The wind tunnel tests done by the Wright brothers were useless
The Wright brothers were not the first to test scaled wings in wind tunnels as Wilbur claimed and the results, obtained on the scaled down models, could not have been useful for the real life plane.
By comparing what Wilbur claimed in (1) with the results obtained in (2), it becomes clear that W. Wright lied about the usefulness of its wind tunnel tests. His experiments would have been of no utility for designing a real size Flyer.
(1) "We finally stopped our wind tunnel experiments just before Christmas, 1901. We really concluded them rather reluctantly because we had a bicycle business to run and a lot of work to do for that as well.
It is difficult to underestimate the value of that very laborious work we did over that homemade wind tunnel. It was, in fact, the first wind tunnel in which small models of wings were tested and their lifting properties accurately noted. From all the data that Orville and I accumulated into tables, an accurate and reliable wing could finally be built. Even modern wind tunnel data with the most sophisticated equipment varies comparatively little from what we first discovered. In fact, the accurate wind tunnel data we developed was so important, it is doubtful if anyone would have ever developed a flyable wing without first developing this data. Sometimes the non-glamorous lab work is absolutely crucial to the success of a project.
In any case, as famous as we became for our "Flyer" and its system of control, it all would never have happened if we had not developed our own wind tunnel and derived our own correct aerodynamic data.
- Wilbur Wright"
Source: The Wright Brothers' Wind Tunnel
(2) "Based on the most accurate surviving description of the Wright Brothers’ wind tunnel, a replica was constructed and used to determine the effect flow quality and experimental method had on the Brothers’ results, and whether those results were useful in a quantitative sense.
The research incorporated static and total pressure measurements, velocity surveys across the jet, and quantitative flow visualization. Velocity surveys involved high resolution dynamic pressure measurements along the horizontal and vertical test section axes. Particle image velocimetry provided velocity magnitudes, turbulence intensities, and vorticity measurements in the test section. Force measurements on an airfoil model supported the conclusions regarding the effect of flow characteristics on aerodynamic measurements.
Testing revealed boundary layers extending 2.5″ from each wall. In the center of the tunnel was a 5″ diameter “dead zone” in which the flow velocity was 20% lower than the maximum tunnel velocity. Isolated pockets of high velocity flow reaching 35 mph existed outside the “dead
zone”. PIV data revealed asymmetric load distributions on the airfoil due to velocity and vorticity gradients, and indicated the Wrights’ lift measurements were at least 7% low due to flow interactions with the lift balance. Direct force measurements showed the Wrights’ lift measurements were at least 6% and as much as 15% low depending on the Wrights’ true tunnel velocity. Scaling from the tunnel to the Wright Flyer increased the CL discrepancy by an additional 14% and showed the Wrights’ drag prediction to be 300% too high, resulting in highly inaccurate efficiency predictions. Thus, though they learned a great deal from their wind tunnel experiments, the Wrights’ quantitative data was not applicable to full scale design.
...
Because of this, the Wrights would have greatly over predicted the drag on their wing. Significantly, this prediction would have forced the Wrights to seek a much greater thrust and much larger engine than actually necessary to overcome the inflated value."
Source: Michael Gary Dodson, "An historical and applied aerodynamic study of the Wright Brothers' wind tunnel test program and application to successful manned flight", Trident Scholar project report no. 335, year 2005,
http://www.dtic.mil/dtic/tr/fulltext/u2/a437187.pdf