Future Transportation Systems - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 272

17.2.1 Near Future Phases of Development
New technological innovations to reduce of fuel consumption will remain the
focus of future airplane technology. Airplanes with large capacity and low oper-
ating costs will work more reliably and sustainably than current types. Future
commercial aircraft will use highly advanced technology, but without spectacular
innovations, similar to other types of transportation.
The design objectives in aviation are lighter structures, better aerodynamics,
and new jet engines with lower fuel consumption, lower pollutant outputs, and
GHG emissions and maximum safety.
17.2.1.1 Improved Aerodynamics
Reducing drag ensures the most benefits in fuel consumption and lowers operating
costs. The improvement in the wing geometry of older models, compared to new
types of airplanes could decrease aerodynamic resistance by approximately 12%.
Variable wing profile in the rear area of the wing could also save 8-10% and will
be advantageous especially when applying extended flaps. Improving aerody-
namics is expected to save 3-4% of fuel while cruising despite the larger size and
weight. The wing box would remain unchanged [ 29 ].
Winglets at the wing tip will be widely introduced and will already increase the
aerodynamic efficiency of airplanes in the near future.
17.2.1.2 New Materials and Designs
Noticeable weight savings are expected through the use of better materials and
improved designs. The best examples are aluminum-lithium alloys, which are 5%
stronger and 10% lighter than conventional aluminum alloys [ 30 ].
In the future, Carbon Fiber Composite (CFC) will be extensively used in load-
bearing structures such as the wings and the fuselage. Reducing weight with CFC
will reduce fuel consumption by up to 25%. The rudder assembly was the first
primary structure built with CFC material.
Today, CFC has already proven itself in secondary structures such as in spoilers
and in landing gear. In the future both the quantity and the quality of new com-
posite materials will increase. However, they will only become advantageous if
their costs are reasonable, the inspection and the maintenance requirements do not
increase, and the risks of using them are safely controlled.
17.2.1.3 New Fuels for Engines
Several airplane manufacturers are attempting to introduce new fuels for airplanes.
Not only environmental and climate protection, but also the price of conventional