This diagram drawn by the Wrights illustrates the aerodynamic forces action on the lift balance.
Scraps of wallpaper from the wind tunnel
Wilbur and Orville recorded the measurements
they made with their first wind tunnel on scraps of wallpaper
they laid in the bottom of the tunnel, including these pieces.
The brothers used the tunnel only for a day, but their results
again showed clear discrepancies with Lilienthal’s data.
The Wrights large wind tunnel
After building and testing a small wind tunnel,
the Wright brothers completed a larger, more sophisticated
one in October 1901. They used it extensively to carry out
aerodynamic research that proved essential in designing their
The wind tunnel consisted of a simple wooden box with a square
glass window on top for viewing the interior during testing.
A fan belted to a one-horsepower engine, which ran the machinery
in their bicycle shop, provided an airflow of about 30 miles
Wright wind tunnel balances
What made the Wrights’ wind tunnel unique
were the instruments they designed and built to measure lift
and drag. Called balances, after the force-balancing concept,
these instruments measured the forces of lift and drag acting
on a wing in terms that could be used in the equations.
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The balances are made from old hacksaw blades and bicycle
spokes. Their crude appearance belies their sophisticated
design. Largely the work of Orville, they represent a solid
understanding of geometry, mathematics, and aerodynamic forces,
and illustrate the Wrights’ engineering talents at their