DIY measure your drag coefficient and rolling resistance

[dieck]

http://www.instructables.com/id/ELEE7STF5Y3TMFK/

This was an interesting article on make.com on how to calculate your own drag coefficient and rolling resistance. With many of your rolling bricks with airbrakes, I thought it might be useful to some of you debating on that roofrack with 15 driving lights.

Good comon sense article.

 

[articulate]

Good comon sense article.

Did you see the photos and captions on the following steps? Those cracked me up. Photon generator. Nice stopwatch, huh? How about the "primitive data storage medium?"

"This is just a girl I found on the side of the road. I said, 'Quick, get in, I need your help with an important scientific experiment.' Works every time."

I give him an A+ for doing a tech article with some quality humor.

 

[DaveInDenver]

Nice, I dig it.

BTW, geeky stuff... I did something like this once and found that using the assumed density of air can introduce some error. Most people assume dry air density at sea level and 25C, but adjusting for temp and altitude alone can change that significantly. For example at 85F in Denver (using 5,280'), ignoring humidity, the density of air would be 0.9563 kg/m^3 (the assumed value is usually 1.2). It can be a fairly significant when you calculate Cd.

 

[dieck]

Nice, I dig it.

BTW, geeky stuff... I did something like this once and found that using the assumed density of air can introduce some error. Most people assume dry air density at sea level and 25C, but adjusting for temp and altitude alone can change that significantly. For example at 85F in Denver (using 5,280'), ignoring humidity, the density of air would be 0.9563 kg/m^3 (the assumed value is usually 1.2). It can be a fairly significant when you calculate Cd.

Good info! Thanks for sharing.

 

[dieck]

Did you see the photos and captions on the following steps? Those cracked me up. Photon generator. Nice stopwatch, huh? How about the "primitive data storage medium?"

"This is just a girl I found on the side of the road. I said, 'Quick, get in, I need your help with an important scientific experiment.' Works every time."

I give him an A+ for doing a tech article with some quality humor.

Yeah, Make is filled with interesting folks. Most of an engineering / tech bent. I find it an interesting read tho as I always learn something.

 

[DenCo40]

Every time I add some power creating / gas saving item to my truck. I always find something else to bolt on to make it even out to where i was before....