multiply 22-mph by the 'scale' to get the proper air velocity required to achieve the necessary Reynolds number and necessary turbulent boundary layer.
EXAMPLE: 1:24-scale requires 24 X 22= 528-mph test section air velocity, however, that puts you in 'transonic' flow with shockwave drag, wrecking any chance of learning anything useful.
Carmakers start @ 1/4-scale, then enlarge models as designs are culled in the tunnel, leaving only more promising shapes for the more expensive models ( $ 68,000 for 1/3rd-scale, in 1988 Dollars ).
