Multimedia Reporting (Bradford-Noland)

The University of Kansas Aerospace Engineering Department is developing an unmanned aerial vehicle (UAV) to be flown in Greenland and Antarctica. The Meridian will have a wingspan of 26.4 feet, and will be used for global warming-related research in coordination with the department’s Center for Remote Sensing of Ice Sheets.

UAV Illustration
Courtesy: Rick Hale

The Meridian will carry a 100-pound ground penetrating radar system that tests the thickness of the polar ice sheets in the area. The UAV’s longest missions in Antarctica would be eight hours, covering about 1,000 miles. During flight, the radar system continually sends signals down through the ice, and records its depth along the way.

"Researchers are trying to study the flow of the ice sheets with global warming and see why some ice sheets seem to be flowing faster than others,” said Kai Siegele, graduate research assistant. By doing this aerial remote sensing, they're able to tell how fast the ice sheets are moving and hopefully discover why."

Current research for the center has been done by heavier radar systems in cold-weather ground vehicles and larger, piloted airplanes. Dr. David Downing, KU aerospace engineering professor said that a great advantage of an unmanned aircraft is that it can fly the exact pattern twice with much better accuracy than a person could.

“As a pilot, you’ve got to know where you are, one advantage of the autopilot system is that it can use GPS points to fly from coordinate to coordinate,” Downing said.

Dr. Richard Hale, KU aerospace engineering professor and co-head of the Meridian project explained that this is imperative because the radar system can only cover a strip of land at a time. Once it covers a strip, the plane will then turn and pass along another parallel track, much like a lawnmower would.

“We can overlay these images to get full, high-resolution imagery of the under surface of the ice,” Hale said.

Hale said that there are other advantages in using an unmanned air vehicle to do the job. The smaller plane means weight is drastically decreased, and fuel cost will go down.

“The bigger, piloted planes currently used in the project use over 10 times more fuel than our model,” Hale said.

Another big concern for the researchers is pilot and crew safety. Hale said the Meridian’s planned eight-hour radar missions; 1,000 feet above the ground, in dangerously cold weather can be too much for even an experienced pilot.

"An engine could fail, you could have bad weather all of the sudden and the plane could go down," Siegele said. "The risks could be injury, death and being stranded out on the ice."

The Meridian project started in 2004 with a $19 million grant from the National Science Foundation. The grant ends in 2009, but Hale and his team remain hopeful that they will be granted the possible five-year extension.

“We’ve planned this as a 10 year project,” Hale said. “We’re only a year and a half in, so hopefully, we’ve still got about eight and a half years to work on the project.”

If the team gets the grant extension, they will continue to refine their UAV, and set up for large-scale production of the aircraft. Siegele said that the center would eventually want to have more than one Meridian in the air, so they can do research in many places at once. He added that with the grant extension, the Meridian might also find a home in other workshops.

"If it's successful, there are possibilities of building the Meridian for other science
payloads," Siegele said. "Scientists in other communities have expressed interest in purchasing one to conduct their experiments."

Aerospace engineering students in 12 different classes worked on the project this semester. Hale’s Aerospace Materials and Processes class fabricated one of the Meridian’s wings. Other classes are examining engine efficiency and testing to find the optimal thickness of the airplane’s skin.

“By integrating this project into so many classes, our students can have some great hands-on experience with the research,” Hale said.

The latest project test was to fly a Piper Cub model airplane, affixed with the V-tail proposed for the Meridian. Bill Donovan, graduate research assistant said that the two surfaces of the V-tail make it more efficient and cost effective than the standard tail affixed to most aircraft, which have a vertical fin with a horizontal surface on either side.

Bill Donovan, graduate research assistant, prepares the V-Cub
Photo courtesy: Rick Hale

“The V-tail creates less drag, it’s lighter, and has fewer actuators,” Donovan said.

The actuators are the movable parts on each tailfin that steer the aircraft. Hale said that a small motor called a “servo” is positioned inside the tail to move each actuator. He added that because there are only two actuators on a V-tail, the cost would drop significantly.

“Another advantage is that there will only need to be two servo’s as opposed to three,” Hale said. “This is important when you realize that the servo’s cost about $10,000 a piece.”

The next step for the “V-Cub” is to install and test the $20,000 Piccolo autopilot system that will be used in the Meridian. The system would sit inside the cockpit of the Cub, and replace its current radio control system.

“This is the same system used by NASA, industry and hobby-grade UAV’s,” Hale said.

The Meridian and its radar system are designed with mission frequency in mind. The 110-pound radar system will store its data on two replaceable hard drives, which will be situated for easy access.

“We’ll be able to bring the plane in, pull the hard drives out, put new ones in, and go right back out,” Hale said.

The fully loaded Meridian UAV will have a 26.4-foot wingspan and weigh just over 1000 pounds, with almost 300 pounds of jet fuel. A full fuel tank gives the Meridian a range of 1,116 miles, or 13 hours. Dr. Hale said the Meridian’s longest missions in Antarctica, would be about eight hours, and would cover about 1,000 miles.

“This isn’t me standing in a field somewhere watching my little remote control airplane; this thing is going to be out in some very extreme conditions,” said Dennis Lane, Environmental Engineering professor. “This plane is going to travel great distances on its own, with just a monitor and an operator at the controls, far away.”

CReSIS researchers will use a hand-held controller for take-off and landing, but will use satellites and GPS to communicate with, and track the Meridian after it gets over the horizon.

Hale said that because there aren’t many satellites over Antarctica, the plane could lose contact with the operator for up to a few minutes at a time. The team is developing a flight management system, so the plane wouldn’t lose control in case of a communication blackout.

“The airplane has to know if it should continue the current flight plan, circle the area until it regains contact, or just turn around and head home,” Hale said.

Another obstacle the design team faces is the possibility of ice building up on the wing.

"It doesn't take a whole lot of ice to change the shape of a wing this size," Hale said. "When the wing changes shape, it loses lift, and just does a nosedive."

The team is exploring some different options to rectify the problem. Siegele said that most commercial planes spray a de-icing chemical onto the wings, but because of environmental restrictions in Antarctica, engineers are leaning towards an internal heater on the wing's leading edge.

This week, Hale and Donovan will take a three-week trip to Antarctica to talk to current CReSIS pilots and test a small, radio-controlled airplane to test takeoff and landing in the extreme cold conditions.

The team plans to have a finished prototype in late 2007, and be flight testing in the U.S. by early 2008. The prototype will then venture to colder weather conditions for testing in Greenland later that year.

KU is the leading researcher in the CReSIS project. Other partner universities include Elizabeth City State University, Haskell Indian Nations University, The Ohio State University, Pennsylvania State University and The University of Maine.