February 24, 2023, ©. Leeham News: In the Sustainable Air Transport series we finished last week, we described new aircraft technologies developed to reduce Green House Gas (GHG) emissions.
There was one area we didn’t discuss, the progress on conventional technologies to reduce the fuel burn of an airliner.
We now start a series, digging deeper into what we can do with conventional technologies to reduce the fuel burned per passenger kilometer and, thus, GHG emissions.
The emissions from burning fossil fuels are at the root of our GHG emissions and, therefore, climate problems. In the Sustainable Air Transport series, we covered what new untried techniques could do in addition to Sustainable Aviation Fuel, SAF, to help lower GHG emissions.
We found only SAF can give short-term relief. But the continuous work on lowering fuel consumption per passenger-km also helps, and we didn’t cover this development.
Now we go through conventional areas that all target a more economical and environmentally friendly future airliner. We divide it on the aircraft-level into airframe and propulsion improvements.
We will cover new structural and aerodynamic developments that aim to lower mass and drag, thus reducing fuel consumption.
Boeing’s truss braced wing work, Figure 1, is an excellent example of such developments. Why does it decrease airplane drag and lower mass? What are the positives and negatives? What are Airbus and other players doing in these fields?
We also look at developments on the propulsion side. What’s the advantage of the geared turbofan? Can direct drive designs continue to evolve?
What about Open Rotor and CFM’s Open Fan called RISE? What are the similarities and differences between Open Fan and Open Rotor? Which solution is better?
If the Open rotor/Open fan is a better way to drive the aircraft forward, why hasn’t it happened to date? The technology was flight-trialed 35 years ago! What has changed that now makes it more likely to find a commercial application?
We will go through all this in depth. To dig deeper, we will use the Leeham aircraft design and performance model to analyze the airframe improvements and GasTurb to look at the propulsion developments. We start with airframe developments next week.