The newly opened Honda Automotive Laboratories of Ohio (HALO) wind tunnel is a $124 million facility that lets the brand test aerodynamics and aeroacoustics. The company will use the site to develop future production vehicles and race cars, in addition to opening up the site to third parties who want to test their own products.
Situated on a former soybean field at the Transportation Research Center in East Liberty, Ohio, this is Honda's first wind tunnel capable of testing full-scale vehicles in the United States. Previously, the company had to rent time at other facilities around the country to do this work.
The HALO wind tunnel has two rolling roads, depending on what the company is developing. A five-belt unit is for testing higher-riding vehicles like crossovers. A single, wide belt is for evaluating machines that are closer to the ground like performance products or race cars. The belts that carry these vehicles are just 0.8 millimeters thick.
It takes about four hours to swap between the five-belt and wide-belt layouts. There's a massive crane that carries the 40-ton assemblies into place.
The heart of the wind tunnel is a fan that measures 26.25 feet (8 meters) in diameter. There are 12 hollow carbon-fiber blades with just a 4-millimeter clearance between them and the exterior surround.
During our tour of the site, Honda engineers told Motor1.com that when the company first installed the fan, the clearance was slightly off, and the blades were scraping against the wall. The company had to grind a little material off of the surround to make them fit.
The fan's maximum speed is 250 revolutions per minute. This doesn't seem like much, but this is enough to move air as quickly as 192.6 miles per hour (310 kilometers per hour). There's a 6,705 horsepower (5-megawatt) electric motor turning it.
During aerodynamic testing, Honda needs to control as many variables as possible. This includes removing the brake pads and driveshafts from vehicles. Plus, there's a gargantuan heat-exchanger wall that's essentially a massive radiator. A glycol mixture can adjust the air temperature between 50 degrees Fahrenheit and 122 degrees Fahrenheit (10 to 50 degrees Celsius) in just 30 minutes.
Sensors in the floor are capable of measuring changes as small as half a pound. There's also a diagnostic arm with stopping precision accuracy as precise as 0.5 millimeters. The engineers can use it to evaluate things like wake vortices coming off the rear of a vehicle.
The wind tunnel is also capable of doing aeroacoustic testing for tweaking the wind noise in vehicles. Swapping from aerodynamic development to aeroacoustics takes less than an hour. The major changes are bringing in an array of 502 microphones that are positioned on each side of the vehicle and above it. The model sits on a sound-dampening aluminum honeycomb panel.
Inside the car, Honda installs 54 internal microphones. There are also devices called Aachenheads, which look like mannequin heads and have microphones in the ear canals that replicate human hearing. The engineers in the control room can visualize the various decibel levels on their computers. And, they can put on headphones to listen to the sound from inside of the vehicle.
It stands to reason that when evaluating wind noise, you need a space that's otherwise quiet. At 87 mph (140 kph) of airspeed, the wind tunnel test chamber experiences just 57 decibels of sound. To put this into perspective, your average office operates at around 60 decibels.
When testing, the vehicles are on a turntable that's capable of rotating up to 180 degrees. This serves multiple functions. First, it allows for evaluating aerodynamics or aeroacoustics not just from straight-on but also from a variety of angles. Second, this setup allows for quick loading and unloading of models from the wind tunnel because the company can point them toward the door and push them out.
This site won't exclusively be for Honda vehicle development. There are four secure garages that include a lift, workspace, bathroom, and small kitchenette for customers who are renting time at the wind tunnel. Honda also has a car wash, machine shop, suspension alignment rack, and a laser scanner for figuring a vehicle's frontal area there.
Honda plans to increase the workload at the wind tunnel slowly. One day each week is for maintenance. By this fall, it should be fully operational. Eventually, the plan is to run multiple shifts of testing there each day.