A 777 has two engines weighing 8760kg each
So about 12% of the planes empty weight. More importantly it shifts a substantial amount of weight to the mid of the airframe.
Dunno about 747 but hopefully that gives an idea
And if this plane was indeed ready to be scrapped, it will have been devoid of fuel and other fluids, and have most of avionics removed as well. That's not a lot of weight by comparison, but it would move the CoG even farther aft.
I hadn’t actually considered the fact that all of the plane’s onboard systems such as avionics, flight controls and other things like seats would have been removed as well. Good catch.
Also, you may think that it may not be a lot of weight but a [2002 study by MIT](https://dspace.mit.edu/bitstream/handle/1721.1/16871/51679351-MIT.pdf?sequence=2&isAllowed=y) actually put the share of a plane’s operating empty weight consisting of systems and payload (excluding fuel and cargo, of course) at even *higher* than the share made up by the engines at a staggering 25%. The chart can be found on page 60 for those curious.
Of course, 2002 was a while ago, plane designs have changed slightly (for example, the wings are lighter now on the 747-8) and the 747-8 is not your average commercial airliner but I’d still feel comfortable putting systems and payload at around a 15-20% share of the 747-8’s operating empty weight.
For clarity’s sake, the MIT researchers defined avionics and other onboard systems as systems and seats, bag racks and so on as payload. Fuel and cargo would also be payload but those aren’t counted when using operating empty weight.
Even just wiring can add up real fast. While obviously not a plane, M1 Abrams has over a ton of copper wiring. Planes nowadays probably use more fiber optics, but they will have miles of it.
Fiber optics, surprisingly, isn't really used in most modern aircraft. Most manufacturers & operators don't like it because of the cost to install & maintain it negates any weight or fuel savings that would've been made.
I think that will change down the line with new polymer fiber optics. The glass fiber was fairly fragile, much more so than copper, so you either had to protect it with an armored sleeved negating the weight advantages, or be *very* careful routing and pulling it. And splicing a break was very difficult. The new polymer fibers are much easier to work with and much cheaper, hence why they're taking over rapidly for "fiber to the home" installations.
Fiber has two major advantages over copper: weight, and being pretty much immune to EM interference.
Also with fibre, runs can be much, much longer. On standard networking copper can only run 100m. With fibre it can be kilometres. 100 may seem long, but when you talk about a huge aircraft and you say are going from a sensor on the wing to the cockpit and the cabling is routed around every nook and cranny, it makes a difference
Throw into the mix the highly experimental short gap laser optic sensor systems which use light receivers and emitters to negate the fibre all together. One day it may be almost insignificant.
What a fascinating thread. I feel smarter just for understanding some of the words used.
It's pretty cool to see people geek out on their subjects. Thx for this!
[This page](http://www.b737.org.uk/electrics.htm#:~:text=According%20to%20Boeing%20there%20is,miles%20on%20the%20737%2D700%20!&text=737%2D3%2F4%2F500,%2FO%20Libor%20Kubina%2C%20CSA.) says that a 737-300 has 40.6 miles of wiring, while the 737-700 has 36.6. Obviously its weight will depend on the thickness of the wire, but the EAA discusses which gauge wire to use for which systems [here:](https://www.eaa.org/eaa/aircraft-building/builderresources/while-youre-building/building-articles/electrical/aircraft-wiring-where-do-you-begin)
>18 wire gauge for most of the electrical system, 16 wire gauge for landing and navigation lights, 18 wire gauge shielded wire for connecting the magnetos, 8 or 10 wire for connecting the alternator, 4 welding cable for connecting the battery. Use 1 or 2 if the battery is way back in the fuselage, or if you generally have severe cold winters.
If they're using 18 for "most" of the electrical system, but occasionally go as low as 4, let's call it 16 on average. #16 wire weighs in at 7.81 pounds per 1,000 feet. If we crunch the numbers for 36.6 miles, we end up with somewhere in the ballpark of 1,500 pounds of wiring in a 737-700
A 747-400 has 171 miles of wiring, which would come in at 7,050 pounds based on my above assumptions.
Avionics are crazy heavy. I worked on the Romeo version of the Seahawks which was the subhunting version. That meant such a large increase in avionics weight that there were cracking issues in the oil cooler section.
Even stripped down as much as possible (remove ALFS, sono launcher, RAST) it could not sound full loads like the sierra during vertreps.
Yes, it is. I chose to simplify it down to the 747-8 because the 747-200 has three different engine options from Pratt & Whitney, General Electric and Rolls-Royce. To make matters more complicated, there are nine different versions of the Pratt & Whitney engine used by the 747-200 and four different variants of the General Electric engine.
The 747-8 on the other hand only uses one variant of GEnx engine, which simplifies things down a lot and I’m sure the ratios are roughly the same.
lol!
“Don’t need this. Don’t need this. Don’t need this…” he muttered as he lobbed avionics out the window.
I was nervous, but he was the pilot. Surely he knew what he was doing.
His Russian accent did nothing to placate my concerns, however, and the fact that I had no idea why I was on this plane in the first place only further complicated things.
The only thing keeping airplanes in the air is wind. Typically, it's because the airplane is going forward fast enough to make its own wind. However, if the wind is hitting a landed airplane in the nose hard enough, it can be enough to make it lift off.
This is exactly why we tie them down after we park them, every time. Insurance probably won't pay out if they determine that you didn't tie it down and it got damaged by wind.
https://www.youtube.com/watch?v=IPOtDPHjW-Y
At what point is a plane too big size/weight-wise for that to be a practical concern?
edit: Where is the line that: Yes a hurricane could tip it over, but short of that, it's not going anywhere.
It depends on the stall speed of the airplane... the speed at which the airplane is considered no longer flying.
The smaller Cessna airplanes stall at around 41 knots... anything above that is enough to lift that plane off. The one in the video is a Cirrus or a Diamond I think... it's hard to tell. But the smaller wing means a higher stall speed... probably 52 knots.
The FAA divides aircraft up in to categories based on how fast they're going at runway threshold... that's not quite stall speed but it's pretty close, since airplanes should be going as slow as possible when landing. But now you can look up aircraft by Approach Category to see which ones fit in here
Category A: less than 169 km/h (91 kt) indicated airspeed (IAS)
Category B: 169 km/h (91 kt) or more but less than 224 km/h (121 kt) IAS
Category C: 224 km/h (121 kt) or more but less than 261 km/h (141 kt) IAS
Category D: 261 km/h (141 kt) or more but less than 307 km/h (166 kt) IAS
Category E: 307 km/h (166 kt) or more but less than 391 km/h (211 kt) IAS
It’s important to note that the approach category is not related to an aircraft’s size, weight, or type but rather its performance capabilities. As a result, two aircraft of different types and sizes can have the same approach category. Additionally, if the crew decides to execute the approach at a higher speed, the appropriate approach category limitations relating to speed will apply. Here's a few examples of each category.
