*Trailer AERODYNAMICS*

[Prem]

More brains and resources are better than one, so I thought I would start a new thread on trailer aerodynamics.

My 12 ft. teardrop trailer, with a sloping roof line that came to a point at the rear hatch yielded 1MPH more at 55MPH than not towing it at the same speed with my full-size van with a V-8 motor.

Towing my cargo trailer conversion of the same length but less weight, even with a V-nose, reduces the efficiency of the same van by 2 MPH at 55MPH. The culprit is the square rear of the cargo trailer versus the taper-to-a-point shape of the rear of the teardrop.

I just ordered AirTabs(tm) to try to (partially) correct this airflow efficiency deficit. See post (scroll down) at:

http://www.tnttt.com/viewtopic.php?t=25377&start=45

Do you know of any other interesting/simple ways or products that would improve the airflow and fuel efficiency of trailers? If so, please post.

Thanks,

Prem

[Roly Nelson]

I know a guy who put an oversize cooling fan behind his radiator, (to help pull the hauler like an airplane propeller), rubbed vasaline on his fenders (to slip through the air more eficiently), and mounted a constricting nozle on the exhaust pipe (to produce a jet powered effect), and he pumped his tires up to twice what they were recommended to be, (to reduce friction on the road). With all of those attempts, he increased his MPG by an amazing 1/4 MPG.
Roly

[Arne]

ah, the old Vaseline trick... works for a while, then road grime builds up and turns it akin to sandpaper... have to redo it every 1/2 hour or so.....

The v nose is only slightly more aero than a flat front, the v is not sharp enough, but it makes it look better and is a great selling point.

[Laredo]

simple things help.

check and lube bearings -- trailer and tow vehicle.
keep tire pressure where it should be.
don't overload axles. lighter is better, and so is slowing down.
travel with a tailwind where you can, a headwind where you must, and when towing try not to have too much sticking up into the windstream.

Now, there are folks who swear by spoilers, and folks who swear by shapes -- the one thing I see in any airplane, rocket, etc. (okay, not spears and arrows, but they don't go that fast) is a tapered-back fuselage at the tail end.

I would bet that if you looked at the tables aircraft engineers use in building these things you'd find an answer you could work with (look at the tailplane of something like a Mooney Mustang as an example).

[Trackstriper]

Prem,

Just saw your AirTabs photo, they look great. Let us know what kind of difference it seems to make, my cargo trailer is a drag machine and might be able to benefit from them too. Do you have any photos of the 12' teardrop so we could see what the side profile is?

[Woody]

The best way to increase fuel economy I found was to drive at or around 60- 65 mph instead of 75-80 mph. But who does that anyway. Anything that causes or increases drag or weight for the tow vehicle has an adverse affect on mpg. One of the things we do instead is travel light by not traveling with full coolers loaded down with food, drink and ice. If you find gear that you have not used in several camping trips, leave it home again more weight savings. there is absolutely no reason to haul every cast iron pan, griddle, pot or DO you own unless you plan on using it everyday camping for example. I have seen people with stacks of cast iron, haul it, show it and not use it at all, Take only what you need. You would be surprised how much crap (weight) one could take camping and not use. I found that two large 100-165 qt coolers can weigh several hundred pounds or more each when totally loaded down withy food, drinks and6 bags of ice. Enroute to the camping area our coolers are used as dry storage boxes and hold necessary camping gear saving space and overall gross vehicle tow weights. Again another vauable savings of a considerable amount of overall total vehicle/trailer weight could adjust your mpg some what upwards. Just carry enough food and drink for the first night and breakfast in a small cooler, Then go into town and stock up food and drink that next morning for the duration of our stay. When leaving just empty the coolers to stow gear again for the ride home. That amount of weight and space saved is quite surprising. Plus if you tow with a pickup it keeps the gear nice and dry when driving in bad weather. Honestly to get all wrapped up in mpg and areodynamics for something that you may tow 3-6 times a year the overall financial savings would be technically mininmal at best. Weight is heck of alot easier to manage and control for long term mpg savings. Aerodynamic considerations have to many variables like headwinds, tailwinds, crosswinds etc. that constantly are changing with the driving enviroment just going down the road. Weight and driving speeds are mpg variables that are real things that one could personally control when towing anywhere

[Prem]

Trackstriper,

The first results for fuel efficiency using the AirTabs on the top and sides of my cargo trailer conversion I posted on the CARGO CONVERSIONS forum under "My 12-foot FEATHERLITE Conversion."



Prem

[Prem]

Arne and Laredo,

Check out the chart:
http://www.frappr.com/?a=viewphoto&id=5381897&pid=10838505&myphotos=1



Prem

[Arne]

interesting..seem we should be under .5 then.