One of the unfortunate side effects of hauling a massive trailer around is the drastic reduction in fuel efficiency and handling. While the increase in weight is partially to blame, it’s not the largest culprit. Aerodynamics is the biggest factor in these situations. This is where vortex generators like Airtab come in.
As an engineer, pilot, and RVer, I have always been fascinated by vortex generators. If you are unfamiliar with vortex generators and what they do, you’re in luck! Today, we’re looking at these valuable products to see if they’ll help you and your vehicle.
What Is an Airtab?
Airtabs are a device also known as vortex generators. Airtab is a brand name of these devices, but there are plenty of manufacturers of them. They are small plastic devices attached to a wide range of square-backed vehicles and trailers. They do the job, whether mounted onto a truck, tractor-trailer, RV, coach, bus, van, or other large, square vehicles. These devices attach to the vehicle and generate small air vortexes behind them.
They claim that drivers experience improved MPGs and driving control due to a change of airflow. They typically mount toward the rear of the trailer and near the gap between a tractor-trailer gap and the rear trailer.
How Do Vortex Generator Airtabs Work?
To truly understand what air tabs do requires having an understanding of fluid dynamic physics. Since most of us don’t, we will keep it simple. Airatbs are a type of device called vortex generators. These are not new or novel devices and are found on many vehicles that travel at high speeds. This includes planes, racecars, and high-speed trains.
The purpose of a vortex generator will depend on its use, but generally, they are designed to improve air movement in such a way that it increases control of the vehicle. Secondly, they can be used to reduce drag allowing for better fuel economy or higher speeds.
Generally, vortex generators create swirling air that can reduce boundary layer separation of air flowing over a surface. This reduction in separation can help the air “stick” to a surface and reduce low-pressure zones or turbulence.
Airtabs are a type of vortex generator called a wishbone design. Each Airtab device produces two rotating vortices. The devices cause the air to spin at up to 3000 RPMs. The air spins four to five-inch diameters for several feet behind the vehicle. This rotating air helps to reduce the turbulence of the low-pressure drag zone that forms behind large vehicles.
What Are the Benefits of Airtabs, and Do They Work?
According to Airtab, drivers using their devices can enjoy anywhere from 2 to 5% fuel savings. Additionally, they claim these devices create a safer driving experience. It does this by stabilizing the vehicle’s rear, which reduces the sway during wind gusts and severe crosswinds. Drivers can relax and experience less stress as they do not have to battle controlling the back of their vehicle.
So this is what they claim, but do they work? Well in independent testing of generic vortex generators installed only on the back tend to produce theoretical values of around 1% fuel efficiency savings. With them installed on a semi on the back of a truck to help air between the truck and trailer, this may improve efficiency further. As for handling, reviews from users tend to say they work extremely well. They are particularly popular among RVers who have problems with handling their RV in wind conditions like passing a large vehicle. We will take a look at more reviews later.
You might expect a product that delivers these kinds of results to require much work to install them. Thankfully, the average installation takes approximately an hour. Even better, they require no maintenance once you install them. The driver and vehicle can immediately start enjoying their benefits.
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What Vehicles Use Airtabs?
We think Airtabs are excellent for a wide range of vehicles. They are good for square-backed trucks, trailers, RVs, coaches, buses, and vans. We also find drivers of any vehicle with a large gap between the tow vehicle and the trailer could benefit.
Drivers of large vehicles will notice the difference once they install them on their trucks or trailer and hit the road. The stability and fuel efficiency might be worth the minimal effort you need to install them.
How Are Airtabs Installed?
No matter what vehicle you’re installing Airtabs on, it’s crucial that you properly prepare the surface. This means cleaning it thoroughly and letting it dry. You want to remove any contaminants or chemicals on the surface. If possible, clean the surface with mineral spirits or isopropyl alcohol and a clean rag. However, always follow the manufacturer’s cleaning instructions.
You’ll need a tape measure and marker to guide you through the installation. The tabs should be no less than 4 inches from the center. If there are rivet heads, lights, or other issues, you’ll want to increase the distance between the units to accommodate them. However, do not decrease the distance, or they will be ineffective.
You should install them in a straight vertical line up the side of the vehicle. Make any necessary adjustments for curves in the surface. It should only take approximately an hour to install the device. Give them at least 15 minutes to set on the vehicle before driving, and avoid power washing the surface for at least two or three days. After approximately 24 hours, the adhesive will completely cure.
To install Airtabs on a trailer, you want to place the devices in front of the roof rain ridges. However, ensure the devices’ placement doesn’t conflict with the hinge bolts from the trailer’s barn door.
Tractors (Semi Truck)
When installing the devices on a tractor, you want to avoid placing them on rubber strips, exhaust stacks, or heat shields. They should only be on flat surfaces of the tractor. If the vehicle has curved surfaces, you must ensure that most of the tape contacts the tractor surface.
Installing Airtabs on an RV requires you to evaluate the position of the RV’s awning. If these are more than 18 inches from the back of the RV, mount them to your rig as close to the rear of the camper as possible. However, if the awning is closer than 18 inches from the back, you’ll want to install them 5 to 6 inches in front of the awning.
Its not uncommon to see vortex generators on sports cars just above the rear window. The reason they are installed in this location is to help air remain attached and reduce low pressure on the hatch area. This can reduce drag significantly but also reduce downforce on the rear wheels.
How Much Do Airtabs Cost?
As of this article Airtabs costs approximately $2.75 per device. You must measure your vehicle or trailer to calculate the exact costs. Proper placement requires three appliances per linear foot on both sides and the roof of the trailer or vehicle. A standard tractor-trailer requires approximately 80 units, equating to $220 before tax and shipping fees.
The retailer suggests ordering a handful of extra devices if you drop one during installation or make a mistake measuring. So ensure you measure as accurately as possible to avoid any potential errors.
What Are the Reviews Like?
If you’re curious to see what customers think of these devices, the reviews are glowing. We personally have not installed them but have talked to owners who have. In general, the consensus seems to be the same they help significantly with wind buffeting and push from other vehicles on the road.
James G. said, “The handling improved so much that I did not constantly scan the rearview mirror or oncoming traffic for trucks in order to anticipate correcting movements caused by them.” If you’ve ever had to battle trucks blowing you around the highway, you know how frustrating it can be.
Additionally, Jack H stated, “My truck would not handle well in strong winds until I installed air tabs. Now my truck is more stable in strong crosswinds or just severe weather conditions.” Dealing with strong winds is never fun, especially in a big vehicle.
If you’re wondering about fuel savings, Ted from Ted’s Garage answers our question. He says, “I have not really noticed what I could consider a fuel economy improvement.” While he says he has noticed a stability improvement, he hasn’t seen the intended benefit of fuel economy.
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Are Airtab Vortex Generators Worth It?
Airtabs can be an excellent addition to your vehicle, especially if you struggle with stability issues. They’re worth a shot for their cost if you want to avoid being blown back and forth over the highway. However, don’t hold your breath if you expect a drastic increase in your MPGs. You’ll likely not notice the minimal savings unless you are a truck driver putting on hundreds of thousands of miles.
As for vortex generators as a whole, you would need to consult an engineer with fluid dynamics background to truly know if they are needed. In general, however, they can be immensely beneficial when used properly on your plane, racecar, or truck.
Would you use Airtabs with your vehicle? Tell us your thoughts in the comments!
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