Thursday, June 12, 2008
What Reynolds number fits into my car
I was thinking which is the highest Reynolds number I can fit into our car for transportation. And it seems like it goes as low as 136000, which makes 40 km/h stall speed (~10 m/s) in wing chord being 0.2 m and length 2 meters where aspect ratio becomes 10. This would already require two separate wings, joint left and right wing are not feasible to transport. So the airfoil selection gets a new twist, I can not reach 500000 in any meaningful way with high aspect ratio wings on a model that fits into a car. Also the achievable Cl is quite limited on the low Reynolds number and Cd is not as nice as could be achieved with higher Reynolds numbers. Even this is quite overkill as 40 km/h is very fast for a small model aircraft.