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Author Topic: Air tempeture effect on air flow  (Read 287 times)
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Location: Chicago
Posts: 4

« on: December 10, 2018, 09:21:40 AM »

Does the temperature of the air flowing across a body have different effects on the aerodynamics?

Basically are they better on a cooler day verses a hot day?

What about engine exhaust, exiting a car mid body and flowing over the body verses coming straight out the back?

I know is kind of a general question but i don't know the answer.

thanks, john

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Age: 72
Location: Costa Mesa, California
Posts: 107

« Reply #1 on: December 10, 2018, 10:13:10 AM »

Air drag, lift, and downforce all go up and down with the air temperature.....

The "rule of thumb" rate is 1% per 11 degrees F of change...

Exhaust thrust is very real with larger supercharged power plants....

Exhaust should be directed as aft as possible and into a "low pressure"
region if possible (such as the wake of the vehicle)....

The WWII P-51's forward thrust (at extreme altitudes where the propeller became more and more inefficient) it was estimated that 20% was contributed by the exhaust and the radiator ducting.....

Robert "Smitty" Smith
Red Baron Race Team
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Location: Llano, CA
Posts: 123

El Mirage M-PG 1000cc record, 141.693

« Reply #2 on: December 10, 2018, 10:13:18 AM »

since hot air is less dense than cool air, I'd say yes.
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