TESTING TIMES
period was relatively short.”Until the tunnel
was completed, it couldn’t be tested, so,
for six months, Sports Aero Solutions
had the task of testing all of the tunnel’s
components – load cells, data acquisition
systems, control systems and electrical
systems. With validation complete, the
paying public has been using the facility
since October last year.
There are many reasons for building a
cycling-specifi c wind tunnel, but the biggest
one is the cost. “There are really only a
few wind tunnels you can use: the Formula
One tunnels like Williams, Mercedes or
McLaren; there’s Southampton University’s
wind tunnel and that’s
really about it,”
points out Salter.
“The amount of time
available is so limited
and is expensive.
It’s thousands of
pounds an hour,
as opposed to our
tunnel, where it
could be hundreds
of pounds an hour.”
The costs and time
allowed for testing
in these motorsport
wind tunnels are even
more prohibitive –
even for professional
cycling teams –
since they must be
decommissioned as a
motorsport wind tunnel
and recommissioned for
use for cycling. Additionally,
they are built with a rolling road, which
needs an attached platform to which the
bicycle is fi xed. This platform affects the
airfl ow around the cyclist, which is also
exacerbated by the fact that motorsport
wind tunnels are designed to run at
150mph, rather than the more ‘sedate
speeds’ of 40-50mph at which cyclists
travel. So, in effect, one is paying a lot
of money for not a lot of testing time in
a wind tunnel that is not working in its
optimum operating window.
Another way in which costs can be
cut is, instead of having a closed loop
confi guration where the air is circulated
and turned, to build an ‘open jet’ tunnel.
The footprint of a closed loop wind tunnel
would be almost three times larger than an
open jet tunnel. And, because of the lower
speeds the air needs to travel through the
Boardman open jet wind tunnel, it sits in
a room measuring just 27 x 14 metres.
The fan is located at the rear of the
cyclist and pulls air through a bell mouth
section at the front, which is fi ve times
larger than the opening in front of which
the cyclist sits. This helps speed the air
to 22-25mph across the athlete. Before it
reaches the athlete, the chaotic air from
the room is channelled through three
screens, two honeycombed ones and a
fi nal fi ne mesh. At each stage, the airfl ow
is straightened out and, by the time it hits
the athlete, it is completely laminar and
concentrated into a 2m x 2m area. Even
while the fan is on, there is no turbulence
around the outside of the tunnel.
“Things have changed since motorsport
tunnels were built, particularly around
software and data acquisition systems,”
explains Salter. “We’ve been able to strip
it right back to being cost-effective. These
wind tunnels don’t cost £20 million to
build. They cost a million and a bit. A
lot of that is because we haven’t got a
rolling road; we don’t have very expensive
proprietary software and data acquisition
systems. We built our own (because you
can now) relatively cost-effectively.”
Sports Aero Solutions has since
become involved in building a second
wind tunnel at Silverstone Park,
Northamptonshire. With a fan measuring
2.5 meters in diameter, and speeds
of approximately 60mph, the tunnel is
all about enabling analysis of sports,
including cycling, running, skiing and even
ski-jumping. The Silverstone tunnel will
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