I finally have measured the frontal area of the new shape and the result has been good as the frontal area for this new shape is 0.36m2.

Calculating the CdA is now 0.36 x 0.21 (Cd) = 0.0756 CdA.

I can calculate using this excellent calculator power outputs and speeds for Veloci-velomobile. The graph below shows that for a modest 150W of power a speed of approx. 46 km/hr can be attained. I used 150W because this is what a untrained but fit cyclist could acheive for any length of time.

Calculating the CdA is now 0.36 x 0.21 (Cd) = 0.0756 CdA.

I can calculate using this excellent calculator power outputs and speeds for Veloci-velomobile. The graph below shows that for a modest 150W of power a speed of approx. 46 km/hr can be attained. I used 150W because this is what a untrained but fit cyclist could acheive for any length of time.

I also found that smoothing my final shape did not make any real difference to the Cd factor, at the most it would have changed it by 0.1 so it is best to leave it as is. Now to build the models and then the real thing!

Did you consider a tapered front end (pointy like a missile or airplane)?

ReplyDeleteYes a pointy front would help the aerodynamics a little but would add too much length which in turn would make the velomobile more unstable in a cross-wind.

DeleteI would have guessed that without making it longer, it would be possible to tuck in the bottom of the front end, and that doing so would help with cross winds, and common off axis "true winds"

ReplyDeleteI see your point of view. My thinking is to allow air to flow around the vehicle and not under as the ground clearance is less than 100mm

ReplyDelete