Porsche’s 550 Alpha Spyder

How a new giant-killer was born

With the arrival of its fully engineered Type 550A in 1956, Porsche would attain giant-killer status for the first time. The new model’s vastly improved suspension and tubular space frame were recipes for future success on all the world’s tracks.

In the little time he had for reflection, Huschke von Hanstein wondered what on earth he was doing here. He had planned to be in Paris this early June weekend, attending to a one-car Porsche entry in a race at Montlhéry and enjoying the pleasures of that great city in his off hours.

Instead he was in Sicily, flogging a Fiat 40 miles daily along the north-coast road from Palermo to the Targa Florio circuit and back, under a pitiless sun, so he and his driver, Umberto Maglioli, could refresh their recollections of that 44.7-mile ring of impossible back roads averaging 20 blind, treacherous turns every mile that was the Piccolo Circuito Madonie. The first car to complete ten laps of it on June 10 would be the winner of the 1956 Targa Florio.

Italian sports-car ace Umberto Maglioli drove the Porsche 550A in the August 4, 1957 mixed F1 and F2 race at the Nürburgring. He retired with a broken stub axle.

Porsche’s approach to racing in the mid-1950s was disarmingly informal, thought Huschke, but this was ridiculous. With brushes and paint pot he and Maglioli gave their silver Spyder a crude coat of German racing white and added an Italian-flag design on its hood in recognition of the nationality of the tall, deceptively easy-going driver, who had just turned 28 on June 5th. Maybe it would fool the bandits who tried to disable non-Italian cars.

They were staying in Palermo with friends. Their two mechanics, Willi and Werner Enz, were sleeping in a hole-in-the-wall workshop in Termini and their interpreter and woman-of-all-work was Maglioli’s Vienna-born wife Gerti. This was the minuscule team fielded by Zuffenhausen to tackle the daunting Targa.

Porsche’s Targa adventure was proposed during a gathering at von Hanstein’s home in Stuttgart on May 28, less than two weeks before the race. On the previous day new 550A Porsche Spyders placed fourth and sixth in the Nürburgring 1,000-kilometer race. Von Hanstein’s guests at his home included Maglioli, co-driver of the fourth-place car, journalists Heinz-Ulrich “Uli” Wieselmann and Bernard Cahier; and Artur Keser, press chief of Daimler-Benz, whose cars had won the Targa Florio the year before. They argued that the Targa should be the next challenge for Porsche’s new and light 550A.

Cahier, a confessed Targa fanatic, insisted that the new Porsche could win overall in Sicily, especially if Maglioli could be persuaded to take the wheel. The Italian had, after all, won the 1953 Targa and was one of the greatest endurance-race drivers. Von Hanstein had planned to be in Paris on the day the Targa was being run, tending Porsche’s entry in a race at Montlhéry that was dear to the interests of importer Veuillet’s Sonauto.

Seen from the front, the new steel space frame of the Porsche 550A showed the transverse tubes housing the car’s front-suspension torsion bars.

Huschke’s visitors urged him to make the trek to Sicily instead, even though the 1956 Targa—40th in the historic series—didn’t count toward the Sports Car Championship. They also pressed for Maglioli to be at the wheel, though this was sure to draw the wrath of Porsche’s German drivers.

The risks were high. The race would test the toughness and versatility of a new breed of racing Porsche, the 550A Spyder. It would also test the driver, for a mistake could bounce him into bridge abutments, trees and roadside boulders—usually with little personal harm because speeds were kept low by the serpentine roads.

Von Hanstein mulled over the idea, discussed it with Ferry Porsche and finally decided to take a sporting chance. Then he assembled his tiny team. Now it was Sunday, race day, and the white Porsche with its number 84 was being flagged away by Vincenzo Florio himself. Roaring away from the start were such daunting competitors as Eugenio Castellotti in a 3.5-liter Ferrari Monza and former Targa winner Piero Taruffi in a 300S Maserati.

Setting a cracking pace as always, Castellotti led the first lap and Maglioli passed in third place. The next lap was too much for the Ferrari’s transmission. When Maglioli passed Cabianca’s OSCA he found himself in the lead after two laps. Taruffi challenged but was slowed by repairs to his Maserati’s fuel tank. Although von Hanstein was standing by for relief, Maglioli kept his seat and his lead when he made his sole pit stop after six of the ten laps.

Long-travel tubular shock absorbers worked well when fitted at the rear of the 1956 550A Spyder. The large sloping engine element was its crankcase ventilation.

