Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- Boeing unlikely to meet FAA’s 90-day deadline for new safety program April 18, 2024
- Focus on quality not slowing innovation, says GKN April 18, 2024
- Boeing defends 787, 777 against whistleblower charges April 17, 2024
- Dissecting Boeing CEO’s statement next new airplane will cost $50bn April 15, 2024
- Bjorn’s Corner: New engine development. Part 3. Propulsive efficiency April 12, 2024
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.
Bjorn’s Corner: Aircraft drag reduction, Part 8
By Bjorn Fehrm
December 08, 2017, ©. Leeham Co: In the last Corner we described how the Wright Brothers developed their own engine, as there were no light engines on the market.
After understanding how to design wings, how to control the aircraft and having designed a suitable engine, the final item the Wrights needed was a working propeller.
Figure 1. The Wright engine for its 1903 Flier, driving the pusher propeller in the background through bicycle chains. Source: Wright-Brothers.org.
Bjorn’s Corner: Aircraft drag reduction, Part 7
By Bjorn Fehrm
December 01, 2017, ©. Leeham Co: In previous Corners, we looked at how the Wright Brothers understood the wing aerodynamics and aircraft control.
We now describe how the Wright cracked the third nut keeping them from manned flight, propulsion.
When they had mastered the design of effective wings and control of their gliders (see previous Corners), the Brothers now worked on finding an engine and a functioning propeller.
Figure 1. The Wright engine for its 1903 Flyer seen from the underside. Source: Wright-Brothers.org.
Bjorn’s Corner: Aircraft drag reduction, Part 6
By Bjorn Fehrm
November 24, 2017, ©. Leeham Co: In the last Corner, we described how the Wright Brothers obtained the aerodynamic data they needed to design gliders and aircraft.
But there was additional knowledge they needed: how to control an aircraft and how to drive it forward.
Figure 1. The Langley manned Aerodrome crashes into the Potomac River 7th of October 1903. Source: Wikipedia.
Bjorn’s Corner: Aircraft drag reduction, Part 5
November 17, 2017, ©. Leeham Co: In the last Corner, we described how the Wright Brothers (bicycle manufacturers in Dayton (OH)) decided to research their own aerodynamic data with the help of their own designed-and-built wind tunnel.
The wind tunnel was not more advanced than what had been done before. But their measurement system was. It built on their bicycle test setup, Figure 1.
Figure 1. The Wright Brothers’ arrangement for testing wing shapes on their bicycle autumn 1901. Source: NASA.