Letter: Letters : Model example

From Stephen Gloor

Perth, Australia

I wonder if the aerodynamics expert Mark Drela was aware of the body of
research done by Michael Selig and others on low Reynolds number aerodynamics
(“Where aircraft fear to go”, 31 May, p 34).
My knowledge of this research comes
from designing and flying high performance model sailplanes that operate at
Reynolds numbers of 300 000 and below.

Selig has been designing and testing aerofoils specifically for this flight
regime in a specially designed wind tunnel. In the article it states that it is
not possible to mimic the flight of an aircraft at Reynolds number 300 000.

The wind tunnel at the University of Illinois routinely tests aerofoils for
use in model gliders at these Reynolds numbers. Perhaps the design work would
have been easier if Drela flew F3B Triple Task gliders.

These gliders fly efficiently at low Reynolds numbers using special laminar
flow aerofoils designed to reduce problems with boundary layer separation and
reattachment.