Research glider sub

[Guest]

Sub uses novel power source:
http://www6.comcast.net/news/articles/s ... GLIDER-DC/

[warpatroller]

Art,

I believe one of these

Art,

I believe one of these underwater drones is called the "Sea Glider" and it uses a ballast system that reminded me of your RCABS, using a bladder with oil instead of air if I recall correctly..I think an oil is pumped in and out of the bladder.

http://www.apl.washington.edu/projects/ ... mmary.html

On the page for the above link, you can see a black bladder on the rear of the internal component picture.

Steve

[skip asay]

Reading this thread has brought

Reading this thread has brought back some fond memories. A little over 20 years ago I worked for Herb Werner, a former U-boat commander. We were building a 42 foot 2 man submarine for a project Herb was involved in. My first responsibility was to build a 1 to 1 (42”) model so we could get an idea of maneuverability, etc. At one point, the idea of “underwater gliding” came up so I built a 12 foot wing (2 6 foot panels), added a secure mounting pad, and went boating. Talk about way cool!! With just minimal amounts of ballast change the boat moved along very nicely. With more substantial amounts of ballast change, the speed was very impressive indeed! And the surprising thing is that the depth variation was less than 3 feet since the depth of the lake I was running at was only 5 feet. Does anybody remember Raceway Park in Englishtown, NJ?

Skip Asay

[warpatroller]

Yes Skip! I was at

Yes Skip! I was at the Raceway at Englishtown, NJ for a Mopar muscle car meet in the summer of 1988. I went with a friend and we picked up a replacement grill for his 71 Challenger R/T. That was the only time I was ever there though.. Based on what you said we were there close to the same time period that you mention in your story.

Your 12 foot wing makes me think of an underwater version of the Horten flying wings...was it something like that?

Steve

[skip asay]

No, nothing so exotic. Each

No, nothing so exotic. Each panel was made of 1/4" pine sanded down to a laminar flow type foil shape. It also had no sweep. If memory serves me, it was approximately 4" chord at the root and 2" at the tip. It was ungainly as all get out out of the water but it was truly a thing of beauty underway, though.

My history with Raceway Park goes way back. I remember watching it being graded before they put the macadam down. I was the second one to ever go down the race track (officially) since they invited some locals to try it out the week before its official opening.

In the beginning, the racetrack also served as a runway for the owner's plane. He was also into drag boats so a few years after the racing started he built a pond alongside (on the pit side) for them but that never materialized. But it was a perfect site for playing with model subs! Crystal clear water, 4-5 foot depth, light sandy bottom, and best of all - no spectators allowed! I knew the owner and his sons well so I had permission to go there whenever I wanted. Sadly, the sons wanted to expand the pit area so most of the lake (pond) has now been filled in.

Skip Asay

[scott t]

http://www.isa.org/Content/ContentGroups/News/20082/February28/Green_glider_passes_ocean_test.htm

Green glider passes ocean test
The

http://www.isa.org/Content/ContentGroups/News/20082/February28/Green_glider_passes_ocean_test.htm

Green glider passes ocean test
The first environmentally powered robotic vehicle successfully flew through the ocean. This robotic glider harvests heat energy from the ocean to propel itself across thousands of kilometers of water.

A prototype “thermal glider” launched off the coast of St. Thomas in December, said Dave Fratantoni of Woods Hole Oceanographic Institution (WHOI) and Roy Watlington of the University of the Virgin Islands. The vehicle has been traveling uninterrupted ever since, crisscrossing the 4,000-meter-deep Virgin Islands Basin between St. Thomas and St. Croix more than 20 times.

Engineers and researchers project the thermal glider could continue its current, “green-powered” mission for as long as six months.

Unlike motorized, propeller-driven vehicles, gliders propel themselves through the ocean by changing their buoyancy to dive and surface. Wings generate lift, while a vertical tail fin and rudder allow the vehicles to steer horizontally. Gliding underwater vehicles trace a saw-tooth profile through the ocean’s layers, surfacing periodically to fix their positions via the Global Positioning System and to communicate via Iridium satellite to a shore lab.

