h a l f b a k e r yFaster than a stationary bullet.
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Car wheel spokes with airfoil cross sections could be used to
add a slight amount of active downforce to the rolling vehicle,
increasing traction.
Bubbling_20Turn_20Signals
Unfortunately the forces developed will play havoc with this idea... [normzone, Jun 18 2012]
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Unless you are actively controlling them, nope. It's not
possible for a passive blades system to produce a non-
uniform radial force. |
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Yes - how do these not give a force which when summed around the whole wheel, cancels itself out? |
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Couldn't you just duct a lateral airflow through the wheels downwards? |
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Downwards you might be able to do, but would produce a lift, not a downforce. Upwards would be through the body of the car, which might be possible on some models. I still wouldn't describe that as the rims providing the down force. |
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Regardless, it's going to be minimaly effective (ducting isn't all that efficient), and far, far less effective than a spoiler in the air-stream that produces a similar drag. Rolling resistance (which this would manifest as) is the last thing you want. |
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But doesn't the top of the wheel go through the air, while the
bottom is not moving? |
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//But doesn't the top of the wheel go through the air, while the bottom is not moving?// |
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You might have something there, but you're still dealing with three quarters of the rotation, with the forward and backward arc fighting each other. That might allow the wheel to produce some downforce from the top arc, but still only at the expense of considerably more drag than the equivalent downforce from a static spoiler. |
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Also the skin effect over the car would tend to negate your point somewhat, since the air right against the car is moving roughly with it. Still, valid point. |
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//But doesn't the top of the wheel go through the air, while the bottom is not moving?// |
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Indeed. There is an item which makes use of this imbalance of lift: a boomerang. However, I somehow doubt boomerang wheels would be beneficial. |
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// I somehow doubt boomerang wheels would be beneficial // |
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They would if you only ever wanted to go back to the place you started from ... |
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<mutters something about ground effect> |
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A bottom-heavy 'spinner' rim (like the ones on taxis that
have advertisements on them) with a canard wing
extending
out from it might work. Some ingenious manner of aerofoil
might be arranged to keep the spinner stationary and the
blade angled properly at higher speeds. It might interfere
with steering dynamics, however. |
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But why stop there? If a wheel can be cleverly configured to create downforce, why not apply additional cleverness and configure it to apply upforce? |
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The rims would have horizontal axes as in the current
art. Forcing air from the inboard side of the car to
the outboard, combined with the restriction of the
air rushing in to replace it (from the front, rear, and
in between the tires), would produce downforce. |
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[+] I'm not quite sure of the technical ability of this, but I love the idea of it! |
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"The rims would have horizontal axes as in the current art. Forcing air from the inboard side of the car to the outboard, combined with the restriction of the air rushing in to replace it (from the front, rear, and in between the tires), would produce downforce." |
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Ergo, forcing air from the outboard side of the car to the inboard, combined with unrestricted replacement air from the sides and top of the car, and outside the tires, would produce upforce. |
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Of course, I'm not buying stock in the Upforce Wheel & Flying Car Company until I see a working prototype. |
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For most downforce / best efficiency, you want your
spoiler to be doing all the work, since it's optimized
to make the most downforce per drag added. |
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I imagine a car with 4 splayed-out turbine/wheels,
tires bent at 45deg scrubbing/skidding madly as the
rims/turbines blow four plumes of blue tire-smoke
into the air. |
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That sounds about right. Better use beadlocks if you plan
on going around corners, too; car tries to go left, wheels
keep
trying to go straight, one or more tires go right and
suddenly pop off, and Jezzer
wins another fiver off Captain Slow. |
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