6 Wind and Water Tunnel Equipment
439
Fig. 6.68 Outdoor scene of a variable density wind tunnel at the Langley Research
Center in NACA
Fig. 6.69 Aerodynamic profile of a variable density wind tunnel at the Langley
Research Center in NACA
have been accustomed to classify the airspace at this height as adjacent
space. For the high-altitude airship, if the airship can use the low-density
air to overcome the gravity, and with the help of the propeller propulsion system to overcome the atmospheric circulation resistance to achieve
a fixed point in the air, then the stratospheric airship has a wide range of
military and civilian value. In recent years, the United States, the United
Kingdom, Germany, France, Russia, Japan, South Korea, and China have
put forward corresponding research plans, setting off a worldwide research
upsurge of the stratospheric airship. According to the change curve of
wind speed with height (as shown in Fig. 6.71) the propeller propulsion
system needs to be at the wind-resistant speed of 10−20 m/s, so it is
439
Fig. 6.68 Outdoor scene of a variable density wind tunnel at the Langley Research
Center in NACA
Fig. 6.69 Aerodynamic profile of a variable density wind tunnel at the Langley
Research Center in NACA
have been accustomed to classify the airspace at this height as adjacent
space. For the high-altitude airship, if the airship can use the low-density
air to overcome the gravity, and with the help of the propeller propulsion system to overcome the atmospheric circulation resistance to achieve
a fixed point in the air, then the stratospheric airship has a wide range of
military and civilian value. In recent years, the United States, the United
Kingdom, Germany, France, Russia, Japan, South Korea, and China have
put forward corresponding research plans, setting off a worldwide research
upsurge of the stratospheric airship. According to the change curve of
wind speed with height (as shown in Fig. 6.71) the propeller propulsion
system needs to be at the wind-resistant speed of 10−20 m/s, so it is