Quote:
Originally Posted by freebeard
That seems reasonable. My 1600cc engine is supposedly produces approx. 1500cfm of cooling air and 1500cfm of exhaust.
I was thinking about the radiator air at max body width. In the wake I'd mix the exhaust and air at the last possible moment, in a stainless steel muffler tip that looks like a high-bypass jet engine.
The Dyson fan may be more or less efficient than you computer cooling fan. It's moving air at 55mph in a still room, in a moving vehicle more velocity might be required. But 1200cfm from 400watts would consume ~1/2 horsepower.
Note the circle is about 1 meter in circumference and the slot is 1.3mm. A 1 foot circle would be at the end of a long boattail.
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That'd be for mixing more air into the wake. They make some Coanda Effect fans that aren't round, they're oblong. I was thinking something like that for the tail air outlet. The engine exhaust would stand in as the fan in this example.
For the air through the cross-over ducts, I have no idea, nor even any idea of how to calculate it. I know my current radiator is about 6 inches by 8 inches and sits at the very front of the bike, and has an air scoop of about 8 inches by 10 inches that forces air into it. That's why my cooling fan has only ever come on twice in the ~10,500 miles I've ridden the bike. I can tell when the fan comes on because it forces warm air out through vertical slits right next to my legs, whereas usually the air flows down through the bodywork and under the engine, through the faired underbody, then out the back.
I suppose I could calculate how much fuel my engine uses, the energy content of the fuel, what the estimated engine efficiency is, how much heat it's throwing out the radiator, then back-engineer that to the radiator size and the airflow through the radiator at road speed, but it'd again be based upon a lot of suppositions and assumptions.