more money
Without wind tunnel testing and other testing, testing in flight would be even more dangerous to the test pilot, and anyone killed should the aeroplane crash.
the purpose is they can find the best shape to go with the wind
In a wind tunnel test the plane never leaves the ground. It's only to see how the wind will affect the plane. When your testing during real flight, your actually in the sky and really flying the plane.
real-time analysis of a model, as you can edit it on-site.
Alan Pope has written: 'Low-speed wind tunnel testing' -- subject(s): Wind tunnels
Robert Frank Robinson has written: 'Introduction to wind tunnel testing'
There is usually an additional throat placed in the tunnel downstream of the test section to shock down the supersonic flow to subsonic. The advantage of a supersonic continuous flow wind tunnel is the longer run times relative to a blowdown tunnel. The major disadvantage is the increased size and operating costs.
R. L. Tobler has written: 'Materials for cryogenic wind tunnel testing' -- subject(s): Cryogenic wind tunnels
A wind tunnel.
The wind tunnel was developed by the American engineer and inventor Frederick W. Lanchester in the early 1900s. He is credited with creating the first closed-circuit wind tunnel in 1907, which allowed for more controlled and accurate aerodynamic testing. Lanchester's work laid the foundation for modern aerodynamics and contributed significantly to the field of aviation and fluid dynamics.
Wind tunnel testing is generally very expensive and time consuming. In addition, if the object to be tested (i.e. a car, an airplane) is too big to fit in the tunnel itself, a very accurate scale model must be produced, and Reynold's numbers (a number describing the flow conditions over the object) must be accurately matched to the expected operating conditions. These models can be prohibitively expensive as well.
A subsonic wind tunnel is a wind tunnel that cannot take testing to Mach 1 (the speed of sound). There are a wide variety of wind tunnels, and they come in a broad range of sizes, too. They span models from ones that test motorcycle helmets to ones that test a whole small aircraft or aircraft model. A link is provided to the Wikipedia article on the wind tunnel, and you'll find that link below.