News from Kenworth: Wind Tunnel Lessons Drive Truck Aerodynamics

NEWS RELEASE

FOR IMMEDIATE RELEASE

CONTACT:    
Jeff Parietti, (425) 828-5196  jparietti@paccar.com
       
Kenworth Engineers Apply Lessons Learned from University of Washington Wind
Tunnel

Seattle is Home to World Class Aerodynamics

KIRKLAND, Wash., December 10, 2001 -  Need a tip on who has the fastest
bobsled?  Ever wonder how they get America's Cup sailboats to move so
effortlessly? Or, how they get large trucks to have drag co-efficients equal
to that of many sports cars? The answers reside in Seattle, home to the
University of Washington's Kirsten Wind Tunnel.

Originally developed in part to test airplanes for Boeing, the wind tunnel
has been an integral part of the Seattle landscape since 1938.  Kenworth
Truck Company has used the wind tunnel since 1975 and it's paid big
dividends. Since then, the company's aerodynamics engineers have been able
to reduce aerodynamic drag by nearly 35 percent as reflected in its current
products.

"Companies and sports figures from around the world come to Seattle for
advanced wind tunnel testing," said David Warren, Kenworth's assistant chief
engineer for advanced concepts.  "They have three world-class facilities to
test small to very large items - they can tell a downhill skier which tuck
position is the most aerodynamic, or which sailboat keel will slice through
water best.  And, they can validate how truck design modifications will
positively impact fuel economy.

"Without the wind tunnel, Kenworth wouldn't be where we're at today," Warren
said. "It's given us a leadership position in aerodynamic truck design which
pays our customers back in the form of better fuel economy."
  
According to Warren, Kenworth's T600 model - the industry's first truly
aerodynamic Class 8 truck introduced in 1985 - was developed with aid from a
wind tunnel.  "Back in the '70s, fuel economy wasn't a factor since the
price of diesel was so low.  But that changed and we were in position to
move the industry toward aerodynamic trucks - greatly in part to
forward-thinking Kenworth engineers, led by the late Larry Orr, and the
University of Washington."

Originally, Kenworth worked with 1/10th scale models and the wind tunnel was
a working laboratory.  "We were doing raw experimental development with
exterior body shapes and vehicle concepts," recalled Warren.  "We'd retrofit
trucks - bring in several different hoods to see the air flow changes - plus
we modified as we worked.  It was a trial and error process.  It was the
best technology we had at that time.

"But times have changed," Warren said. Kenworth now uses 1/5th scale models
which give company engineers better air flow assessments. In addition, the
company uses full-scale models when validating smaller components such as
mirrors and visors.

Kenworth also used the wind tunnel to test and validate the aerodynamic
package for a specially built T2000 race truck in June 1998. The T2000 later
set a highway hauler world land speed record of over 162 miles per hour at
the famed Bonneville Salt Flats.

"Thanks to our CFD (computational fluid dynamics) program, we now use the
wind tunnel to validate our computer findings, instead of using it as a work
in progress," explained Warren.  "This greatly increases how fast we can
bring aerodynamic enhancements to market."

After wind tunnel validation, Kenworth takes its new vehicle on the road.
"We have a very unique proprietary tool to measure full-scale aerodynamic
drag at our proving grounds," said Warren.  "We can very accurately measure
rolling resistance and aerodynamic forces on the vehicle.  We feel our
three-phase program - CFD, the wind tunnel, and our proprietary program at
the PACCAR Technical Center in Mount Vernon, Washington - is the best in the
business.  It allows us to stay ahead of the competition."

To assist fleets and owner operators interested in improving their fuel
efficiency, Kenworth recently launched a major Fuel Economy Awareness
Program. Kenworth also has produced a "White Paper on Fuel Economy", which
can be electronically downloaded at the "Dynamics of Fuel Efficiency" link
at www.kenworth.com.

Copies of the white paper may be requested at: Kenworth White Paper on Fuel
Economy, c/o Brandhammer, 121 Lake Street South, Kirkland, WA 98033.

Kenworth Truck Company, a division of PACCAR Inc, is a leading manufacturer
of heavy and medium duty trucks.

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Sidebar:  The University of Washington's Kirsten Wind Tunnel is a subsonic,
closed circuit, double return wind tunnel. The tunnel has a test section
with a rectangular 8' x 12' cross-section that is 10 feet long. Two sets of
14' 9"-diameter seven-bladed propellers move air up to 200 mph through the
test section. A PC-based data acquisition system running LabVIEW software
records data from a six-component external balance. The data is then sent
via a serial connection to an on-line plotting PC.

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NOTE TO EDITORS: if you would like high-res versions of the attached low-
res images, please reply to this email.  Other high-res images are also
available by request.  Here is caption information:

windtunnel1lr.jpg - Kenworth T2000 scale model with trailer in wind tunnel
windlandspeed.jpg - Kenworth T2000 scale model in wind tunnel (with test
smoke blowing over truck)
KWlandspeedlr.jpg - Kenworth T2000 land speed scale model in wind tunnel
KWlandspeed2.jpg - Kenworth T2000 land speed world recordholder (with
open parachute)