1947 Chevrolet Cadet: The Revolutionary Postwar “Light Car” Chevrolet Never Actually Built

Between 1945 and 1947, Chevrolet developed an advanced postwar compact called the Cadet. Originally intended as a “light car” that would sell for less than $1,000, it quickly evolved into one of the most ambitious and sophisticated U.S. car designs of the postwar period — only to be canceled in 1947, before more than a handful of prototypes had been built. Here is the complete history of the Cadet as presented by Karl Ludvigsen in Special Interest Autos magazine in 1974, supplemented with additional technical illustrations from lead design engineer Earle MacPherson’s March 1947 patent filing.

This article, “The Truth About Chevy’s Cashiered Cadet,” first appeared in Hemmings Special Interest Autos No. 20 in January–February 1974. It was never reprinted in any of the Hemmings compilations of SIA material, but back in 2009, Hemmings presented it on their website; Paul linked to that post back in 2011. Unfortunately, changes to the Hemmings website following their acquisition by American Business Journals broke all the image links (apparently inadvertently), and Hemmings eventually just took all those posts down. (They may not have had the right to reprint those articles in the first place; the late Richard M. Langworth complained that his original deal with SIA gave them only first publication rights.)

However, the Cadet is such an important chunk of American automotive history that I think it’s important to keep it available in some form, so I’m presenting it again here, with higher-resolution scans from the original magazine. (I’m not going to transcribe the entire text — click the images for the full-size version for that — but I’ll transcribe some significant passages.)

 

The lead engineer on the Cadet project was Earle Steele MacPherson (whose name is misspelled with relentless frequency even in authoritative sources). I can fill in a few biographical details beyond what Ludvigsen presents:

Originally from Highland Park, Illinois, Earle MacPherson got his B.S. in mechanical engineering from the University of Illinois College of Engineering in 1915. He then became a research engineer for Chalmers Motor Co. from June 1915 to 1917. In June 1917, he joined Maj. Raynal C. Bolling’s “Bolling Mission” to Europe, which was essentially a study group to determine how the U.S. should establish its military air force. That December, MacPherson became a captain with the new technical service division of the U.S. Air Service, stationed in France. After the Armistice, he left the service in March 1919 and married a Frenchwoman, Albertine Billet, in May, before returning to the U.S. to begin a new job as assistant chief engineer of Liberty Motor Car Co.

In November 1922, MacPherson became assistant chief engineer of Hupp Motor Car Corp., where he remained until early 1934. During that time, he received 27 U.S. patents, most related to engine and suspension design. MacPherson went to GM Engineering Staff in early 1934 and Chevrolet Motor Car Division in 1935.

 

I’ll defer to Ludvigsen about the origins of the Chevrolet Cadet project in 1945:

The origins of the Cadet could be traced back 25 years. After World War I, a business depression followed that nearly ruined General Motors. In 1921, GM’s Chevrolet Div. was a money loser to the tune of about $5 million. Its chief finance officer, M. E. Coyle, became Chevrolet general manager in 1933 and still held that post in 1945. It’s likely (yet only my assumption) that Coyle feared a repetition of this postwar downturn in the years just after World War IL I believe he was thus willing to support a plan to introduce an all-new, low-priced Chevrolet. Specifically, the aim was to produce a car to sell for $1000 or less. In 1947 the cheapest Fords and Chevys were about $1050, and only the baby Crosley cost less than $1000.

There wasn’t universal agreement in General Motors that a small car was needed. One who strongly opposed it was GM’s chairman, Alfred P. Sloan, Sloan pushed for an expansion of the company’s ability to make conventional cars, believing that the auto business would boom after the war. As a compromise between these points of view (I believe), the Chevrolet Light Car Project, as it was known, was set up completely on its own in the early spring of 1945, with Earle MacPherson its chief engineer.

It’s important to emphasize that when this project began, the U.S. was still at war. The war in Europe was winding down (V-E Day was May 8, 1945), but the war with Japan continued, and no one was sure how much longer it might go on. Civilian automobile production was still frozen, although some passenger car production would resume in July 1945.

 

Incidentally, in early 1947, the cheapest Ford DeLuxe 6 coupe was $1,110 and the cheapest Chevrolet Master DeLuxe coupe was $1,137, both including federal excise tax.

