In a previous RET-Monitor article we looked at how these ‘Back Torque Limiters’ or ‘Slipper Clutch’ units operate, and their particular advantages in motorcycle applications. They allow a controlled slipping of the clutch until the speeds of both the rear wheel and the engine are matched, and have found their way into many motorcycle race formulae including World and British Superbike, Supermoto and even Motocross. While not exclusively suited to motorcycle applications, installing these units into bike-engined kit cars has become more commonplace. Read more…

Although attaining speeds up to and in excess of 100 mph on tarmac is not an arduous task, it is a rather more multi-faceted undertaking on water. One of the many considerations of high-speed marine applications is transmission and propeller design. There are a number of high-speed marine formulae that use various propulsion systems, including water-jet drives, super-cavitating and surface-piercing propeller drives.

The Oulton Broads and surrounding areas, in Suffolk,

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In the previous article on this subject, I looked at a reversing differential for a bike-engined car where the engine is mounted longitudinally. Many bike-engined cars are configured with the engine mounted transversely, as it is in the motorcycle from which it is taken. This arrangement is commonly seen in Formula Student, for example.

One particularly enterprising car constructor has developed, and very successfully used, its own Read more…

While most press coverage of motorsport tends to look at big-budget motor racing, there are interesting technical features on many of the lower-budget machines that pound around the circuits during the summer weekends. There are a number of race series where lightweight cars powered by motorcycle engines are popular and successful. In the UK, Radical in particular has made a very successful business out of building bike-engined sportscars, and its V8 car has an engine based on two motorcycle top ends. Read more…

In the previous article, we looked at the prototype Formula One constantly variable transmission (CVT) system that Williams developed in conjunction with Van Doorn in the early 1990s, and spoke to engineer Arnaud Boulanger who was involved with the project.

Anyone who follows Formula One closely will remember the dominant position that Williams had at that time. The CVT’s development happened during a golden era for Williams; having the best car, they attracted the best drivers and for years were considered ‘kingmakers’ owing to the fact that, more often than not, the world champions drove a Williams. Read more…

More than 15 years ago, a young David Coulthard said he was “very excited” about a new development at Williams, going on to say that “machine is working better than man”. The reason for his enthusiasm was that he had just tested Williams’ revolutionary continuously variable transmission (CVT) system. This was in 1993, and the system so worried other competitors and the FIA that it was banned before it could be raced. There is video on the internet of the car being tested in CVT guise, and it is well worth watching - and listening to. Read more…

With the adoption of independent, or de Dion rear suspension by racing car constructors during the 1930s, some means of transmitting the torque from the transmission into the wheel hubs had to be devised that accommodated the vertical motion of the wheel.

When using a swing axle, this was usually achieved by using a ball-and-socket arrangement integrated into the differential output shafts, while fully independent and de Dion systems required some form of universal joint at each end of the driveshaft. Read more…

In the last edition of Monitor we introduced the concept of ‘Tractive Effort’ curves plotted against road speed to analyse performance.

Most ‘racers’ are familiar with using the traditional straight line plot of road speed against engine rpm as a method of choosing ratios. Whilst this gives an indication of maximum speed in each gear and helps to assess the drop in engine rpm associated with changing up into the next ratio, its use is otherwise limited. In particular it does not

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In recent RET-Monitor features we have considered several aspects of transmission design and engineering, each time with the implicit assumption that some means of gearing between the power unit and road wheels was a prerequisite feature.

Why should this be so, and how do we then determine what we need?

Essentially we seek to transform rotational motion Read more…

One of the problems faced by race car designers is the conflicting requirement of keeping a low centre of gravity for the engine (and transmission), whilst keeping the driveshaft within acceptable values. Whatever the chosen method of coupling excessive angularity will lead to increased power losses and ultimately, failure of the joints.

Putting some numbers to this, consider a Formula Three car whose engine is dry sumped and running a 140 mm diameter race clutch on a lightweight flywheel. Read more…