Today's drafting experiment (Hypermiling/Ecodriving tip #38)

[PaulB2]

Get behind a big truck while riding a motorcycle. You'll see soon enough how much grit gets thrown at you, even on supposedly clean roads. I used to drive behind big trucks but I avoid them now. Maybe driving a beater it would be OK.

[RedDevil]

At 2 seconds distance there is no grit strike to speak of.
I see no benefit in getting any closer; turbulence increases close by and ruins the aerodynamic flow, nullifying any gain.
In my biking days I have felt the buffeting of the tail winds in the few instances I was that close by a truck. Usually when merging into a busy highway, the gaps don't get that big...

I can hear the occasional grit stone hit my car, but when that happens there is always someone very close by in the next lane.
It never happens when I'm just alone behind the semi and there's no car in the next lane.

[rbrowning]

I think you benefit from 3 factors:
1, you are going slower which may help your engine into a more efficient operating speed.
2, the big truck punches a big hole in the air for you reducing how hard your car has to work to go down the road.
3, drivers of big trucks sit up high and can see further down the road and they tend to maintain a smoother speed.

[whatmaycome14]

Originally Posted by rbrowning

I think you benefit from 3 factors:
1, you are going slower which may help your engine into a more efficient operating speed.
2, the big truck punches a big hole in the air for you reducing how hard your car has to work to go down the road.
3, drivers of big trucks sit up high and can see further down the road and they tend to maintain a smoother speed.

#3 especially! I drive behind trucks because at a 2-3 second distance, it is usually safer. AND of course better MPG...

[sendler]

Originally Posted by whatmaycome14

#3 especially! I drive behind trucks because at a 2-3 second distance, it is usually safer. AND of course better MPG...

Following is much safer than leading out alone.
.
http://ecomodder.com/forum/showthrea...ing-20209.html
.

[sendler]

More about the safety benefits of following was discussed here:
.
http://ecomodder.com/forum/378722-post34.html
.

[user removed]

3 stripes behind a big rig is right at 130 feet, a little less than two seconds depending on your speed. After almost 24 k miles with a good bit of that in traffic so heavy you get cut off if you leave more space (average separation 3-4 car lengths or 60 feet), my Fiesta's front end still looks great as well as the windshield and it was wrecked and repainted 24k miles ago.

I think I'm #38 on the gas car list and thats an auto tranny. My average speed is close to 40 MPH or higher on almost every tank.

I could P&G engine on and hit 65 if I wanted to average 25 MPH. I generally don't draft when traffic is light, mostly when it is unavoidable, which here is most of the time, and as was posted previously big rig drivers are professionals, expecially thoseewho are employees of corporations like WalMart or UPS. Another advantage is they are "agressive driver repellants".

regards
Mech

[user removed]

We drove 3.5 miles (each way) to the Mexican restaurant last weekend and I got to 50 MPG on that round trip (indicated),from a cold start and a restart.

regards
Mech

[digital rules]

Originally Posted by Old Mechanic

We drove 3.5 miles (each way) to the Mexican restaurant last weekend and I got to 50 MPG on that round trip (indicated),from a cold start and a restart.

regards
Mech

Awesome, just loving the warmer temps & summer gas. Jealous of you all down in Tidewater with some of the cheapest gas in the US

[serialk11r]

I definitely get rocks thrown at me by semis even at 2 seconds following distance, but I do employ Old Mechanic's "pulse draft" method and I try to draft vans and smaller trucks, as they don't rip the road up and spray it at my car. I love when impatient people tailgate me, the drag reduction is really noticable!