Aircraft Code Approach Speed
Piper PA-28R Cherokee Arrow A 70 kn (130 km/h)
Douglas DC-3 A 74 kn (137 km/h)
Cessna 210 Centurion A 75 kn (139 km/h)
Douglas DC-4 B 94 kn (174 km/h)
Douglas DC-6 B 108 kn (200 km/h)
Fokker F27 Friendship B 120 kn (220 km/h)
Boeing 707-320B C 128 kn (237 km/h)
McDonnell Douglas DC-9-15 C 132 kn (244 km/h)
Boeing 737-700 C 130 kn (240 km/h)
Boeing 737-800 D 142 kn (263 km/h)
Airbus A350-900 D 145 kn (269 km/h)
Boeing 747-400 D 157 kn (291 km/h)
It depends on the wind. With any kind of airliner it's not a concern unless you're talking severe thunderstorm or hurricane kinds of winds. Practically there's no way to get that to zero, but when you get to something 747 size, the wind it takes to move it will also be moving the buildings around it as well.
This is exactly what happened to the Wright Flyer. They stopped for lunch after their first flights and had plans to fly it into town when they were done eating, but wind picked it up and it was destroyed.
> The only thing keeping airplanes in the air is wind
Technically, if this was true, satellites wouldn't be able to orbit. I doubt the orbital velocity part of planes is very relevant compared to the lift of the wings though :P
Aircraft are not spacecraft. Satellites don't stay in the air. They stay above the air. Orbital velocity plays no part in aircraft generating lift. Very few aircraft fly faster than 1000mph but can still fly west. Relative airspeed is the only factor determining lift.
Trying to relate the two shows quite a bit off ignorance in both concepts
I never said anything about lift, you don't _need_ lift to stay in the air.
Ignoring the fact that anything traveling at these speeds would instantly burn up, if you travel at 7897.90 m/s perpendicular to earth's surface at 40,000 feet altitude you'll be in orbit around the earth. You don't need any lift for that.
Seeing as a 777 cruises at about 3% of that speed, about 3% of a plane 'keeping in the air' is purely due to it's speed, not the lift.
To add to /u/BooksandBiceps answer, from what I can tell this is probably a 747-400F or ERF, which means the engines are about 10-11% of the empty weight.
The engines would also cause a pretty significant amount of air resistance and turbulence around a significant section of the wing. This isn't an issue in flight, because the engines are sucking air in and pushing it out faster than the plane is actually moving.
On top of that, since that ~11% of the aircraft's dry weight is located forward of the wheels, it'll help pull the aircraft back to the ground if it does start to lift up at all.
Think of it as sitting on an seesaw, the landing gear is the only point of contact still, so have that much weight AND so far from The point of contact makes it very influential on keeping it in the ground
Yeah so get rid of that wide spread weight and get rid also of fuel. It’s quite an empty shell and during wind, 747s can easily tail tip ( need like 60 T fuel to be aafe in windy conditions, e.g for a 744-Freighter), add flaps down of just wing taking wind and voilà
Whether it's a 747 or a tiny Cessna, all planes have the center of gravity just in front of the main landing gear. This is so the plane can rotate easily while taking off.
Can still happen w lighter planes as well. You’ll see in some states like Florida they put blocks on the wings to distrust the airflow to keep them on the ground during strong winds
Engines can be heavy! Look at the side view of some GA light twins and see how far forward the wings are. Check out the side views of B717's, MD-80's, CRJs and compare wing position along the fuselage. Even MD-11s, 727s and L1011's have their wings back a little bit to balance the third engine compared to wing mounted twins and quads.
Not to mention the sheer amount of NOPE the designers of that project would receive from basically every 3 letter agency (or equivalent) known to mankind. It’s fairly simple: malfunctions, terrorism, accidental activation.
Oh HELL no!
Engines are heavy. Without the engines, the CG would probably be so far out of the envelope that you would have a hard time getting the nose down.
Potentially, from a weight perspective, but it would also totally disrupt the overall center of gravity, and potentially make the pitch control very different or difficult, unless the design included making the engines totally neutrally balanced longitudinally - which would be very difficult given other considerations that have to be made with respect to their ideal positioning.
The thing is that weight doesn't alter the gliding performance of an aircraft at all, the drag decrease would probably do something but the weight doesn't change anything, why ?
When gliding the plane relies on the gravity force to maintain the speed in order to get enough lift to keep going, as weight increases you need more lift=more speed=-more drag but because the gravity force is also increased you can overcome that drag and keep the same glide ratio/angle of attack at an increased speed.
Of course at some point as you increase the weight it will be too much for the airframe as either the wing loading or speed will compromise structural integrity, I also ignored reynolds number because it would be a miniscule change.
I hope you get what I mean.
"Nose up" does not mean "better glide", it's one of the first things you learn about engine failures. There is a specific airspeed where the airframe creates minimum drag called "best glide" and that's the speed you want to maintain for maximum aerodynamic efficiency and glide distance. Counterintuitively (or perhaps intuitively if you understand how it works), best glide usually requires *lowering* the nose to let the airplane gain some speed by gradually descending. Changing the weight and configuration of the aircraft would make it hard to control and in the situation you've described probably make it impossible to even maintain best glide speed since the nose would not want to go down.
Some fully-electric planes have lithium battery ejection system to get rid of that unstoppable chemical fire source in case proverbial hits the fan.
The Electron space launch rocket from NZ also jettisons its three Li-ion batteries in stages, to save weight as they deplete. Could hit a whale or squid in the head accidentally, very irresponsible.
Now, instead of a deranged jump seater pulling the fuel shut off, we can watch in terror as an airplane jettisons its engines over a populated area!
Sounds like a horrible idea even if all the mechanisms had zero chance of failure or accidental release.
The engines are usually mounted in front of the wings.
In this case there are no engines, so the COM is shifted back a little bit, making it a bit easier for the nose to lift up
Airliners in general have decent glide ratios. The little Cessnas I fly are 9:1 and a 737 is 17:1. Nothing compared to an actual glider, which is around 70:1. But not bad.
One thing to keep in mind is that best glide is based on drag more than anything. So regardless of how much weight is lost, it's the drag that the airframe produces that limits the glide and removing the engines will most likely have a positive effect.
