Quote:
Originally Posted by Braebyrn
I wonder about the air behind the truck and between the trailer.? If I put scoops to pull the air in and then drop it out behind the truck? I was thinking about that drag.
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According to Hucho's book,the gap is responsible for up to 20% of the rigs overall air drag and can mean an extra 10% mpg if you can make it go away.
If you 'rob' the airflow and shunt it internally,you will destroy the surrounding flow,precipitate flow separation,and ruin any chance for aft-body modifications to perform,as they are completely dependent on clean laminar onset flow from ahead.
The partial gap-fillers you see on contemporary 18-wheelers are a proven fuel-saver.
Consider that you want only a single collision with the air,not multiple strikes,then allow the air to decelerate while building static pressure,such that when it finally does separate,it's at the highest possible pressure.