NACA Submerged Air Ducts
NACA ducts are useful when air needs to be drawn into an area, which isn't exposed, to the direct airflow the scoop has access to. Quite often you will see NACA ducts along the sides of a car. The NACA duct takes advantage of a boundary layer, a layer of slow moving air that "clings" to the bodywork of the car, especially where the bodywork flattens, or does not accelerate or decelerate the airflow. Areas like the roof and side body panels are good examples. The longer the roof or body panels, the thicker the layer becomes (a source of drag that grows as the layer thickens too).
The NACA duct scavenges this slower moving area by means of a specially shaped intake. The intake shape drops in toward the inside of the bodywork, and this draws the slow moving air into the opening at the end of the NACA duct. Vortices are also generated by the "walls" of the duct shape, aiding in the scavenging.
Typical uses for NACA ducts, as applied to real racecars, include engine air intakes and cooling. This same concept is now being applied to racecars on a much smaller scale, R/C cars.
Positive Flow Hood Scoops
Hood scoops are very effective at drawing in air from a direct air flow. They are used quite commonly on real racecars to provide a positive flow of air to components such as intakes, oil coolers, and brakes. We've designed this smaller version for R/C car and truck applications to cool your car's hottest components.
For more additional information see our Installation Page
How do we know they work?
We actually built a wind tunnel to test the use of scoops and NACA ducts vs. conventional methods of cooling.
Temperature decay test were done to compare the two methods of cooling. The test engine up with a heat gun. When it was good and hot, a body was placed onto the mocked up car and then placed into the wind tunnel.
When the engine cooled to a predetermined temp (usually 220deg), the wind tunnel and a stop watch were turned on. We timed how long it took for the temperature to drop 50 deg. This procedure was repeated five times to get an average.
We used this method of testing to compare many different ways of cooling. As you see above, A scoop on the hood, a large NACA duct or LP scoop on the roof, and the two small NACA ducts on the side windows was our best setup for nitro onroad cars.
We chose to focus on nitro on road cars because they require the most efficient methods of cooling. However, all other vehicle types can benefit from additional or alternative cooling methods.
