disagreeing with his comment. He proposed a "critical flaw" in messenger's comment and there was none (that I could see). Simple as that. I sincerely doubt it ruined his day.

I'm sorry if you were offended, sirex. I'm sure you are a swell person.

Better?

I guess critical flaw is perhaps over-egging it. But the original statement seems misleading to me. It suggests that without a propulsion system any aircraft is incapable of flight, which is obviously incorrect. Its likely just a case of clarification, but yes, once airborne the aircraft will lose forward momentum and be carried by the wind the same as any lump of rubbish in a hurricane, at that stage its likely its acting as a kite rather than anything aerodynamic.

(Also, i couldn't care less about comment votes. Its the internet.)

>> ^Fletch:

A downvote is harsh? My god, are you people really this fragile? I wasn't questioning his parentage. I was disagreeing with his comment. He proposed a "critical flaw" in messenger's comment and there was none (that I could see). Simple as that. I sincerely doubt it ruined his day.
I'm sorry if you were offended, sirex. I'm sure you are a swell person.
Better?


Sorry, I guess I'm transfering from statements made by people who frequently get downvoted, more than any looking up in a FAQ -or asking anyone for that matter- sort of thing. 15 Upvotes gets you a power point, (Ya whoopdie, but they do allow you to do other, more concrete actions), and I was assuming a downvote made that harder to achieve.

From my years here I just really got the impression downvotes were mostly for slapping someone. Differences of opinion -or outright corrections- being done as a quote or @(namehere)'ing someone.

Somehow, I don't think that this new civilian version of the harrier will takeoff in popularity...

And Away We Go........