The Kurtis frame was sized...
The Kurtis frame was sized to fit most popular kit car chassis. Note X-bracing that strengthened frame and transverse torsion bars.
Today's kit car builders have a plethora of choices in chassis and running gear. Most Cobra clones have ladder frames mounting Mustang, Jag, or Corvette suspension, while the sturdy Fiero still provides underpinnings for most mid-engined exotic replicas. Super Se7en-style kits use neatly triangulated space frames to mount sophisticated suspension systems. There are even fabricated aluminum and steel monocoque chassis for everything from GT-40 replicas to snake skins. But it wasn't always so.
In the '50s few of the available kits had their own dedicated chassis. Most early kit bodies mounted on production car chassis that had been modified for kit use. There were only a handful of manufacturers who sold chassis for use under kit cars. Most relied on Ford sedan straight-axle suspension front and rear. Here's a look to help you determine what underpinnings are keeping your beloved 1952 Whatzit off the ground.
Frank Kurtis had been building winning Indy cars in his California garage when he first took notice of the fledgling kit car industry. The cut-down Ford chassis were nothing to write home about, so Kurtis decided to build a chassis kit that could be ordered in various wheelbases to fit different kit bodywork. For inspiration he adapted his Indy car chassis (as used under Billy Vukovich's 1953 Indy winner) to two-seat configuration and called the new chassis model the 500KK. The round-tube frame was a simple ladder affair with a large X-beam in the middle and low sides. The torsion bar suspension was patterned after his Indy cars and featured torsion bar springing fore and aft locating straight axles. The frames were made from 0.093-inch wall seamless steel tubing.
The Kurtis KK chassis looks...
The Kurtis KK chassis looks simple, but the torsion-bar suspension was vastly superior to the Ford transverse springs used on most kit cars of the '50s.
Bare frames weighed in at just less than 300 pounds. The rolling chassis, less body and engine, was around 800 pounds. The front suspension mounted the torsion bar on top in a trailing configuration with a lower trailing radius arm, while leading links were used in back to provide a long spring base. The torsion bars were adjustable for quick changes in ride height and suspension tuning, and an adjustable-ratio 1939 Ford steering box was hooked to a custom pitman arm and drag link arrangement. Sway bars were used front and rear.
The Kurtis frames were popular in the early '50s, selling for $1,290 with suspension included, or $399 as a bare frame. Most had drum brakes, although some Kurtis racing sports cars were fitted with erratic Halibrand spot disc brakes. These chassis were used under many period bodies, including Allied, Sorrell, Byers, Glasspar, Woodill, and others. The same basic chassis design was later beefed up and used under the Kurtis 500S racing sports cars and the Kurtis 500M street sports car.
Two army buddies, Ted Mangels and Ed Martindale, spent part of 1952 pouring concrete over the dirt floor of an old barn on Martindale's parents' farm. Then they fabricated a car frame with a 100-inch wheelbase that they intended to sell for use under kit cars. The young entrepreneurs moved their operation to California before going into production in 1953.
Mameco frames were designed...
Mameco frames were designed to fit Glasspar bodies, as shown here. The Engine is set back for better weight distribution.
The name of their new company was Mameco (for Mangels and Martindale Engineering Company) and their frame was sturdy, if unsophisticated. Ford 1939-to-1941 crossmembers were welded into a simple ladder-frame constructed of 2x3-inch rectangular steel tubing with a 1/8-inch wall. Three of the crossmember joints were gusseted and the frame ends were not capped. Ford suspension and brakes were intended to be used. The frames were sold bare.
Mangels and Martindale soon met Bill Tritt, who was building the Glasspar kit cars in California. Tritt had been using frames built by Shorty Post, but was looking for something stronger. The first Mameco chassis was sold to Tritt, who installed it under his Glasspar factory racecar, which was powered by a CT Automotive flathead Ford engine with Ardun heads. It was competitive right out of the box and did well in a number of events.
Victress also offered Mameco frames to fit their bodies. They were similar to the ones used under Glasspars and were based on 1939 to 1948 Ford suspension and brake parts. Martindale recently recalled that they built about 300 chassis to fit Glasspar, Woodill, Victress, and Allied bodies. Most were sold to Glasspar, and Mameco also built a short run of a different chassis design for the aborted Glasspar Ascot sports car, which used Studebaker running gear. Mameco chassis were normally sold bare, but they also assembled a handful of complete cars from 1953 to 1955-when they closed their doors.
Chattanooga Boiler and Tank...
Chattanooga Boiler and Tank built a handful of these Glasspar-bodied sports cars.