Four laps later sunburned Umberto took the checkered flag, braked to a stop and clambered stiffly from the Porsche’s seat. After a single-handed drive of almost eight hours, at a faster pace over a longer distance than the 1954 victor, Maglioli won the Targa. His win was rightly hailed as “Porsche’s greatest victory” since the company started making cars. To top it off, a private Porsche team scored a class victory in the race at Montlhéry that same day.

Maglioli’s 1956 triumph was the first of eleven conquests that Porsche was to claim in the classic Sicilian road race. The first three of those wins—the ones that laid the foundation for a legend—fell to the credit of the rugged, space-framed, four-cylinder racers.

Seeds of this new generation of Spyders were planted during 1955 by the turn of speed shown by Maseratis, AWEs and Borgwards in the 1,500-cc class. Porsche gained direct knowledge of the strength of the opposition when Richard von Frankenberg went to Modena in the winter of 1955 to test-drive a 150S Maserati being bought by American Tony Parravano’s stable. Richard brought back to Zuffenhausen a report on more than the cuisine at the Albergo Reale.

Seen before the start of the 1,000 km of the Nürburgring on May 27, 1956 were mechanic Eberhard Storz on the left, behind him John Wyer and at the 550A Spyder on the right, mechanic Ludwig Schmid.

Power was not the main problem. The 1500 RS engine was still in the early stages of its development, although there was some uncertainty as to how best to proceed with that development. New R&D chief Klaus von Rücker was not yet fully established in Zuffenhausen and the engine’s designer Ernst Fuhrmann—who in any case was not directly responsible for its development—was on the brink of leaving.

Pursuing work already done to increase power for the fast Avus race late in 1955, Porsche’s engineers raised the compression ratio to 9.8:1. Instead of Solexes, more costly Weber carburetors were fitted to all works engines. In the most important change of all, the two distributors were driven from the nose of the crankshaft instead of from the inlet camshafts.

“The reason was because of play in the gear drive before it reached the distributors,” Fuhrmann recalled. “It was too great and also unequal for both sides so you got imprecise timing. It was very rough. Finally we changed the location and the problem was over.” “Only after the changeover to the drive from the crankshaft,” read a Porsche report on the Type 547 engine, “could optimum performance be achieved. The unevenness of the camshafts had an unfavorable effect on the distributors and the ignition.”

Driven by worm gears from a crankshaft extension, the distributors were placed in a narrow vee, nearly vertical, at the front of the engine. They and their gearcase were supported by a cast-aluminum brace attached by the same cap screws that retained the oil pumps. The twin ignition coils were moved to mounts atop the transverse torsion-bar housing.

A view of a 550A Spyder dash equipped with a rally odometer showed that the ignition switch of these cars was on the driver’s right—contrary to Porsche propaganda.

Stabilizing the ignition did indeed unlock power. Typical outputs for the engines of factory cars in 1956 ranged from 125 to 130 net bhp. The peak reached in late-1956 development was 135 bhp at 7,200 rpm, with power remaining above 125 bhp at a heady 8,000 rpm. Maximum torque was sharply bettered to 107 lb-ft at 5,900 rpm.

Hydraulically operated coil-spring clutches were carried over—they were used on all the Spyders—as was the transmission used in late 1955 with its fifth starting gear. Its shift linkage was redesigned, both to strengthen it and to eliminate the woolly feel of the Type 550 shift.

Ancillary improvements during 1956 included the change from six- to twelve-volt electrical systems and the addition of a side-mounted fuel tank for factory cars, also adaptable to private ones. For long-distance events the added tank brought fuel capacity to 34 gallons which, in 1956, was the legal maximum for the cars for Le Mans.

Much more in need of renovation was the 550 chassis. Except for the reversal of the rear torsion-bar arms and the addition of stiffening tubes on the late-550 frames, the Spyder’s chassis concept was essentially the same as it had been in the first Glöckler special of 1950.

Why, one might ask, had the Type 550 been built in 1953 with a relatively inefficient ladder-type tubular frame? The reason was that it had been created by the racers rather than the engineers at a time when the little company’s resources were strained to their limits. Not until 1955 was Porsche able to give as much attention to the chassis of the Type 550 as it had earlier devoted to its Type 547 engine.

A completed Porsche 550A Spyder for an eager customer was a handsome machine with forward-folding headrest, shrouded rear-view mirror and token passenger seat.

