Posts Tagged airplane

Sustainable Air Travel

Posted by on Saturday, 19 February, 2011

Airplanes produce greenhouse gas emissions and other pollutants when they burn fuel. Some pollutants such as nitrogen dioxides and sulfur dioxides are released over a wide area from high altitudes, harming people on the ground and possibly contributing to 8,000 deaths a year, according to the Massachusetts Institute of Technology. To solve these problems, several airlines are working to offset the carbon emissions that they produce, and reduce the environmental pollution from other compounds by researching cleaner airplane fuel.

Airplanes do not produce a majority of carbon emissions, but the amount of emissions they do produce is rising as more passengers can afford air travel. According to Boeing, in 2010 airplanes produced 2 percent of total carbon emissions from all sources, and this number will rise to 3 percent in 2030 unless airlines make fuel efficiency improvements.

A group of airlines has created an organization known as SAFUG, or the Sustainable Airline Fuel Users Group. The goal of this organization is to use renewable resources to produce fuel instead of petroleum based fuel. Because some types of fuels use food crops such as corn, contributing to higher food prices and food shortages, this organization also pledges not to use food crops to produce airline fuel or use excessive water to produce the biofuels.

Airplane engines are more efficient than they were in the past. According to SAFUG, a modern airliner uses 70 percent less fuel than the airliners that were in use 40 years ago. Some airliners are even more efficient, and there are some smaller commercial airliners that only use as much fuel as a car, such as the Boeing 787.

Logistics improvements can also reduce fuel costs and reduce pollution. Updating air traffic control systems allows airplanes to arrive at an airport without waiting in the air for several minutes for a runway to open up for landing.

Some airlines purchase their own carbon offsets, but they may also make offsets available as an option when a customer purchases tickets. According to Virgin Australia, about 10 percent of passengers who purchased tickets online also purchased carbon offsets, although only 1 percent of passengers were willing to purchase carbon offsets after buying tickets. Carbon offsets balance the emissions that the airplane produces by removing carbon emitted by other sources.

To eliminate carbon emissions without offsets, some car manufacturers are producing electric vehicles. Most electric car engines available for purchase are weaker than gasoline powered engines, and this also holds for airplanes. Some smaller airplane manufacturers have successfully produced electric airplanes. According to the University of Tennessee, smaller airplanes can run on electric power. An electric airplane can use a combination of fuel cells and solar panels, so that it can recharge some of its energy while flying. Like electric cars, electric airplanes usually have a shorter range because petroleum based fuel stores a large amount of energy in comparison with other power sources. Texas A&M University gives an example of an electric powered airplane prototype that has much larger wings than a standard airliner, but is also a lot lighter.

Fuel Efficient Airplane Engines

Posted by on Friday, 10 September, 2010

I went on a plane trip from Los Angeles to Minneapolis, and while I was waiting in the terminal I picked up a copy of the Economist to read. In the Economist’s Technology Quarterly, there is an article called Powering Up, that explains how to make airplane engines more efficient.

The Economist reports that modern airplane engines use about half as much fuel as the first jet engines did, but there is still a way to reduce their fuel consumption by another quarter. David Lior of R-Jet Engineering is building engines that have spinning rotors in their combustion chamber. Engines have fans that rotate air, but usually these are only in the compressor, which is in front of the combustion chamber. NASA provides an explanation of each part that makes up the airplane turbine. Notice that their example of the compression chamber does not contain rotors or fans, although several sections of the engine do. When the rotors circulate the air, it ensures that the fuel and air mixture steadily mixes throughout the chamber, ensuring that all of the fuel ignites so no fuel is wasted. This not only conserves fuel, it reduces combustion because complete combustion reduces the amount of smog and acid rain caused by byproducts that do not completely burn.

R-Jet would like to place these turbines in jet planes, but this new type of engine will require demonstration of its safety before the airlines will purchase an engine with this type of combustion chamber to use in a passenger jet. R-Jet’s plan involves using this technology to operate wind turbines, since a failure of a single turbine would not be critical if it occurred in a farm with a thousand turbines. The other demonstration use of these engines is in unmanned drones, such as Predator drones. If these crash it costs the military a lot of money, but it wouldn’t kill a pilot or any passengers. Since this orbital combustion nozzle technology reduces fuel capacity requirements, it could also increase the range of a missile.

According to Globes Online, airplane engines are much more efficient than car engines, but only at high speeds. Inventors at the firm Newton Technologies created an engine that combines the best efficiency aspects of the traditional combustion engine and the airplane engine. This combination engine is much smaller than the engines in most vehicles, greatly reducing the material requirements to build a car engine. A larger engine that produces much more horsepower than cars normally have would still easily fit in a car. The inventors also mention that this type of hybrid engine can burn many types of fuel, including biodiesel, without additional modifications.