Anyone know about hydrodynamics concerning a wing cutting through the water and lift?

[fuzzybabybunny]

I want to develop something that uses the same principles of a hang glider, only for water.

As you're falling in air, the hang glider catches the air and translates some of that to forward movement instead of straight downwards movement. I want to do the same for water. When this object is sinking, it's got a wing that catches the water and translates some of that to forward movement.

There are such objects in existence:

Underwater Glider:

https://www.google.com/search?sugex...Q&biw=1745&bih=899&sei=pV_lT7fjKaO-2gW2spDaCQ

By comparison, a hang glider:

https://www.google.com/search?sugex...Q&biw=1745&bih=899&sei=xl_lT9ePFqjO2gXxhdTZCQ

The design of the wings are night and day apart. The underwater one is basically a missile with little fins poking out. Am I to assume that if you had a big hang glider wing design underwater that it wouldn't go anywhere or be incredible destabilized by water currents?

On the other hand, how do the tiny fins on the underwater glider manage to get enough lift? I want something that has a greater than 1 glide ratio. The higher the better. Even modern wingsuits have glide ratios of 2.5 - for every 1 meter down, it goes 2.5 meters forward. I'm looking for an underwater glider design with the same properties.

 

[OCGuy]

Wait....so is there a treadmill involved or no?

 

[foghorn67]

Independent Rear Suspension or Live Axle?

 

[eLiu]

Stick to snorgling.

 

[The Boston Dangler]

http://www.theweatherprediction.com/habyhints/216/

 

[Puppies04]

On the other hand, how do the tiny fins on the underwater glider manage to get enough lift?

Quick question, do you fall as fast in water as you do in air..... go have a coffee and think about that for a while.

 

[Bignate603]

This won't end well.

 

[Doppel]

Quick question, do you fall as fast in water as you do in air..... go have a coffee and think about that for a while.

Water is dense but I don't know that it alone is the reason for the different shapes. The water glider link has machines with a lot of equipment. They may be interested in speed, too. I'm inclined to think that a large shape like a hang glider would work under water as long as it could be kept oriented properly. The first pic in the first link is of a pretty flat shape.

 

[the DRIZZLE]

What's the point of this? Why not just use a sea scooter?

 

[Greenman]

If you're looking for something to propel you forward in the water as it sinks, you're sunk. You realistically have about thirty feet of depth to deal with and a medium that's seven hundred times denser than air.

 

[Capt Caveman]

Since these things already exist, you believe you can improve upon what scientists and the military have already developed?

 

[skyking]

it is the classical "solution seeking a problem" question, made popular by too much idle time and the perceived existence of a ready audience.
Let the games begin!

 

[MagnusTheBrewer]

it is the classical "solution seeking a problem" question, made popular by too much idle time and the perceived existence of a ready audience.
Let the games begin!

Maybe this is the critical piece of the puzzle that will finally tie together relationships, sleeping in cars, motorcycles and, or course, bunnies. This could be bigger than Higgs Boson! A unified field theory for all things FBB! Think of the possibilities! We could predict future insanity!

 

[destrekor]

Maybe this is the critical piece of the puzzle that will finally tie together relationships, sleeping in cars, motorcycles and, or course, bunnies. This could be bigger than Higgs Boson! A unified field theory for all things FBB! Think of the possibilities! We could predict future insanity!

A complete understanding of Snorgle Theory has evaded us all for years! Think we are any closer?
Is there a Snorgle Particle to be found, perhaps?

 

[MagnusTheBrewer]

A complete understanding of Snorgle Theory has evaded us all for years! Think we are any closer?
Is there a Snorgle Particle to be found, perhaps?

I think first we have to define it before we look for it. Perhaps a working hypothesis could be the smallest observable wtf moment?

 

[AeroEngy]

... On the other hand, how do the tiny fins on the underwater glider manage to get enough lift? I want something that has a greater than 1 glide ratio. The higher the better. Even modern wingsuits have glide ratios of 2.5 - for every 1 meter down, it goes 2.5 meters forward. I'm looking for an underwater glider design with the same properties.

I am not a hydrodynamics expert however, lift when all other things are equal is directly proportional to the density of the medium. Water is about 1000 times as dense as air therefore much smaller wings are required. Also the wings with highest lift to drag ratios are high aspect ratio wings like that on a sailplane and not the triangular wing of a hang glider. Hang gliders have a pretty good L/D ratio but there shape is more a function of not needing a tail, more forgiving center of gravity, and other various reasons.

Glide ratios are numerically equivalent to lift to drag ratio. Just of the top of my head this presents a few problems for underwater vehicles trying to glide forward. First since it will presumably be mostly buoyant very little lift is required. Second drag will be high since just like lift it is directly proportional to density of the fluid medium. I imagine this is one reason the velocity of one of the linked underwater gliders is in the 0.5 mph range. This is also probably why it is torpedo shaped so it is long a skinny to present a small cross section to forward movement reducing drag as much as possible.

There are probably also several physical differences I am not thinking about due to the incompressibility of water.

 

[OVerLoRDI]

I am not a hydrodynamics expert however, lift when all other things are equal is directly proportional to the density of the medium. Water is about 1000 times as dense as air therefore much smaller wings are required. Also the wings with highest lift to drag ratios are high aspect ratio wings like that on a sailplane and not the triangular wing of a hang glider. Hang gliders have a pretty good L/D ratio but there shape is more a function of not needing a tail, more forgiving center of gravity, and other various reasons.

Glide ratios are numerically equivalent to lift to drag ratio. Just of the top of my head this presents a few problems for underwater vehicles trying to glide forward. First since it will presumably be mostly buoyant very little lift is required. Second drag will be high since just like lift it is directly proportional to density of the fluid medium. I imagine this is one reason the velocity of one of the linked underwater gliders is in the 0.5 mph range. This is also probably why it is torpedo shaped so it is long a skinny to present a small cross section to forward movement reducing drag as much as possible.

There are probably also several physical differences I am not thinking about due to the incompressibility of water.

 

[Gibsons]

http://en.wikipedia.org/wiki/Hydrofoil

 

[SSSnail]

This gives me an idea, I'm gonna go and try to invent this device that gives carriages a smoother ride. Something involving rubber and air...

Edit: Ah, I get it, you ultimately want to end up on the ocean floor, that's the only explanation for this "invention".