Slashdot Mirror
Solar-Powered Plane Making 24-hour Flight
After technical glitches threw a kink in its schedule, Solar Impulse, the solar-powered plane first mentioned here in June, has finally taken off. Reader asukasoryu writes "An experimental solar-powered plane took off from western Switzerland on Wednesday for a 24-hour test flight — a key step in a historic effort to one day circle the globe using only energy collected from the sun. The plane left Payerne airfield shortly before 7 a.m. after overcoming an equipment problem that delayed a previous attempt. Although the goal is to show that emissions-free air travel is possible, the team says it doesn't see solar technology replacing conventional jet propulsion any time soon. Instead, the project is designed to test and promote new energy-efficient technologies." You can follow the flight's progress at the project's site.
I submitted an article recently about that very thing: C02 + Solar Power = Petrol or petrol like substance. (in theory at least) http://www.hindustantimes.com/Soon-you-can-fill-your-car-with-petrol-made-from-CO2/Article1-567293.aspx
We’re all counting on you.
P.S.,
This is what part of the alphabet would look like if Q and R were eliminated.
All energy can be traced back to the Big Bang. Therefore I'm going to fail to see any relevant differences between any form of energy today and call that being smart.
The enemies of Democracy are
This plane is not emissions-free, since there were some in its manufacture, which must be divided over its lifetime, and then whatever emissions are involved in the disposal/recycling of the craft as well. Lower-emissions, sure, but not emissions-free.
We aren't playing Civilization here. We can research more than one thing at a time.
I have issues with the project web site and the lack of information. One of my main issues is that the site touts the use of new technology but nowhere does it explain exactly what "new" technology it uses. What is it's cruising speed? If it is over 50Kmph I would be surprised.
Another important issue is that it never states is the batteries were full or empty at takeoff and how much of that battery power was used to get the plane to altitude. What if the energy used was only 20% of capacity and the main method of altitude gain was thermals and mountain wave? Recharging that 20% should not be an issue. What then happens if the plane requires 80% of the battery capacity to stay up over night? They would last one night but run out half way through the second night.
I always love obvious spin. When asked when the non stop around the world flight will happen the site says "60 years between the first world tour with stopovers and the first world tour without stopovers in a traditional motor airplane". On the other hand, when asked if solar airplanes will replace conventional airplanes they state "when the great Wright brothers got their first plane to fly a distance of 200 meters in 1903, could they have imagined that 66 years later, two men would walk on the moon?" The spin is that from the first flight to the moon landing there has always been increases in speed, capacity and duration aloft. This technology turn back the clock to a low speed single seater aircraft and assumes we can still advance as far.
An economically viable passenger plane would be required to carry passengers, be pressurized and go much faster; I am sure no one would want to take 100 hours to go from London to Newyork. This may require an energy output a hundred times that of the Solar Impulse. The current plane is already has a wing span of 63m. Even with a increase of solar panel efficiency to 80% that would require an increase in wing area by 25 times. That is one huge plane to carry a few people.
Today, gliders with no electric motors can stay aloft for extended periods of time. The gliding community has stopped tracking duration aloft records due to the dangers of exhaustion. Here are some other current glider records; altitude 12 637 m; distance 1078.2 km; speed over an out-and-return course of 1 000 km 133.89 km/h. What has been created is in effect a huge glider with a electric motor backup.
Look at the real time charts. By "real time" I mean what altitude, power and speed are NOW
How cool is that!
The reason I am not impressed is that there is no new technology in the aircraft. We already have solars cells, electric motors,ultralight construction and high aspect ratio sailplanes. A competent aeronautical engineer could have done the design and shown that it could easily work. Sure it is cool but it does not advance technology.
Now that the flight is over, lets take a look at a few of the numbers from http://www.solarimpulse.com/nightFlights/charts.php.
1. They need a more accurate speed and altitude sensor. There are quite a few spikes in the charts. Some of them have "disappeared". They were probably fixed in the data by averaging.
2. They started with the battery 69% charged.
3. The low point in battery level was 46%
4. It took 7.5 hours to get to full charge.
5. When air temp decreased below 0 the efficiency of the solar cells also decreased dramatically.
6. For a 2.5 hour period when the engine power was at 4% with 0% solar charging the battery charge did not decrease; strange.
7. When the battery was used, it drained at about 10% per hour.
8. The airspeed was about 23kmph most of the time.