Big Rig Aero

I think Luigi Colani has an awesome design.

I've seen several trailers recently with a big plastic thing underneath that I can't fathom. Looks like a chute for dropping things out the bottom but it could also be an air foil for the rear tire assembly, I suppose. My Google Foo isn't pulling up any photos because I don't know what to call it.

Gasoline wrote:

PLEASE do this!

stafford1500 wrote:

bgkast wrote: I'm surprised the tail isn't longer and more tapered.

There is likely some overall length for a single trailer limitation, otherwise the trailers themselves would be longer... In Kamm-back cars there is a limit to how long and how fine a point you try to make. The length can be cut short in a truncated form and you get 99% of the drag benefit. I suspect the tapered trailer extensions are following the same process. If the get longer they have to be stowable for load/unload and they ad weight which starts to limit the structure to hold them up in service.

Also, those kammbacks are designed to fold flat against the door, so they can only be so long before they won't fold into the door.

I saw his posts a couple years ago and was pushing 10-12mpg in his rig. I knew he had factory support (freightshaker?)for much of his work and he's more of a testbed than a hobbiest driver.

ross2004 wrote:

I have recently started seeing trailers with this system around here. Thought the rear bumper thing was a reinforcement so vehicles wouldnt go under the trailer.

I'm also noticing more of those plastic under-trailer spoilers. Neat to see aero being applied to all sorts of vehicles, not just the fun ones.

SVreX wrote: There are 45 billion gallons of on-highway diesel fuel sold per year in the US annually. If that guy could increase the fuel economy by that much, his idea would be a $100 BILLION dollar per year industry fuel savings. That's 100,000 piles of $1 million. I think he could do pretty well for himself. Instead, he's spending all his time posting on Ecomodder. Nope.

There's definitely a big opportunity there for the right person/team.

In reply to David S. Wallens:

Everything is aerodynamic, just some are better than others...

There was a comment about the drag vs frontal area a few posts ago. The way to compare different vehicles is CD*frontal area. Since the frontal area of a big truck is significantly more than a typical pick-up truck the CD value may be quite low for big trucks. Their shape is long and skinny, which generally leads to lower CD values.

Now consider the CD and frontal area of motorcycles... The have a much smaller area, but much high CD. CD is generally pretty speed independent, at typical road speeds.

stanger_missle wrote: I think Luigi Colani has an awesome design.

He's been all about big rig aero for quite some time now. He's a big fan of Syd Mead. Seeing that stuff come into full scale prototypes is pretty awesome.

I remember an OMNI magazine feature from the early 80's that conceputalized big rigs like that, but they never came to be.

That said, it's cool to see big rig aero starting to take hold. It makes a ludicrous amount of sense.

SVreX wrote:

tjbell wrote: I would venture to guess a lot, there is a guy over on ecomodder forum who drives a bigrig, fully loaded he was doing something like 6.5 MPG after he did some aero work he was doing 14.4 MPG...

Sorry. I'm throwing out the BS flag. I spent 2 years working on fuel efficiency studies and improvements for big rigs in a company I used to work for. We had data from over 1000 trucks covering over 100,000,000 miles from fleet managers in 3 different countries. These trucks were carefully monitored, including onboard systems that collected real time data and uploaded it continuously. We tried hundreds of different methods to improve. 10% improvement was considered great. 15% was incredible. We never saw a 150% increase in a simple aero mod. Not even close. 80,0000 lb vehicle punching a 100 SF hole through a wall of air at 70 mph getting 14.4 mpg? Physics says it didn't happen.

There was a rather large amount of buzz on this setup a year or two ago. It is, in fact, legit.

The changes were not JUST aero, but most were. Ended up looking really bizarre, but all claims were verified.

http://www.google.com/search?q=airflow+bullet+truck&safe=active&source=lnms&sa=X&ei=kMm9U5nLKMeSyATb8YJg&ved=0CAUQ_AUoAA&biw=1280&bih=895&dpr=1

In reply to Swank Force One:

Looks.....interesting...

Let's just go ahead and get it over with and build Ark 2.

I read the title of this thread as "Big Red Aero" and came in expecting this.

I am sorely disappointed.

JG Pasterjak wrote: Let's just go ahead and get it over with and build Ark 2.

