Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- The BWB has a long way to go before flying passengers, freight May 12, 2025
- Bjorn’s Corner: Air Transport’s route to 2050. Part 21. May 9, 2025
- Does an A220-500 need a new wing and engines? Part 2. May 8, 2025
- Embraer downplays tariff impact on 2025 results May 6, 2025
- JetZero readies effort for private equity fund raising May 5, 2025
Bjorn’s Corner: Aircraft drag reduction, Part 18
By Bjorn Fehrm
February 23, 2018, ©. Leeham Co: In the last Corner we discussed transonic flow and drag. Now it’s time to finish the drag type discussion by adding some less dominant but still important drag types.
Knowing their origin will help us understand why aircraft are made like they are.
Figure 1. Low-pressure (green) shows areas with high flow speeds for the 787 during cruise. Source: Boeing and Leeham Co.
Bjorn’s Corner: Aircraft drag reduction, Part 17
By Bjorn Fehrm
February 16, 2018, ©. Leeham Co: In the last Corner, we discussed supersonic flow and drag. Now it’s time to talk about the drag created by transonic flow on an aircraft.
Figure 1. Pressure distribution of 787 during cruise. Source: Boeing and Leeham Co.
Bjorn’s Corner: Aircraft drag reduction, Part 16
By Bjorn Fehrm
February 9, 2018, ©. Leeham Co: In the last Corner, we discussed some further aspects of supersonic flow. Now it’s time to talk about the drag created by supersonic flow on an aircraft.
We will start with the full supersonic case this week, followed by the transonic case next week.
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Bjorn’s Corner: Aircraft drag reduction, Part 15
By Bjorn Fehrm
February 2, 2018, ©. Leeham Co: In the last Corner, we discussed the basics of supersonic flow, to prepare for a supersonic and transonic drag discussion.
We will continue the supersonic aerodynamics discussion, however, as there are some further areas needing an explanation before we move on.
Figure 1. The first supersonic airliner, the Concorde. Source: Google images.
Bjorn’s Corner: Aircraft drag reduction, Part 14
By Bjorn Fehrm
January 26, 2018, ©. Leeham Co: In the last Corner, we discussed Induced drag after having covered Friction drag and Form drag. These are the main drag components of a subsonic aircraft.
As the aircraft flies over Mach 0.5, an additional drag is added, this time based on the air’s compressibility, transonic or supersonic drag.
Figure 1. The first supersonic airliner, the Concorde. Source: Google images.
Bjorn’s Corner: Aircraft drag reduction, Part 13
By Bjorn Fehrm
January 19, 2018, ©. Leeham Co: In the last Corner, we described how the boundary layer theory lead to the understanding of Friction drag for aircraft. The mechanisms behind Induced drag was understood about the same time.
Once again Prandtl was involved, but it was an English person who first postulated the physical root of induced drag, Fredrick Lanchester.
Figure 1. Focke-Wulf Condor, a high aspect ratio aircraft from the 1930s. Source: Wikipedia.
Bjorn’s Corner: Aircraft drag reduction, Part 12
By Bjorn Fehrm
January 12, 2018, ©. Leeham Co: In the last Corner, we described how the theory for the boundary layer was proposed by Ludwig Prandtl, and how this led to an understanding of the source of Friction drag for an aircraft.
We will now continue with describing how the role of Friction drag was researched and how aircraft designers learned how to reduce it.
Figure 1. Sopwith Camel fighter of the WW 1. Source: Google images.
Bjorn’s Corner: Aircraft drag reduction, Part 11
By Bjorn Fehrm
January 05, 2018, ©. Leeham Co: In the last Corner we described a dominant drag component affecting the Wright Brothers’ Flyer, Form drag. The many wires and braces on the Flyer created separations and a high Form drag was the result.
At the time, Langley and others thought friction drag could be neglected. Now we describe how it was discovered one couldn’t and how it gradually made its way to the top of the drag contributors.
Figure 1. The Supermarine Spitfire with its elliptical lift distribution wing. Source: Google images.
Bjorn’s Corner: Aircraft drag reduction, Part 10
By Bjorn Fehrm
December 22, 2017, ©. Leeham Co: In the last Corner, we described how the Wright Brothers flew a manned aircraft for the first time, propelled by its own power.
Now we will disscuss what was known about what stopped so many projects from achieving the flight distances the Wright’s could do, the aircraft’s drag.
Figure 1. The Wright Flyer flies at Kitty Hawk, NC, at 17th December 1903. Source: Wright-Brothers.org.
Bjorn’s Corner: Aircraft drag reduction, Part 9
By Bjorn Fehrm
December 15, 2017, ©. Leeham Co: In the last Corner, we described how the Wright Brothers developed the first theory for propellers. It was based on their wing work and allowed them to design an efficient pair of propellers for their 1903 Wright Flyer.
We will now describe their first propelled flights, December 1903, and prepare for looking at the lift and drag of the aircraft.
Figure 1. The Wright Flyer is prepared for flight at Kitty Hawk, 17th December 1903. Source: Wright-Brothers.org.