Every year many Israelis celebrate Yom Ha’atzmaut by adorning their cars with flags. Like most I assumed these would have some kind of deleterious effect on fuel economy and one tweeter even told me they increased fuel use by 8%.
As usual I put two of these flags on my car this year. Any difference they make to my car would be exactly the same on a petrol car, it’s just the absolute efficiency of my car is much easier to measure. If my range is 120km in normal use including freeway driving at fast speeds, an 8% reduction would drop that range by 8% which is 10km.
Well it didn’t I drove to Jerusalem and back twice with the flags in place and noticed no measurable increase in electricity usage. I drove at Israel’s legal limit (ahem) of 110km wherever possible. A straight drive from my home to Gina Sakarov switching station in Jerusalem had me arriving there with 30% battery. That’s absolutely the same as I usually experience without flags.
Overall, for the couple of weeks I’ve had the flags on the car, I can see no significant increase in electricity use.
I’m sure they make some difference, but it’s sub 1% and very hard to measure, even on an electric car as sensitive to this kind of thing as mine. Rain actually makes more of a difference.
Brian, I would be interested to know the effect on fuel economy if you drove the same route with your head stuck out the window. I bet there would be some real drag there.
Why would you ever drive with your head out of the window ?
My dad did it once because of a broken windshield, but not exactly the most safe and fun way to travel, plus there is the question of the “stoning birtheight” of Palestinians and I wouldn’t want Brian to lose his face for an experiment.
I think Brian is just dedicated enough to the scientific method and having a strong desire to satisfy his intellectual curiosity to do it. I never thought about the stone throwing aspect, but I think it’s well worth it for Brian to take that risk to advance this scientific discovery.
How much of an effect do you notice driving in the rain?