Tag: Aerodynamics

Big-rig trucks have long faced an intractable problem: they need a large gap between the tractor and trailer to allow turning at low speeds. But at high speeds, airflow into this gap creates drag and wastes fuel.

At TruckLabs, we fixed this problem back in 2016.

Our solution, TruckWings, deploys when a truck is moving above 50 mph to streamline the airflow at high speeds, when aerodynamics matter, and then automatically retracts when a truck slows down to allow the driver to make turns. We have installed TruckWings on six of the ten largest fleets in North America and have proven results of 3-6% in overall fuel savings.

In 2023, Daimler/Freightliner agreed with us!

Seven years later, we’re thrilled to see our concept validated by one of the world’s largest truck manufacturers, Daimler Truck.  

They recently unveiled their concept truck, whose development could be funded by the Department of Energy’s SuperTruck program aimed at improving heavy-duty truck freight efficiency. The truck has an active gap-closing device much like our TruckWings. These “wings” do exactly what we describe: when you travel at highway speeds, the sides and top fold out to close the gap and save an impressive amount of fuel. 

As Daimler Truck clearly understands, the gap between the tractor and the trailer is one of the best opportunities to improve semi-truck aerodynamics, especially on day cabs and CNG/Electric trucks where the gaps are very large. Covering the gap can reduce drag by as much as 9 percent in regular conditions, and by even more during crosswinds. 

Validation that Wings Are Essential

The “wings” on Daimler’s Freightliner SuperTruck validate what TruckLabs has known since 2016:  closing the tractor-trailer gap works to reduce fuel usage. The NACFE has said it; we have said it (and proven it with an external CFD assessment from TotalSIM); and now Daimler Truck is saying it: we need to close the gap to improve fuel efficiency and emissions. 

Fleet owners don’t have to wait for this conceptual prototype to go into production to start improving fuel efficiency on their trucks. 

They can get the benefits of the futuristic Freightliner SuperTruck today.  TruckWings are available today for trucks of all fuel types, including diesel, CNG, and electric. TruckWings units are standard “drop-in” products that work across multiple OEM trucks for day cabs, sleepers, and reefers. Not only have TruckWings been validated by multiple OEM-level tests, they have been successfully deployed on trucks traveling over 600 million miles–and counting.

So congratulations to Daimler on their Freightliner SuperTruck. Welcome to the world we know and love of active aerodynamics. 

Did you know that improving trailer aerodynamics can significantly impact drag and fuel efficiency?

Aerodynamic drag is responsible for 65% of the energy used while pulling a trailer. That’s why more fleets are turning to products like trailer aerodynamic products to help reduce drag and save money on fuel costs.

But what are trailer aerodynamics, exactly?

And which product is right for your fleet?

Answering these questions requires understanding the effects of aerodynamic drag on tractor-trailers and the different types of products available to reduce it.

What Are Trailer Aerodynamics?

Trailer aerodynamics refers to the study of how air flows around and over a trailer.

When a truck moves, air resistance (or drag) slows it down and uses up fuel. Reducing drag can lower fuel consumption by up to 12%. This would save more than $10 billion in diesel fuel per year.

The Main Points of Drag on Tractor Trailers

To understand how to reduce drag, it’s essential to know where it comes from.

There are three main points of drag on tractor-trailers:

• Back of the trailer near the doors: When air circulates around a trailer, it forms a vortex behind the rear door, causing a significant decrease in air pressure.

• Front of the trailer near the gap: One of the worst low-pressure areas on a truck is the gap between the cabin and trailer.

• Trailer undercarriage: When air passes under the bottom of the trailer where the wheels are, it causes drag and decreases fuel economy.

Addressing these areas can significantly improve trailer aerodynamics.

Products and Devices to Reduce Tractor-Trailer Drag

Aerodynamic devices are effective at reducing drag and improving fuel efficiency.

And the faster the speed, the more efficient they become. Many products and devices on the market can help reduce drag.

• Trailer fairings: The trailer fairings (or skirts) keep the wind from blowing under the trailer and into the bogie. They work best when they start from the landing gear and end at the front face of the front trailer axle, close to the ground.

• Trailer tails: Trailer tails are devices mounted at the back of trailers to alter the airflow as it leaves the trailing edge of a truck’s side and top surfaces. While they can boost vehicle fuel efficiency by up to 6%, the sale of trailer tails ceased in 2020.

• Wheel covers and mud flaps: Wheel covers are devices inserted into the wheel that help direct airflow around the tires. Mudflaps are installed behind the wheels and help deflect air away from the undercarriage.

When choosing an aerodynamic device, it’s important to remember that many will complement each other. For example, using trailer tails with wheel covers further reduces drag.

Of course, fleet owners must consider the unique needs of their operation when choosing products.

Trailers Are Only Part of the Equation

While trailer aerodynamics are important, they account for only some of the drag that impacts fuel efficiency.

The front tractor section also accounts for a significant amount of drag (about 25%). To address this, some truck manufacturers are exploring a more aerodynamic design for the front of the truck.

Some solutions include adding pedestal door mirrors and sloped-front windshields.

The gap between the cab and trailer also accounts for about 25% of the overall drag. High-speed air rushing in causes a low-pressure area which then drags on the tractor and decreases fuel economy.

Closing the gap would result in a decrease in airspeed and less turbulence downstream. Increased pressure at the back of the cab would decrease overall drag, especially where crosswinds are strong.

For fleet owners, this could mean a significant decrease in fuel consumption and savings amounting to millions of dollars each year.

Learn how Ryder Systems saved 4.1% on fuel with TruckWings.

Improve Trailer Aerodynamics and Fuel Efficiency

Cutting emissions and fuel costs is a high priority for trucking fleets.

