747 Tries to escape Graveyard
 

So I take it the plane is tethered down. Also it must have its flaps in different positions than the other planes causing the lift.

Plane from what I've read was unteathered, the parking brake was set, but the reason it bucked up was the engines were gone from the wings, so there was not a lot of weight there, I guess it's in the process of being scrapped

What is curious is that you don't see the weeds leaned over in the wind, or any debris flying by. I realize that the absence of the engines is decreasing the stall speed considerably, but it still is almost suspicious.

I wonder what the stall speed of a 747 is, 140MPH? Even if the absence of engines cut the stall speed in half, you would think there would be other indications of a 70MPH wind.

Viewed full screen, you can clearly see the cut up sections of a fuselage and other pieces rolling in the background too. Without the weight of the engines, and the nose not secured, it seems elementary that lift would occur.
I wonder how they do things at Davis-Monthan when they need to strip parts & engines form their a/c?

at about 56 seconds you can see a dust cloud zip by.

I can see movement in the grasses, some dust clouds and every now and then some stuff blows across the pavement.

Time to clean some dust off that monitor, Larry. ;):D

Okay that explains it. I did not view it full screen and I'm viewing it on my laptop with my wore out old eyes. The fact that you guys saw other clear indications of wind lends much more credibility.

If we knew exactly where, the date and time, we could find out how much wind there was that day.

BTW, aquatic', thanks for posting it. I found it interesting.

Poor thing, it's trying so hard. Got to be like a bird trying to fly after having its wings clipped. :D

Without engines, the CG of the aircraft moves aft to a significant degree and, apparently, is just slightly forward of the main gear.

It wouldn't take much lift to bring the nose off the ground as was evidenced in the video.

Whether the wings would generate any lift at 70 kts. is the real question.

Typically, such an aircraft would never generate any lift until it rotates and it needs 120 kts. for sufficient downforce on the tail to effect rotation.

So, I'm a bit skeptical of the result.

of what result?

I'm also skeptical, but if the plane is as stripped down as some folks indicate, the wing loading would be so light, it wouldn't take a whole lot of wind.

If you look closely of a 747 in the background of the two the planes, you will see it is actually lifting also. But not as much as the one in the foreground.


Thanks Aquaticedge for posting this video.



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Neat! Looks like the rear tail wings (I don't know the term) are in the lift position, pushing down on the tail and using the wheels as the fulcrum, and of course the wings giving lift helps too.

Too bad it's been done already
http://www.youtube.com/watch?v=WcLJ49MGe-s

It should generate lift, the thing is it hasn't created enough to cause buoyancy on the whole airframe.
Its getting lift off the fuselage too.
The interior could be missing in the front cabin, you never know.

You'd think doing that it'd punch holes through the tarmac O_o

Actually they just fit some low-rider hydraulics to it and started it bouncing, then slowed the video way down to make it look like the wind did it. :P ;)

I just posted the video out of interest. Kinda poetic in a way :/ an airplane trying to fly free from being in a airliner graveyard :( kinda sad

Yes, I understand what you saw in it and that's why I thanked you for posting it. I enjoyed it.:D

I'm a bit skeptical about you. :eek::D:D:D

well, being that i am almost as old as dirt, i remember when the 747 first started flying. and, yes, it's kind of sad to see one stuck in the boneyard.

also - off topic - sad to know that there are very probably no extant, unmodified, airworthy 377/stratocruisers remaining. time marches on.

The flaps were also deployed which would help matters even further. Also for all we know they decided to gut in interior and store everything in the tail section :D

In reality, the wings cannot generate any lift with the airplane lacking rotation.

The real issue is the position of the elevators and the CG. If the CG is very close to the main gear, it only takes a bit of downforce on the tail to raise the nose.

If, as was suggested, the horizontal stabilizer was trimmed for nose up, a relatively low level wind (70 mph) could provide sufficient force to lift the nose.

The wings still generate no lift. They are essentially irrelevant in the equation.

Hmm... okay, then what generates lift in straight and level flight? Sure, it will generate more lift at a higher angle of attack, but it still generates lift with wings level. Acelerate down the runway and if you build enough speed with the fuselage level, it willl fly off the ground seemingly by itself.

It's just a matter of, is it ENOUGH lift? Also as the weight goes down the stall speed goes down because the wings don't have to overcome as much weight. They are much more lightly loaded.

You know, the old "lift = weight & thrust = drag" in straight and level steady speed flight thing.

Cheers:)

If you want to generate sufficient lift with the airplane with a perfectly zero pitch attitude, you'd need to have 250 kt. of speed or so.

I suppose the airplane can generate sufficient lift to offset its weight without any rotation. It might be possible at 250 kt. airspeed, but, effectively, that's not likely to happen.

In this situation, you don't need to lift the wings at all. If you simply push down on the tailplane with sufficient force, the nose will lift. The only question that begs is the amount of the force and whether a 70 mph wind can generate it.

Yes, indeed in a 747 it would take LOTS of speed to come off the runway in a level attitude. It ain't no Cessna for sure! Remember though, this is a plane at a fraction of Max Gross weight. The Vso and Vfe speeds will be Way lower than a complete plane.

Also remember that the tail section is an airfoil as well. Air flow both under and over the tail section will cause lift. Air pressure on the top of the elevator would create down force.

Anyway, regardless of whether it is for real or not, which I think it is, it's fun to watch.:)

Negative.

On these airliners, the tail section always generates downforce. It's the only thing that keeps the equilibrium in pitch.

The CG of any airliner must be forward of the center of lift. That's why the CG calculation is critical for every flight. The further forward the CG, the more downforce is required on the tailplane (and the more fuel is consumed due to drag).

Well I think I will politely withdraw from this discussion. As a licensed pilot I totally understand the forces involved with flight and calculate weight and balance before every flight, but I don't want this to turn into any sort of pissing match.

Very best regards,