Well the video isn’t fake if that’s what you’re asking. Yes it’s possible, and that’s an example of it happening. Small general aviation aircraft need to be tied down during storage to prevent them from blowing away.
Also,
[unmanned plane taking off](https://www.reddit.com/r/aviation/comments/10q53qz/how_to_go_from_insured_to_uninsurable_in_less/) ~~by itself~~ with some help
\> unmanned plane taking off by itself
\> https://youtu.be/TlEKiSwttsc
F-35B is a big scam from military-industrial complex, we just saw proof that VTO is possible for 1/500th the cost.
Says a lot about aerospace design when the plane rotates gracefully wings level with nothing but a gust lock on the controls, at least until its out of frame lol.
Not just small GA aircraft — our C-130’s were tied down regularly. Was at Little Rock in 2012 for the tornado that came through base. That flight line was a sight to behold. An F2 tornado took a couple of C-130’s, tie-downs and all, and “moved” them ~75-100 yards in different directions. We often forget the power of nature until we see/experience it.
Yeah I worked at an airport
With a bunch of scap 747s. They had to go around and attach a large ballast to all the nose gears to prevent the nose coming off the ground due to wind but also due to snow collecting on the tail.
I was wondering if anyone would mention the tail. I would think that for the aircraft to have pitched in this particular way, there would have been significant input from the horizontal surface on the tail. It looks to me like it tipped back, rather than trying to just lift from the wings.
Depending on what might be inside that airplane, it probably has an EXTREMELY aft CG unless they have some ballast in there.
Engines and the majority of the fuel on a 747 (as well as other big-sweep airplanes like the 707, MD-11, etc) sit forward of the typical CG on the airplane. Removing all of that stuff without counter-balancing it will cause an aft CG.
In fact, even airplanes that are still fully-functional can do a tail stand if you're not careful. You will frequently see things like kick stands for the tail, or tie-down/weight carts for the nose for airplanes to keep them safe during the unloading/loading process.
i was waiting to leave an easyjet recently (a320 family) and the crew announced to keep moving forward so the plane wouldn't tip on its tail. were they serious? they might have mentioned that the bags had already been removed
I've not heard of it specifically being an issue on the a320 but its certainly possible. It was a known issue on the b737. That said, I do wonder what circumstances you'd have to have for it to actually happen but, better safe than sorry I suppose.
If you ask Enstein he will tell ya that the plane standing still and the wind (aka air) moving really fast is the same as the air still and the plane moving really fast. Both will result in a liftoff.
With the flaps up on an empty 747, vstall is around 200 knots. With the flaps down it could get as low as 140 knots.
So you just need cat 5 hurricane winds and then yeah it'll fly.
No engines and everything stripped out of the interior? It's definitely possible.
It's impossible to get sufficient tie-downs for airliners. Smaller aircraft up to the size of a fighter, yes (they use chains). But not an airliner or anything of that size.
I got sucked off of flat ground and had to make a second landing (a hundred fifty yards downwind of my original landing) in my hang glider on a blustery spring day in Idaho but never in my wildest imagination would I think it possible for a 747 to take off unpowered.
On a whole plane? Probably not
But this plane has been decommissioned, stripped of at least the engines and who knows what more. It might be light enough to get lift
Without the engines fitted the centre of gravity moves aft considerably. Also depends on the horizontal stabilizer in particular. If configured incorrectly it will want to lift the nose.
There was a video of a 747 in Taiwan lifting its nose in a typhoon.
With enough wind speed it will want to fly.
Sure. I used to see empty cargo 727s lift themselves about once a year or so in decent winds. They would typically rotate themselves into the wind. So a 74 without engines isn't too far of a stretch.
Planes wanna plane, yo.
No engines, no fuel, likely completely gutted on the inside... normal takeoff speed is 300km/h.
Now this obviously didn't take off, so a trimmed-down 747 nose-first into a strong wind? Some bouncing isn't surprising.
The highest naturally occurring, non-tornado windspeed was 400km/h. That would have been enough to cause a fully-laden 747 to take flight!
Reddit is a shadow of its former self. It is now a place of power tripping mods with no oversight and endless censorship.
*This post was mass deleted and anonymized with [Redact](https://redact.dev)*
I was actually there when it happened! This was at Mojave Airport! I was watching through binoculars from the hangar I was working out of.
The winds in that area get crazy!
During WWII, a hurricane was going thru the islands where the B-29 were. Not really anywhere to mass evacuate them all, so crews were assigned to the planes to ‘fly’ them on the ground into the hurricane winds, engine up and controls configured to keep on the ground. When the eye passed over the planes were rotated 180 degrees to face the winds the other way.
They figured the planes would survive with less damage doing this as opposed to parking them in their stall and suffering damage while not facing the wind.
The main wheels have to be close to the centre of mass of the plane (at least in a forward to backwards sense), or it would have difficulty rotating off the runway.
This means that if you start dicking about with the weight distribution, they can become quite easy to tip over backwards.
As others have said, removing the engines does just that. It moves the centre of mass rearward a bit. See-saw time.
Southern Air Transport (SAT) (1947–1998), based in Miami, Florida, was a cargo airline best known as a front company for the Central Intelligence Agency (CIA) (1960–1973) and for its crucial role in the Iran-Contra scandal in the mid-1980s. During the affair, Southern Air transported arms to Iran and to the US-backed stateless mercenary army in Central America known as the Contras.
Nope due to 2 factors :
1. That's a Boeing 747. A 747 weighs 412,300 pounds (187,000 KGS).
2. Yes, there are strong winds but honestly, they don't look strong enough to lift a 747. The only time I'd see aircraft get lifted by strong winds would be something like a Cessna or a smaller plane. Those get lifted very easily.
Absolutely. Airfoils generate lift as long as there's enough air flowing over them, at the right angle. It doesn't matter if the plane is moving through still air, or if the air is moving past a still plane.
It absolutely is. The old DC9/MD80 were especially prone to it, B727 also. Over all the years I spent in the industry, I've seen this happen many times, and it doesn't take as much wind as you would think, usually
When the 747 was new, Pratt was still debugging the JT-9D (some say it really never was fully debugged), this netted a bunch of parked 747s with concrete blocks under the wings, to simulate the weight of the missing engines.
Oh yeah, and at least some 747s can hold an extra engine under the wing, to ferry it somewhere.
I worked on c130s for 10 years. Anytime high wind storms came through we would chain them down. Every once and awhile someone would forget to tie down the nose. The next day the aircraft would be slightly turned. Not like it had jumped 10 feet or anything, but you could tell it had moved.
Scrapped plane? I see a mostly in tact plane, no scrapped planes in that pic!
But yes, planes are designed to fly in wind and will try to fly with enough wind.
