Solar-powered BARKING SANDS, Kauai >> "If everything goes as planned, we'll be setting some major records," said John Del Frate, project manager for NASA's Helios solar-powered flying wing, which begins test flights at the U.S. Navy's Pacific Missile Range on Kauai in May.
NASA aircraft to
attempt record
Helios, the fourth in a series
of prototypes, will try for an
altitude of 100,000 feet>> Workshops to highlight Helios mission
By Anthony Sommer
Star-BulletinThis summer, NASA plans to fly the unmanned Helios to an altitude of 100,000 feet, higher than any aircraft without a rocket motor ever has flown.
Helios is the fourth generation of solar-powered aircraft developed by NASA and AeroVironment Inc., a California company that has been experimenting with solar-powered aircraft since the late 1970s.
It is intended to be the final prototype leading to a production solar aircraft that can stay aloft up to six months and perform any of the functions now carried out by far more expensive satellites.
Helios is the Greek word for sun and is the name of the sun god.
NASA's first solar plane, Pathfinder, set a world altitude record for propeller-driven aircraft of 71,530 feet while flying over Kauai in 1997.
In 1998 a souped-up version of the same aircraft, renamed Pathfinder Plus, soared to 80,201 feet during a test flight off Kauai, again setting a record for propeller-driven aircraft.
The third version, Centurion, did not attempt any altitude records. It was used to test components to be used on Helios.
If the fourth version, Helios, climbs to 100,000 feet, it will beat the altitude records for all jet aircraft, including the high-flying SR-71 Blackbird spy plane, Del Frate said in a phone interview from NASA's Dryden Flight Research Center at Edwards Air Force Base, Calif. Del Frate also was NASA project manager on Pathfinder Plus.
Helios has a wingspan of 247 feet, twice that of Pathfinder Plus. Helios' wingspan is longer than that of a Boeing 747 jumbo jet (195 feet) or of the Air Force C-5 transport (222 feet).
Powered by 14 electric motors each producing 2 horsepower and driving a 79-inch diameter propeller, Helios does not need the oxygen required by piston or jet engines for fuel combustion. The electricity to drive the motors is provided by $10 million worth of solar cells covering the upper surface of the wing.
The only unknown is how the design of the wing -- and Helios is all wing, with no fuselage -- will perform in the thin air. The density of air at 100,000 feet is only 1.3 percent of the density of air at sea level.
"There is no wind tunnel that can emulate that environment," Del Frate said. Wind tunnels cannot duplicate the light turbulence at high altitudes. Del Frate said the effects of that turbulence on Helios are a major unknown.
Helios has five pods mounted under the wing. Each pod contains landing wheels and storage space for batteries and, in the future, scientific equipment.
The five sets of wheels cover such a wide area that Helios will not be able to take off or land on the Pacific Missile Range's main runway. Instead, it will use an adjoining tarmac that is much wider.
"Takeoff is pretty simple because it should only need a distance equivalent to its wingspan to get off the ground," Del Frate said. "But it needs a lot of room to land because it is so light and sensitive to the wind that it's difficult to pinpoint the touchdown location as it's descending."
Perhaps the world's most exotic radio-controlled plane, Helios is flown by a pilot sitting in a command van beside the tarmac. Actually, a team of pilots are involved because the missions will last up to 18 hours.
A variety of sensors, including miniature TV cameras, give the pilot a constant flow of information.
Helios is controlled by 72 elevators that control pitch. Either the pilot or a computer on board the aircraft maintains the proper trim by using small motors to adjust the elevators.
Since there is no rudder, turning is controlled by speeding up the motors on one side of the wing while slowing down those on the opposite side. Its top speed is 25 mph.
NASA has been bringing its solar planes to Kauai for testing because the Pacific Missile Range includes thousands of square miles of open ocean with no commercial ship or aircraft traffic. If the aircraft has to be brought down in an emergency (and it is equipped with a parachute and locator beacon) there is no chance of it hitting anything on land.
This year's series of test flights is designed to determine whether Helios can reach its design altitude of 100,000 feet. It has been flown successfully at low altitudes over the California desert.
Helios will carry enough batteries to power it during takeoff and for up to five hours after sundown.
It will fly a large box-shape pattern northeast of Kauai, constantly keeping its solar panels facing the sun.
Four flights are scheduled. The first, probably in late May, will be strictly a checkout flight. The first attempt at 100,000 feet likely will be in June.
Wingspan: 247 feet [ HELIOS AT A GLANCE ]
Length: 12 feet
Wing thickness: 11.5 inches
Empty weight: 1,322 pounds
Maximum gross weight: 2,048 pounds
Maximum payload: 726 pounds
Propulsion: 14 direct-current electric motors, each rated at 2 horsepower driving two-bladed 79-inch propellers
Cruising speed: 19 mph, with a top speed of 25 mph
Maximum altitude: 100,000 feet
Endurance: Daylight hours plus up to five hours on batteries; when equipped with an energy storage system, several months
"EXTREME AIRPLANES at Extreme Altitudes," a series of teacher and parent/child workshops offered by aerospace education specialists from the NASA Dryden Flight Research Center in Edwards, Calif., is scheduled between April 3 and 17 on Maui, Kauai, Oahu and the Big Island. Workshops to highlight
Helios missionSeminars for teachers, parents
and children will be held on
several islandsBy Anthony Sommer
Star-BulletinThe workshops highlight NASA's high-altitude scientific research aircraft Helios Prototype and its mission at Pacific Missile Range Facility on Kauai.
The teacher workshops will include demonstrations of NASA math and science education products and services related to the aircraft and NASA aeronautics.
At the parent/child workshops, parents and children (ages 7 through 14) will participate in cooperative hands-on activities.
Teacher workshop schedule:
>> Bishop Museum (Oahu): April 3 and 4, 3:30-6:30 p.m.
Contact Cindy Hoddick, (808) 848-4195, for reservations.>> Parker Ranch (Big Island): April 10, 4-6:30 p.m.
Contact Fran French, (808) 887-6074, for reservations.>> Maui Arts & Cultural Center (Maui): April 6, 3:30-6:30 p.m.
Contact Trudi Vierra, (808) 573-8760 or (808) 878-3553, for reservations.>> Kukui Grove Center (Kauai): April 17, 3:30-6:30 p.m.
Contact Cheryl Shintani, (808) 742-6838, for reservations.
Parent/child workshop schedule:
>> Parker Ranch (Big Island): April 11, 6:30-8 p.m.
Contact Fran French, (808) 887-6074, for reservations.>> Maui Arts & Cultural Center (Maui): April 7, 6:30-8:30 p.m.
Contact Trudi Vierra, (808) 573-8760 or (808) 878-3553, for reservations.>> Kukui Grove Center (Kauai): April 14, 3:30-5 p.m.
Contact Cheryl Shintani, (808) 742-6838, for reservations.In addition to the workshops, two museums will host a Helios Prototype display.
Call the Bishop Museum (Oahu) at (808) 847-3511 or the Kauai Children's Discovery Museum (Kauai) at (808) 823-8222 for dates and times.