This is bit of a treatise on the rear suspension of the Lotus 72C, part of an overall conversion of a 1/12 Tamiya Lotus 72D to Jochen Rindt’s car that I started about ten years ago. Recently, while reading the book Jochen Rindt, Uncrowned Champion, I pulled the kit out to take a look at how far I had taken the project. The answer was: not very far. I had added the NACA ducts to the nose and done a few other minor things like assemble the engine block, but that was about it.
Part of what had stopped me years ago was the 72C rear suspension. At the time, I had been unable to find much, if any, information on what the exact configuration was. Since then, I had acquired access to more resources and a lot more information has become available on the internet, so I decided to see if I could discover enough information to model the 72C rear suspension.
Rindt raced only one 72, chassis #2 (72/2), so I decided to start with Michael Oliver’s book and carefully go through all the modifications listed for 72/2, from its debut at the Spanish Grand Prix through Rindt’s fatal crash in practice at Monza. At Spain, and at the non-championship International Trophy race, it was in the original 72A configuration, with anti-dive/anti-squat suspension geometry. Prior to Spa, the car was rebuilt as a 72C (there was no 72B) and, among other modifications, the anti-dive/anti-squat was removed from the suspension. Rindt did not trust the 72C enough to drive it at Spa, preferring instead to use his proven 49C, and his first drive in the rebuilt car was the next race at Zandvoort, which he won.
According to Oliver, after the rebuild there were only two changes to 72/2’s rear suspension. Prior to the French Grand Prix the dampers were moved outboard, away from the exhaust pipes, and prior to the German Grand Prix the suspension arms (front and rear) were chrome plated. I had decided, for various reasons, that I would build the Zandvoort version, the car’s first win.
Unfortunately, Oliver’s book does not go into detail about exactly what removing the anti-squat entailed, and there are not many good 72C rear suspension photos around, especially with the inboard dampers. The original 72A suspension is pretty well documented, with photos and several cutaway drawings available, and the later 72D configuration, which the model represents, is also well known. The question was, exactly what was the 72C’s suspension configuration, was it more 72A, or 72D, or something completely different? I started searching on the internet and, in the end, with the information I was able to find (photos and drawings) plus a few assumptions, I was able to assemble a reasonably clear picture.
What I found was somewhat of a surprise to me. I had suspected that I might have to completely scratchbuild something similar to a 72A type rear suspension (not a simple task), but, in many respects, the 72C’s suspension turns out to be very similar to the 72D’s. In fact, the 72D rear suspension was apparently a refinement and simplification of the 72C’s, not a major change, as I had always assumed, and some of the kit’s suspension parts can be used as-is or slightly modified.
The photo below show the components that are the major differences between the 72C and 72D suspension:
Here are some shots of it all semi-assembled:
This is a photo of my rather crude effort at one of the lower arm’s front attachment points:
Sorry for this lengthy post on what is a fairly esoteric subject, hopefully it will be of interest and use to some. I would add that, aside from converting the Tamiya kit, I think that most of this could also be applied to correcting the 1/20 MFH 72C which, disappointingly, comes with a 72D rear suspension.
Steve Sobieralski