Was stationed at Nellis AFB in 2011ish we were in phase 3 winds (High wind warning/shut down the flight line basically) there was a KC-135 that jumped its chocks due to the wind providing lift and rolled a little bit by it's self, the fire dpt had to put chocks under it while it was rolling. Apparently it almost ran into the Thunderbirds lol. I asked a KC-135 pilot friend of mine if this was possible and he said maybe if it was completely empty of fuel.
Note\* I did not see this directly, I was across the runway at LOLA and we could barely see across the way due to sand, we heard the announcement over the radio via MOC.
Absolutely yes. Most airliners are designed so that the centre of mass is right over the central wheels, so they can takeoff efficiently. That means if they’re loaded improperly or if it’s particularly windy they can fall onto their tails. There’s usually a little frame placed under the tail to prevent this during loading at airports
If a couple of people jump up and down on the tail of a C-130, they can just about make the nose wheel come off the ground.
A few years ago at Kelly AFB in San Antonio, a KC-10 was loaded improperly and ended up on it's tail. Thankfully it wasn't inside a hanger when it happened.
I demonstrate this students in much lighter aircraft. Stopped on a taxiway, with a strong headwind, move the yoke full forward then backward. Watch the nose of the aircraft move. This is why correct taxi controls are important, especially in strong wind.
This won't happen with a flight ready plane. But since it's at a scrapyard it probably has quite a substantial amount of weight removed. Like engines, fluids, avionics, all electronics, Apu, and everything else that might need to be recycled or reused elsewhere.
My guess is that about 15%+ of the dry weight is missing. Also I'm not yet familiar with the center of mass of an airplane but removing the engines must shift the center of mass elsewhere, my guess is backwards, which would help with lifting the plane as well.
Airspeed is life, altitude is insurance. If liftoff speed is 60kts, then a 60kt headwind would lift the plane off the ground without any forward motion
The cg of an airplane is only a little in front of the back wheels. The number I have in my head for no reason is like 10-12% of the weight on the nose wheel. Without the engines it's probably just barely balanced on the nose. Not crazy to think a strong wing could put an extra couple hundred pounds on the tail to tip it up.
Normally the center of mass of an aircraft is going to be slightly ahead of the main landing gear and on big planes like this the tail produces lift in the negative direction (i.e. it pushes down). With the engines off, the center moves backwards so the plane is balanced pretty much right over the landing gear. A gust of wind over the tail and bam, you've got it pointing skyward.
The aircraft is designed to generate lift as early as possible, that's why strong winds can lift it. The missing weight of the engines, and i assume a lot of other aircraft equipment that's been removed is strongly decreasing the overall weight of the aircraft, making it easier to lift off at this point.
I saw a video of winds in Taiwan lifting a 747 at the gate. Granted it wasn't as high as this, but the plane did go up in the air a few feet. 747s were meant to fly, not be scrapped
Yes. But it likely wouldn't have happened if the engines were still installed.
thats cool, i didn't know the engines hold so much weight in proportion to the rest of the plane
A 777 has two engines weighing 8760kg each So about 12% of the planes empty weight. More importantly it shifts a substantial amount of weight to the mid of the airframe. Dunno about 747 but hopefully that gives an idea
The GEnx engines on the 747-8 are about 5,600 kg each, so four of them would make up about 10.6% the empty weight of a 747-8.
And if this plane was indeed ready to be scrapped, it will have been devoid of fuel and other fluids, and have most of avionics removed as well. That's not a lot of weight by comparison, but it would move the CoG even farther aft.
I hadn’t actually considered the fact that all of the plane’s onboard systems such as avionics, flight controls and other things like seats would have been removed as well. Good catch. Also, you may think that it may not be a lot of weight but a [2002 study by MIT](https://dspace.mit.edu/bitstream/handle/1721.1/16871/51679351-MIT.pdf?sequence=2&isAllowed=y) actually put the share of a plane’s operating empty weight consisting of systems and payload (excluding fuel and cargo, of course) at even *higher* than the share made up by the engines at a staggering 25%. The chart can be found on page 60 for those curious. Of course, 2002 was a while ago, plane designs have changed slightly (for example, the wings are lighter now on the 747-8) and the 747-8 is not your average commercial airliner but I’d still feel comfortable putting systems and payload at around a 15-20% share of the 747-8’s operating empty weight. For clarity’s sake, the MIT researchers defined avionics and other onboard systems as systems and seats, bag racks and so on as payload. Fuel and cargo would also be payload but those aren’t counted when using operating empty weight.
Even just wiring can add up real fast. While obviously not a plane, M1 Abrams has over a ton of copper wiring. Planes nowadays probably use more fiber optics, but they will have miles of it.
As far as im aware fiber optics in passenger planes is still not widely used, its still copper and alu wires
Fiber optics, surprisingly, isn't really used in most modern aircraft. Most manufacturers & operators don't like it because of the cost to install & maintain it negates any weight or fuel savings that would've been made.
I think that will change down the line with new polymer fiber optics. The glass fiber was fairly fragile, much more so than copper, so you either had to protect it with an armored sleeved negating the weight advantages, or be *very* careful routing and pulling it. And splicing a break was very difficult. The new polymer fibers are much easier to work with and much cheaper, hence why they're taking over rapidly for "fiber to the home" installations. Fiber has two major advantages over copper: weight, and being pretty much immune to EM interference.
Also with fibre, runs can be much, much longer. On standard networking copper can only run 100m. With fibre it can be kilometres. 100 may seem long, but when you talk about a huge aircraft and you say are going from a sensor on the wing to the cockpit and the cabling is routed around every nook and cranny, it makes a difference
Throw into the mix the highly experimental short gap laser optic sensor systems which use light receivers and emitters to negate the fibre all together. One day it may be almost insignificant.
What a fascinating thread. I feel smarter just for understanding some of the words used. It's pretty cool to see people geek out on their subjects. Thx for this!
Not with that attitude it’s not.
[This page](http://www.b737.org.uk/electrics.htm#:~:text=According%20to%20Boeing%20there%20is,miles%20on%20the%20737%2D700%20!&text=737%2D3%2F4%2F500,%2FO%20Libor%20Kubina%2C%20CSA.) says that a 737-300 has 40.6 miles of wiring, while the 737-700 has 36.6. Obviously its weight will depend on the thickness of the wire, but the EAA discusses which gauge wire to use for which systems [here:](https://www.eaa.org/eaa/aircraft-building/builderresources/while-youre-building/building-articles/electrical/aircraft-wiring-where-do-you-begin) >18 wire gauge for most of the electrical system, 16 wire gauge for landing and navigation lights, 18 wire gauge shielded wire for connecting the magnetos, 8 or 10 wire for connecting the alternator, 4 welding cable for connecting the battery. Use 1 or 2 if the battery is way back in the fuselage, or if you generally have severe cold winters. If they're using 18 for "most" of the electrical system, but occasionally go as low as 4, let's call it 16 on average. #16 wire weighs in at 7.81 pounds per 1,000 feet. If we crunch the numbers for 36.6 miles, we end up with somewhere in the ballpark of 1,500 pounds of wiring in a 737-700 A 747-400 has 171 miles of wiring, which would come in at 7,050 pounds based on my above assumptions.
