Before We Had the Mazda RX-7, NSU Gave Us Their Rotary-Powered Spider

[Editor's Note: This article originally ran in the July 2007 issue of Classic Motorsports.]

 

What’s so complicated about it? Spin a single wedge-shaped “piston” through its four-stroke combustion cycle instead of firing it up and down. As a result, throw away a boatload of heavy parts, like a long crankshaft, connecting rods, pistons and valve train. Now rev the sucker way up there where reciprocating piston engines fear to go. After all, what can go wrong in an engine with only two moving parts?

As it turns out, it hasn’t been quite that simple. Some 50 years after Felix Wankel designed it, the rotary engine is still trying to rev its way to widespread acceptance and respectable sales in the automotive marketplace. Today, while numerous automakers hold licensing agreements to produce rotary engines, only Mazda uses it to power cars.

Almost King of the World

Mazda might be today’s remaining rotary engine proponent, but German manufacturer NSU holds the honors for being the first company to produce a car for sale with this unique engine. This venerable manufacturer goes back to 1880 in the town of Neckarsulm, and from the town’s name came the abbreviation NSU. 

The company made cars, trucks, bicycles and even motorcycles—in the 1930s, NSU operated the largest motorcycle plant in the world. Known as a forward-thinking enterprise, NSU was the first Wankel licensee, and using this revolutionary engine to power a sporty, new model would represent a departure from the company’s standard lineup of small, boxy sedans driven by small-bore, air-cooled engines. 

After years of rotary research and development, NSU introduced its Spider at the Frankfort Auto Show in 1963. The car got generally good reviews from Europe’s motoring press. 

So in 1964, NSU had high hopes when it launched the Spider in the North American market. The rotary engine was virtually unknown, and the company played up the gee-whiz factor in early releases. Working the same theme, some automotive writers might have set the motoring public’s expectations too high in terms of jet turbine-like performance. 

An excerpt from a Motor article paints a picture that almost sounds too good to be true: “…the engine appears only to be doing half the rpm than it is. This feeling is reinforced by the lack of mechanical noise and by the complete absence of out-of-balance vibrations which can be demonstrated by holding the engine at 6000 rpm in neutral.” (No doubt that last test made NSU’s engineers cringe.)

Another press account also heaped praises. “May be driven like a conventional car,” it stated. 

As it turns out, after all the hype, the first rotary-powered car might have driven entirely too much like a conventional, small-bore car to impress some potential buyers. 

The diminutive NSU Spider has decent space for luggage up front. The shifter gets a good workout helping to keep the engine revs up in the meat of the rotary’s power band.

NSU’s sporty little entry was based on their Sport Prinz and powered by a single-rotor Wankel engine. It ran on 12-inch wheels and sported a tiny 79.5-inch wheelbase. The suspension was all independent, with wishbones and coils in the front and semi-trailing arms at the rear. Front disc brakes and drum rears provided good stopping power for a car that weighed only 1543 pounds, and the rack-and-pinion steering offered a responsive, light feel. 

The 497cc powerplant, which hung behind the rear axle line, weighed only 275 pounds including flywheel, starter, generator, carburetor and air cleaner. As drivers quickly learned, this 50-horsepower engine didn’t produce much low-end torque, meaning high revs were needed to keep up with traffic. 

And to keep those revs high, they needed to stir the four-speed, all-synchro transmission early and often. Many drivers, accustomed to low-revving piston engines with gobs of torque, found it a chore to keep this engine happy.

A Car and Driver tester didn’t mince words when describing the situation: “The driver should avoid anything under 3000 rpm like the plague.” Despite the lack of low-end grunt, reviewers liked the quiet, vibration-free cruising at higher speeds. At 75 mph in top gear, the Spider was turning just over 4200 rpm with little noise and no vibration. 

Driven properly, this car made the most of its half-liter displacement, and contemporary tests show that the Spider was generally a match for competitors like the Triumph Spitfire and the 850 Fiat Spider—all three needed about 15 seconds to reach 60 mph and could almost reach 100 mph. 

