Type 550A Spyder

The Type 550 spyder laid the foundation for a new generation of sports cars from the Porsche stable in Stuttgart, which earned them the reputation as the ‘giant killer’ with the model’s continued racing successes. The new Type 550A spyder was more than an evolution of the 550 spyder, it was a revolution in car design for Porsche. The ladder type chassis design of the 550 was created by racers, but the space frame chassis of the 550A was designed by engineers.

Early in 1956, the production of the remaining ten 550s were still in progress when the 550As started to be assembled at the Werks 1 Factory in Zuffenhausen. Coach builder Wendler Karosserie, with their factory in Reutlingen, was again given the contract to produce the bodies with the new refined shape of the Type 550A and started production in March with 550A-0101 and 550A-0102, the first of the Werks race cars for testing. In April they were entered in the Mille Miglia without a result, but podium finishes for both cars in the 1000km Nurburgring, the following month. It wasn’t until the Targa Florio in June 1956 where Italian ace Umberto Maglioli, in a hand painted white 550A-0101, single handedly took outright honours. Hailed as ‘Porsche’s greatest victory’, Maglioli won overall with a margin of 12 min 58 seconds over a distance of 447 miles, ten laps of the little Madonie circuit in Sicily.

By May, 550A-0103 and 550A-0104 were ready for the LeMans race scheduled in June, both fitted with a hard top on a silver body similar to the Prototype 550 LeMans racers of 1953. It wasn’t until January 1957 when the customer 550As went into production, with a third of them destined for the US market, starting with the priority delivery of 550A-0111 through to 550A-0114, for the 12 hour Sebring race on 23rd March 1957, along with 550A-0104. Three of the spyders didn’t finish but 550A-0111 came first in class followed by 550A-0104.

After the initial four prototypes, the main production schedule started with 550A-0111 through to 550A-0145 which was completed in May 1958. One extra car was built – 550A-0146 in February 1959, which brought the total to 40 builds. There were nine Werks cars in the Type 550A production run, which were used to represent Porsche in races around the world. Silver was the only original factory colour available for all 550A spyders except for two – 550A-0132 ordered by Ed Hugus and 550A-0135 ordered by Newton Davis, which were painted white.

The 550As were not displayed on the dealership showroom floors in any countries for sale, they were all on consignment for allocated drivers. The 550A spyder was the first true purpose built car designed solely for racing by Porsche, unlike the 550 which was designed for both road and track. With the success of the 550 on the track and the latest offering being released so shortly after, drivers were promised a new car designed from the frame up, that would exceed their racing expectations. Prospective customers paid a premium price and had the option of ordering their spyder through their local dealership or direct from the Porsche Factory, where the car was delivered to their home in a wooden crate, if they weren’t located near a local Porsche dealer.

Senior Porsche engineer Leopold Schmid played a pivotal role in the revolutionary structural design of the new 550A space frame chassis, which was composed of front and rear tubular boxes connected through a central box at the cockpit, by cross-bracing diagonals that lowered the frame height near the door openings. The new frame was three times stiffer compared to the old ladder design and no less than five times stiffer when stressed as a beam. In spite of this, it was 16 kg (35 lbs) lighter than the 550 Spyder frame, weighing only 43 kg (95 lbs). The frame’s steel tubing had walls of only 1mm thick but up to 2mm were used in critical frame cross members. The weight of the complete body was also reduced by no less than 27 kg (60 Ibs) to 63 kg (139 lbs), thanks to the fact that the space frame provided higher body mounting points and so allowed many body reinforcements to be eliminated.

Another major improvement to the Type 550A was a fully independent rear suspension. Designed by Porsche engineer Wilhelm Hild, it was updated from a typical swing axle to a low pivot, two joint swing axle, as he repositioned the axle pivot point downward and inward to the car’s centreline. A new front anti-roll bar reduced the car’s oversteer and combined with a static negative camber, it resulted in better grip in the corners and improved controllability at higher speeds.

A new 5 speed gearbox was adopted as the spyder’s standard gearing from 1956 onwards. First gear however was only a starting gear, contained in a small separate housing. It was not synchronized and could be selected only after operating a catch, just as for the reverse gear. This somewhat increased its shifter throw, as the drivers had to move the lever past the first-gear lockout to get to the remaining gears. Although the synchronization of the other gears was exemplary, all the Werks drivers normally used double-clutched downshifts (as is still done today). The final drive was by spiral bevel gears and wheel spin was reduced by a ZF limited-slip differential.

Besides the frame and mechanical upgrades, the 550A was also given a new aluminium body with a lighter, more aerodynamic design. For a better centre of gravity, the spare tyre was removed from the mount over the transmission, as found in the 550, and positioned under the front hood in front of the fuel tank which had been shaped to accommodate it. The rear body shell was further lightened by removing the hinged rear tilt feature, with the rear shell now removable by manually lifting it off in one piece. To compensate for accessibility to the engine bay in the pits, the inclusion of small hinged louvered panels on its flanks gave quick access to the carburettors and spark plugs. The rear grills were also positioned lower towards the tail, allowing better airflow and cooling to the engine. Both front and rear running-brake lights were of a smaller design, and instead of the damper flap used ahead of the oil coolers of the 550s, the 550As had a thermostat in the oil piping to shunt the lubricant away from the cooler until the engine was up to temperature. With the new FIA rules introduced during the 1957 season, driver roll bars became a mandatory safety requirement, which was concealed by a headrest fairing as a standard feature in the 550A design. Each 550A also came with a convertible canvas top to meet regulations.

OPERATING INSTRUCTIONS

  1. Trouble light socket
  2. Speedometer
  3. Trip mileage indicator (odometer)
  4. Blinker switch
  5. High beam indicator light (blue)
  6. Light switch
  1. Oil pressure indicator
  2. Oil pressure warning light (green)
  3. Ignition switch
  4. Fuel pump switch
  5. Switch for ignition coil I
  6. Switch for ignition coil II
  1. Total mileage indicator
  2. Tachometer
  3. Blinker indicator light (red)
  4. Generator indicator light (red)
  5. Oil temperature gauge
  6. Starter button

SPECIFICATIONS

Dry weight: 530 kg (1168 Ibs.) excluding fuel (including compulsory spare wheel)
Engine: Type 547 box motor, air cooler, horizontal opposed, 4 overhead camshafts
Carburettors: 2 x Weber 40 DCM twin-choke downdraft carburettors
Engine power: 135 bhp at 7200 rpm
Compression ratio: 9.8:1
Standing start to one kilometre:
26.6 seconds with a speed of 205 km/h (127.5 mph)
0 – 100 km/h (60 mph) – 7.2 sec
0 – 130 km/h (80 mph) – 10.5 sec
0 – 160 km/h (100 mph) – 14.4 sec
0 – 200 km/h (120 mph) – 22.6 sec
Maximum speed: 240 km/h (150 mph)
Gearbox: 5 speed synchro gear box (5th starting gear)
Crankshaft: Hirth’s roller bearing with lightweight cylinder barrels
Braking: dual braking circuits
Front drums: 60 mm (lateral drilling of brake drum aluminium fins for lightness/additional cooling)
Rear drums: 40 mm
Fuel tank capacity: 80 litres (21.1 gallons)
Auxiliary tank fitted for long distance races: 130 litres (34.3 gallons)
Electrical system: 12 volt