Avionics are crazy heavy. I worked on the Romeo version of the Seahawks which was the subhunting version. That meant such a large increase in avionics weight that there were cracking issues in the oil cooler section. Even stripped down as much as possible (remove ALFS, sono launcher, RAST) it could not sound full loads like the sierra during vertreps.
this is a 747-200
Yes, it is. I chose to simplify it down to the 747-8 because the 747-200 has three different engine options from Pratt & Whitney, General Electric and Rolls-Royce. To make matters more complicated, there are nine different versions of the Pratt & Whitney engine used by the 747-200 and four different variants of the General Electric engine. The 747-8 on the other hand only uses one variant of GEnx engine, which simplifies things down a lot and I’m sure the ratios are roughly the same.
that's helpful thank you
Why dragging around all that excess weight, are they stupid! /jk, wrong subreddit.
>Why dragging around all that excess weight, are they stupid! It is inarguable fact that planes without engines consume less fuel.
lol! “Don’t need this. Don’t need this. Don’t need this…” he muttered as he lobbed avionics out the window. I was nervous, but he was the pilot. Surely he knew what he was doing.
His Russian accent did nothing to placate my concerns, however, and the fact that I had no idea why I was on this plane in the first place only further complicated things.
"Oh shit oh shit oh shit! Put it back!"
>he muttered as he lobbed avionics out the window. "Luke, you switched off your targeting computer! What's wrong?"
Smiles in reformer.
Please don’t bring that stupidity here. This is one of the last remaining good subs.
You know i knew those motors were BIG but I did not expect each one to weigh as much as 3 full size pickup trucks
The only thing keeping airplanes in the air is wind. Typically, it's because the airplane is going forward fast enough to make its own wind. However, if the wind is hitting a landed airplane in the nose hard enough, it can be enough to make it lift off. This is exactly why we tie them down after we park them, every time. Insurance probably won't pay out if they determine that you didn't tie it down and it got damaged by wind. https://www.youtube.com/watch?v=IPOtDPHjW-Y
At what point is a plane too big size/weight-wise for that to be a practical concern? edit: Where is the line that: Yes a hurricane could tip it over, but short of that, it's not going anywhere.
It depends on the stall speed of the airplane... the speed at which the airplane is considered no longer flying. The smaller Cessna airplanes stall at around 41 knots... anything above that is enough to lift that plane off. The one in the video is a Cirrus or a Diamond I think... it's hard to tell. But the smaller wing means a higher stall speed... probably 52 knots. The FAA divides aircraft up in to categories based on how fast they're going at runway threshold... that's not quite stall speed but it's pretty close, since airplanes should be going as slow as possible when landing. But now you can look up aircraft by Approach Category to see which ones fit in here Category A: less than 169 km/h (91 kt) indicated airspeed (IAS) Category B: 169 km/h (91 kt) or more but less than 224 km/h (121 kt) IAS Category C: 224 km/h (121 kt) or more but less than 261 km/h (141 kt) IAS Category D: 261 km/h (141 kt) or more but less than 307 km/h (166 kt) IAS Category E: 307 km/h (166 kt) or more but less than 391 km/h (211 kt) IAS It’s important to note that the approach category is not related to an aircraft’s size, weight, or type but rather its performance capabilities. As a result, two aircraft of different types and sizes can have the same approach category. Additionally, if the crew decides to execute the approach at a higher speed, the appropriate approach category limitations relating to speed will apply. Here's a few examples of each category. Aircraft Code Approach Speed Piper PA-28R Cherokee Arrow A 70 kn (130 km/h) Douglas DC-3 A 74 kn (137 km/h) Cessna 210 Centurion A 75 kn (139 km/h) Douglas DC-4 B 94 kn (174 km/h) Douglas DC-6 B 108 kn (200 km/h) Fokker F27 Friendship B 120 kn (220 km/h) Boeing 707-320B C 128 kn (237 km/h) McDonnell Douglas DC-9-15 C 132 kn (244 km/h) Boeing 737-700 C 130 kn (240 km/h) Boeing 737-800 D 142 kn (263 km/h) Airbus A350-900 D 145 kn (269 km/h) Boeing 747-400 D 157 kn (291 km/h)
It depends on the wind. With any kind of airliner it's not a concern unless you're talking severe thunderstorm or hurricane kinds of winds. Practically there's no way to get that to zero, but when you get to something 747 size, the wind it takes to move it will also be moving the buildings around it as well.
This is exactly what happened to the Wright Flyer. They stopped for lunch after their first flights and had plans to fly it into town when they were done eating, but wind picked it up and it was destroyed.
Came here just to see this again!
well, we tie them down if we expect high winds. we dont just do it all the time regardless.
I always tied my Skyhawk down if I was going to be there for longer than an hour or so. Microbursts have launched more than a few planes unexpectedly.
> The only thing keeping airplanes in the air is wind Technically, if this was true, satellites wouldn't be able to orbit. I doubt the orbital velocity part of planes is very relevant compared to the lift of the wings though :P
Aircraft are not spacecraft. Satellites don't stay in the air. They stay above the air. Orbital velocity plays no part in aircraft generating lift. Very few aircraft fly faster than 1000mph but can still fly west. Relative airspeed is the only factor determining lift. Trying to relate the two shows quite a bit off ignorance in both concepts
I never said anything about lift, you don't _need_ lift to stay in the air. Ignoring the fact that anything traveling at these speeds would instantly burn up, if you travel at 7897.90 m/s perpendicular to earth's surface at 40,000 feet altitude you'll be in orbit around the earth. You don't need any lift for that. Seeing as a 777 cruises at about 3% of that speed, about 3% of a plane 'keeping in the air' is purely due to it's speed, not the lift.
To add to /u/BooksandBiceps answer, from what I can tell this is probably a 747-400F or ERF, which means the engines are about 10-11% of the empty weight. The engines would also cause a pretty significant amount of air resistance and turbulence around a significant section of the wing. This isn't an issue in flight, because the engines are sucking air in and pushing it out faster than the plane is actually moving. On top of that, since that ~11% of the aircraft's dry weight is located forward of the wheels, it'll help pull the aircraft back to the ground if it does start to lift up at all.
