GM belly tank Lakester to run at Goodwood
No vehicle expresses the ingenuity and unbridled innovation of hot rodding more forcefully than the belly tank lakester, and a modern version is appearing at the Goodwood Festival of Speed, June 25-27. It is similar in design to past lakesters, but has GM’s latest advanced technology – the Ecotec engine.
Conceived by hot rodders in the late ’40s as a method of reducing aerodynamic drag, belly tank lakesters were fashioned from war surplus auxiliary fuel tanks that had been mounted on the underside of military aircraft. These open-wheeled inventions set records on the dry lakebeds of Southern California – hence the „lakester“ nickname – and on the glistening white salt flat of Bonneville.
One of the most famous of the breed was the So-Cal Speed Shop belly tank. Featured on the cover of Hot Rod in January 1949, the streamlined projectile was fabricated from found materials and built by hand on a nonexistent budget. Now, 55 years on, the soul of the original So-Cal lakester has been reborn.
GM Performance Division conceived a belly tank lakester for the 21st century to demonstrate the versatility of the Ecotec engine. Instead of the original’s war surplus components, the reinvented lakester was constructed from high-tech materials using advanced digital design techniques; and in place of a rudimentary flathead V-8 is a sophisticated, supercharged Ecotec engine. But despite the vast differences in materials and technology that distinguish the two vehicles, the modern version remains true to the spirit of the famous So-Cal belly tank lakester.
“The original belly tanks are hot rodding icons,” said Frank Saucedo, director of design for the GM Advanced Studio in North Hollywood, Calif. “We didn’t want to stray too far from the streamlined look of the originals when we designed this updated version. Our goal was to use GM’s advanced technology and processes to update a classic design. We thought of the project as creating a belly tank for the 21st century.”
The sculptured skin is formed from lightweight composite materials (including carbon fiber, Kevlar and Lexan), with a silhouette that follows the curve of the original and a three-dimensional scallop that echoes the original So-Cal Speed Shop paint scheme.
“We wanted to marry the technology that’s used in modern Formula One race cars with the traditional form of the belly tank lakester,” Saucedo said. “Fabricating the tubular steel chassis and composite body required a combination of old-fashioned craftsmanship and modern computer-aided design and manufacturing. The chassis design was digitized, and we had access to the math data for the production Ecotec engine. Using this information, all of the body surfaces were developed mathematically.”
The exposed Ecotec engine is a radical departure from the fully enclosed streamliners of the past. It is powered by a transverse-mounted 200-horsepower supercharged Ecotec with a production Saturn Ion transmission driving the rear wheels. A “crate engine” version of the engine will be available from GM Performance Parts in mid-2004.
The science of aerodynamics has yet to improve on the original belly tank design.
“A teardrop is considered the ideal aerodynamic shape for low drag,” explained Kevin Bayless, GM Racing’s aerodynamics specialist in the Indy Racing League. “The tapered tail keeps the airflow attached to the surface, minimizing the turbulence that creates drag. If maximum speed is the objective, then a teardrop is the optimum shape for a race car.”
In the world of hot rodding, the leap from war surplus gas tanks to digitally designed concept cars is simply another expression of the abiding passion for innovative automobiles.