 

Ludvigsen continued:

On May 15, 1945 GM made this brief announcement of its plans: “C. E. Wilson, President of General Motors, announced today that General Motors, through its Chevrolet Division, plans to produce a lighter weight and more economical car in the postwar period. Because of the necessity of putting war production first, the car is only in the idea stage, and therefore, it cannot be placed in production until a considerable period of time after the close of the war with Japan. The car will be manufactured by Chevrolet and distributed through Chevrolet dealers.” Early in 1946, GM said that its aim was to have the new car in production in the middle of 1947, presumably as a 1948 model.

The caption of the illustration at the bottom of the page says, “Ned Nickels, later behind the ’53 Buick Skylark, had charge of the Cadet’s exterior styling. Its 12- inch wheels allowed front fender skirts. Ohv 6 angled down at rear so trans that stood under front seat. Early protos used all-independent MacPherson-strut suspension.”

Ludvigsen went on:

There was no part of this car that didn’t reflect the result of a probing questioning of the conventional way to build an automobile. It had a front engine and rear drive, solely because MacPherson had independently decided that this was the best way to build a 4-passenger sedan to a target weight of 2000 to 2200 pounds. Interior room was strictly for four, dimensions having been taken from a 1935 Chevrolet, and the car’s track, as a result, was narrow—a little more than 48 inches. Wheelbase was 108 inches or eight shorter than the regular Chevy.

Unfortunately, I don’t have complete dimensions for the Cadet. Based on the photo of the full-size model and the diameter of the wheels, it looks like it was about 150 inches long including bumper guards, and something like 58 inches high, but that’s just a rough estimate.

The Light Car’s suspension was revolutionary. The engineers who worked with MacPherson thought he might have been inspired by some foreign designs he had seen—though nothing then existed of a comparable logic and clarity. But otherwise they viewed the suspension as coming “from nowhere.” MacPherson combined the tubular shock absorbers with external coil springs in tall towers that also served to guide the vertical travel of the wheels. All four wheels were independently suspended. Two simple tubular radius rods controlled the movement of the lower end of each tower. At the front, the vertical tower (or strut, as it has since become known) also served as the pivot line around which the front wheels turned for steering. The Light Car was, in short, the first car with true MacPherson-strut suspension. This layout has since become the norm for automobiles built abroad—and the Cadet had it both front and rear.

I’m going to be pedantic for a moment about Ludvigsen’s claim that the Cadet had “true MacPherson-strut suspension”; MacPherson subsequently developed that after he went to Ford, and it was subject to a separate Ford patent. (The biggest difference is that the Cadet had no front anti-roll bar, where “true” MacPherson strut suspension used the anti-roll bar to locate the struts.) However, it was definitely A MacPherson strut suspension. Here’s what the Cadet front suspension looked like, as illustrated in MacPherson’s 1947 patent (US2624592), both in plan view …

… and from the front looking backwards:

You’ll notice that the front view shows lines connecting the top of each strut to the engine air cleaner. This acted as a breather for the flexible bellows at the top of the shock tube, preventing air pressure buildup.

Ludvigsen continued:

At the front, the struts were attached to the ends of a tube that served as a subframe, passing under the center of the engine’s oil pan. Because it carried so many components, including the two engine mounts, the tube was nicknamed the “Christmas tree.” The body structure was fully integral, planned by MacPherson without the aid of Fisher Body but with reference to a huge book of typical body sections he had compiled. All five of the Light Car prototypes that were built had the same 4-window, 4-door sedan body.

Precedents were also shattered by the drive line of the Cadet-to-be. The clutch had a diaphragm spring and hydraulic actuation, both ahead of their time. To gain fool room, the 3-speed gearbox was moved back under the front seat and rigidly connected to the clutch housing by a 4-inch-diameter steel tube. Within this tube, a small-diameter tubular driveshaft angled downward sharply, in line with the rearward-sloping crankshaft centerline, to a constant-velocity universal joint at the input shaft to the gearbox. Then from the transmission back to the differential there was another rigid tube, about three inches in diameter, holding them firmly together. Thus the engine, transmission, and differential were all unified into a single assembly. This unit hung from two mounts at the front and one at the extreme rear of the chassis. … Open halfshafts, with pot-type universal joints at the outer ends (so splines wouldn’t be needed) took the drive to the rear wheels.

Ludvigsen compared it to the 1961 Pontiac Tempest, which I think is misleading (albeit not wholly wrong). Here’s another patent illustration showing what this looked like. I’ve highlighted the gearbox in red:

One of the problems with this layout would have been that separating the clutch from the gearbox in this way would have increased the load on the synchronizers, since they would have had to handle the additional rotational inertia of the longer input shaft.