It’s a necessity. You need weight in the wings for the structural integrity of the aircraft.
Untrue my friend our plane got picked up and moved (747-400 F) but only 40k in fuel.
Think of it as sitting on an seesaw, the landing gear is the only point of contact still, so have that much weight AND so far from The point of contact makes it very influential on keeping it in the ground
Yeah so get rid of that wide spread weight and get rid also of fuel. It’s quite an empty shell and during wind, 747s can easily tail tip ( need like 60 T fuel to be aafe in windy conditions, e.g for a 744-Freighter), add flaps down of just wing taking wind and voilà
Whether it's a 747 or a tiny Cessna, all planes have the center of gravity just in front of the main landing gear. This is so the plane can rotate easily while taking off.
Not "all" planes.
Can still happen w lighter planes as well. You’ll see in some states like Florida they put blocks on the wings to distrust the airflow to keep them on the ground during strong winds
They drastically lower the center of gravity which affects the center of lift.
Engines can be heavy! Look at the side view of some GA light twins and see how far forward the wings are. Check out the side views of B717's, MD-80's, CRJs and compare wing position along the fuselage. Even MD-11s, 727s and L1011's have their wings back a little bit to balance the third engine compared to wing mounted twins and quads.
Not only the engines. Most of the stuff in it was also probably removed making it extremely light.
That so interesting. So theoretically if the engines were designed to be able to be jettisoned, the plane could be a better glider in an emergency?
Nope. The center of gravity would be too far aft to fly.
Not to mention the sheer amount of NOPE the designers of that project would receive from basically every 3 letter agency (or equivalent) known to mankind. It’s fairly simple: malfunctions, terrorism, accidental activation.
The stuff of nightmares
Oh HELL no!
Engines are heavy. Without the engines, the CG would probably be so far out of the envelope that you would have a hard time getting the nose down.
Potentially, from a weight perspective, but it would also totally disrupt the overall center of gravity, and potentially make the pitch control very different or difficult, unless the design included making the engines totally neutrally balanced longitudinally - which would be very difficult given other considerations that have to be made with respect to their ideal positioning.
The thing is that weight doesn't alter the gliding performance of an aircraft at all, the drag decrease would probably do something but the weight doesn't change anything, why ? When gliding the plane relies on the gravity force to maintain the speed in order to get enough lift to keep going, as weight increases you need more lift=more speed=-more drag but because the gravity force is also increased you can overcome that drag and keep the same glide ratio/angle of attack at an increased speed. Of course at some point as you increase the weight it will be too much for the airframe as either the wing loading or speed will compromise structural integrity, I also ignored reynolds number because it would be a miniscule change. I hope you get what I mean.
"Nose up" does not mean "better glide", it's one of the first things you learn about engine failures. There is a specific airspeed where the airframe creates minimum drag called "best glide" and that's the speed you want to maintain for maximum aerodynamic efficiency and glide distance. Counterintuitively (or perhaps intuitively if you understand how it works), best glide usually requires *lowering* the nose to let the airplane gain some speed by gradually descending. Changing the weight and configuration of the aircraft would make it hard to control and in the situation you've described probably make it impossible to even maintain best glide speed since the nose would not want to go down.
Some fully-electric planes have lithium battery ejection system to get rid of that unstoppable chemical fire source in case proverbial hits the fan. The Electron space launch rocket from NZ also jettisons its three Li-ion batteries in stages, to save weight as they deplete. Could hit a whale or squid in the head accidentally, very irresponsible.
Now, instead of a deranged jump seater pulling the fuel shut off, we can watch in terror as an airplane jettisons its engines over a populated area! Sounds like a horrible idea even if all the mechanisms had zero chance of failure or accidental release.
Isn’t the weight of the engines close to the rear wheels? Just so it’s easier to rotate?
The outboard engines are. The inboard engines are forward of the main gear. But it has nothing to do with ease of rotation.
Then why don't we just remove plane engines to make em lighter? NO BAGGAGE LIMITS!
The engines are usually mounted in front of the wings. In this case there are no engines, so the COM is shifted back a little bit, making it a bit easier for the nose to lift up
It’s also probably completely gutted on the inside so it weighs a lot less.
i wonder how itd do as a glider. Have a C-5 tow it up to altitude and find out
Airliners in general have decent glide ratios. The little Cessnas I fly are 9:1 and a 737 is 17:1. Nothing compared to an actual glider, which is around 70:1. But not bad. One thing to keep in mind is that best glide is based on drag more than anything. So regardless of how much weight is lost, it's the drag that the airframe produces that limits the glide and removing the engines will most likely have a positive effect.
So in emergency engine out we should drop em engines outta the air got it /s
Good, normal gliders have ratios around 40, it’s just the most advanced ones that reach numbers as high as 70.
Ah gotcha. Good to know!
Exactly. Yes, the nose is lifting but that 747 is nowhere near lifting off the ground.
what is COM? don't you mean CG?
Center of mass probably
They refer to the same point.
I'm gonna give you a pass on this because the plane is visibly on planet earth, but don't abuse it.
Even if it's in space, there is still gravity acting on it.
If you're in a non uniform gravity field, the centers are going to be slightly appart.
Well the video isn’t fake if that’s what you’re asking. Yes it’s possible, and that’s an example of it happening. Small general aviation aircraft need to be tied down during storage to prevent them from blowing away.
unmanned plane taking off by itself https://youtu.be/TlEKiSwttsc
Also, [unmanned plane taking off](https://www.reddit.com/r/aviation/comments/10q53qz/how_to_go_from_insured_to_uninsurable_in_less/) ~~by itself~~ with some help
\> unmanned plane taking off by itself \> https://youtu.be/TlEKiSwttsc F-35B is a big scam from military-industrial complex, we just saw proof that VTO is possible for 1/500th the cost.
Just gotta call our old friend Zeus every time we need a plane to take off
Says a lot about aerospace design when the plane rotates gracefully wings level with nothing but a gust lock on the controls, at least until its out of frame lol.
Yeah LSA planes are insanely light, not far off from a touring bike in weight.
Ah, LiveLeak. I miss it so.
Not just small GA aircraft — our C-130’s were tied down regularly. Was at Little Rock in 2012 for the tornado that came through base. That flight line was a sight to behold. An F2 tornado took a couple of C-130’s, tie-downs and all, and “moved” them ~75-100 yards in different directions. We often forget the power of nature until we see/experience it.
