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Now some technical stuff
The first thing to calculate is the size and power required.
Ideally the tunnel would accomodate a full scale car or small plane without having to have a tanker ship engine to power it.
Reportedly several "small" engines and propellers can be run parallel.
For wind flow and speed calculation ease all propellers will need to be identical. Do all propellers need to run at the same time? At the same rpm?
Some wind tunnels like A2 a2wt.com can operate them at different rpms. Why is that?
What ratios of propeller area to test section area can be used?
I heard that higher wind speeds can be achieved by constricting the tunnel I mean a narrower test section area than the propeller area by Venturi effect.
How much of the test section cross area can be used for the model?
Are there ways to increase this useful area?
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