Here’s how the whole layout looked in plan view:

Here’s a larger view of the rear suspension, viewed from the front looking backward. Although it’s not terribly clear from Ludvigsen’s description, this was NOT a swing-axle setup: Each driveshaft had a universal joint at each end. (You can probably see by this point why the “under $1,000” goal was a lost cause!)

One of the more unusual features of the rear suspension was the very long tie rods that provided lateral location. Each rod was more than half the track width, so they had to be bowed in different directions (as you can see in the Figure 8 illustration above) so they wouldn’t hit each other. The patent doesn’t explain the purpose of the long arms, but I assume it was to increase the effective swing arm length (the radius of the arc through which each wheel moves) to minimize camber changes as the rear wheels rose and fell.

Ludvigsen continued:

Independent rear suspension had been chosen for two reasons: 1) to get more rear-seat and trunk room in a low car, and 2) to reduce unsprung weight so the Light Car could have a good ride. To help the ride, MacPherson went even further. He used wheels and tires that were a radically tiny 12 inches in diameter, to make them as light as possible. Each wheel was piloted onto the hub by a single central bolt and held tightly by four more studs per wheel. Small wheels meant drum brakes that were even smaller—7.5 inches in diameter and 1.75 inches wide. In the final design, the front spindles were “live,” rotating inside the hub carrier on tapered roller bearings.

By the ’70s and early ’80s, 12-inch wheels had become fairly common on European B-segment hatchbacks, for the same reasons. Speaking of “radically tiny” wheels, the BMC Mini originally used 10-inch wheels.

Broadly conventional, the pushrod ohv, in-line 6 was rife with unusual and advanced details. It was slightly oversquare, and its compression ratio was high by the standards of that time. Running in four main bearings, the crankshaft had flywheels at both ends. This allowed the rear one to be small, just big enough to suit the clutch, so the engine could be inclined rearward. The front flywheel carried the ring gear for the starter, which was placed along the left side of the block. At first the engine had high pop-up pistons protruding into deep combustion chambers. A shallower wedge-type chamber was adopted in the final experimental engines. Both the camshaft and the oil pump were driven by a train of gears at the nose of the crankshaft. Wet and with the clutch and all accessories, the engine weighed 408 pounds.

Even “wet,” 408 lbs was not outstandingly light for a 132.6 cu. in. (2,176 cc) engine, so apparently there was some weight penalty for the dual flywheels.

 

Regarding the styling, Ludvigsen explained:

So independent was the Light Car project that it had its own small group of stylists, lent for the occasion by Harley Earl. (Earl and MacPherson didn’t get along too well, even though they both belonged to the same college fraternity [Phi Delta Theta].) It was headed by the ubiquitous Ned Nickels (later to head the Buick studio and now chief of international exteriors), assisted by Chester Angeloni. They started work on the design in one of GM’s downtown buildings, then moved their operations to the bank building during the UAW strike that shut down GM’s plants from late 1945 through March 13, 1946.

Unusually the Cadet was styled and modeled only in 3/8 scale. No full-sized clay model of the car was ever made. Its all-enveloping shape was advanced, of course, as was the enclosure of the front wheels. “That was in the wind then,” says Nickels. “It was just the thing to do.” The small wheels, of course, made it easier to get a good turning circle in spite of their enclosure. The design allowed “Nick” Nickels to give the car a longer look with two chrome strips from bumper to bumper. They worked on the emblem for the car, a cadet helmet in the center of a winged vee, and designed a simple dash with two large dials, speedometer and clock, flanking a central radio speaker grille.

I unfortunately have never been able to find any images of the Cadet interior. For comparison, here’s the dashboard of the 1947 full-size Chevrolet, which is broadly similar to Ludvigsen’s description at least in layout:

 

Ludvigsen went on:

Templates taken from the 3/8-scale model were converted to full-sized drawings from which wooden die models were made. Early in 1946, the first three prototypes were being built, cars bearing numbers 811, 812, and 813. And that spring, preparations to build the Cadet were also well advanced. … Brand-new factories were being erected in the Cleveland, Ohio, suburbs to produce the Cadet. Engines, gearboxes, axles, and other components were to be made in a million-square-foot plant in Brookpark, and a building half again as large in Parma was to house stamping presses, painting, body assembly, and final car assembly as well as administrative offices. Total new employment in the two plants was estimated at about 10,000. That’s how serious Chevrolet was about going ahead with Cadet production.