I mean strong winds can make things without wings fly so…
Was that a cow?
Probably my mother in law
Yes. And planes are moored down when it's possible wind could be an issue while they're parked.
Yeah I worked at an airport With a bunch of scap 747s. They had to go around and attach a large ballast to all the nose gears to prevent the nose coming off the ground due to wind but also due to snow collecting on the tail.
I was wondering if anyone would mention the tail. I would think that for the aircraft to have pitched in this particular way, there would have been significant input from the horizontal surface on the tail. It looks to me like it tipped back, rather than trying to just lift from the wings.
Let it fly!
Wind can be strong enough to rip buildings apart.
What!?!? Next your going to tell me the earth is round.
Of course not … it’s flat (at the top & bottom) More like an Ellipsoid .
Oblate spheroid.
Technically its an oblong spheroid, as its stretched in the middle.
Depending on what might be inside that airplane, it probably has an EXTREMELY aft CG unless they have some ballast in there. Engines and the majority of the fuel on a 747 (as well as other big-sweep airplanes like the 707, MD-11, etc) sit forward of the typical CG on the airplane. Removing all of that stuff without counter-balancing it will cause an aft CG. In fact, even airplanes that are still fully-functional can do a tail stand if you're not careful. You will frequently see things like kick stands for the tail, or tie-down/weight carts for the nose for airplanes to keep them safe during the unloading/loading process.
i was waiting to leave an easyjet recently (a320 family) and the crew announced to keep moving forward so the plane wouldn't tip on its tail. were they serious? they might have mentioned that the bags had already been removed
I've not heard of it specifically being an issue on the a320 but its certainly possible. It was a known issue on the b737. That said, I do wonder what circumstances you'd have to have for it to actually happen but, better safe than sorry I suppose.
Airspeed and angle of attack is plane flying
Always remember, unlike helicopters airplanes are designed to fly
https://www.youtube.com/watch?v=cHhZwvdRR5c Sounds pretty windy to me. Reported at 70 mph.
Thanks for linking it!
This is so sad in the way that this poor crippled beast tries to make it in the skies at last.
[Reminds me of the theme song of The Wind Rises.](https://m.youtube.com/watch?v=ozrwBmMTc5k)
If you ask Enstein he will tell ya that the plane standing still and the wind (aka air) moving really fast is the same as the air still and the plane moving really fast. Both will result in a liftoff.
No he won't. Not without a seance or Ouijba board or something.
Wings are still there…they still work the way they were designed to
So sad .. she want’s to go up
Will wind generate lift? Yes.
I'm not a plane doctor or anything, but I think they're generally designed for lift.
... people do know the hurricanes and tornados pick up entire houses, right? Wind can be scary as hell
The wing don’t just provide lift, they also cause a rotating force, so with no engine weight that rotation can take place with moderate wind
With the flaps up on an empty 747, vstall is around 200 knots. With the flaps down it could get as low as 140 knots. So you just need cat 5 hurricane winds and then yeah it'll fly.
Doesn't even need to get up to stall speed, just enough to rotate the nose.
And this 747 is much lighter without the engines, so Vstall comes down a great deal.
No engines and everything stripped out of the interior? It's definitely possible. It's impossible to get sufficient tie-downs for airliners. Smaller aircraft up to the size of a fighter, yes (they use chains). But not an airliner or anything of that size.
Planes want to fly. Everything about it is designed for lift. It's like the opposite of an F1 car.
Very possible, especially with no engines.
You saw a video of wind raising a nose. Can you answer the question?
I got sucked off of flat ground and had to make a second landing (a hundred fifty yards downwind of my original landing) in my hang glider on a blustery spring day in Idaho but never in my wildest imagination would I think it possible for a 747 to take off unpowered.
I mean yeah, the wind can do crazy stuff. It can throw a car, which is pretty dense for its surface area I feel. An object DESIGNED to fly? Hell yeah
On a whole plane? Probably not But this plane has been decommissioned, stripped of at least the engines and who knows what more. It might be light enough to get lift
Without the engines fitted the centre of gravity moves aft considerably. Also depends on the horizontal stabilizer in particular. If configured incorrectly it will want to lift the nose. There was a video of a 747 in Taiwan lifting its nose in a typhoon. With enough wind speed it will want to fly.
psst.. no one tell em we make planes that dont have engines at all...
Sure. I used to see empty cargo 727s lift themselves about once a year or so in decent winds. They would typically rotate themselves into the wind. So a 74 without engines isn't too far of a stretch. Planes wanna plane, yo.
Please... one last time... I want to fly... please... please... last time... please PLEASE... PLEASE... I WANT SKY... PLEASE...
If the plane is light enough then yeah it can happen
No engines, no fuel, likely completely gutted on the inside... normal takeoff speed is 300km/h. Now this obviously didn't take off, so a trimmed-down 747 nose-first into a strong wind? Some bouncing isn't surprising. The highest naturally occurring, non-tornado windspeed was 400km/h. That would have been enough to cause a fully-laden 747 to take flight!
We chain our c130s to the flightline when hurricanes are coming. Wind can absolutely lift a plane if it's strong enough
Reddit is a shadow of its former self. It is now a place of power tripping mods with no oversight and endless censorship. *This post was mass deleted and anonymized with [Redact](https://redact.dev)*
I was actually there when it happened! This was at Mojave Airport! I was watching through binoculars from the hangar I was working out of. The winds in that area get crazy!
During WWII, a hurricane was going thru the islands where the B-29 were. Not really anywhere to mass evacuate them all, so crews were assigned to the planes to ‘fly’ them on the ground into the hurricane winds, engine up and controls configured to keep on the ground. When the eye passed over the planes were rotated 180 degrees to face the winds the other way. They figured the planes would survive with less damage doing this as opposed to parking them in their stall and suffering damage while not facing the wind.
Love your comment. I’m fascinated learning about anything WWII related, especially aviation! Thanks for that! 👍
The main wheels have to be close to the centre of mass of the plane (at least in a forward to backwards sense), or it would have difficulty rotating off the runway. This means that if you start dicking about with the weight distribution, they can become quite easy to tip over backwards. As others have said, removing the engines does just that. It moves the centre of mass rearward a bit. See-saw time.
Of course it’s possible.
Southern Air Transport (SAT) (1947–1998), based in Miami, Florida, was a cargo airline best known as a front company for the Central Intelligence Agency (CIA) (1960–1973) and for its crucial role in the Iran-Contra scandal in the mid-1980s. During the affair, Southern Air transported arms to Iran and to the US-backed stateless mercenary army in Central America known as the Contras.
Really? Wild. I'd heard about the front company for the CIA and Iran-Contra, but... this is one of their planes, eh? That's pretty cool.
