Quote:
Originally Posted by Big Dave
Excellent work, Sepp.
I think you are very close to the optimal shape. Yeah, a boat-tail or teardrp might have a lower Cd, the vehicle gets too long to be generally practical and a pickup is all about general practicality.
I like the curved shape. From the simulator ,the curved shape and the straight cap seem to have about the same drag characteristics, but the curved shape looks soooooo much more graceful.
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yup, the simulation showed how much more effective the theardrop shape was. i think something "could" be made, like a solid backpack that clips onto the rear to complete the virtual teardrop shape. and that would only be used when going on vacation or when doing trips that don't require city traffic or finding parking spots
it did seem to me from the simulation that mainly with the straight cap and also somewhat with my previous cap model, that the airflow tended to detach before reaching the end, and that the airflow coming from underneath was sucked upward back on the cap. wich all pretty much didn't happen with this model, but i think the outward curling rear edge of the cap helps preventing the rear turbulences from disturbing the airflow over the cap. i think an inward curling edge, like on bondo's cap looks nicer visually. but i think it encourages the rear turbulences to climb on the cap.
anyway there is already a notable difference on the road, i can coast down longer and i keep my speed much longer. on a downward slope where i used to lose about 10-15km/h when coasting down, im now only loosing 3-4 km/h wich caused some surprises as i need to adjust my driving again because i keep to much speed and need to waste energy through braking because i keep coming on to fast when i need to take a turn or so.