Tuesday, December 6, 2016

Porsche 956 and the Le Mans stable

Latest completion: the 1985 Porsche 956 in Canon livery that finished second at Le Mans that year. Regular readers (if any -- let me know if you still are out there, and still interested) will recall my (incomplete) 956 pickup truck that made liberal use of the 1984 version in Kenwood livery, but this is the first one I have actually completed -- my previous 956, by an Italian firm named Protar, is quite poorly detailed. (By the way, I am not aware of any decent 962s in styrene -- all are curbside. I am not sure why this is. The MFH version can be found on eBay at outrageous prices.)

This is a typical Tamiya kit. If you have built a Tamiya Le Mans car, you will know what to expect.

The real interesting point is comparing a raft of Le Mans cars from the 1980s and early 1990s. All, except the Porsche GT1 which was designed to meet a quite different set of homologation rules, share a very common aerodynamic layout: narrow cockpit with ducting in the door sills leading to side-mounted heat exchangers of various kinds, gas tank behind and to either side of the cockpit, and a rear-mounted engine bolted to a flat floor with a venturi rear section. The venturi dictates a lot of things: gearbox width and exhaust pipe layouts designed to maximise venturi width and depth, rear suspension links designed to minimise stuff intruding into the airflow in the venturi, etc.

The real story is in the engines, clockwise from lower left: a pair of turbo flat-6 motors (GT1 and 956), a 4-chamber rotary (Mazda 787B), a turbo V8 (Nissan R90V), a 7-litre SOHC V12 (Jaguar XJ9R LM), and a screaming 3.5-litre V10 (Peugeot 905). Still on the shelf: two more turbo V8s (Sauber Mercedes C9 and Toyota TS-One), a V12 turbo-Diesel (Revell's Audi R10), and a recently acquired copy of Fujimi's Dome Zero with a Cosworth DFV motor.

(The 905 is a poorly detailed Airfix kit; the rest are all Tamiya.) There are differences: the 905 stands out with its narrow roofline allowing the mirrors to be mounted inside the windscreen profile out of the airflow, and the wing on the 956 is mounted to the engine cover, not directly to the chassis via the gearbox as the others.

But the biggest difference is between the two Porsches, showing the magnitude of the role played by regulations. The classic Group C cars were theoretically road cars, the proof being the German cottage industry that made a living in the '90s converting obsolete 956 and 962 chassis to road-going trim (for an interesting example, click here), but apart from this exception, no one has really driven a Le Mans car on the street since Ford beat Ferrari until the rules changed in the mid-90s. The GT1, being subject to a newer set of regulations designed to bring "road cars" back to Le Mans, has a street exhaust and minimal venturi floor pan, and sits quite a bit higher due to the more-or-less standard 911 cockpit. (There is also a McLaren F1 GTR sitting on the shelf, which, like the GT1, is essentially a road car in racing trim). The new generation of LMP cars has come up with some very different aero theories, witness the latest Audis and the Ford GT.

Looking ahead, I am tempted to build up the Le Mans collection. I am sitting on 33 kits of Le Mans cars, of which only 9 are complete. Incomplete or un-started kits range from a 1930 blower Bentley (Revell) to the 1997 McLaren F1 GTR (Aoshima). As a start, I went back and had a look at the magnificent but challenging 908/03. I now have a few other MFH kits, including the successfully completed Abarth Periscopio, and it now seems to me that the 908/03 is extraordinarily complex, even for MFH, and was probably a bad place to start my adventures with multi-media kits. MFH's 917 looks equally challenging with lots of little space frame tubes made of flexible spun-cast white metal (sample instruction sheet below).

On the other hand I am getting better at the resin so maybe I need to push one of the Profil 24 kits through. The 1959 Aston DBR1 is partially complete and maybe this is a good place to start. Stay tuned!

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