How much drag is created by fluttering winch straps?
That depends on the relative speed of the truck (with headwind or tailwind), strap length exposed to the wind, the gap between the straps and load, and the shape of the load (e.g. lumber, pipes, crates).
Why use StrapWings instead of twisting the straps?
Twisting the straps will reduce the vibrations, but they will still create drag from the spiral vortex as the wind passes over them. Also, one of the leading winch strap manufacturers says twisting a winch strap "compromises the overall integrity of the strap." Full article HERE
What keeps them attached?
The StrapWings have internal notches that clamp onto the winch straps, and the pressure of the wind flowing across them keeps them clamped tight. The faster the wind the tighter the grip.
Is the StrapWing part of the EPA SmartWay program?
Not yet because the SmartWay is currently focused only on cabs and box trailers. StrapWing will apply to the SmartWay Verified List of Aerodynamic Devices if flatbed trailers are included in the future.
Can using StrapWings reduce the abrasions that damage winch straps?
Yes. Normal wear and tear is expected on winch straps, but reducing vibrations caused by flutter extends the life of the straps.
What are the best scenarios for using StrapWings?
They work best on tall loads and any that have a lot of exposed winch straps to the wind. Long-haul and regional truckers will see the fastest payback period, but even shorter trips can benefit from reducing fluttering straps.
Are StrapWings needed on the top of a load?
Usually, no, but it depends if there's a gap between the strap and the load. If you decide to use them on top, always follow safety rules regarding climbing on loads. (30 CFR 56.15005 Safety belts and lines)
How effective are StrapWings?
Each trucker will experience different results when using StrapWings based on their driving conditions. Temperature, humidity, rain, snow and barometric pressure all affect the density of the airmass a truck will pass through as it moves along the highway.
Also, the relative airspeed during a trip will affect the results. For example, it is possible a truck could be driving at 60 MPH and face a 30 MPH headwind for a relative airspeed of 90 MPH. Increasing airspeed by 50% (e.g. 60 MPH to 90 MPH) roughly doubles the aerodynamic drag, so efficiency becomes more important at higher speeds.