'Sometimes a cigar is just a cigar'

I thought many years ago (20?)that road tractors should look like bullet trains...

in the quest for better MPGs in a big rig.. it is a shame they cannot adopt cylinder deactivation like some of the GM cars. Once you have that 40 tons up to speed, you really do not need all the power the engine can make..

Of course, this is also where a hybrid like the original Honda Insight could work. Smaller diesel main engine and an electric battery and motor for a boost to get truck up to speed

Swank Force One wrote: There was a rather large amount of buzz on this setup a year or two ago. It is, in fact, legit. The changes were not JUST aero, but most were. Ended up looking really bizarre, but all claims were verified. http://www.google.com/search?q=airflow+bullet+truck&safe=active&source=lnms&sa=X&ei=kMm9U5nLKMeSyATb8YJg&ved=0CAUQ_AUoAA&biw=1280&bih=895&dpr=1

I like to see more of this "verified" information.

There are a couple of factors suspiciously absent from their website, most notably the GVW (it sounds like a 10,000 lb load). They also offer no specs on the engine (Cummins ISX- what generation? What horsepower?), emissions controls, etc.

Driving patterns? Drivers can account for about 30% variations.

They DID say they set the cruise at 55 for 3000 miles. That is worth at least 2 mpg.

Did they use DEF? If so, did they include the 25 gallons or so they consumed in their calculations? (Could have dropped the fuel economy by nearly 2 mpg). I am not accusing them of error, but they have not posted their methodology or specs. I am just asking the questions.

Mathematically, a 20% aerodynamic improvement should equate to approximately a 12% fuel savings over 50 mph. It's just not adding up as presented.

I'm not doubting it CAN happen (just like I don't doubt that hypermilers have conquered 100 mpg's). I'd like to know more, and I question the real world viability (there is a reason they are not in production 2 years after the prototype "proved" itself).

It's an obvious improvement. I still doubt 2.5X in any real world application.

Swanky, you said it was legit and verified. More info??

I think they took a truck that got a pretty solid 6.5 mpg, added terrific aero for a 15% improvement (7.5 mpg). Then they put a light load in it and drove using hypermiler techniques (10.5 mpg). Add to that an "oversight" in the calculations leaving out the DEF (12.5 mpg). Plus a 7% net fuel economy increase for the DEF usage would give them...13.4 mpg.

But that is a very different scenario...

there was a very informative thread about aero on the pro-touring.com board a couple of years ago... i think that's where i first saw this truck...

anyways, there were links in that thread to NASA wind tunnel research back in the 60's where they were trying to get fuel efficiency improvements in big trucks... that research is why modern big rig trailers have rounded corners- just putting that 4" or whatever radius on the front corners dropped the drag numbers a LOT, while making the trailer itself more structually strong. it's also where they developed the deflector that got added to the top of the cab to direct air over the top of the trailer, which led to the shape of trucks on the road today..

one thing about that particular truck: it's kind of fugly and girly looking.. and truckers don't want a fugly girly looking vehicle. they like chrome grilles and shiny fuel tanks and lots of lights and dual cb antenna whips and what not. but if they start mass producing and selling trucks that get 10+ mpg with the average guy hauling the average load and they are reliable, they will find their way out onto the highways..

While the individual haulers won't buy them (At first) the fleet buyers will. the fuel savings alone at basically doubling the economy will make it a no brainer

In reply to gamby:

When I was in elementary school in the mid-eighties, there was a book in the school library that had drawings and pictures of futuristic vehicles. It also talked about how aerodynamics would make large trucks and commercial vehicles not faster but more fuel efficient. It was the coolest thing my 8 year old brain had ever seen. I checked it out every week. Some of the drawings could of been from Syd Mead. I have been looking forever to find it but I never have.

The Airflow Bullet Truck will haunt your dreams:

That's what I am talking about!!!

I like it!

stanger_missle wrote: I think Luigi Colani has an awesome design.

This reminds me of this.

Not that that's a bad thing. I was acutally thinking about this the other day when I was thinking about a custom car hauler with a cab shaped more like the Wienermobiles, front end and then with some canvas or silk to cover the bed and car. Bring the back to a point behind the loaded car, and you have a teardrop turned sideways on a sled.

There's just too much frontal area on trucks like the Isuzu NPR and such that prevents them from being more aerodynamic.

If someone could Photoshop this on a deep space back round flying (?) past Saturn it would probably look better...