“Gliders can be put to work on tasks that humans wouldn’t want to do or cannot do because of time and cost concerns,” said Fratantoni, an associate scientist in the WHOI Department of Physical Oceanography. “They can work around the clock in all weather conditions.” The vehicles can carry a variety of sensors to collect measurements such as temperature, salinity, and biological productivity. Gliders operate quietly, which makes them ideal for acoustic studies.

Though the thermal glider is not the first autonomous underwater vehicle to traverse great distances or stay at sea for long periods, it is the first to do so with green energy. Most gliders rely on battery-powered motors and mechanical pumps to move ballast water or oil from inside the vehicle’s pressure hull to outside. The idea is to increase or decrease the displacement (volume) of the glider without changing its mass.

The new thermal glider draws its energy for propulsion from the differences in temperature—thermal stratification—between warm surface waters and colder, deeper layers of the ocean. The heat content of the ocean warms wax-filled tubes inside the engine. The expansion of the warming wax converts heat to mechanical energy, which it stores and uses to push oil from a bladder inside the vehicle’s hull to one outside, changing its buoyancy. Cooling of the wax at depth completes the cycle.

“We are tapping a virtually unlimited energy source for propulsion,” said Fratantoni. The computers, radio transmitters, and other electronics on the glider get their power from alkaline batteries, which are, for now, the principal limit on the length of operation. Webb Research is working to reduce the electrical needs of the instruments, while also developing the capability to convert some of the thermal energy to power for the electronics.

“The current mission is an engineering test-drive, but it’s also occurring in a scientifically compelling location,” said Fratantoni. Swirling water currents, known as eddies, form upstream of the Virgin Islands. The data collected by the new glider system will help researchers understand how these eddies affect regional circulation and redistribute the larvae of coral reef fish and man-made pollutants.

The engineering trial for the thermal glider is the first step in a broader plan by Fratantoni to launch a fleet of gliders for studies of the waters in the subtropical gyre of the North Atlantic, a key region for assessing the ocean’s response to climate change. He plans to test the glider with a trip from St. Thomas to Bermuda later this spring.

[u-5075]

Here's more news about the

Here's more news about the Robo-Sub

The Robo-Sub That Helps Predict Where the Ocean's Headed
An underwater glider measures parts of the ocean that scientists can't reach.
http://discovermagazine.com/2008/apr/25 ... n.s-headed
Article contains photo gallery.

by Alana Range

Global ocean levels have risen by 4 to 10 inches over the past 100 years. How much more will they rise in 10 years? What about in 50?

This kind of question is critical for planning future coastal development, but taking the measurements necessary to make predictions can be difficult and downright risky for human surveyors, who could be smashed by falling chunks of ice the size of the Empire State Building.

So send in a bot, says David Holland, an oceanographer at New York University, who teamed up with the National Research Council of Canada (NRC) to deploy a five-foot-long autonomous submarine beneath an iceberg off the coast of Greenland. Called the Slocum underwater glider, the sub propels itself through water with a single-stroke piston, thereby conserving most of its energy for data collection. Sensors under the port-side wing measure conductivity (to find the salinity of the water), temperature, and depth, sending the data to processors within the sub.
Icebergs are difficult to navigate, even for a sophisticated machine like this. In the pitch-black shadow under the iceberg, the Slocum glider has no access to satellite GPS and no visual markers to verify that it is following its intended path. To help the glider get and keep its bearings, the NRC plans to test an acoustic beacon system whose components would be placed underwater at strategic points around an iceberg, allowing the glider to triangulate by sound.

By collecting data on how much and how quickly Greenland’s ice is melting, Holland hopes to create a computer model that will simulate and forecast glacial melt—and the future rise in sea levels—around the world.