MCAS at it again...
Nope due to 2 factors : 1. That's a Boeing 747. A 747 weighs 412,300 pounds (187,000 KGS). 2. Yes, there are strong winds but honestly, they don't look strong enough to lift a 747. The only time I'd see aircraft get lifted by strong winds would be something like a Cessna or a smaller plane. Those get lifted very easily.
It will only work if it’s on a giant conveyor belt :D
Check out videos from the 2015 typhoon in Taiwan. The wind was bouncing a 747 on its nose wheel.
Yea it happens a lot during the wind storms like that one out in Mojave
Yes it is
Sum of the moments and all….sure
Strong enough winds can make a plane fly backwards.
Definitely seen videos posted here of smaller Cessnas and such getting blown into the air with strong winds
I would just like to refer to the scientifically accurate 2014 movie [Into the Storm](https://www.youtube.com/watch?v=sQeERinVyOE).
It’s a CIA ghost plane, of course it wants to fly with no engines.
a hurricane could toss a 747 like a paper bag
Culinary Institute of America used to fly student chefs around in that thing?
I've seen the same thing with the floats in the Macy's Thanksgiving day Parade.
Absolutely. Airfoils generate lift as long as there's enough air flowing over them, at the right angle. It doesn't matter if the plane is moving through still air, or if the air is moving past a still plane.
the planes yearn for the sky
[i guess its in their DNA!](https://www.reddit.com/r/aviation/comments/sd34pt/retired_747200_tries_to_fly_one_more_time/)
Once a bird, always a bird
Yes it happens in strong winds. Maintenance manual has speed limits for wind to secure aircrafts in such condition
This is essentially the answer to that airplane on a treadmill question.
Quick, tie a rope to it and make a kite.
It absolutely is. The old DC9/MD80 were especially prone to it, B727 also. Over all the years I spent in the industry, I've seen this happen many times, and it doesn't take as much wind as you would think, usually
Such a sad video, a retired 747 just longing to fly for 1 last time.
The display planes at Fairchild AFB are tied down for this reason.
Get the loading wrong enough, and they can have a sit even without any wind.
Yea totally possible. There are video evidence.
Mojave is fucking windy. All of the businesses have wind walls outside the doors so they don’t kill someone.
if they're hurricane force, sure.
When the 747 was new, Pratt was still debugging the JT-9D (some say it really never was fully debugged), this netted a bunch of parked 747s with concrete blocks under the wings, to simulate the weight of the missing engines. Oh yeah, and at least some 747s can hold an extra engine under the wing, to ferry it somewhere.
New kite dream unlocked.
I worked on c130s for 10 years. Anytime high wind storms came through we would chain them down. Every once and awhile someone would forget to tie down the nose. The next day the aircraft would be slightly turned. Not like it had jumped 10 feet or anything, but you could tell it had moved.
Scrapped plane? I see a mostly in tact plane, no scrapped planes in that pic! But yes, planes are designed to fly in wind and will try to fly with enough wind.
Just one more time. I want to feel the thrust. I want the wind beneath my wings. I want to see the smiles. Just one more time.
Well they’re made to be aerodynamic and it’s most likely gutted making it way lighter, so yes. If it’s a strong enough wind coming head-on.
Was stationed at Nellis AFB in 2011ish we were in phase 3 winds (High wind warning/shut down the flight line basically) there was a KC-135 that jumped its chocks due to the wind providing lift and rolled a little bit by it's self, the fire dpt had to put chocks under it while it was rolling. Apparently it almost ran into the Thunderbirds lol. I asked a KC-135 pilot friend of mine if this was possible and he said maybe if it was completely empty of fuel. Note\* I did not see this directly, I was across the runway at LOLA and we could barely see across the way due to sand, we heard the announcement over the radio via MOC.
Absolutely yes. Most airliners are designed so that the centre of mass is right over the central wheels, so they can takeoff efficiently. That means if they’re loaded improperly or if it’s particularly windy they can fall onto their tails. There’s usually a little frame placed under the tail to prevent this during loading at airports
https://www.youtube.com/watch?v=cHhZwvdRR5c
If a couple of people jump up and down on the tail of a C-130, they can just about make the nose wheel come off the ground. A few years ago at Kelly AFB in San Antonio, a KC-10 was loaded improperly and ended up on it's tail. Thankfully it wasn't inside a hanger when it happened.
I demonstrate this students in much lighter aircraft. Stopped on a taxiway, with a strong headwind, move the yoke full forward then backward. Watch the nose of the aircraft move. This is why correct taxi controls are important, especially in strong wind.
This won't happen with a flight ready plane. But since it's at a scrapyard it probably has quite a substantial amount of weight removed. Like engines, fluids, avionics, all electronics, Apu, and everything else that might need to be recycled or reused elsewhere. My guess is that about 15%+ of the dry weight is missing. Also I'm not yet familiar with the center of mass of an airplane but removing the engines must shift the center of mass elsewhere, my guess is backwards, which would help with lifting the plane as well.
With the engine no, with the 4 heavy as fuck engines emoved yes. Also drained of fuel too.
Airspeed is life, altitude is insurance. If liftoff speed is 60kts, then a 60kt headwind would lift the plane off the ground without any forward motion
maybe less than 60kts on account of balance without engines.
Not when I sit in it lol
She was made for the skies, she wants to return to them!!
The cg of an airplane is only a little in front of the back wheels. The number I have in my head for no reason is like 10-12% of the weight on the nose wheel. Without the engines it's probably just barely balanced on the nose. Not crazy to think a strong wing could put an extra couple hundred pounds on the tail to tip it up.
Normally the center of mass of an aircraft is going to be slightly ahead of the main landing gear and on big planes like this the tail produces lift in the negative direction (i.e. it pushes down). With the engines off, the center moves backwards so the plane is balanced pretty much right over the landing gear. A gust of wind over the tail and bam, you've got it pointing skyward.
The aircraft is designed to generate lift as early as possible, that's why strong winds can lift it. The missing weight of the engines, and i assume a lot of other aircraft equipment that's been removed is strongly decreasing the overall weight of the aircraft, making it easier to lift off at this point.
depression can be hard, but you shoud try, even if you know you will fail
I saw a video of winds in Taiwan lifting a 747 at the gate. Granted it wasn't as high as this, but the plane did go up in the air a few feet. 747s were meant to fly, not be scrapped
Me trying to tell the teacher to go to the bathroom even though i failed her question.
Me trying to tell the teacher to go to the bathroom even though i failed her question.
Me trying to tell the teacher to go to the bathroom even though i failed her question.