The San Diego Wind Tunnel, built in 1945, was originally constructed to provide aerodynamic testing for Consolidated Aircraft, the manufacturer of the B-24. During the 60+ years of its existence, various owners have overseen the operation of this low-speed wind tunnel (LSWT), with a vast array of industries perfecting its design through testing and analysis. In 2006, the San Diego Air & Space Museum acquired ownership of this unique facility, one of a handful in the United States and the only one in the U.S. that is privately owned. The tunnel operates five days a week with a booked schedule of time rented to a wide variety of industries.
Aerodynamic considerations have long been a historical concern of cyclists. The drop shape of road racing handlebars, the clingy-ness of cycling clothing, even the stereotypical “shaved legs” are all efforts to make gains in the aerodynamics. This focus comes from the exponential consequence of drag on the cyclist. Doubling speed from 10 mph to 20 mph, a two-fold increase, requires four times the energy. This four-fold power requirement means four times as many calories are burned. This energy consumption is due to the stickiness of air upon an object traveling through it – air resistance. By making small gains in aerodynamics, large aggregate improvements are made in overall efficiency. This translates to faster speeds and seconds or even minutes shaved off performance time.
Wind Tunnel Obsolescence?
In previous years, many changes and improvements have been made to the steps involved in a product’s design. Software has long been able to provide computer analysis of flow dynamics, but recently, the costs of such software, and the computers required to run it, have dropped significantly in price. Consequently, the wind tunnel has been used less frequently for product testing because computers are able to model a similar environment without the associated costs of renting a physical wind tunnel. These days, the tunnel is used to supplement athletic training by simulating the flow dynamics of moving through space at speed but doing so in a static environment where the changes and instructions can take place simultaneously.
A criticism of wind tunnels is the static nature of the environment. There are no crosswinds or other environmental changes. For product testing, this limitation of variables can be problematic. Product designers want to know all the environmental cues that may affect the design of their wheels, frame or other piece of equipment. For athletic training, keeping variables static allows for adjustments and subsequent measurements can result in marginal gains that could otherwise be lost to inaccurate measuring tools and such environmental changes as barometric pressure or air temperature, both kept static in the tunnel.
We accompanied Rally Cycling to the San Diego Wind Tunnel earlier this month, and had the opportunity to see how the team uses the tunnel. Members of the team brought their bikes into the chamber and mounted them atop an aluminum platform that measures the effects on the static bike/rider combo by the forced air circulated by a 20-foot propeller on the other side of the building. When the bike/rider is more efficiently aerodynamic, less force is transmitted to the platform and a subsequent calculation of drag can be derived. A display projected onto the floor provides the rider with real-time data. The rider can then make minor adjustments to form and determine the quantifiable measurement of benefit.
When speaking with Christopher “Dino” Edin, lead product developer and designer at HED Cycling, he mentioned the hours of field coaching that had preceded their time in the tunnel, working on different forms and getting comfortable with the equipment. “Many teams I’ve worked with in the past would send their riders into a tunnel without prior skill-training. They’d get to the tunnel and spend their time on basic training that we now work out before we even get here.”
The team began their season with a training camp in Calabasas which BICYCLIST covered in issue #130. This is where many of the drills and techniques are developed. Muscle memory and form are a core focus of these training camps and ensure that the long hours in the saddle maximize power efficiency. Edin shared the strategy they have developed after many seasons of wind tunnel testing, “It’s about giving these guys confidence on the bike. They come in here after the weeks of training and we make minor adjustments, small incremental changes. The big changes have already been made.”
Rally cycling would go on to sweep the 2016 Men’s and Women’s USPRO Team Time Trial Championships with team-mates Brad Huff winning first place for the men and Elle Anderson, second for the women.