|The cone hanging from the top of the vertical fin is a static air-pressure drogue.
Why did Boeing do that? If you walked around the Boeing 787, you may have wondered about some of what you saw.
Here are a few answers:
The cone hanging from the top of the vertical fin is a static air-pressure drogue. A difficult flight-testing task is calibrating the airspeed indication system. The problem: finding truly “static,” free and undisturbed air pressure.
The solution: trail a static port far behind the airplane to measure undisturbed air. The cone’s drag keeps the static port behind the airplane.
The pointed shark teeth on the trailing edge of the engine nacelles are a form of vortex generator. Exhaust from a high bypass turbofan engine is a combination of cold high-volume, low-velocity air from the bypass fan and hot, low-volume very high-velocity air from the engine core. The “teeth” help mix the two exhaust streams. The better mix between the two streams, the more efficient and quiet the engine.
The 787 fuselage is made mostly from composite materials, but if you look closely you will see rows of fasteners similar to those on a metal airframe. Those fasteners support the resin that bonds the composite material so a small bonding failure does not degrade the structure’s overall strength.
Did you notice how quiet the auxiliary power unit (APU) was on the 787? APUs—a small jet engine turning a generator to produce power while the jet is on the ground—often shriek at almost unbearable levels. Boeing’s clearly quieted 787 APU meet new international regulations demanding quieter operation.
What’s with all those orange wires visible all over landing gear, wheel wells, and all over the cabin (if you were fortunate enough to tour the airplane)? They carry test data to computers and recorders and their color is an indication to everyone involved that they will be gone in finished airplanes.
Read more about the Dreamliner and see video