Porsche 917K
The Porsche 917K: the short-tail variant that tamed the 917's aerodynamics.
The Porsche 917K is a variant of the Porsche 917 sports prototype race car, developed by German manufacturer Porsche. It was introduced after handling problems were investigated in late 1969 at a joint test at the Österreichring by factory engineers and their new race team partners JW Automotive. After exhaustive experimentation and comparison to a CanAm 917 PA spyder, its shorter, more upswept tail was found to give the spyder more aerodynamic stability at speed. The changes were quickly adopted into the wedge-tail 917K, K for Kurzheck, or 'short-tail'.
Quick Facts
- Design origin
- Kurzheck (Short Tail)
Lore & Background
The 917K models were generally used for shorter road courses such as Sebring, Brands Hatch, Monza and Spa-Francorchamps. The 917K was a variant of the 917 that addressed the aerodynamic lift issues of the original long-tail version. In 1971, a variant of the 917K appeared with a less upswept tail and vertical fins, featuring the concave rear deck that had proved so effective on the 1970 version of the 917L. The fins kept the clean downforce-inducing air on the top of the tail and allowed the angle of the deck to be reduced, reducing drag in direct proportion, resulting in a more attractive looking car that maintained downforce for less drag and higher top speed.
Reader's Guide
The 917K was powered by the Type 912 flat-12 engine, which was progressively enlarged from 4.5 to 5.0 litres. By 1971, the 5-litre engine produced a maximum of 630 bhp. The car's chassis was a very light spaceframe chassis (42 kg) which was permanently pressurised with gas to detect cracks. The driving position was so far forward that the driver's feet were beyond the front wheel axle. The car used many components made of titanium, magnesium and exotic alloys, and bodywork made from fiberglass saved weight.
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