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We already know that driving closer the truck saves fuel from mythbusters and other tests done earlier in the books like hucho... What I would like to know what are the savings at proper safety distance like @ 62 MPH 100km/h 3 seconds rule --> 273 feet or 83,4 meters
Also modify the truck lenght so that it is 83,4 meters/4 --> 20,85 meters
Then do simulations also to 62,25, 41,7 meters safety distances. According to Huchos book the drag should decrase with similar steps or how was the example in the book. Someone who has that book can tell the basic laws valid to this drafting.
Lastly make a truck train with 4 trucks with 41,7 meter safety distance and keep the same distance to the last truck with the car 83,4 meters. You should see some nice results this way.
How long does it take to make one simulation like that?
Here is waht I wrote to TDIClub forum on the similar topic:
There are benefits already at that distance about 3 second and more. Savings will come related to the vehicle length in front of you and how large cross section does it have. Also your own car Cd effects and the cross section you have in your car. If I would drive behind small car there would be no gains at those distances. Check book aerodynamic of road vehicles by hucho for hard data. If you like you can also find mythbusters test on the same topic Drafting Semi uploaded by tremorfalcon. 100 tf gave 11% better fuel consumtion.
In europe max length for truck + 2 trailer combination is 25.25 meters. On mythbuster that was only truck with one trailer about 17 meters. So with 8 meters longer combination you can drive that 8 meters more behind and still see the same savings. So that 100 ft or 30 meters would be with 25.25 meter long truck 44.5 meters or 146 feet. and still get 11% fuel savings in that same test truck. If your car smaller you get more savings. So about 3 second behind you can see about 1-6% fuel savigs. If you are driving behind a long truck "convoy" savings will be even greater because the distace needed is then about one convoy not one truck lengt and you can see that 11% at 3 seconds behind the convoy.
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