Boat tail reduces truck fuel consumption by 7.5 percent

On November 5, 2009, Darren Quick put up this post in Gizmag, about how a Boat Tail on a truck saves fuel. Even though it was not smooth and graceful, but rather slab sided and boxy - it still turned in "fuel savings of 7.5 percent".

He goes on to say - "The fuel savings, which also means a cut in emissions, were realized by the boat tail dramatically reducing the drag caused by the lower-pressure effect that occurs in the wake of a vehicle." The key thing is the trailing edge or tail end of the vehicle, is the moree critical aspace for airflow control, and wake managment.

He Shows that these were not just one-off, random tests, but long running hard comparisons, averaged out over time - with various changes to the Boat Tail length: "The lorry was driven for a period of one year with a boat tail of varying lengths and one year without a boat tail. The improved aerodynamics were dependent on the length of the boat tail, with the optimum length found to be two meters (6.5-feet)."

In his story, he also points out the many other aero-structures that Trucks have added to them today to save on fuel: "Trucks already sport a range of modifications designed to improve the aerodynamics of the vehicle, such as side panels, aerodynamic mudguards and mirrors, and roof deflectors. Of these only side panels are more effective at cutting fuel consumption (9 percent) so it’s hard to imagine we won’t be seeing trucks on the roads with a little extra junk on their trunks in the near future."

However - there are a few things I have discovered by attending a presentation at the University of Toronto, on Vehicle Aerodynamics - putting small vortex generators on those cab side panels causes the air to spin up and tighten up the air flow over the gap between cab and trailer that still exists, and cuts the interference drag at this area caused by air trying to escape from between the trailer and the cab, making a new wall of air, so the air stays attached - from cab to trailer.

Aerodynamics Gets Noticed - Again!

August 26th, 2009: Next-gen trailer aerodynamics project gets $500,000!

New York State has made available nearly $500,000 to ATDynamics to continue development of next-generation trailer aerodynamics, the company has announced.

The Article - In Fleet Owner - goes on to say the the money was awarded by the New York State Energy Research and Development Authority - NYSERDA - which is a 50% Cost Share Match with ATDynamics.

Also on August 26th, 2009, was announced by cnet News - Green Tech: Hummer gets better than 100 mpg?
"The plug-in hybrid Hummer H3E by Raser Technologies actually gets better mileage than originally estimated."

"It plans to reduce the size of the battery pack so that the SUV gets the original target of all-electricity for the first 40 miles. By doing that, the company can reduce vehicle weight and make the SUV available to customers for a cheaper price, according to Raser."

On August 29, 2009, Autospies got a report out about:
The BMW That Will Change The Way Alt. Energy Vehicles Are Perceived: Vision EfficientDynamics

Down in the article - not quite 1/3rd the way down - comes the Headline of reference:
Aerodynamic qualities reflecting BMW’s Motorsport experience.
"BMW Vision EfficientDynamics also takes a new approach in its design and streamlining, the body and the interior clearly expressing the unique combination of supreme efficiency and the sporting performance of the brand. Following BMW’s design language, this concept car visualizes both highly efficient aerodynamics and intelligent lightweight construction."

All of the above is to say that Vehicle Aerodynamics are becoming more focused, and that the AeroCap Project is travelling along a path that is becoming more considered, and promoted by the Major Auto makers. Even General Motors admitted that they needed to clean up the aerodynamics of the Volt Prototype to get the desired 40 Miles per Charge thwy wanted!