trailer aero

[PorkPie]

Sum, the aerodynamic of your pick up is so bad that the teardrop trailer behind improve the aerodynamic.

[PorkPie]

The gap between the tow car and trailer is always a problem - the airflow collapse into this gap, try to go out again and produce turbulences and vacuums to the same time.
That's the reason why here in Germany short tows are very popular for truck/trailer combinations.

About the airflow under the trailer - give the air enough space that it can go through.....your never can close it so that you get an aerodynamic improvement. Important is, that the floor under the trailer is so flat as possible to create no interuption from the airflow......normally you got the axle and the "tow" pipe to the towing vehicle in this airflow. If his parts are covered, so that this aera is a smooth surface it will help to get a clean airflow.......

[Uncle Jimbo]

A suburban is a brick in the air.....and moving a brick faster cost mpg.....

A spoiler and a vortex are two totally different things.....a spoiler is a kind of a wing and helps a lot to get a better mpg.....a vortex are small - two by three inches - plastic shapes which people add on the end of the side panels to interupt the turbulences.......a spoiler/wing clean the airflow.......

Thanks PorkPie - I did go to the Nish Motorsport web site and got educated on the difference between spoiler and vortex generator. (being a bike guy, and some what of a cyber neanderthal, Iam still educating myself with this high tech stuff.)  I do think that the spoiler on the rear roof of the GMC helps.  And Sumner, getting close to 20 mpg would put me in GMC heaven. To answer does the mpg drop over 70 with or without the trailer, is you betcha it does.  If there are any cost effective tips you guyz may have to improve mpg with da boat, I am all ears. Thanks, all you guys and this web site are great.   

[thundersalt]

I believe  the type of tow vehicle is a main factor in your milage. My 03 chevy HD2500 has an 8.1 in it . When I tow my 13000 lb 5th wheel it gets 8 mpg. When I tow the race car the milage improves to 8 mpg.  Driving empty with no trailer the milage increases all the way up to 8 mpg.

[fredvance]

OK so if I am towing with a pickup the air is not going to flow over the trailer, put a round nose v and angle the v down from the trailer body to v?? Next what about something like a mud flap in fornt of the tire to deal with the air around the tire?

[Dave Cox]

Reducing frontal area and trying to fill gaps work pretty well.



without a car on the top, the mileage is good (14mpg), add a car to the top and it drops to 11. I built the top rack on the trailer close to the cab and at the same height, it really helps.

Dave

[Seldom Seen Slim]

Thundersalt:  You oughta have a diesel in that HD2500 of yours.  25 mpg on the way to and from Maxton last weekend.  14 mpg towing cross-country to Bville -- trailer weight about 7,000.  19 mpg towing our old 6x12 trailer to Bonneville.

Fred:  Would you mind explaining a little bit about your last post?  The "round nose V" and "angle the V down" isn't as clear as it could be -- at least to me.  Whaddaya mean?

Air around the tire -- might be improved by a front flap, but don't hang it down too far or it'll rip off when you try pulling over a curb.  But if you don't go down far enough it won't do much for aero.  You're stuck either way, I guess.  But -- I like Pork Pie's advice about the underside -- I'll make sure to cover the botton surface with either weatherproofed plywood or maybe some sheet metal.

I don't know if any of youse guys pay attention to semi trailers go down the road, but at least one major national carrier is now running trailers with side skirts that stretch from just behind the drive wheels of the road tractor all the way to right in front of the trailer tires.  The skirts get down to less than a foot off the ground, I believe, and probably help a bunch to keep the air smoother under there.  I don't remember if that company runs it's tractors with an air dam in front, though. . .

[Clay Pitkin]

Hey Fred,
Back in the early 90's there was a gentleman who ran at Bonneville by the name of Ron Pruett and he ran Thunderbird. I believe him and Mike cook were in the same class??? Mike Cook also ran a Blue Thunderbird.

Any how Ron's trailer had a rounded nose on the front. I wouldnt know how to contact him, maybe Mike Coook would know?

TIA
Clay

[Glen]

I just googled this and found the following. There is more as well on google. This one has diagrams and CD by type.



or try www.nosecone.com

Click on aerodynamics then open table 1

[fredvance]

Sorry Jon I was afraid  that description was as clear as mud. I'll try again, looking at the front of the trailer it is 5' tall then it v's forward but the v is 4' tall then from front to back  the v tapers to 5' in another v. Is that any better?

Fred

[thundersalt]

Hey Slim, is that a Duramax? I just bought a new TPD race trailer yesterday so Celia won't let me get a new truck for a few more years. I have a lot of customers here at the rv shop that comment on their diesel's and I get milage responses from 10 mpg to 20 mpg. So when it's time to buy I'm not sure which way to go.

[Sumner]

Sum, the aerodynamic of your pick up is so bad that the teardrop trailer behind improve the aerodynamic.

Hey not so loud, my truck heard that and it has feelings also  .  It is somewhat better than when it was stock and 18 inches (1/2 meter) higher  .

Sum

[Sumner]

........... If there are any cost effective tips you guyz may have to improve mpg with da boat, I am all ears. Thanks, all you guys and this web site are great.   

Let a woman drive it.  My wife always got better gas mileage than I did  ,

Sum

[Milwaukee Midget]

The DIY ethic is to be admired, but a recommendation I received from a friend of mine who hauls band gear is the Excalibur Trailer.  They were built here in Milwaukee at the old Excalibur plant (the Brook Stevens designed Studebaker, and later Chevy powered neo-classic roadsters) until about five years ago when they went belly-up.  While he gave no statistics, he claimed it was better than his old, square trailer.  Unfortunately, they are no longer being made, but there is an outfit in Iowa that took the design and ran with it.  Here's the link -

http://www.oldinc.com/magseries.htm

You can even order it with flames.  It sure looks slick.

[Seldom Seen Slim]

Thundersalt:

Yes, it's a Duramax, but it's an '04 LLY option.  The LLY was a second-half-of-the-year model, with more HP than the early version, but quite a bit less power than the new (current) models.  I was talking with a guy at Maxton this weekend -- he's got an '06 and an '08 Duramax and says he's never ever gotten anything over 20 mpg.  But -- we never drive at speeds over the speed limit.  This weekend we spent most of 2,400 miles on freeways posted at 65-75 mph -- and went about 63 or less the whole time.  When we've gone faster -- as little as 5 mph faster -- the economy drops drastically, like a couple of mpg.  And we use the cruise control as much as possible, which probably also helps get good mileage.

Keep your tires properly inflated, and also -- I run Rotella 5W40 synthetic oil, which gave me a one mpg boost instantly when I started using it a couple of years ago.