Put A Fairing On or PAFON
by Joe Mc.
August 2019
My other posts in this Renewable Energy blogger site have some energy efficient transportation blogs, so this one continues with that theme. Here I show how to build a fairing for a Gen2 Prius 2006. Fairings, whether in front or back, help reduce the energy to move. Cars tend to have abrupt rear ends, so the energy efficiency isn't great. Even the Prius has a large flat back hatch.
I recycled some discarded coroplast signs which in hindsight were the perfect dimensions. Four corners of the fairings are all the same, cut to the same template.
I free handed the template for this initial proof of concept. Any subsequent developments will have the blades cut to much better tolerances.
The metal wiring used to display the signs were utilized to help make the fairing robust. And it is all held together with zip-ties in strategic places and clear tape.
Two pieces of the Coroplast were used for the top and bottom (slightly less wide) as well as a back plate. 7 pieces of Coroplast total.
I had some signals with brake lights which I wired to the Prius, and have a license plate on the back. Used bathtub caulk and couple cans of spray paint. A Saris Bones trunk mount 3 bike rack is used to hold the fairing in place. The whole device weights in at 25 lbs including the Saris.
This fairing increases my gas mileage about 10% on initial testing, about 5 mpg more. I found that the lower speeds were better than higher speeds. Probably because many edge details are still not aerodynamic. The hatch is still completely accessible. Bungee cord loops through the tow connections under the car. But the hatch is hard to open because of the added weight.
If this is going to be permanent on the back of the car I have some more work to do. Move the back up camera lens to the back of the fairing. This will actually help a lot to make sure backing up is safe to not hit the bulbous fairing. And address edge details to increase aerodynamics at higher speeds. Already have decals and stickers to apply. Electric bolts, flames? The fairing has to withstand high winds, cross winds, rain, snow, ice and being hit.
Questions, comments; don't hesitate to discuss below? energyideas@gmailcom
