There is visual evidence that the Corvair influenced the stylists for a number of European cars, Italian (Fiat), German (NSU 1000). As far as the Hillman Imp is concerned the evidence goes a little further.

The Corvair and the Imp

1964 convertable Corvair

There are many parallels with the Imp:

Differences


About the Chevrolet Corvair

The impetus for the Corvair came directly from Ed Cole, the engineering-oriented Vice President in charge of Chevrolet Division.
The popularity of compact economy cars in the USA was inspired partly by the economic recession of 1958 and partly as protest against the gas-guzzling chrome-laden full-size cars being sold by the American manufacturers during this period. During this era, only European cars were imported.

In the '50s Chevrolet decided it needed a small, easy-to-make and 'European type' (=compact) modern car. It should be sort-of an American VW Beetle. This idea came from the 'import car craze' of the late 1950s.
A special studio set up for Corvair body design deserves all possible credit for the shape. Ned Nickles had a big part in Corvair design. The styling of the first and second series Corvairs is generally attributed to William Mitchell. Mitchell, who let himself be inspired by German and Italian cars, was the head of styling for all of General Motors. He may have been more of a supervisor than an hands-on stylist with respect to Corvair design. The Corvair's appearance was possibly thought up after a look at the general layout of Preston Tucker's Franklin-powered 'production cars': this had a six-cylinder boxer engine in the rear and so has the Corvair.

The GM engineers felt that they knew enough about the use of light alloys in engine design to overcome the problem of a heavy tail, and they made Ed Cole feel confident enough to go along with the idea to put the Corvair's engine in the back.


Introduction of the Corvair was in late 1959. At that time only the sedan was offered in 500 or 700 trim.
The 500 was the very basic model. The 700 had better upholstery, more interior colors and trim. The bodyshell included a stainless steel moulding going completely around the body belt line.

It certainly was an odd car for conservative Chevrolet. They believed that, if they manufactured a compact car that was merely a down-sized version of its full-size cars, it would steal sales away from the full-size cars. They hoped that the Corvair, by virtue of its technical differences, would instead steal sales away from the imports.
While it was marketed as an economy car, it was neither easy nor inexpensive to make, due to the somewhat complex and unusual design. Other Chevrolets made $300 more profit for GM.

Americans in those days were used to large V8s. The Corvair had a comparatively small flat six cylinder unit - mounted at the rear. It was an aluminum air-cooled 140cui (2295cc) engine, delivering 80hp. The car seemed to be designed around this rear-mounted (Beetle-inspired ?) engine. The materials used were high-duty aluminum alloys with a high silicon percentage.
Twin Rochester carburetors; automatic choke, placed at the air entry to the single air cleaner which is novel, too, having a spongy polyurethane element soaked with oil.
Transmission was a manual 3-speed or the 2-speed Powerglide automatic. Engine plus transmission weighs roughly 340 pounds. The aluminium cased gearbox kept the weight of the transmission unit down to 30 pounds. The automatic unit weighs 53 pounds more.
Originally it was intended to market the Corvair with automatic transmission only. The standard shift was introduced, because performance and mileage didn't come quite up to expectations with the automatic, but the main reason was to cut costs - necessary to meet Chrysler and Ford competition.
Traction is outstanding.

In May 1960 an optional 95hp and 4-speed gearbox became available.
The 1961 engine was enlarged to 145cui, still delivering 80hp in standard form and a 98hp version as an option. From 1962 on, there was an optional engine which delivered 102hp which was coupled to a 3 or 4 speed or an automatic.
The emphasis was definitely on smooth running and reliability.

cut-away early Corvair coupe, 1960

May 1960 the 900 Monza Club Coupé made her appearance. This was the model that would make the Corvair popular. Sales rose steadily to around 300,000 units per year after its introduction. It had bucket seats trimmed in nice leather-like vinyl, more chrome and including all options available on the 700 series. A year later the Monza was offered as a sedan.

The same year the stationwagon, the passenger van and a closed van saw the light. Plus the Loadside pick-up and the Rampside pick-up. Engines ware a bit more 'heavy duty' than the standard cars with special bearings and an oil fillerpipe and dipstick to be able to still check a car carying load.

The Monza became available as a convertible in 1962. It could be had as a Spyder: a 150HP turbocharged engine and included more 'sport' goodies available like heavy-duty suspension and sintered metallic brakes.

GM, the holder of Chevrolet, developed Buick, Pontiac and Oldsmobile versions of the Corvair, but they were never released.

Corvairs and Imp suffered the same type of joke:

These two old women were driving down the road in their Corvairs, one behind the other, when the one in front had engine trouble and pulled over. The woman following pulled over in sympathy to see if she could help. The two women got out and briefly discussed the problem and then the second led the two of them to the front of the faulty car and opened what she thought was the hood. Immediately she exclaimed "Well no wonder you're having problems, you don't have an engine! Come with me, I found a spare engine in my trunk yesterday."

