Homecoming for Glider RU26

Late yesterday evening we recovered glider RU26, which had been cruising the waters of the Ross Sea since December 11. After 55 days, RU26 had traveled 732 miles, made 2,187 dives, and come within 2 miles of crossing the International Dateline and becoming a Golden Dragon like the rest of us (see yesterday’s post).

But just a week before the planned end of its mission something had gone wrong. A malfunctioning compass had caused a glitch in the glider’s normal operation, and RU26 sank to the ocean floor. This triggered a self-rescue program that jettisoned a weight and turned on the glider’s satellite phone. RU26 floated to the surface and sent Eli Hunter an email telling him we needed to go save the glider.

Gliders are ingenious machines that fly through the water without propellers or engines. They get all their motion by playing two forces against each other: gravity and buoyancy. When they need to float, they increase their volume so that buoyancy pulls them upward. When they want to sink, they reduce their volume so that they become denser than water and gravity pulls them down.

Whether they’re rising or falling, the glider’s wings turn some of that vertical motion into forward motion (about half a mile an hour). The only energy requirements are powering a pump to move oil in or out of the glider’s rigid interior—that’s what changes the buoyancy—and adjusting whether the glider tilts nose-up or nose-down.

A few people have left comments asking us how the glider flies, so we thought this was a good chance to look into gliders a bit more closely. Read on through the slideshow to see how they work:

Thanks to everyone who asked us about the gliders and prompted us to write this post. We love getting your questions and we’re answering every one of them. It may take a few days because of our e-mail connection and the amount of work going on the ship—but keep checking back on your questions, because we’ll post an answer sooner or later.

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About Hugh Powell

Hugh is a staff writer at the Cornell Lab of Ornithology and is on special assignment with the Rutgers University Institute of Marine and Coastal Sciences. He has previously written for the Woods Hole Oceanographic Institution.

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