Wind Tunnel Test

Constructing the Model

When we decided that wind tunnel tests were worth doing, one of the first hurdles we faced was obtaining the 1/8^th scale model that would be used for the tests.  Constructing a wind tunnel model is no easy task.  It requires a lot of engineering know-how and a lot of time.  Not only must the model faithfully reproduce the full size aircraft (right down to the small details), it must also be structurally sound (the “wind” in the wind tunnel that was used for the Phoenix tests was traveling at about 230 knots).

Fortunately, one of our guys happens to be an Aeronautical Engineer and a whiz at CNC machining and he was able to do the job really well.  Basically, the first step in the process was to provide him with CAD files showing the scaled down airplane with the model surfaces defined.  He then translated the surface information from the CAD files into “machine language” that the computer on the CNC mill understood (this language produces a matrix of X-Y-Z points that tells the cutter where to go, in space).    

The model shown in the photos below was machined from solid 6061-T6 billets using a 4 axis CNC mill, over a period of 4 months.  All the components were then finished by hand to produce the surface smoothness required for the tests.  Note the detail.  Even the canard flap tracks (very small components) are faithfully reproduced.  The hollow fuselage (cut in two halves), incorporated the mounting interface between the model and the wind tunnel apparatus as well as an internal sensor used for determining model pitch angle.

GALLERY (click to enlarge)
Figure 1 - Machining the Fuselage	Figure 2 - Machining the Wing	Figure 3 - Completed Fuselage
Figure 4 - Wing and Fuselage	Figure 5 - All the Parts	Figure 6 - The Finished Model
Figure 7 - Wing Flap Detail	Figure 8 - Canard Flap Detail	Figure 9 - Canard Flap Tracks