In Hellenic mythology, the tale of Icarus flight from Crete deals with man’s wish to fly like birds, with no external power source but one’s arms. Daedalus fashioned two pairs of wings out of wax and feathers for himself and his son in order that they might escape Minos, the ruler of Crete.
In the myth, Icarus ignored his father’s instruction to keep to moderate altitude. Like pilots of all eras, the lure of altitude pulled him from the safety zone specified by the design and construction of his wings. The resultant materials failure left him suddenly aware that he was guilty of exceeding design specs, and involved in history’s first recorded pilot error, or PFU. As with many young pilots, he was guilty of living fast and leaving behind a beautiful corpse.
Notice the bevy of bare-breasted young women at his wake. He departed this plane of existence in a manner that would satisfy many test pilots down through aviation history.
Now the game has changed markedly. From the pursuit of ever faster, high-reaching aircraft of phenomenal speed and power, requiring on-board pilots with lightning-fast reflexes; the goal has become slower, feather-light, long-endurance craft that feed off the sun and leave no sonic booms, contrails, or pollution.
Instead of avoiding the sun, the chains are off and the goal is no longer speed but sustainable flight at altitudes above the clouds. The higher these featherless craft can fly the more power they can absorb. We are seeing quantum changes in aircraft design and function. UAV’s will likely become the primary combat aircraft, sparing pilot lives but lessening the glory of previous air combat. The ability to program loiter time and upload mission changes from half a world away to gossamer craft that don’t require on-board crew opens up new ways to use aircraft in military and civil purposes.
Up in the air, Junior Birdmen.
http://us.cnn.com/2010/TECH/innovation/07/16/solar.plane.unmanned.zephyr/index.html?hpt=C2
Unmanned solar plane smashes records
By Matthew Knight, for CNN
July 17, 2010 8:10 a.m. EDT
QinetiQ's "Zephyr" aircraft has been in the air for seven days smashing all previous records for unmanned flight.
London, England (CNN) -- An unmanned solar aircraft has smashed the world record for continuous flight.
The "Zephyr" plane, developed by UK defense technology company, QinetiQ, took off from the U.S. Army's Yuma Proving Ground in Arizona on July 9. Seven days on, it was still flying high.
The British MOD project produced a featherweight aircraft with amazing design specs.” Zephyr is a UAV that can carry communications modules and imaging modules. The example cited is a plane fitted with thermal sensors and radio relays to aid fire fighters in mountainous and poorly accessible terrain. Obviously military application modules are in design status. The extreme loiter time demonstrated by keeping Zephyr aloft for a week has tremendous possibilities in searching for lost humans, support for ground missions, and other recon and communication possibilities.
Design specs call for a working altitude of 60,000 feet. The UAV configuration does away with the need for heavy and expensive life support systems that would be necessary for a pilot at such altitudes.
Weighing just 53 kilograms (117 pounds), the plane has a wingspan of 22.5 meters (74 feet) and a wing area of around 30 square meters (323 square feet), the top side of which is covered in solar panels thinner than a sheet of paper. The panels are rigged up to lithium-sulphur batteries which power the plane at night.
http://us.cnn.com/2010/TECH/innovation/07/16/solar.plane.unmanned.zephyr/index.html?hpt=C2
Also in the air this week, Impulse.
“Solar Impulse has a wingspan of more than 206 feet (63 meters) -- the same as an Airbus A340 -- and is nearly 72 feet (22 meters) long. It weighs about 3,500 pounds (1,600 kilograms) and has nearly 12,000 solar cells attached to its wings and horizontal stabilizers.
The plane is equipped with four electric engines and has a top speed of about 43 miles (70 kilometers) per hour. It has been piloted to an altitude of nearly 28,000 feet (8,500 meters).
http://www.pvresources.com/en/helios.php
Helios, NASA research craft
HELIOS - technical data
Wing span: 75,3 m
Length: 3,6 m
Wing thickness: 0.3 m
Height: 2 m, without upper blades of the propellers
Wing area: 186.6 m2
Mass: 600 kg - unloaded plane
Allowed mass: up to 930 kg, depends on flight purpose and available energy.
Cargo: up to 330 kg, depends on measurement equipment weight.
Propulsion: 14 DC brushless electric motors (the power of each motor is 1,5 kW) with two blades, specially designed for high altitude flights. The weight of each motor is less than 5 kg. Length of both propeller blades is 1,7 m.
Energy source: Bifacial solar cells - dimensions 1.25" x 2.75" (Front side efficiency 22 %, backside efficiency 11 %) placed on transparent wings. Energy source in the dark are lithium batteries. Fuel cells will be used as main energy source in the dark in the future.
Speed: Typical flight speed is 30 to 40 km/h. The highest speed is 270 km/h.
Flight height: Maximal flight height is 30000 m - typical height depends on flight mission and it is typical 15000 to 22000 m.
Flight: The anticipated autonomy in the future together with fuel cells will reach for uninterrupted flights (several months of autonomy).
Materials: All main parts of the plane are made of carbon fibres and styrofoam. Wings are covered with special designed and produced plastic sheet.
In the future, such planes will also be used for interesting research purposes and missions, such as:
Fly through the volcano for the purposes of volcano plume study
Fly over the North and South Poles
Fly for weeks and months at a time collecting scientific data, which varies according to the sun position or the season of the year
Explore conditions on Mars
More than 60,000 high efficiency (22.5% at AM 1.5) solar cells produced by SunPower Corporation were used as an energy source for HELIOS. The peak power of solar cell array was approximately 30 kW. The total costs for HELIOS solar cells reached around US$ 9 million (200 US$/W). HELIOS was equipped with 14 propeller motors, which were purposely designed for use in very thin air on high altitudes. HELIOS' wings (in fact, there's only one wing) were longer than wings of a Boeing 747 or a Lockheed C-5 military transport plane.
Helios in Hawaii
Depicted is the historical development of NASA’s workable solar planes from Pathfinder to Helios.
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