Streamline your RV
Save Fuel & Money
NASA developed a way to streamline your RV and save fuel and money as one of the spinoffs from streamlining the Space Shuttle.
Once you are up to about 55 km/h or 35 mph, air drag accounts for around half your fuel use and slows you down a lot. When you increase speed beyond that, the drag increases dramatically.
If you reduce drag, you can maintain the same speed for less fuel or use the same amount of fuel but travel faster. And a more streamlined rig is safer and has more stability at all speeds above 55 km/h or 35 mph.
Where to get the best payback when you streamline your RV
There are three key areas for drag:
- The frontal area - how big the front of your vehicle combination is. Imagine this as a big flat panel being pushed through the air. The best things to do here are hard to do once you have bought your RV:
- You could saw the top off your RV to make it smaller, but I doubt that anyone would try that
- You can smooth the edges and corners so the air flows more smoothly over bumps and changes in shape. This can be done on some rigs, but is unrealistic for most people.
- The gap between the towing vehicle and the towed vehicle. Obviously this is not relevant if you have a motorhome. Closing the gap between the cab and the trailer of trucks is very effective, but it is hard to do much here with an RV combination such as a fifth-wheel RV or a car/SUV and a travel trailer or caravan. However, the NASA-developed Airtabs described below allow you to do something about this area at minimal cost.
- The square back on the vehicle or trailer. If you look at the rear of many of these square backed vehicles and trailers, you will see a lot of debris deposited there by the air rushing in to fill the partial vacuum created by the speed and the air shooting past in a continuation of the sides of the vehicle or trailer. Again, the NASA-developed Airtabs described below allow you to do something about this area at minimal cost.
| Aerodynamics is about the flow of air over aircraft, trucks, RVs and cars. Today it's a big deal and it will get bigger every time the price of oil rises. |
"We use aerodynamics a lot now in production to get better fuel economy. That’s a big thing on the mind of the customer right now. Also, from a wind noise perspective, to make the vehicle as quiet as possible." Louis Jamail, Ford vehicle dynamics engineer
You may have noticed the small winglets - little wing-like extensions that go vertically up or down from the wingtips of many modern planes. They are part of a family of devices that do not necessarily look like they would improve aerodynamics, but they do.
When NASA started working on the problem, they took the boxiest truck they could find and started testing and modifying. In the process they developed a small object that looks like a chicken wishbone fused with a flat piece of plastic. It is called the Airtab.
This wishbone creates a special type of turbulence that disrupts the main cause of drag on boxy vehicles such as trucks and RVs. As a result:
- drag is reduced,
- less fuel is used,
- stability increases
- passing and overtaking vehicles have less impact on the RV
- speeds can increase safely
- the rear of the RV stays cleaner because there are fewer bugs and less dirt deposited there.
Airtabs are vortex generators that create two controlled swirls of air, or vortexes that combine to reduce the suction and drag at the rear of vehicles traveling at speeds above 35 mph or 55 km/h. Airtabs can streamline your RV and are also effective at the rear roof lines of vehicles that have a rear window slope of greater than 30 degrees.
They improve vehicle stability by converting the large random eddies at the rear surface to an array of small vigorous "streamwise" vortexes. Users comment on the improved vehicle handling especially in gusty crosswinds or when passing (or being passed by) other vehicles. This improved handling reduces wandering and sudden movements into the next lane.
Airtabs reduce drag in two ways to streamline your RV by:
- Shifting the airflow pattern from vertical to horizontal eliminates large eddies and
- Smoothing the airflow to artificially simulate a tapered rear of the vehicle makes the air follow a path similar to the one it would take if the vehicle had a tapered rear or boat tail.
You can find out more about how Airtabs Streamline your RV and Save Fuel and Money and there are links to your local supplier
Although at first it may seem difficult to streamline your RV and save fuel, it turns out that with Airtabs, it is easy.