It can't be that costly to add an efficient motor to the landing gear so that the engines only need to be fired up once the plane is ready for takeoff at the head of the runway. When the capital development of a country becomes a by-product of the activities of a casino, the job is likely to be ill-done. — John M. Keynes
But for now everybody is looking for eliminating weight. For instance: stewards have to calculate before the flight how much coffee will be needed ( number of passengers, adults, duration..) so they can load the coffee-machine with what is needed and not a liter more.
Also the constructors try to find ways to eliminate weight: Boeing: Boeing Completes 737 Carbon Brakes Certification Testing
SEATTLE, May 02, 2008 -- Boeing [NYSE:BA] recently completed certification testing of new carbon brakes designed for the Next-Generation 737 airplane family by French supplier Messier-Bugatti. A Next-Generation 737-900ER (Extended Range) airplane is shown performing a high-speed rejected takeoff test, designed to verify that an airplane at maximum weight with greatly worn brakes can stop safely after a refused takeoff decision. Boeing will submit the test results to the U.S. Federal Aviation Administration for certification the second quarter this year. Entry into production is expected by third quarter. Boeing will offer a retrofit program for airplanes already in service. Through a month-long test program, Boeing reached its goal to show equivalent performance between steel and carbon brakes, and verified a weight savings of 700 pounds (320 kg) compared to high-capacity steel brakes for Next-Generation 737-700/800/900ERs, and 550 pounds (250 kg) on standard-capacity steel brakes for Next-Generation 737-600/700s. Reduced weight contributes to reductions in associated fuel burn and CO2 emissions depending on airline operations.
SEATTLE, May 02, 2008 -- Boeing [NYSE:BA] recently completed certification testing of new carbon brakes designed for the Next-Generation 737 airplane family by French supplier Messier-Bugatti.
A Next-Generation 737-900ER (Extended Range) airplane is shown performing a high-speed rejected takeoff test, designed to verify that an airplane at maximum weight with greatly worn brakes can stop safely after a refused takeoff decision. Boeing will submit the test results to the U.S. Federal Aviation Administration for certification the second quarter this year. Entry into production is expected by third quarter. Boeing will offer a retrofit program for airplanes already in service.
Through a month-long test program, Boeing reached its goal to show equivalent performance between steel and carbon brakes, and verified a weight savings of 700 pounds (320 kg) compared to high-capacity steel brakes for Next-Generation 737-700/800/900ERs, and 550 pounds (250 kg) on standard-capacity steel brakes for Next-Generation 737-600/700s. Reduced weight contributes to reductions in associated fuel burn and CO2 emissions depending on airline operations.
The struggle of man against tyranny is the struggle of memory against forgetting.(Kundera)
Tractors solve all of those problems, at the cost of some extra traffic control on the ground and perhaps some extra waiting around.
Airliner tugs were standard issue at airports thirty years ago. I'm not sure why they disappeared.
