Science and technology
The longest flight
A new record for solar-powered aviation
Jul 23rd 2010, 16:05 by P.M. | LONDON
AFTER Solar Impulse made aviation history on July 8th carrying pilot André Borschberg aloft for more than 26 hours, another solar-powered aircraft 
set a new record on July 23rd. This plane, called Zephyr, was unmanned and it managed to stay in the air for 14 days and 24 minutes continuously. It was launched from the Yuma Proving Ground in Arizona on July 9th and landed back there. This beats the previous official world record for the longest flight by an unmanned aircraft, held by a Northrop Grumman Global Hawk, a military unmanned aerial vehicle (UAV), which stayed aloft for 30 hours 24 minutes.
So what is the point of these aviation records being smashed? Babbage is a great believer in pushing technology to its limits. There is a lot more to discover about solar power and what it could be capable of. For the Swiss team behind Solar Impulse the eventual goal is to circle the globe in a manned aircraft using only power from the sun. For QinetiQ, a British technology company, and its partners in the Zephyr project there is the potential of an airborne communications and surveillance system which could remain aloft for weeks at a time, using no fuel and costing a lot less than a jet-powered UAV or a satellite.
Besides defence applications, there are a number of civil uses. These, says QinetiQ, include monitoring crops, forest fires, pollution levels and delivering telecommunications to remote areas. This could be especially useful in a disaster zone. After the earthquake in Haiti, a Global Hawk was over the area in 37 hours (although some 30 hours of that was spent obtaining the necessary approvals). It remained on station for 14 hours, monitoring damage and where survivors were gathering and building temporary shelters–including a field where helicopters were planning to land. The helicopters were then safely diverted to another location. Breaking flight records with green technologies has a long way to go.
Picture: QinetiQ
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I wonder if making the aircraft's body a bit wider and thicker, so it could hold more volume - then filling that extra space with helium - would make the airplane lighter, and consequently more energy efficient? It would neither be a balloon nor a blimp - but a plane with increased buoyancy. In this case that approach might make for a dramatic improvement in performance.
Good solar power aviation. I think that it is good one for our mother earth. :D
Great article! I hope they keep updated in the newer record. :D
mahonjal, you're right, of course, that the plane has limitations.
However, I believe I read elsewhere that it's designed to fly in the 65-70k-foot range, above much of the wind. It will have to *get* there, true, and I can't think of an easy way to have it hauled aloft without some serious re-design, particularly of the wings, since they're no long. (I should add I'm not an aeronautical engineer, however.)
At that altitude, it could function well for communications, surveillance, etc. Those would be useful, and not just for battlefield applications. It could be used in disaster relief, monitoring wildfires, crops and wild vegetation, and the like.
I tried to find its payload capacity but had no luck. Obviously, it will be able to take only a light package, but with modern, light-weight equipment, it could (I assume) do it.
There are at least a couple of private firms in the US alone working on next-generation solar film as well with much better power generation than is currently available. DARPA -- the US Defense Advanced Research Projects Agency (in case you don't know) is working on this as well.
But perhaps it won't work out in the end. I do hope it does; to fly just over two weeks is awfully impressive.
This is extraordinary! Not ready yet for commercial use? OK, I am not in a hurry. Loved the picture.
The problem with these is the speed.
They are so slow, that they will not be able to hold position in more than a 30 mph (or so) wind.
They are more like balloons than airplanes.
UAVs such as global hawk are fast enough to hold a position until their fuel runs out. One of these would be OK until it gets blown off course, or you try to land it in a crosswind.
Lots of people are trying to improve solar cells, but not many people are trying to make very light solar cells, as the market is too small, so I do not see rapid advancement in solar cell efficiency for planes.
We may well see the Solar Impulse fly around the world, but it will be following the prevailing winds, and I would defy them to fly the same path in the reverse direction.
I can see the benefits of a partially solar plane (more power during daylight), but not for a pure solar plane.
There just isn't the power density for useful flying.