DIY full size wind tunnel

[NeilBlanchard]

I have a couple of leaf blowers, and that could be useful! Tuft testing can take various forms.

[aerohead]

your reading should have revealed that your model cannot exceed 5% of the cross-sectional area of the tunnels test-section.
So 5% of your garage test-section will define your model size.
Verisimilitude is your next challenge.Based on your models frontal area, the test-section air velocity would need to be such that you achieved at least the same Reynolds number as say at 20mph at full-scale.
If say you had a 1/4-scale model,you'd need a minimum of 80 mph air in the test-section to get your Reynolds number.
For a 1/4 model of a 22 sq ft frontal area car you'd need a 110 sq ft section.
That would require 774,400 cubic-feet per minute of air.
It would get loud and expensive.
The tunnel at Texas Tech has only a nozzle of around 3X4 feet,@ 80 mph and requires a 50-hp motor ( 37,300 Watts ) which exceeds the typical electrical service for a home.
And my experience is that models cost more to build than a real car.

[Vekke]

#hangintherebaby Blog on deviantART: MythBusters 7.16 - Hurricane Windows

I saw mythbusters last week and this was there. Best way to make the tunnel portable like they have done. Already contacted the manufacturer of that Medusa and try get more info. Costs of that machine was 500000 dollars.