Has anyone measured the impact of wind on FE?

[bear15]

Has anyone measured the impact of wind on FE? We seemed to get significantly better FE with a tail wind.

[brick]

Wind has a huge impact. Not just head and tail winds, but crosswinds too.

[basjoos]

The effect of winds is fairly straightforward. For head or tail winds, you add or subtract the windspeed to your groundspeed to see its effect on your FE. If you are traveling at 55mph into a 25mph headwind, your car is seeing the aerodynamic drag of traveling at 80mph (lousy FE). Change it into a tailwind and your car is seeing the aero drag at 30mph (great FE). For crosswinds it gets a little more complicated, since a lot of cars have a drastically lower Cd when the wind is approaching at an angle rather than from straight ahead. Its effect on your FE would depend on the crosswind component of the wind and your car's Cd at that wind angle.

[xcel]

Hi Bear15:

___Have not seen a better study then that created by Wayne Brown over at Hybrid Synergy Simulator. The following link in particular is particularly brilliant imho.

Wind assist screens.



___Good Luck

___Wayne

[bear15]

Hi Xcel ~ I could not get this link to work. Any suggestions?

[xcel]

Hi Bear15:

___I blew the url tag on the first link. The second should have worked however? Both should work for you now. Sorry about that

___Good Luck

___Wayne

[bear15]

Wind Speed Effect on Fuel Economy

How much effect does wind direction have on fuel economy using a 2006 Honda Civic Hybrid (HCH II)?

Methodology

We completed 3 sets of testing. We drove one mile into a headwind of 5 miles per hour (MPH) or more, turned the car around, recorded Trip A miles per gallon (MPG) meter at precisely a distance of one mile, reset Trip A MPG meter, and drove the same distance in a tailwind and then record the MPG. We traveled from 0 - 35 MPH keeping the revolutions per minute (RPM) just under 2000 until we reached 35 MPH and maintained this speed for the remainder of the one mile stretch. We also recorded how long it took for us to go from 0 – 35 MPH and how much time to complete the total 1 mile stretch.

We recorded: MPG, Wind Speed based on Kestrel 3000 Pocketweather meter, Temperature based on reading recorded from car’s computer readout, car’s MPH, Time from 0 – 35 MPH and total 1 mile distance (under 2000 RPM).

Materials and Equipment

-Kestrel 3000 Pocketweather meter
-Stop Watch
-Chart for recording
-Compass
-2006 Honda Civic Hybrid (HCH II)
-Writing Utensil

Conditions

Fairly level road, headwind of 5 MPH or more, sunny, relative humidity 34%, approximately 1:00 PM central standard time, traffic was not a factor, tire pressure was 55 pounds per square inch (psi), all windows were up and fans were off, the gasoline tank was half full with regular unleaded, and location was rural Plainfield, IL.




Odometer Start: 8,746.7

Trip A Start: 381.3

Trip A MPG Start: 52.8

Odometer End: 8,753.5

Results

Average MPG with headwind: 58.233 MPG

Average MPG with tailwind: 69.133 MPG

Outcome: There was an increase in Fuel Efficiency of 18.7% with tailwind

[tbaleno]

WOW. I new there was a benefit, but I didn't think the difference was so large.

[kickflipjr]

Thats only with a 5-7mph wind. 15-20mph winds could be dramatic.

[philmcneal]

so the more areodynamic the car is, the bigger benifit for the tailwind?