But then it became clear that the car hadn't been Moose tested. A couple of accidents happened with the Corvair. People managed to make the car roll over.
The car handled no different from any other American car of the era. In fact it had been praised by Car and Driver in 1959 as a lot of fun to drive, with precise control: fine steering and stable braking. Better than what they had come across in many years.
But GM had not forseen that the Corvair picked up a sporty image - they had intended it for the market as an economy car, aimed at conservative drivers. While the car handled well when driven sedately, a driver who tested its limits might get it to roll over...
The designers who had planned the Corvair had prefered to add anti-sway bars. But to save a measly $4 per car, those bars were not included in the final product.
The Corvair had 62-percent of its weight on the back wheels. It would have been a good idea to use better suspension techniques than a simple swing-axle in order to make it not suffer oversteer.

Law suits were started against Chevrolet, nearly 300 cases. The previously nearly unknown Ralph Nader made a career on writing the bestseller Unsafe at any speed. The first lawsuit resulted in 70.000$ to the 'victim'. A number of trials then started, Chevrolet won all 9 of them.
But all the bad press had already done the damage.

In 1964 a stabilizer was fitted, due to pressure from media, which was interpreted as the car had some design flaws.

GM tried to change to publics opinion through a thorough inside and out redesign: the second series Corvair, produced from 1965 to 1969. But that did not help either. While it did fix the shortcomings of the Corvair (eg. the rear swing axles were replaced by trailing arm suspension), it did do nothing for the Corvair's name or the relatively high cost to build it.
In 1969 only 6.000 Corvairs were made and Chevrolet lay down production on May 14th.
Some 300.000 Corvairs of a total of 1.650.000 built are still driven.

This was a car that drew the attention of governmental bodies all over the world to make rules around just about anything involving cars. Rules about crash safety, handling, fuel-emissions etc. The industry didn't look the same after the Corvair.

SCI Analysis: 1959 Corvair When the first meetings were held in the Fall of 1956 it was possible to review fairly complete proposals for both the mechanical layout and styling of a 'smaller car' which had already been prepared just in case by the Research components of both the Styling and Engineering departments. By Fall of 1957 these had been translated to detail drawings and to prototype engines which were put to work on the test benches There was adequate time in the Summer and Winter of 1958 to hammer the prototypes across the country from the 120 degrees of Mesa, Arizona to 30 below at Duluth, Minnesota, proving many features, but primarily the feasibility of air cooling. In the meantime the stylists had completed their revision of the lines, enabling Fisher Body to put together the final prototypes for debugging in early 1959. Only the four-door edition will be introduced for 1960, but other body styles are sure to follow if the Corvair is well received. Many happy returns to sanity are evident in the Corvair, one being the use of an old-fashioned non-wraparound windshield which makes it a lot easier to get in and out of this relatively small car. Further help comes from the doors, which are very wide and open at a generous angle. Locking is effected by the interior handle instead of the traditional GM window sill buttons. Though the door pillars aren't especially slim they're well placed, and vision all around is superb. A special effort was made to reduce costs in the instrument panel layout, but it doesn't show it. (It isn't as cheap as the had hoped, either!) Easy adaptation to right-hand-drive is facilitated by the twin-hood layout, the radio, when fitted, being slung from the center of the dash. A 100-mph speedometer is accompanied by a fuel gauge of a new, more accurate counter-balanced-pointer type. A warning light flashes on if the oil's temperature is too high or its pressure too low, while another lights up if the fan belt ceases to drive the generator or blower. Even on the deluxe 700 model (chrome window moldings, door-operated interior light) there's no horn ring on the appealingly simple steering wheel. For a tall driver the Corvair offers plenty of head room, and the unobstructed floor leaves adequate area for big feet, but Chevy engineers didn't quite catch the secret of the VW's remarkable habitability. When only two passengers are riding in the German car -- the most common situation you'll grant -- it's possible to move the front seat well to the back, almost touching the rear seat. Attempting to retain rear seat leg room under all circumstances, Chevy limited front seat travel just at that point where a moderately tall driver feels somewhat cramped. A running change to a longer rearward travel is respectfully but urgently suggested. Similarly, if Renault's clever stowage of the spare tire had been imitated or at least paralleled the Corvair's "trunk" would not be any roomier but would have a more usable shape and would be easier on fine leathers. About 9 1/2-cubic feet at the front are supplemented by a 4 1/2-cubic-foot volume behind the rear seat, VW-style. A very attractive option at moderate extra cost is a rear seat that folds forward, station-wagon-style, to form a flat platform from the front seat to the firewall on which most anything can be heaped. The conversion can be made quickly and easily. Some trunk space is stolen by the optional gas-fueled heater developed by Harrison Division of GM to lick the twin heating problems of a car that is both rear-engined and air cooled. A 2700 rpm centrifugal blower supplies air to the seven-inch cylindrical stainless-steel burner, which receives fuel at 4 to 5 psi from the engine fuel pump and is lit by a simple igniter which continues to spark constantly while the unit is in operation, as a precaution against "flame-out". Before passing to a tiny exhaust pipe under the car, the hot gases from this burner flow though a heat exchanger which warms the interior air, drawn from the cowl vent and fed to the cockpit by a two-speed centrifugal blower. A thermostatic control adjusts temperature by turning the fuel supply on and off as required. Several precautionary controls are provided. One switch cuts off the gasoline supply if the unit temperature rises too high, while another does the same if too much fuel drains back, unburned, to the gas tank. A third switch keeps the combustion blower running half a minute after the heater is shut off, to purge all gases from the system. Chevrolet states that the maximum possible fuel consumption of the unit is about a quarter of a gallon per hour, a more normal winter figure being a tenth of a gallon per hour (or ten hours per gallon). This seems a moderate price for instant and powerful heating. Convenient to all this is the 11-gallon gas tank, nestling between the front suspension and the toeboard. It's held up against a fiber cushion by a single transverse strap and receives fuel from a filler on the left front fender. The rear 'hood' (Chevy is just as confused over what to call these lids as SCI) is opened by a pressing a trigger next to the license plate light. Like all the crevices at top and bottom of the engine room this trigger is rubber-sealed to ensure that the air flow goes just as the engineers planned, a detail that was found essential to quick hot starting. Cooling air enters through rear deck louvers equipped with pans to catch and drain away rain water. Aerodynamic tests made recently, well after the styling was finalized, indicated that by lucky chance there was a high-pressure area just over the intake louvers! Ned Nickles and the special studio set up for Corvair body design deserve all possible credit for a shape which has proved aerodynamically sound and which also, less definably, reflects the functional and useful character of the Corvair without actually flaunting these facets of the car. Its lines are trim and meaningful and its ornamentation more restrained than on most European cars. Assembled completely by Fisher, the body is united on the line with suspension and engine in very quick time, the chassis assemblies rising to meet the descending body shell.



