Frontal Area and the Myth of the “V”
One of the most important aspects of aerodynamic efficiency is frontal area. Some trailer manufacturers make an attempt at reducing drag by simply angling the nose of their trailers into a V shape or incorporating a slope nose. Those tricks don’t reduce frontal area however. It’s an uneducated guess, or at best an attempt in reducing the CD (co-efficient of drag), but, believe me… sharp angles don’t help much.
If you’ve ever towed a trailer in the rain you may have noticed the rain doesn’t hit the front of a trailer straight on. It’s actually deflected towards the sides… the reason being that the trailer is always being towed behind something. The air that hits the trailer has to go around the towing vehicle first. It is only when the air finally clears the tow vehicle and starts to fill in the void just behind it, that it hits the trailer. Unless you have a 10 foot tongue, the air won’t fill in around your tow vehicle efficiently enough to even hit the center of a V-nose trailer.
More important to reducing frontal area than a V-shape is the height and shape of the nose of a trailer. If a trailer’s nose is higher than your tow vehicle it’s sticking up into the oncoming flow of air like a huge air brake. Even if it’s lower than your tow vehicle’s cab, the air is still hitting the top forward edge of the trailer. Designing the whole trailer as low and smoothly shaped as possible, so the air can flow over the forward end and around the sides is critical. Keeping air attached to the surface as it flows over the entire form, is key to efficient aerodynamic design and to gain the rewards of reduced fuel consumption and good handling.