Quote:
Originally Posted by serialk11r
I understand the inside of the wheel itself being a big void probably contributes more drag than the spokes, but say you had streamlined spokes instead of the typical rectangular chunks, how much of a difference would that make? Would you be better off with a partial cover (a full cover missing a circle in the middle)?
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The concept of a streamlined spoke is kinda oxymoronish if you think about them.
*In a calm situation,the spokes are shielded inside the wheel from the oncoming flow.
*They are churning within an environment of sequestered air.
*Their boundary layers and individual wakes travel in a circular train with the wheel.
*If their next to an open engine bay,we'd probably have transverse flow,moving through the turning spokes,creating a pulsation perturbation which destroys the flow.
*If in a crosswind,some of the spokes may remain shielded,while others are attacked by the free-stream entering the void.
*If the spokes were airfoil sections,they'd perhaps have a minimum windage drag in the context of their peculiar flow,but it would still be intermittent flow.
*You can't model this in CFD yet.
*It would cost perhaps a $100,000 to experiment with them in a tunnel.
*Low drag concepts use full wheelcovers (or full disc wheels) inside a full skirt,if not with an inner fender as with Ford's Probe-IV.
*As far as aesthetics and aero go,the closer you get to a full disc the better the drag situation,but then you lose the 'look.'
*If you were to cover partially,you'd cover the center and leave your opening out close to the rim.