The use of composite materials in racecars is not new; nor does it represent a particular novelty for race engines. The strength, stiffness and low density make them ideal for many components, both structural and decorative.
It is now pretty rare to find a race engine airbox, certainly on ‘formula’ cars, made from anything other than carbon-fibre reinforced polymer (CFRP) composites. It has also been used to good effect for plenums on turbocharged engines, on structural covers for race engines and in parts used specifically to increase the stiffness of the engine in order to provide a performance benefit to the vehicle as a whole. It is widely used for electrical boxes and cosmetic covers too. Read more…
We have, in previous articles, looked at the importance of correct pre-load for fasteners, and this is especially important where there are cyclic loads involved that might causes fatigue failures.
Continuing the discussion of wire thread inserts in previous articles, this month I’ll consider ’solid’ types of insert. There are at least two varieties of ’solid’ inserts in common use, and these are used mainly for repairs and, less often, in situations where female thread strength is felt to be a problem and that without such an insert, the chances of thread stripping are high.
In the previous article on thread inserts, Wayne Ward briefly discussed some of the reasons why people might choose to specify a thread insert and looked in a little detail on one of the types of insert which find common use in current racing engines. There is one further reason why a wire insert may be an advantage and that is in improving the fatigue life of the bolt installed therein, or of the female threaded component.
In previous articles on the subject of fasteners, we have dwelt very little on the subject of female threads, other than in the article talking of bespoke nuts. The other main situation where we will find female threads is where these have been machined into castings or into machined parts. Unless the rules forbid their use, it is likely that we will have chosen an aluminium block, or where we are designing bespoke parts, aluminium is a very popular material, either in its cast or wrought forms, owing to its low density. Where 
There are a plethora of different kinds of nuts on the market, and many are aimed at the racing market. Most of these will have been designed originally for the aerospace sector, and here we benefit from the exceptional quality control that the aerospace industry demands. Despite this range of good quality proprietary parts being available to us, there are also a considerable number of racing engine manufacturers who have bespoke nuts manufactured to their own designs. These might be to fit into a particularly confined space, maybe to minimise the height of the nut, or perhaps to 
In the recent Race Engine Technology magazine article on the subject of fasteners, 
After having calculated bolt stiffness, or measured the load-deflection curve directly, the best way to calculate pre-load is to measure the extension of the bolt directly. This method is preferred for con rod bolts and all con rod and bolt suppliers generally recommend this method. The fasteners require design features to allow measurement with a special micrometer. This method is impossible for fasteners in blind holes. For large fasteners in blind holes the extension can be measured directly if there is sufficient access for other measuring equipment.
In previous articles we have looked at how to calculate fastener and joint stiffness, and seen how these values of stiffness can affect the proportion of the working load experienced by the fastener by calculating the ‘load coefficient’.
Last month, we looked at some basic calculations regarding cyclic loading of fasteners. We must apologise for the recurring errors in printing symbols. The questions marks last month should have been ‘delta’ symbols. For example strain was given as:
