# I can fly without wings

I can fly without wings,
only carried by the wind.
I am heavier when empty,
the bigger I am, the more I can carry.

What am I ?

I think you are a:

Helium balloon or a hot air balloon.

They fly (float) and have no propulsion, so get carried by wind
Since helium and hot air reduce the weight, they are heavier when empty and when bigger, they have more helium and hot air and can lift more.

• This isn't correct - Helium and hot air have a lower density than air or fabric/wood/whatever your balloon is built out of. This means filling the balloon with those gases reduces its overall density, allowing it to fly. It is however lighter when not filled. Mar 27 '15 at 17:58
• @zlobi.wan.kenobi This isn't correct. When the balloon is full of hot air, it's less dense than air, so it likes to ascend. It's definitely heavier than when it's empty! This answer just doesn't work out really, unfortunately. Mar 27 '15 at 19:33
• A filled balloon has more mass, less density, and is perceived to be "lighter" due to buoyancy. So, it really depends on what you're going for with weight. Generally, it's the force exerted on a scale under normal conditions. Mar 27 '15 at 19:35
• The confusion here comes from weight vs mass. Weight is the apparent downward force, where as mass is the amount of 'stuff' that makes it up. A balloon is heavier when empty, yet it is less 'massive' when empty. Mar 27 '15 at 20:58
• @kadreal the confusion isn't about weight and mass, it's about weight and bouyancy. An object's weight is the force that object exerts in a downward direction as a result of its mass. Hot air balloons don't float because they have a low weight. They float because the downward force of their weight is less than the upward force exerted on the balloon by the mass of the air that it displaces. Mar 27 '15 at 22:06

First timer here. I think you could be:

A promise.

I can fly without wings, only carried by the wind.

A "promise in the wind". I think it means the promise is the only thing you have, the promise-maker might be away or unreachable and all that's left is the promise itself.

I am heavier when empty,

The weight of an empty promise...

the bigger I am, the more I can carry.

...contrasted with what a big promise can carry. "Her hopes and dreams ride on the promise that one day her father would return."

• Ooo deep man. Way deep. Got me thinking Mar 27 '15 at 20:45

I would say JonTheMon's answer is more accurate but here's my attempt: You are a

Cloud

I can fly without wings, only carried by the wind.

Cloud 'fly' without wings but move by the wind

I am heavier when empty

Heavy "rain" from the cloud until it's 'empty'

the bigger I am, the more I can carry.

Bigger cloud carries more liquid droplets

• I was thinking cloud at first, but the heavier when empty doesn't fit. As you mention, the water makes it heavier 'until it's empty'. When it's empty it's not heavier. Mar 27 '15 at 19:33

Second Guess

Paper

I can fly without wings

Paper doesn't have wings. Yet it glides along the wind.

only carried by the wind

Paper can get carried by wind.

I am heavier when empty

Darn! I don't know...

the bigger I am, the more I carry

A blgger piece of paper contains more information than a smaller piece of paper

Original Guess

I think it is

words

I can fly without wings,

"Words fly all over the place"?

only carried by the wind.

Words are, when spoken,sound: carried by wind.

I am heavier when empty, the bigger I am, the more I can carry.

• The second guess makes sense Mar 28 '15 at 8:38

Time

I can fly without wings

Time can 'fly' but has no wings

only carried by the wind

Here 'wind' could refer not to moving air, but to the 'winding up' of a clock. Could also perhaps be a reference to the 'Winds of Time'...

I am heavier when empty

Empty time tends to drag heavily, due to boredom

the bigger I am, the more I carry

The more time you have, the more you can fit into it

A "by-the-wind sailor" type jellyfish: http://en.wikipedia.org/wiki/Velella

No wings, blown by the wind

Self explanatory

Heavier when empty

Well, it wouldn't be empty (of water) unless it was dead and removed from the sea, at which point it would be true.

The bigger I am, the more I can carry

This is my first time here; go easy on me!

• Is it "blown by the wind" though, if it lives on the water? Mar 28 '15 at 11:24
• Aren't boats blown by the wind?
– bye
Mar 28 '15 at 11:30
• Boats have sails; does this jellyfish have some sort of sail? (I'm not saying you're wrong, just that maybe you should explain the first line a little more!) Mar 28 '15 at 11:39
• Perhaps if you clicked on the link in the first line of my answer, all would become a little clearer?
– bye
Mar 28 '15 at 11:50
• I did click on it and skimmed through the article. Having now read it a little more closely, I found the line "the small rigid sail projects into the air and catches the wind". But be warned: a lot of people aren't going to be interested enough to do that, and they may DV your answer! +1 from me though - and welcome to Puzzling.SE btw! :-) Mar 28 '15 at 11:53

A parachute.
It "flies" on wind power alone, and can carry heavier loads as its surface area increases.

But that doesn't quite seem to fit the third line.

You are the fuel tank of a cargo helicopter.

1. Rotors are airfoils, but they're not wings.
2. Accelerated air is wind. Downwardly accelerated air creates lift.
3. When the fuel tank becomes empty, the helicopter suddenly becomes much heavier.
4. The bigger the tank, the more you can carry...
• How does the helicopter become heavier when the tank is empty? Mar 28 '15 at 12:31
• @jazzpi - Weight = mass * acceleration due to gravity. When fuel is exhausted, the engine stops running, the rotor disc stops producing lift to offset gravity, and the weight of the aircraft increases. The mass never changes, but the weight does. Mar 28 '15 at 14:25
• As you said, $W = m g$, not $W = m a$. Whilst a helicopter's rotors can provide acceleration opposite to $g$ so that $a$ = 0, they don't actually affect $g$ so they don't affect the weight. Mar 28 '15 at 16:34