117 Godspeed Lane,
Mooresville NC 28115
What is a Wind Tunnel?
A wind tunnel is a research tool or a testing laboratory with a controlled environment used to understand aerodynamically what is happening to a particular shape or object. Or in this case... a type of vehicle. It is used to quantify and validate what is going on aerodynamically to the vehicle by measuring forces exerted on the body through a 6 component balance underneath the floor that the vehicle is fixed to by use of adjustable wheel pads.
Adding a rear wing to your car might gain you down force, but a wind tunnel will tell you in fact if it is, how much, and how it affected the overall front to rear balance of your car. Each test will output the drag, down force (front & rear), and side force (front & rear), yaw/pitch/roll moments, in order to see the big picture of what is really happening for any given configuration. Even though we test at 85mph we can scale the force data to virtually any speed you would see with your vehicle to see what the aero forces would be at that speed.
Have you ever wondered why wind tunnel testing seems to be so vital amongst the top race teams, and why every time you turn on a NASCAR or F1 race someone is talking about how they just had their car in the wind tunnel? It is hard to imagine that something you cannot see could have such a significant influence on the performance of a vehicle. More and more racers are catching on to the importance of aerodynamic testing and the value it can bring to just about any application. Whether you have a specific handling issue, or you just looking for more top speed, a wind tunnel is a good place to make some measurable differences.
Aerodynamic drag is a force in the opposite direction of the vehicles forward movement. You need enough power and torque to overcome this force and move the air around the vehicle. At low speeds drag is not a major concern, but as the speed increases, the aerodynamic drag will increase with the square of the speed (speed2). This means, in order to double the speed you will increase the drag force by four times.
If your drag force is 70 lbs at 50 mph, then the force at 100mph is 280 lbs. At 200 mph the drag force would be 1120 lbs, and so on.
Just when you get over that fact, there is one more that will really get your attention. Horsepower is affected by the speed as well, but HP = Drag force x velocity. This means as the speed increases the Horsepower required is now the cube of the speed. Every time the speed doubles the HP required to overcome the drag forces is increased by 8 times!!
If it requires 15 HP to overcome the drag forces at 50 mph, then it would take 120 HP to overcome the drag force at 100 mph. To reach 200 mph you would need 960 HP. 300mph would require 2700HP!! This is why you can add 50, even 100HP to your engine and not see a big gain in top speed.
Example of how a 15% reduction in CD would translate into Horse Power and Drag Force.
HOW CAN A WIND TUNNEL HELP YOU
Landspeed and Drag Racing:
There are two way to improve your top speed significantly… 1) massive horsepower gains. 2) Reduction of aerodynamic drag.
Some cars can actually produce lift and become very unstable at high speeds. A wind tunnel can aid in the vehicles balance (front to rear) along with improving the drag as shown in the set of photos below. The top image is the car sitting at the static ride height (mirrored to be oriented the same direction), notice the ride heights in order to compare to the lower 3 pictures. The second picture down is the car as run in April at Maxton, NC (landspeed 1 mile event). Notice the front fender gap and the driver said the car was a hand full at 180 mph. The car was then wind tunnel tested and a major lift problem was found on the front end of the car and some development was done to correct the problem. The car was raced the next day at the MayMaxton meet as shown in the third picture down. Notice the lift is dramatically reduced and the fender gap is much closer to the static ride height and in this configuration there was still a little lift (as seen in the wind tunnel) and you can still see the fender slightly higher than static ride height where the car ran 190 mph. In the fourth picture down the car was run in June with all wind tunnel modifications performed on the car that gave it a better overall balance (downforce front & rear). You can now see that the fender gap is a little lower than static ride height which correlates with the wind tunnel in this configuration that gave the nose downforce. In the optimized configuration the car ran 193 mph.
Thanks to Gary & Pam Beineke for the photos of their '71 Dodge Daytona
Balance is key to fast lap times , and teams are always trying to find the proper front to rear balance for optimum handling. You can improve your lap times by getting the car through the corner faster. Any time you can improve your traction you will be able to improve your corner speeds. Aerodynamic downforce is better then adding weight because by adding weight you will add inertia which will be harder to slow under breaking. Adding downforce can keep your car light and use the air to push your vehicle to the ground. If you are using the brakes or lifting out of the throttle, you need more downforce. >>>
Rider position is as important to the performance of the motorcycle. Helmets and even rider suits can have a significant affect on the aerodynamic performance.
Anywhere from 70-90% of a riders power output will go to overcome the resistance of the air. Positioning becomes extremely important for cyclist to be able to maintain a low drag while still producing sufficient power because the rider accounts for the majority of frontal area. Any rider can get into an exceptionally aero position and acquire excellent numbers in a wind tunnel, but if he/she cannot produce efficient power there is no way they will reach their full potential on the bike. Along with drag measurement we use a Computrainer® to measure power output in Watts, cadence, wheel speed, and heart rate to determine if a position change helped or hurt the overall performance of the rider. Also, there is no magical position or mold that will make all riders fast. Bicycle aerodynamics are very specific to each different rider’s body size and type. A position that works well with one will not work well for another, and this is the same with equipment, such as helmets as well. Get into A2 today and learn the facts!!
Aftermarket & Production performance (Aesthetics and functionality)
Marketing a more fuel efficient after market accessory (Wind Tunnel Tested)
Fuel efficiency for production vehicles
Most people don’t understand the importance of aerodynamic testing. You can think of a wind tunnel for your car the same way you look at a dynamometer for your engine. Just because you have the biggest pistons, cam, headers, and carburetor… it doesn’t mean that you will make the most horsepower out of your engine. A dynamometer is used to tune your engine the same way a wind tunnel is used to tune your vehicles/riders body.
People also perform modifications because someone told them it’s “fast” or everyone else is doing it so it must work. Some teams think there is nothing they can do to the car or they are not going fast enough to be concerned about aero. If you are moving through the air, you are being affected by aero.
Think about this... NASCAR has some 30 templates that the cars must fit at close tolerances while they go through a rigorous inspection process for each race. These guys are in the tunnel every week trying to find something between those templates where they can find an advantage, gain down force, or lose drag. AeroDYN, which is our “Big Brother” tunnel, tests 24 hours/day, 5 day/week, and can be booked year in advance with nothing but NASCAR teams. These teams know how important aerodynamics are for getting the balance of the car just right in order to qualify good and race up front every week.
In other words, the less you are restricted by rules, the more you could benefit in a wind tunnel.
© 2013 A2 Wind Tunnel