Porsche’s racers didn’t have to look far to find a model on which they could base the new Spyder’s frame. Since the beginning of 1955 an in-house alternative was available in the shape of the tubular space frame designed for the Type 645 “Mickey Mouse” Spyder project of Egon Forstner. In every important respect this served as the pattern from which they derived the frame of the 550A.

Between the transverse tubes housing the torsion bars for the front and rear suspension, the frame of the Type 645 was virtually duplicated. A cautionary decision was to make the bottom tubes significantly larger than those at the top. This was unlike the 645, which did have a difference in tube diameters but to a smaller degree. Stiffening webbing was added to the corners of the quadrilateral of large tubes that formed the cowl structure. While the cross-bracing through the cockpit was identical, the side bracing of the front box was reversed in its angularity.

The greatest difference was behind the cockpit. While the 645’s rear frame was exiguous, the 550A’s was elaborate and much heavier with an additional box and two large lower crossmembers supporting the engine and gearbox. A pyramidal extension carried an outboard mount for the rear of the gearbox. The frame needed more structure at the rear to carry the new suspension design that was adopted for the 550A. Only in some crossmembers was the wall thickness of the tubes as great as 1.5 to 2 mm; most of the tube walls were 1 mm thick.

The new frame was an improvement in every way except, perhaps, in accessibility. It was three times stiffer in torsion than the old design and no less than five times more rigid when stressed as a beam. In spite of this it was 35 pounds lighter than the 550 frame, weighing only 95 pounds. Its much higher profile brought added benefits in that the separate supports that previously had been needed for the body were now eliminated.

The rear body shell was lightened by doing away with the up-pivoting feature. Instead hinged lids were fitted at each side to give access to the carburetors and spark plugs. The rear shell was still removable, lifting off in one piece for major surgery. By such means the body weight was cut to 139 pounds, a 59-pound reduction.

A snap during practice for the May 1956 race at the Nürburgring found Umberto Maglioli in dark glasses discussing the new 550A Porsche’s preparation.

Given its stiffer frame, the suspension and shock absorbers had to work harder on the 550A. Used at the front were Fichtel & Sachs dampers with finned housings to keep their fluid cool, a feature developed during 1954 and 1955 for the Mercedes-Benz Grand Prix cars. A new steering gear was fitted, the ZF-built Ross-design box that would be adopted for the production 356A Porsches in the autumn of 1957. The overall decrease in weight reduced the burden on the brakes. Wide front drums adopted during 1955 were retained, while on the factory team cars a tandem master cylinder was added with separate front and rear brake circuits.

The other major improvement in the 550A affected its rear suspension. Though its principles were readily available for use, the suspension designed by the Forstner team for the 645, with its clear derivation from the Type 360 Cisitalia, was not chosen. When the 550A was designed its mismatch between front and rear suspension that made the 645’s handling so erratic hadn’t yet been diagnosed or even manifested in the metal.

The technical team led by Wilhelm Hild turned to a demonstrably successful design, the low-pivot swing-axle suspension used by Daimler-Benz since early 1954 on both racing cars and its 220-series production cars. In previous Porsche swing axles and all the 356-series rear suspensions, the location of the swing-axle pivot point was determined by the needs of the universal joints at the inner ends of the axle shafts, not by the requirements of the suspension.

What Daimler-Benz had done and what Hild did with his suspension design for the 550A was to keep the swing-axle principle while relocating the axle pivot point both downward and inward to the car’s centerline. This offered several advantages. One was that the rear roll center was lowered. This helped reduce the car’s oversteer by shifting more of the roll couple to the front wheels. Another boon was that it preserved more consistently the rear-wheel negative camber, which was set at about 1½ degrees at normal height.

The lower pivot also reduced the jacking effect of the classic swing axle, whereby the reaction from the grip of the outer wheel on the road tends to lift the back of the car. At the same time the amount of camber change with jounce was reduced by the significantly greater length of the rear-wheel swing arms.

Squeezed as it was between the transmission housing and the necessary ground clearance, the axles’ pivot point didn’t offer a wide choice of heights. Such adjustment as was possible was carried out by experiment with the first 550A on the Malmsheim Airport skid pad, with excellent results. The speed at which rear-wheel breakaway occurred on the pad’s largest-radius curve rose from 47 to 56 mph, an improvement of almost 20 percent.

