Automotive

Aerodynamic long tail improves fuel efficiency 15 percent

Aerodynamic long tail improves...
Ecomodder.com's Darin Cosgrove recently added this 1.37 tailpeice to his Pontiac Firefly to improve its drag coefficient from 0.34 to 0.23 and its fuel efficiency by 15.1 percent at 90 kmh (56mph).
Ecomodder.com's Darin Cosgrove recently added this 1.37 tailpeice to his Pontiac Firefly to improve its drag coefficient from 0.34 to 0.23 and its fuel efficiency by 15.1 percent at 90 kmh (56mph).
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Ecomodder.com's Darin Cosgrove recently added this 1.37 tailpeice to his Pontiac Firefly to improve its drag coefficient from 0.34 to 0.23 and its fuel efficiency by 15.1 percent at 90 kmh (56mph).
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Ecomodder.com's Darin Cosgrove recently added this 1.37 tailpeice to his Pontiac Firefly to improve its drag coefficient from 0.34 to 0.23 and its fuel efficiency by 15.1 percent at 90 kmh (56mph).

While windtunnels have long been employed in aerospace and all forms of race engineering, we’re likely to see them employed more frequently in future in the quest for improved fuel efficiency from our automobiles. Ecomodder.com’s Darin Cosgrove recently added this 1.37 tailpiece to his Pontiac Firefly to improve its drag coefficient from 0.34 to 0.23 and its fuel efficiency by 15.1 percent at 90kmh (56mph).

The 15 percent improvement is just from the tail, and was comprehensively proven with multiple bi-directional averaged runs at exactly 90kmh on a straight and level road, with no other traffic. The tail was removed and reinstalled during the test so the ‘A-B-A’ comparisons could be made in identical conditions.

The moral of the story is that it’s just as important to leave the air undisturbed as it is to slice through it effectively and one wonders just what shape our cars (and trucks) will be a few decades from now given the remarkable results of this homemade fuel extender.

Via Wired from Ecomodder.com

20 comments
foghorn
Good job Mr Cosgrove. So many of the cars on the road would have better aerodynamics if they were driving backwards! There oughta be a law against that...
Facebook User
well, compared with a current BMW 0,34 is ridiculous! http://www.bmw.de/de/de/newvehicles/3series/sedan/2008/allfacts/engine/technical_data.html so here you can see, what is really bad .. http://www.autobild.de/artikel/autos-im-windkanal_666465.html
josh kahan
Cool -- any triathlete / time trialist that uses one of those dorky aero helmets is going to be happy to hear this.
PrometheusGoneWild.com
I have seen this done before. The problem is now you have a 15 foot economy car. Try parking this in the city. How do you put the pac and play in the trunk? The soon to be out Chevy Volt has gotten its drag down to .28 without extreme measures like the one above: http://gm-volt.com/2009/12/04/chevy-volts-coefficient-of-drag-is-0-28-beats-prius-and-insight/ I am sure the battle for better drag numbers will continue.... -Dennis www.PrometheusGonewild.com
mrhuckfin
It almost seems like this used to be known at one time. If you look at old stream line cars from the 1920\'s and 1930\'s you will see that they almost always had a long cone shape on the back of them, was this just something we lost and are now re-discovering?
Gadgeteer
Not being rediscovered at all. The long, tapered tail was discarded as a practical design decades ago. It\'s wasted volume and material. The Kamm tail is far more practical and just as efficient. What Cosgrove did was improve a car with terrible aerodynamics. That\'s not hard.
Mark Daoust
It\'s not a battle for better drag numbers, It\'s not something we\'ve forgotten. we\'ve always known this. we just ignore it. At speeds well below the speed of sound a teardrop, round side forward, gives the least drag. So I\'m voting with Foghorn (above) on this one: >So many of the cars on the road would have better aerodynamics if they were driving backwards! It\'s a battle for better drag numbers while ensuring that the car looks like what we\'re used to. yeah, it\'s 15 feet long but only because it was designed without the tail in mind. hopefully, since the price of gas is never going back down, and we\'ll start accepting cars that look like reverse hatch-backs (hatch-fronts?).
Skytenna
I have seen several times in past 60 years , it is nice that this is brought up from time to time.
Craig Jennings
They\'ve been working on drag since day dot. Just making it sexy is the hard part ;) Otherwise we\'d all drive artillery shells around Where\'s a force field when you need one? Then we could all drive boxes with invisible tear drops to stealth our way through the air :P
Nick Gencarelle
Maybe we can add something to the trunk that extends during driving like planes retract their wings for efficiency. It also acts as a bumper extender-cushion-and comes back into the trunk area when not needed.