Trailer-skirt success

Jan. 1, 2006
TESTS EARLIER THIS YEAR at the Goodyear Proving Grounds showed that the wind-tunnel-developed Laydon Trailer Skirt package reduces fuel consumption by

TESTS EARLIER THIS YEAR at the Goodyear Proving Grounds showed that the wind-tunnel-developed Laydon Trailer Skirt package reduces fuel consumption by 5% to 6% on a 53' trailer.

That's good enough for Road Systems Inc, which is installing the Laydon Trailer Skirt on its trailers.

Made of impact-resistant ABS plastic and rubber by Laydon Composites Ltd (LCL), the skirt is designed to stand up to a trailer's harsh environment and at the same time reduce road spray.

Goodyear measured up to 6.3% on its test track in San Angelo, Texas, using the SAE Type III fuel consumption test.

“That's huge right there,” said Andy Acott, sales manager for Laydon. “It's big that Goodyear was involved, and not us. It shows they did the test and we didn't. When they report the results, they don't care if there are added fuel costs. They're just messengers.”

LCL started operations in 1994 with the objective of identifying select market opportunities where it would design and develop proprietary-patented products using fiberglass, thermoplastic, vacuum forming, infusion molding, and injection molding for the transportation industry.

LCL has state-of-the-art design software and equipment coupled with a high level of specialized engineering and technical skills to solve problems relating to the design and processing of composite transportation components. It uses the latest design automation tools like Pro/ENGINEER, Solid Works, and ANSYS software for finite element analysis.

Its use of wind tunnels and flow-dynamics software ensure maximum drag coefficients without interfering with the tractor-trailer's daily operation.

The manufacturing process employs the use of five multi-axis robotics to maintain the highest level of quality. Its products include fuel-saving devices such as collapsible roof fairings, wind deflectors, and trailer skirts.

Proving Grounds

SAE type II and III fuel consumption tests were run on March 9 for Road Systems, a trailer modification facility. The purpose of the tests was to compare the fuel-economy benefit of aerodynamic fairing mounted on 53' box trailers. The “8 Mile” test track was used for the test course, with four laps being run for a total of 32.8 miles.

The first test compared the standard van trailer to the modified fairing trailer using the SAE J1526 type III fuel economy test procedure. The fairing was modified by removing the bottom 6" of fairing material to allow more ground clearance. Two test segments were required to obtain the data necessary for the comparison.

In the first test segment, the standard trailer was paired with Truck A/Driver A and the modified fairing trailer was paired with Truck B/Driver B.

In the second test segment, the trailers and drivers were switched — the standard trailer now had Truck B/Driver B and the modified fairing trailer had Truck A/Driver A. Fuel consumption calculations were performed using the total fuel used by the standard trailer/truck combination during test segments 1 and 2 vs the total fuel used by the modified fairing trailer/truck combination during test segments 1 and 2.

The results showed that the trucks paired with the modified fairing trailer burned 5.36% less fuel than the standard trailer. The difference between the trailers is considered statistically significant since the least significant difference was calculated to be 0.8% using the Student T method based on the fuel (T/C) ratios.

For the second fuel economy test, a different test procedure was used in the interest of efficiency. Using the SAE J1321 Type II test procedure, both the modified and full fairing trailers were evaluated on the same truck/driver (Truck 948-5017, Fred Mucha).

The other truck/driver (Truck 948-5033/Mark Clise) remained unmodified during the test. The time and labor savings comes from having to change the trailer on one truck as opposed to the SAE Type III procedure, where both trucks would have to change trailers and an additional test segment would have to be run.

Fuel consumption calculations were performed using the T/C (Test Truck fuel weight/Control Truck fuel weight) ratios. The results showed that the full fairing trailer was 1.13% more fuel-efficient than the modified fairing trailer. The difference between the trailers is considered to be significant since the percent difference exceeds the calculated least significant difference of 0.8%. The least significant difference was calculated using the Student T method based on the fuel (T/C) ratios.

The test speed was 60 mph, cruise control was not used, and the test weight for the vehicles was 80,000 lb gross vehicle.