Chattanooga Boiler And Tank
An unlikely company built one of the more sophisticated kit car chassis of the early '50s and was featured in the May 1953 issue of Road & Track. The Chattanooga Boiler and Tank chassis was designed to fit under the Glasspar body (the most popular body at the time) and was constructed of oval-section framerails that tapered from 3x5 inches in the center of the car down to 2 inches round at each end. A sturdy X-member was welded into the frame behind the transmission area and modified Willys suspension was used all around. A Willys front axle was sprung by semi-elliptic springs, while in back a Ford rear axle was mounted with 1940 Willys rear springs. The same year Willys provided a Gemmer steering box that was fitted with a longer Pitman arm to reduce the turns from lock-to-lock. The first cars had a combination of 9-inch Lockheed drums in front and 10-inch Bendix drums in back, with part of the rear lining area removed to provide better brake balance. The company felt these brakes were adequate for street use, but not big enough for racing.
The first car built had a flathead Ford engine and weighed 2,150 pounds. Chattanooga built at least three more complete cars, one of which had a Cadillac V-8 and was intended for racing. They intended to sell chassis for around $300 each, but it isn't known how many were sold. Two of the original cars survive, as well as at least one frame under a non-Glasspar body.
The Chattanooga chassis was...
The Chattanooga chassis was beautifully fabricated and the framerails tapered off in size at each end.
Shorty PostHarold "Shorty" Post was a California hot rodder who built and raced flathead and Hemi-powered streamliners on the salt lakes in the early '50s. He also built special chassis and customized cars on the side. In 1952, he was called on to design a chassis for the Woodill Wildfire kit car utilizing as many Willys parts as possible. This was because Woodill was trying to convince Willys to pay them to produce the Wildfire. Post laid out a very simple C-section steel ladder frame with minimal bracing that used Willys suspension, brakes and running gear. Unfortunately, less than 10 were built before Willys changed hands and the program ground to a halt. Woodill changed tactics and had Post revise the frame to accept prewar Ford suspension and running gear. The frame lacked an X-member, but included a firewall, floorboards, and a driveshaft tunnel. Post welded body mounts to the framerails. A buyer could also send in '50s-era Ford independent front suspension and crossmember assembly and Post would graft it onto the front of the frame. Woodill built their frames in-house using a wooden jig to hold the parts in place while they were being welded. Less than 100 Woodills are thought to have been built. Post had earlier sold frames to Glasspar, but they soon switched to a Mameco frame.
Manning Plan Sets
Chuck Manning was an aircraft stress engineer who decided to build his own road-racing car. He laid out a strong, round tube frame with stacked parallel 2.75-inch mild steel tubes (0.049 wall) on each side mounting 1939 Ford suspension, hydraulic drum brakes, and a Mercury flathead engine. The 85-pound frame was very light and stiff for the time, and the radius rods for the front and rear suspension were short and aimed at the center of the car. The leaf springs had half their leaves removed to soften them up for the lighter car. Ford 1940-model lever shocks were used at the rear. The car was very quick and won a major race at Palm Springs, California, in 1952. Manning wrote a series of articles for Road & Track describing the process of designing a chassis. Manning then sold a plan set showing how to fabricate a copy of his chassis. This was the inspiration for a number of cars built in the '50s.
The Schaghticoke Special was...
The Schaghticoke Special was built from a Manning plan set in 1955. It used a Mercury flathead engine and is shown here at the Monterey Historic Races.
In the late '50s, Manning designed a simpler tube frame for the Kellison kit car company to use under their sports cars. These box-style frames were built from four-inch tubing with an 0.060-inch wall thickness and used straight axles at both ends. These frames could also be purchased for $650 to use under other bodies, and a set of plans for home fabrication was offered as well. Bare frames weighed 140 pounds. In the '60s, Kellison introduced a new frame that mounted later-model running gear with Chevy or Mopar independent front suspension. These were also sold under the Astra name.
Most of the kit car chassis designs of the early '50s were light and reasonably sturdy, but setting a competitive price made unsophisticated prewar Ford suspension the components of choice. The cost of fabricating a frame prompted most kit manufacturers to use modified production car chassis instead. The typical ladder frames were remarkably similar to those used under the 289 Cobra of the '60s (right down to the cross-springing). The availability of these custom frames allowed some early kits to perform as well as most factory-built sports cars of the era!
A special thanks to kit historian Geoff Hacker for photos, diagrams, and info. He's co-writing Forgotten Fiberglass with automobile historian Rick D'Louhy, focusing on the history of the fiberglass kit car industry (fiberglasssportscars.com/books/books.htm). And thanks to kit car pioneer Ed Martindale for help on the Mameco section!