I wanted to take a few minutes to share what I've been working on with Outrider, the company I work with.
We have a 8000 mile summer tour, and decided to make an aerodynamic trailer to carry our ultralight adventure vehicles and compliment the TDi Sportwagen that's pulling it.
This project has a few goals:
1. Maximum possible aerodynamics
2. Easy Access to UAVs
3. Weatherproof
We decided to use a utility trailer as the base, and add an aluminum shell that tapers the bodyshape of the Sportwagen that's pulling it.
We used aluminum tubing as the skeleton, and then covered it with thin sheetmetal.
Here's what we started with, a 5x11 utility trailer with Ipe decking:
The ribs in progress:
Finished ribs:
Aluminum sheet added:
Shell partially opened:
Shell fully opened:
View from the rear:
The vehicles we're carrying:
Our maiden journey with the new aero trailer was from Asheville, NC to Vail, CO on a nonstop trip to show at the GoPro Mountain Games.
For reference, the car is loaded with three 180 lb men, and about 200 lbs of gear. The trailer has a gross weight of about 1200 lbs with two Outriders, camping gear, and tools. We started out cruising at about 65 mph average, and we were averaging around 38 MPG. Then we realized we were running late, and we upped the average speed to 75 mph, dropping our mileage to 33 MPG average for the 1500 mile trip.
The trailer worked great. We have a few improvements in mind, however, to further improve aerodynamics.
After arriving to Vail, we've changed from a 2" rise hitch, to a 1" drop hitch to better align the nose of the trailer with the rear end of the car. We haven't yet collected numbers from this setup, as we've been in the mountains and it's difficult to quantify, but it's clear visually that this will improve the aerodynamics further.
We're now in Boulder, CO. When we arrive in Park City, UT, we plan on adding a spandex skirt that stretches from the vehicle to the trailer, filling the gap between the two, and keeping aeroflow attached over the whole shape. I imagine we'll see good returns from this modification.
Our overall goals are to see over 40 MPG on the return trip back across the country to NC. I imagine we'll hit that number, with the addition of the skirt, the better aligned trailer, and reduced speeds on the return trip.
I'll soon add photos of the trailer with the shell fully opened, a shot that shows the improved alignment after the 1" drop hitch, and some detailed shots when we add the skirt.
We had one of our coworkers at Outrider ship us our sewing machine, spandex, laminX, and industrial velcro. We plan on sewing up the skirt in the woods of Utah, powering the sewing machine off of an inverter that runs off the batteries on one of our Outrider vehicles. Should be a trip.
Cheers!
Tommy