Imp in America

Although Rootes (and later, Chrysler) imported the Hillman Minx, Sunbeam Alpine, Sunbeam Tiger, and Hillman Avenger to the United States, the Imp was hardly seen there. That should not be surprising; when Chevrolet introduced the Corvair, Chrylser responded with press-releases biased against rear engine automobiles. (Chrysler's counterpart in the American market was the Valiant, a very conventional front-engine/ rear-wheel-drive compact car). It would have been difficult, from a marketing perspective, for Chrysler dealers to introduce the Imp, given the parent company's anti-Corvair sales propaganda! Consequently, the Imp remains somewhat of a curiosity in the U.S.

first became aware of the Imp through a book written by Michael Sedgewick

Car and Driver: Corvair, 1959


Imp: a Corvair as a puppy

Seeing the Imp from a Corvair enthusiast's perspective:

Poor Man's Porsche, English Style

by Al Lacki

published by two chapters of the Corvair Society of America: the Lehigh Valley Corvair Club (newsletter: "Fifth Wheel") and the New Jersey Association of Corvair Enthusiasts (newsletter: "Fanbelt").

The late 1950s and early 1960s were a well spring of creative automotive design, especially in the U.K. Most NJACE readers are aware of the transverse-engine front wheel drive Austin Mini, designed by Alec Issigonis. The Mini's basic power train layout, so brilliant because of its compact packaging, continues to serve as the blue-print for almost every passenger car line in production today. However, the Mini was not the only small British sedan worthy of our interest. The U.K. also produced its own 'Poor Man's Porsche'.

At the same time that Chevrolet was developing prototypes for the Corvair, the Rootes Group in England was designing a smaller but similar rear engine economy car, the Hillman Imp. Development of the Imp began in 1955, but production did not start until 1963, three years after the Corvair was introduced. The Imp remained in the Rootes lineup until 1976.

Head-on, the Imp looks like a miniature early series Corvair. The resemblance is more than coincidental. While Rootes stylists were borrowing contours from the Corvair body, Rootes engineers were test driving the Corvair, looking for technical solutions to rear engine design problems. Unlike their counterparts in the styling department, the engineers didn't like what they found. After crashing one 'Vair rather severely at the test track, Rootes rejected swing axles and adopted a fully-articulated multi-link rear suspension for the Imp. And, to minimize rearward weight bias, the Rootes engineering staff insisted on a lightweight all-aluminum engine.