Cadet prototype testing on the GM Proving Ground in Milford, Michigan, revealed some weaknesses, including squeaks from the struts and overheating of the small rear axle. However, Ludvigsen noted:

These early Cadets were also showing outstanding characteristics as cars. With long wheel travel, they coped easily with the Belgian-block roads. Handling was light and pleasant, and performance was “snappy,” thanks to a weight of only 2200 pounds. “They demonstrated handling characteristics that were better than the Chevrolet, and even better than the Cadillac,” says Tom Scott, adding wryly, “Of course, you just can’t have that! The car’s chief performance shortcoming was in braking. The tiny drums simply weren’t up to the job.

It’s worth noting that aside from its fully independent suspension, the Cadet strut suspension included (obviously) tubular shock absorbers and ball joints — contemporary Cadillac and Chevrolet cars still used lever-action shocks and kingpins.

 

Here’s the specification box, set as a list rather than a table for the sake of my sanity:

SPECIFICATIONS: 1945-47 Chevrolet Cadet

• Engine: Ohv 6, in-line.
• Bore & stroke: 3.0625 x 3.0 in.
• Displacement: 132.6 cid [2,127 cc].
• Compression ratio: 7.25:1.
• Max. bhp at rpm: 64.5 @ 4000.
• Max. torque at rpm: 108 @ 1200.
• Mph per 1000 rpm in high: 17.7 mph.
• Car speed at 4000 rpm: 70.8 mph.
• Fuel economy: 28 mpg av.
• Gear ratios: 1st 2.685:1, 2nd, 1.653:1, 1.000:1, Reverse 2.685:1
• Differential ratio: 3.875:1.
• Wheelbase: 108.0 in.
• Front & rear tread: 48.25 & 49.0 in.
• Curb weight: 2200 lb.

You can probably guess the downside of all this engineering ambition:

They were good cars—but they weren’t cheap. Coyle, the financial man, had been content to leave to his engineers the task of meeting the $1000 objective, but “the car couldn’t be built for $1000,” remembers Scott. “There were just too many inventions in it.” This problem came under the scrutiny of a new Chevrolet general manager in June 1946, when Coyle rose higher in GM and Nicholas Dreystadt, an experienced engineer/builder, moved in from the top slot at Cadillac. Dreystadt supported the Light Car project but sharply questioned the need for independent rear suspension. Under his prodding, MacPherson’s men designed both Hotchkiss and torque-tube rear suspensions and fought hard at the same time to show how much better the car would be with independent rear suspension. They managed to hold their ground.

The fact that there was no way Chevrolet could build a car like this for less than $1,000 really should have been obvious at a much earlier stage. The interesting, unanswered question is how much the Cadet would have had to cost to sell in this form — $100 more than a full-size Chevrolet?

In any case, that wasn’t the only problem:

By the fall of 1946, the long strike earlier that year had a delayed impact on the Chevrolet Light Car. Materials had already been bought for the factory buildings, so they were completed, including some equipment for the body plant and foundry. Other materials purchased earlier for car components were sold, at considerable profit, and the production plans were suspended. This was the official announcement by C. E. Wilson on Sept. 13, 1946:

“Because of the current shortage of basic materials, such as lead, copper, pig iron, and flat rolled steel, and the uncertainty as to when they will be available for the models already in production, all preparations for the manufacture of the Chevrolet Light Car have been stopped until such time as this material situation may have been clarified.”

Despite the materials issues, Ludvigsen said:

Design and development work did not stop, though. A fourth prototype car, #814, was put in hand to test improvements. Suspended brake and clutch pedals, another advanced feature, were arranged to work hydraulic cylinders through an indirect linkage. New heads with flat-topped pistons were fitted to the test engines, along with aluminum intake manifolds. The gear-driven oil pump was set aside in favor of a conventional placement at the bottom of the distributor driveshaft, because testers found that its damping effect, in that position, helped them reduce the distributor’s ignition timing error range or “scatter.”

However, there was no way around the cost problem:

Early in 1947, the final moment of truth approached for the Cadet. Based on the sales price objective and a 3-year period of amortization for the tools, GM financial men concluded that yearly Cadet sales would have to be 300,000 if the car were to earn a satisfactory profit [emphasis added]. Chevy’s salesmen were asked whether they thought they could market that many Cadets. They solemnly shook their heads no. They’d never felt very close to the Light Car project anyway, isolated as it was, and had had little faith in its future. The answer from Sales was that they felt the target was much too high.

