It was suggested last week that we should run with a theme of Supersonic Transports this week, or SST’s. We liked the idea, and there’s a huge wealth of topics to discuss, so we decided to run with it. And what’s one of the first things that come to mind when that topic is raised? Why, the droop nose, of course.
So what’s the scoop there? Well, simply put, the Concorde was designed as a delta-wing aircraft. This meant that the craft eliminated the need for horizontal tailplanes, as the massive wings served a dual purpose; it was considered the leading technological option of its day, and the most useful for an efficient supersonic airliner. That design, however, produced a unique problem for pilots attempting to land the craft.
A delta-wing design requires a greater angle of attack on landing, which means that the nose is pointing higher in the air than it would be on a conventional airliner. As such, with the severely pointed nose required for the Concorde to efficiently achieve supersonic speeds, the pilots would be effectively blind when attempting to land. Concorde’s designers solved this problem with an innovative nose-section that moved or “drooped” when the craft was landing. Not only did the nose move, but the forward windscreens could adjust their position to allow the pilots even greater visibility. There were three positions for the nose, one raised to the horizontal, one drooped by 5°, and one drooped by 12.5°, depending on the requirements.
While behind the scenes facts are hard to come by from the Soviet Union, there are reports that the Tu-144 adopted the Concorde’s droop-nose design without fully understanding its purpose, or the variety of functions it was designed to perform. This would seem accurate, as the Tupolev was designed to land at over twice the speed of the Concorde; it could not maintain the higher angle of attack that the Concorde relied on for its low-speed landings without stalling, and as such the drooping nose was not as critically important. Nevertheless the Tupolev and the Concorde were the only planes built to utilize this design, and it remains their trademark even in retirement.
In later years, wing design has improved to the point where this feature would be unnecessary were the craft built today. Nevertheless, the engineers commitment to innovative solutions to solve a problem that their technology could not overcome make for a design that we cannot help but admire.
[Image source: ConcordeSST.com]