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Aerodynamic Lift/Drag land speed record at 600.601 mph with his Sonic I
“Spirit of America,” his 4-wheel successor to his first
Slows 600 mph Sonic I “Spirit” and a 10,000 hp GE-J79-3 jet engine.
In one test run at over 600 mph the car’s front wheels
became partially airborne, air pressure caved in the
“WHEN you hit 600 mph the car falls flat on its face, right rear fender, forcing metal against the tire. One inch
it runs into a wall. The answer is not in going faster, of rubber was scraped from the 49-in. rear tire but
not in more power. There’s got to be a reduction in none of the Goodyear tires, tested at 850 mph on the
lift and drag.” That’s speed champ Craig Breedlove dyno, failed. The centrifugal force acting against the
talking. In November, 1965 he established the world 36-in. front wheels at 600 mph was 948,000 lb.

Group 7 car design, tail ap­ Los Angeles at a unique sym­ 35% more fuel economy and 25%
pearance, light weight, compact­ posium devoted to sports and higher top and cruising speeds.
ness are frequently considered competition car aerodynamics. Korff sees Detroit’s autodom
more important than drag co­ They discussed dragsters, Group eventually publishing drag co­
efficient. 7 cars and high speed land record efficient values and acceleration
Yet for tomorrow’s high speed vehicles. in terms of pounds per Available
car designers, aerodynamics Even production car aerody­ Power for Acceleration (APA)
means paying more attention to namics came under study. For­ rather than lb/hp ratio. Further
such things as lift and drag mer Lockheed aerodynamicist aerodynamic improvements re­
ratios, airflow paths, pitch, yaw, Walter Korff, designer of the sulting from experience on rec­
and roll studies. It means serious speed record holding, piston-en­ ord-breaking vehicles would in­
analysis of stability, rake angles, gine Goldenrod (409.277 mph in clude directing air flow for
pitch angles, induced drag, 1965), says aerodynamic stream­ boundary layer control, spoilers
ground effects, boundary layer lining has assumed greater im­ and flaps for high-speed brak­
control and blunt aft bodies. portance with our sustained driv­ ing and Similar sophisticated
Perhaps the dragster or funny ing speeds on new expressways. appurtenances.
car are classic examples of seat- And at freeway speeds a prac­ Solution to many aerodynamic
of-the-pants aerodynamic design. tical aerodynamically stream­ problems facing high speed race
What progress has been made is lined car would have these ad­ cars is to be found in a much
mostly through trial and error vantages: natural beauty of a low “misunderstood” wind tunnel, as
guided by an intuitive feeling for drag shape, better stability and well as in road testing. The
the physics involved. control (no lift), 8% more ac­ more complex cars almost have
Aerodynamicists and competi­ celeration at 60 mph, 20% more to have quantitative data. Get­
tion car buffs recently huddled in at 80 mph, less wind buffeting, ting that on the road is tedious
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24 Machine Design