Aware that their baby might die prematurely, the more than 20 engineers and 100 draftsmen in the bank building tried manfully to lower its cost in April and May of 1947 by designing a more conventional rear axle. They left the gearbox in its position under the front seat and fitted a universal joint behind it, as part of the pivot for a strut-braced torque-tube rear axle. Semi-ellipitc [sic] rear leaf springs were proposed, and even here there was a break with convention: They were single-leaf springs, which finally made production with the 1962 Chevy II.

In May 1947, GM’s powerful Engineering Policy Group met to weigh the merits of the Chevrolet Light Car concept. The demand for GM’s conventional cars was so high by that time that they saw little value in taking a risk on a smaller auto. They decided to call off the Light Car venture. This was the official epitaph on May 15, 1947: “The proposed Chevrolet lighter car project has been indefinitely deferred due to a continuing material shortage, both for new plants and car production, and the desire of the General Motors Corporation to devote all the productive facilities and available materials of the Chevrolet Motor Division to meet the overwhelming demands of the motoring public for the established line of Chevrolet vehicles.”

The existing Light Car program was then shifted from Chevrolet to the corporate Engineering Staff:

Trimmed to about a fifth of its former size, the design cadre became a GM corporate body, Product Study Group No. 6, assigned to wrap up the work on the Light Car. It now fell under the purview of James M. Crawford, who had been chief engineer of Chevrolet from 1929 until June, 1945, when he rose to the GM engineering vice presidency. Crawford made no bones of his feelings about the MacPherson Light Car design. It was “too much of a jewel of a car,” he said, and pressed for further simplicity.

At this time, starting in the summer of 1947, the fifth Light Car prototype was built, #815, with the live torque-tube rear axle on single-leaf springs. Work also continued on the last all-independent car, #814, further improving the detail design of the suspension struts.

MacPherson soon butted heads with Crawford — I’m not sure if Ludvigsen’s comment about their having “tangled violently” was meant literally or figuratively — and left for Ford that summer, arriving in Dearborn in September.

Continuing for more than a year, Product Study Group No. 6 was winding up its activities in Sept. 1948 with attention to the torque-tube axle, the shape of the body rear, and the rear-wheel skirts. … Within GM, [however,] the principles developed for the ingenious Light Car saw no further use. The Cadet was not related in any way to the Australian Holden, which was a separate and earlier project, or to any other GM overseas models [emphasis added]. Nor to the later Corvair. It was simply locked away and forgotten—the fate so many projects suffer—and written out of GM’s and Chevrolet’s history. In 1968, the last remaining Light Car prototype was scrapped by GM—the tragic loss of an irreplaceable historical artifact. In Cleveland, the Light Car plants were converted to other Chevrolet uses, such as the production of the first Powerglide transmission. The Light Car, which had held such promise of a postwar renaissance of fine automotive engineering, was no more.

As Ludvigsen explained, Earle MacPherson spent the rest of his career at Ford. He filed a patent on the definitive version of the MacPherson strut front suspension in January 1949, and it went into production in 1951 on the English Ford Consul and Zephyr. MacPherson became Ford VP of engineering in 1952, also representing Ford on the Automobile Manufacturers Association Engineering Advisory Committee. He retired in 1958 and died just two years later.

 

The obvious question is whether it was a mistake for GM to shelve the Cadet. It was a remarkable package, and with updated styling and a little more power, it would still have been competitive in many respects 10 or 15 years later. However, whether U.S. buyers of the ’40s or ’50s would have been willing to spend at least as much as a full-size Chevrolet (if not more) for such a car is a tougher question. I could see a modest niche for it as a well-trimmed upscale urban car along the lines of the 1950–1953 Nash Rambler, but I’m skeptical that even the mighty Chevrolet dealer network could have sold 300,000 a year, and they were obviously not eager to try.

It wasn’t just that the Cadet specifications were too ambitions — it would have shared nothing but bits and bobs with the full-size Chevrolet, making it a massive tooling investment, at a time when GM was already spending $83 million on reconversion to civilian production and $588 million on a new postwar expansion program. A related issue Ludvigsen didn’t mention was that GM’s U.S. divisions had little experience with unit construction. Vauxhall and Opel had been making unit-bodied cars since the ’30s, so the principles were not a mystery, but Fisher Body had never built a monocoque car.

Those challenges weren’t insuperable, but taken together, they were like the difference between digging a ditch and building the Suez Canal, with a much hazier ROI.

 

Related CC reading:

The Radically Advanced But Aborted 1947 Chevy Cadet: GM’s First Deadly Sin?  by P.Niedermeyer