Friday, May 17, 2013

Specialized's new Wind Tunnel

The only way to make aerodynamics not matter is to stop moving. That line basically sums up Specialized’s philosophy regarding aerodynamics from here forward. Aerodynamics are so important on a bike in fact, that Specialized has now invested a huge amount of time and money in creating their own bicycle specific wind tunnel – an industry first.
Aerodynamics is about more than TT bikes and aero road helmets. By utilizing their new wind tunnel, Specialized aims to improve aerodynamics for every bicycle along with components from here on out.
Get a detailed look at the tunnel, next.

Up to this point, wind tunnel testing has mostly been reserved for the highest level athletes and the development of wind cheating TT/Tri bikes and gear. This isn’t because other segments of the market can’t benefit from testing, but more because wind tunnel time is so expensive and complicated. Typically, taking a product to a wind tunnel requires up to a month of lead time and once the company is there, they have a limited amount of time. The other issue facing bicycle companies who wish to improve on aerodynamics is that most wind tunnels are designed for testing aerospace and automotive parts which see wind speeds and forces 100-1000s of times stronger than what is encountered on a bike. Running these tunnels that are design for such high speeds at essentially the lowest speed possible results in air with more disturbance than what Specialized built specifically for bicycles and human powered speeds.
Building the Specialized Wind Tunnel
From left to right, Chris Yu, Mark Cote, Chuck Texeira, and Chris D’Aluisio
Working with some of the best minds in aerodynamics including Chuck Texeira, Chris d’Alusio, Chris Yu, Mark Cote, Mark Hopkins, and Bruce Storms, Specialized set out to build a bicycle specific wind tunnel from scratch. The goal wasn’t just to own their own wind tunnel, but create a measurement system perfectly calibrated for the world of bicycles. Capable of wind speeds from 0-100 KPH, the tunnel offers precise control and a custom force balance that was designed by Chuck Texeira. The balance is essentially like a bathroom scale that sits 6 feet underneath the bike in the tunnel and measures the force of the wind resistance. As an illustration of the force balance’s precision, imagine a bathroom scale that would detect the person standing on it being given a paper clip. That same scale also has to read minute differences very rapidly as the wind changes, so designing the balance was no small task. On top of the balance sits a rotary turn table which the bike is mounted to. The turn table allows for testing at various yaw angles and the whole unit is completely isolated from the rest of the building for pinpoint accuracy.
Specialized wind tunnel ends
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Built as an open return tunnel, Specialized’s tunnel features a single tube that is completely sealed off from the rest of the building. Six fans are positioned at the back of the tunnel, which draw air in from the front through a honeycomb mesh, then continuous fine mesh which serve to straighten out the airflow and remove disturbances. The decision was made to use 6 smaller fans instead of 1 large one due to the fact that 1 large fan would have to be custom built. If anything on the smaller fans malfunction, they can be quickly and easily replaced. Fans are housed in a carbon fiber fan shroud that was hand laid by many Specialized employees. Why carbon? Why not?

Another difference than other wind tunnels is the physical size of the test chamber. At 30 ft long, 10 ft wide, and 16 ft tall, it allows Specialized to include other features in the test such as other bikes to simulate a peloton. The widely spaced walls also offer cleaner air flow reading in the center of the tunnel when testing a single bike. Air exits the tunnel through a 50ft diffuser section which slows the air down gently to prevent turbulence from making its way back to the force balance. Only by watching the video of the tunnel being built can you get a feel for the sheer size of this thing.
The S-Works McLaren helmet above is a perfect example of CFD (computational fluid dynamics) and wind tunnel testing working together to form the final product. The helmet went through 56 different prototypes before even making a model, with the designs computer tested through CFD to confirm the design. Obviously, this was created before Specialized finished the wind tunnel, but in the future Specialized is capable of working very similar to F1 teams – design on Monday, test on Friday. New designs can literally go from paper to testable prototype in an extremely short period of time. Since Specialized owns the wind tunnel and it is located 5 minutes from their main headquarters, there is no longer any limit to how much time they have for testing. In addition to being able to visit the wind tunnel whenever they like, Specialized built the tunnel with an observation room that will function as an employee and SBCU class room. Anyone from employees, to dealers, to athletes can come to the tunnel and really see what aerodynamics is all about.
If you didn’t already see it coming, Aero is more than just the new black. Aero is everything.

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