While reviewers were intrigued with the rotary’s technical advances and potential, some were less than thrilled with real-world performance. Car and Driver ended its evaluation this way: “Our experience with the NSU Spider seems to justify cautious optimism.” 

Alas, American buyers did not share even that faint praise. Spider sales never soared. At $2979 the car was pricey, and the early rotary engines soon gained a reputation for questionable reliability, as well as excessive oil usage and poor gas mileage. 

The factory said the engine’s seals and bearings would last 30,000 miles. However, since the engine revved so freely, many owners did just that, significantly shortening the life of these components. The brand’s dealer network, which generally sold a selection of other European cars along with NSUs, quickly became stretched thin. These dealers, even with good intentions, were often hampered by slow response from the factory for parts and warranty support. 

From 1964 through 1967, NSU made about 2400 Spiders before discontinuing production. Reluctant to give up on the Wankel, the company continued to use a rotary engine—this one a two-rotor version—in its Ro80 four-door sedan. The Ro80 was produced until 1977 and was the last car to wear an NSU badge.

Living With a Spider

Rex Birkmire, a Florida collector who owns our featured car, admits to a weakness for “orphan” cars. He also owns the Nissan Silvia we recently profiled.

He grew up in the car-crazy 1960s in Columbus, Ohio, where his neighbor owned an NSU Spider that seemed to be permanently parked. This particular car, like many early Wankels, suffered from a cracked rotor housing that generally required a replacement housing or engine as a cure. 

“His car basically sat in front of my house for a few years,” Rex recalls. “It never ran, and I watched the leaves pile up in the fall and the snow pile up in the winter. I thought the whole thing was very sad.”

Rex says he was drawn to the perky Bertone body that sat on tiny wheels, and he felt the little car was unusual and appealing—especially in the muscle car era. Many years and a bunch of cars later, he recalled that forlorn Wankel Spider of his youth and decided to try and find one.

It’s fun to play “where’s the engine” with the rear cover panel in place over the NSU Spider’s small half-liter Wankel engine.

For 18 months, he ran ads in magazines and on the Internet with no results. Then he stumbled across The Neckarsulm News, a publication by “The NSU Enthusiasts USA” that is devoted, as its editor puts it, “to the betterment, advancement, and furtherment (sic) of NSU fandom, and, of course, to those funny vehicles with the strange letters NSU.” 

Using the club’s roster of listed Spider owners, Rex called all 33 of them on the list. He found six members with running examples and only three who would consider selling. 

One of the three was an 85-year-old original owner living in Olympia, Wash. After buying the Spider new in Germany, the owner had driven it only 33,000 miles while lavishing it with care. He even stored the Spider in a heated garage. Never modified or molested, the Spider still retained the original interior
and top. 

And since this owner was an engineer, he had come up with a NASA-grade epoxy fix that cured his car’s cracked rotor housing. Overall, this car was as close to original—even down to the hubcaps—as one could expect to find. 

Rex ended up buying the Spider, and it has more than exceeded his expectations. He loves the simple, slab-sided styling punctuated by a long rear deck. He’s also taken with the fact that this is the world’s first production rotary. “It’s toy-like and quirky,” he says, “and it also qualifies as a microcar.” 

Whenever he parks his NSU, people ask what it is. Rex reports that many car enthusiasts are not even familiar with the diminutive Spider. Many others mistake the car for an Alfa Romeo and even an Amphicar. 

As a conversation starter, he enjoys pulling the “Where’s the engine?” routine. He lifts both the front boot lid and the rear engine cover. Perplexed, most people still can’t find the engine, which is hidden under the rear compartment panel. “Folks are amazed to finally see a bread box-sized engine under that rear panel,” he says. 

Since this Spider is one of the few original examples left, Rex wants to keep it that way. “My main goal is to preserve this car,” its caretaker dutifully says. 

Dissecting the Spider

No question about it, this car is pint-sized. In fact, it’s so tiny that the full-size, factory-installed Talbot mirror looks just too big. 

Still, when one stands back and walks around the Spider, the proportions and simple lines seem to work well together, vaguely recalling a scaled-down 1950s Studebaker. And with its saucy, nose-high stance, this car (dare we call it cute?) assumes a bit of an attitude. The original red paint—NSU offered only red and white as color options—still shines with few blemishes. 

A closer exam reveals some interesting and innovative features: The large-for-the-car radiator and its electric fan are mounted up front behind the grille, with coolant circulation tubes routed back to the engine and oil/water heat exchanger. The radiator filler tank, however, is mounted in the engine compartment. A tiny air inlet—complete with logo—on the rear deck lid provides a breath of fresh air to the single Solex carburetor. A large vent cover under the rear bumper helps extract heat from the engine compartment and provides some air circulation around the large, transverse muffler. The owner says that the car runs cool despite Florida’s heat, and always starts immediately, even after sitting for a couple of months. 

Dropping the convertible top is slick and easy. As it folds down, the top slides neatly back on two tracks and disappears under the rear deck for a clean, uncluttered look. No struggle, no cursing. Other manufacturers would have done well to copy this design. And though it’s small, the Spider offers plenty of storage front and rear. 

Rex’s NSU Spider is a rare and entirely original survivor, although the previous owner did have to repair a cracked rotor housing with some space-age epoxy. Journalists of the time noted that the rotary mill was remarkably smooth at high revs. It’s a shame other companies didn’t mimic NSU’s slick convertible top design.

Let’s drive it. The door swings wide for easy entry. Slipping behind the wheel, which is angled up like that in a bus, is a bit of a trick for taller drivers. The front wheel arch also intrudes into the foot space.

Once you’re wedged in, the seat offers good support and you’re faced with a large VDO speedometer and tachometer plus a smaller fuel gauge. Heater controls and three switches fill the center of the otherwise Spartan dashboard. The interior trim package is simple, functional and has held up remarkably well over the years. 

Turn the key and the rotary fires up with a buzz. The clutch and steering are light and precise, but the four-speed shifter is vague (the owner says it needs adjusting), so it’s difficult to find the next gear and shift smoothly. 

Once up to speed, the car rides quietly without fuss and corners with little lean. Like any good rotary, the faster you drive it, the faster it wants to go. However, we did resist the impulse to hold the revs at 6000 in neutral to see if this rotary was free of vibration. That test aside, driving the Spider is simple, unpretentious and fun. Its owner says it’s dependable—all he’s done is change the oil—and the only driving problems he’s experienced have come from dodging curious drivers who swoop in for a close look at the weird car.

Overall, the Spider goes, turns and stops well enough to make one wonder what this little car would have done with a bit more punch. Actually, NSU’s RennSpider rotaries—juiced up with almost twice this car’s horsepower—went well enough to win a German rally championship in 1966 and a hill climb championship in 1967, so it did have some development potential. 

Coulda, Woulda, Shoulda

Despite the fact that the Wankel engine has never lived up to its potential for powering masses of cars for the street, it’s been a top dog at the track, a place where emissions and economy are generally not prime concerns. Around the world, rotary racers have won hundreds of races and a flock of championships. Among the rotary’s top honors: It is the only non-piston engine to win an overall victory in the 24 Hours of
Le Mans, which it did in 1991. 

As the rotary spins toward its 50th birthday, it’s difficult to predict what future development will bring. Mazda’s Renesis rotary, which powers the RX-8, generates 232 horsepower from 1.3 liters and offers better fuel economy, reliability and is more environmentally friendly than any other rotary in history. And some experts predict that a hydrogen-powered rotary might play a larger role in our driving future.

Sitting in this little car and reflecting on the auto scene of the 1960s, it’s easy to visualize the optimism and verve that launched this technology. Every road trip must start somewhere, and the rotary engine’s long, strange trip began in this car. So let’s give this NSU Spider some respect; it is more than entitled to fill its niche in automotive history.

Besides, even on the shady side of 40, it’s still pretty darned cute.

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