That’s why many fleet owners are investing in trailer aerodynamic devices.

There are two types of trailer aerodynamic devices:

• Hardware-only devices that require driver interaction.
• Smart products that are automated and require no driver interaction.

TruckWings and TrailerTails are two devices that are sometimes confused, but there are key differences between them. TrailerTail (discontinued) was a hardware-only device installed on the back of the trailer that required the driver to close it manually. TruckWings is the only fully automated, tractor-mounted device that works without interaction, allowing for the best driver experience.

By automatically closing the gap between the cab and trailer, the device:

• Improves stability
• Increases fuel efficiency
• Reduces drag

TruckWings also:

• Provides potential fuel savings of 4-6%, reaching an ROI in under 200,000 miles with zero operational downtime

• Operates in two positions — closed when the truck travels fast on an open highway and open when going slow or making turns

• Uses smart sensors to track carbon and fuel savings

• Provides uptime reporting

If you want to improve fuel efficiency, contact us to learn more about TruckWings.

FAQ

How do I reduce drag on my truck trailer?

There are several ways to reduce drag on your trailer, including:

• Adding trailer fairings (or trailer skirts) to keep the wind from blowing under the trailer and into the bogie.

• Installing mudflaps and wheel covers to help direct airflow around the tires.

• Adding a trailer tail to alter the airflow as it leaves the trailing edge of a truck’s side and top surfaces.

Why do truck trailers have wings?

Wings help keep the trailer more stable and improve fuel economy.

Do truck wings work?

Yes, they are an effective way to reduce drag and fuel costs. In fact, TruckWings provides potential fuel savings of 3-6% mpg with 12-18 months ROI resulting in millions of dollars saved per fleet.

Learn how Ryder Systems saved 4.1% on fuel with TruckWings.

Rising fuel prices – topping off at more than 75 percent higher than last year – have left the trucking industry scrambling for solutions to reduce fuel costs and improve the efficiency of their fleets.

Diesel prices have reached record levels and not since the 1970s has there been a tougher time to manage fuel hikes and keep trucks running.

The seemingly endless trend in the wrong direction has trucking operators turning their attention from the inside of the tank to the outside of the truck, reconsidering truck aerodynamics and new advances in products and devices that curb their losses.

The Impact of Aerodynamics on Fuel Economy

Semi-truck aerodynamics plays a large role in how fuel efficient a truck can be when traveling at high speeds along an interstate highway.

At highway speeds, a semi-truck consumes more than half of its fuel by pushing through air resistance created by the size and shape of the semi-truck and trailer. This so-called aerodynamic drag decreases fuel efficiency.

That drag is created along multiple points of the truck and trailer, including the front of the truck, the gap between the trailer and the tractor, the sides and underbody of the trailer, and the back of the trailer. The smoother the airflow around those points, the lower the drag.

Improving aerodynamics can deliver significant fuel cost savings. In fact, industry reports indicate that using multiple devices to reduce aerodynamic drag can reduce trucking industry fuel consumption by more than 12 percent – or some $10 billion in diesel fuel costs.

The Most Common Drags

Trucking companies have popularized many products over the years that improve semi-truck aerodynamics, including streamlined shields, trailer skirts, trailer tails, and devices that cover the gap between the tractor and trailer.

All are directed at reducing the percentage of drag created by each aerodynamic-resistant component of a truck and trailer.

Among the leading offenders on a truck, when it comes to wind resistance, is the gap between the tractor and the trailer, which can produce 25 percent of the overall drag. Any gap of 18 inches or more between the tractor and trailer can produce increased air resistance, researchers say. Covering the gap can reduce drag by as much as 9 percent.

The front end of a tractor also produces a significant amount of drag or about 25 percent. Many truck manufacturers are eyeing the front of the truck for more aerodynamic design, including sloped front windshields and pedestal door mirrors.

All along the side of a semi-trailer, aerodynamics are impacted, along with the underbody. Combined, that’s another 25 percent of overall drag created by a tractor-trailer rolling down a highway.

Finally, the back of the trailer creates yet another point of drag when air gets trapped around the tail.

5 Easy Ways to Improve Semi-Truck Aerodynamics

Devices on the market today can create much-improved aerodynamics on semi-trucks and are readily available. Here are five leading ways to boost fuel efficiency.

1. Reduce the gap between truck and trailer: Using an aerodynamic device to cover the gap can significantly reduce drag and improve fuel efficiency. Trucking industry giant Ryder System, Inc. partnered with us to use our TruckWings device, which delivered them a fuel saving of 4.1 percent. TruckWings automatically deploys at speeds above 52 mph, covering the gap without any distraction to the driver, and retracts when speeds drop below 50 mph, allowing for safe maneuverability on surface streets.
2. Reduce airflow underneath: Side skirts reduce airflow underneath trailers, leading to fuel savings of more than 4 percent, according to manufacturers.
3. Minimize tail drag: Trailer tails, or “boat tails” that reduce turbulence can knock fuel costs down by around 6 percent for semi-trucks traveling at 65 miles per hour
4. Check your wheels: Wheel covers allow air to flow past the tires, reducing aerodynamic drag.
5. Make mud flaps aerodynamic: Switch from heavy, solid rubber flaps to slotted mudflaps, which allow air to pass through them.

Improve Aerodynamics, Cut Fuel Costs

In the face of unprecedented fuel costs, fleet owners are finding a growing number of options on the market for improving truck trailer aerodynamics and creating fuel-efficient designs.

Leading the way in preventing costly wind resistance is TruckWings, providing an accessible, automated aerodynamic option that can significantly trim fuel costs across an entire fleet.

Ready to face down fuel inflation? Get in touch today and learn more.