And what an engine it was! Rather than start with a clean sheet of paper, Rootes called upon Coventry Climax, one of the most renown engine designers in the world. Coventry Climax engines powered some of that period's most successful Formula 1 cars, including the Lotus 18 and the Cooper T51.
Coventry Climax was eager to capitalize on its racing success and sold Rootes the production rights to a contemporary overhead cam 750 cc four cylinder engine design. Rootes proceeded to modify the design to make it suitable for the Imp by opening it up to 875 cc, laying it over on a 45 degree angle, increasing the compression ratio to 10:1, and die-casting the block and head in aluminum.

One of the problems of an aluminum block is that, without steel liners, cylinder bores are subject to premature wear. However, the process of pressing steel cylinder liners into an aluminum block represents a considerable manufacturing expense. Like the engineers who developed the Corvair engine, Rootes almost specified a hard high-silicon alloy to negate the need for liners. However, Rootes found that it could not master the technique of machining this unproven material.

Rather than give up, Rootes chose another alternative, opting for an aluminum block with iron liners cast in-situ, just like Buick's 1961 aluminum V-8. The quest for weight reduction paid off. The finished engine weighed just 170 pounds, 'including accessories'.

Unlike the Corvair, the little Climax engine was water-cooled, so the engineers positioned the radiator alongside the engine behind the rear seat. This solution, common to the Fiat 600, Simca 1000, Renault R8, and other European rear engine cars, compromised cooling efficiency but avoided the need to mount the radiator in the front luggage compartment. This simplified the plumbing and provided a modest boost in luggage space.

This is not to say that the Hillman Imp was a spacious automobile. It was merely a four seat econo-box intended to compete at the bottom of the English market. It's technical features were innovative but costly to produce and complicated to maintain. Soon after their introduction, Imps gained a reputation for teething problems, again like the Corvair. Rootes worked hard to correct these problems, but many English car buyers took the practical approach and selected Brand X instead. Over thirteen years of production, fewer than 500,000 Imps were sold.

Sports car enthusiasts, however, recognized that the Imp offered great driving fun at reasonable cost. The Coventry Climax engine was smooth and could be revved with confidence up to 7,000 rpm. English car magazines raved about the Imp's excellent handling, which apparently was as good as the Austin Minis. All over the island, enthusiasts entered Imps in club events for many years. Two specialty manufacturers, Ginetta and Clan, produced hand-built sports cars based on Imp components, quite similar to the Corvair-based Fitch Phoenix in concept.

If you would like to read more about the Hillman Imp, there are a number of web-sites that will satisfy your interest, including 'The Imp Site', which served as the source for much of the information in this article.



Another rear-engined car of the 60s

Tatra

In the early 1930s Tatra has started experimenting with aerodynamics for use on a production car. These experiments resulted in a most unique car, the Tatra T77, fitted with a rear-mounted air-cooled V8-engine of 2973 cc and 44,1 kW (60 HP). The Tatra T77 was first introduced to the press on March 5th, 1934 in Prague. By then this was the first serially produced aerodynamic car and was a real sensation in the motoring world. In it's introduction year a Tatra T77 was also used for the '1000 Czechoslovakian miles' race. It finished in 4th place in the absolute classement.
In 1936 the Tatra T77 was followed by the Tatra T87, an updated version of the T77 with a smaller body and smaller and lighter air-cooled V8-engine to reduce the weight and improve the roadholding. Alongside the T87 a smaller version was offered, the Tatra T97, fitted with a rear-mounted air-cooled four-cylinder engine and an aerodynamic body.
This car was used after W.W.II as a basic lay-out for a new model, the Tatra T600 'Tatraplan'. Like the T97 the T600 was also fitted with a rear-mounted air-cooled engine and an aerodynamic body, but of a more perfected design better adapted to mass-production. This first new post-war car was to take the world by surprise. In the hand of capable factory drivers such as Pavelka, Sojka, Vrdlovech, Chovanec and others the T600 won many sporting events such as the 'Internationale sterreichse Alpenfarht' in 1949 where four T600's took the first four places in overall classification. Based on the T600 a couple of sports- and racing cars have been built, the aluminium two-door T601 Monte Carlo and the T602 Tatraplan Sport. The T602 was built for the Czechoslovakian Grand Prix, held on the 25th of September 1949.
Taken from: http://www.tatra.demon.nl/cars-racing.htm

Tatra T2-603

1957-1963
a rear-mounted air-cooled all-aluminium engine - 97.9bhp 2.5-litre V8
independent suspension all round aerodynamic shape
won rallies
carries five people in comfort
Hans Ledwinka, famous in automotive design:

Tatra : the legacy of Hans Ledwinka / by Ivan Margolius and John G. Henry. - S.A.F., 1990. - 160 p.
This book was awarded the Cugnot Award of Distinction in 1991 (Society of Automotive Historians)



Miscelaneous Imp files
The Imp Site
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