In the destructive world of NHRA Full Throttle Drag Racing Series Funny Car competition, few parts take more of a beating than valve springs. "What kills them is going up and down 8000 times a minute uncompressed, as close as we can get them," says Jim Dunn, who runs his eponymous Funny Car race team from a small workshop in South Gate, California. Dunn is pretty much of a throwback to the earlier days of straight-line competition, a man who prefers not to use computers in his...
In the previous article on valves, I turned to the subject of reed valves and their use in the induction section of a two-stroke engine. In race series where two-stroke engines are still popular, reed valves are commonly used and, owing to their mechanical simplicity, are likely to remain so. They require no mechanical drive or other actuation, and depend only on pressure differentials to open and close. There have been a number of uses of reed valves on four-stroke engines, some of which...
My previous article on titanium alloys looked at the possible benefits that Ti10-2-3 - an alloy containing 10% vanadium, 2% iron and 3% aluminium - might offer compared to the widely used Ti6-4 material. Ti10-2-3 has found wide use on military and civilian aircraft, commonly in structures where steel has traditionally been the material of choice. As in motor racing, there is a great advantage to be had in the aerospace industry in terms of mass reduction. Since the widespread adoption of...
During 2010, Porsche achieved another significant first when it won an important motor race using a hybrid vehicle that stored its energy mechanically. When Formula One embraced KERS technology in 2009, the teams which raced these systems did so successfully using chemical storage of energy in the form of batteries. Williams had developed, but didn't race, its flywheel/electric system. Flybrid's pure mechanical system promises excellent efficiency, low mass and good durability, but...
A few months ago, in May I believe, we looked at a variable duration cam made in two pieces. While this was a novel approach to optimising the airflow into an engine over a range of conditions, reader Reine Gustafson of AGAP in Sweden contacted me recently about another cam design idea. This too consists of more than one piece and, as you will see, is simplicity itself. Now there can't be a cam designer or engine builder who hasn't been confronted with this problem at times and who...