Its road registration was painted on the nose of the Porsche 550A Spyder driven by Targa winner Umberto Maglioli in the Nürburgring’s 1957 Formula 2 Grand Prix.

Not only was breakaway higher, but also the driver could get closer to it more consistently with the new rear suspension and rigid frame. As Type 645 creator Egon Forstner observed, “Breakaway occurs only in a much gentler manner and thus can be more quickly perceived and brought under control by counter-steering. That’s a relief for the driver, who can devote his attention to other happenings.”

The same torsion bars and drilled blade-like trailing arms that were used on the 550 controlled the rear hubs of the 550A. Swing-axle arms, which passed under the axle shafts, were welded of sheet steel. They swung from spherical pivots that were side by side and carried between two frame crossmembers under the transaxle.

Downward extensions were attached to the bottom ends of the rear dampers, which were now more rigidly mounted to the new, well-braced frame. The changed rear-end geometry required the axle shafts to have sliding splines to allow their lengths to change. Also required were outboard universal joints, simple Hooke-type joints encircled by the outer end of the swing axle. Wheel travel at the rear was 3.5 inches in jounce and only 1.4 inches in rebound; at the front it was 2.6 and 2.8 inches in jounce and rebound respectively.

A 14 mm anti-roll bar was kept at the front wheels of the 550A. Rear anti-roll bars were tried but were found to accentuate oversteer. Static negative camber at the rear was altered to suit the tastes of the drivers. With this sophisticated fully independent rear suspension Porsche was one-up on its class competitors, who used either live rear axles (OSCA) or rigid de Dion axles (Borgward, AWE, Maserati).

The 550A/1500RS Porsche was much lighter than its predecessor, weighing in at 1,166 pounds with its spare wheel and an empty fuel tank. Although it was always officially the 550A, this first space-frame Spyder was often known by its “RS” nickname. “The sum total of the various modifications,” wrote Ken Miles in Sports Car Graphic, “was an improvement in handling that was almost unbelievable. Gone was the excessive oversteer. The RS was now about as forgiving a car as one could possibly wish to meet.”

In the May 12, 1957 Mille Miglia, Swiss racer Heinz Schiller drove a 550A Spyder to second in class behind Umberto Maglioli in a similar car and 11th place overall.

Continued Miles, who started racing an ex-works 550A in 1957, “Steering the Type 550 was very much a matter of very large steering-wheel movement to produce the desired result; the RS could be steered with a mere flick of the wrist. For the first time one could place the car with great accuracy and expect it to follow the chosen line.” Commending the “gentlemanly behavior” of the 550A, Miles said “it must surely be one of today’s most successful designs.” Porsche’s own figures showed it capable of accelerating from rest to 60 mph in 7.2 seconds, to 80 in 10.5, to 100 in 14.4, and to 120 in 22.6 seconds.

It was still topcoat weather near Stuttgart early in 1956 when the first 550A was test-driven by Huschke von Hanstein, Hans Herrmann and Hans Klauser, the Porsche service manager who also handled timing and scoring for the team at Le Mans. Unpainted, hammer marks still speckling its aluminum skin, the racer was bravely sent to Brescia for the start of the Mille Miglia on April 28.

At that early date the car was utterly unproven, so its makers were not surprised when it failed to figure in the race. Driven by Hans Herrmann with mechanic Werner Enz, it reached the control in Rome three hours off the pace in its class after a finger follower had broken, calling upon engine-man Enz to deactivate that cylinder. Pulling out of the race, Herrmann and Enz headed for dinner and bed.

Ken Miles scored many victories in 1957 with this Porsche 550A, including this one-hour contest on May 19 at Santa Barbara, California.

A month later, on May 27, 1956, this light new Spyder made its debut before the German public in the 1,000-kilometer race at the Nürburgring. Driven by Wolfgang von Trips and Maglioli, it was joined there by a newer sister car that was visibly different in several ways. The newer car lacked the rearward-facing vents above the carburetors that appeared only on the first 550A and on some late works 550s, while the louvered access flaps in the rear fenders were curved more deeply downward to give the mechanics more room to work.

In the 1956 ‘Ring race the new 550As finished first and second in their class and fourth and sixth overall. The excellent fourth was to the credit of von Trips and Maglioli while Hans Herrmann and Richard von Frankenberg were sixth in the newer machine. After the race the first 550A, still distinguishable by the vents above its carburetors, made its epic journey to Sicily to win the Targa Florio. A new giant-killer was born.