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82 Spring 2015 | Unmanned Systems Technology PS | Wankel engines O ne of my strongest memories of Le Mans 1990 [writes Ian Bamsey] is of the post-race voluntary work I undertook at the behest of Mazda’s PR team. Let’s face it, who better qualified than members of the media to take time out to help them dispose of all that surplus-to-requirements celebratory champagne? No such luck the following year though, as the historic win for the rotary engine meant that all the reserve bottles were (quite rightly) rushed over to the pits, to reward those whose hard work had made it possible. That triumph by Mazda remains the pinnacle of achievement of the Wankel- type engine in motor racing. On the road, the Japanese company kept the concept alive for the best part of 50 years, but in recent times it was defeated by emissions regulations – or at least by the understandable failure of that engine type to meet changing requirements without a huge amount of additional development cost. Understandable because the conventional four-stroke internal combustion engine is in its second century of evolution, with the vast majority of the resources of a massively powerful automotive powertrain world having long been dedicated to it. By contrast, Mazda’s lone championing of the rotary engine was a drop in the ocean. Who knows what would have been the case had that development scenario been reversed? The rotary engine has certain inherent advantages, not least that it is far simpler, smaller and lighter than a conventional four-stroke of comparable output. The comparison with two-strokes is less clear-cut, yet the rotary engine has been impressive in the world of motorcycle racing, highlighted by Norton using one to win the Senior TT on the Isle of Man in 1992. Over the years a number of motorcycle manufacturers looked seriously at the Wankel concept, but it was Norton primarily which exploited it on road and track. Sadly, the company then fell apart, and although it was revived in 2008, the current incarnation has no apparent interest in a Wankel- type engine. Others have carried the concept forward though. In fact, at the moment, around the world there are at least five companies offering rotary engines specifically for use in UAVs, the creation of some of which was directly inspired by Norton’s experiences. In a UAV, power-to-weight ratio is a crucial consideration, and this is where the Wankel concept scores, together with its multi-fuel potential and smooth running, as UAVs tend to be bristling with electronics that need protection from vibration. The point is that Felix Wankel’s very clever innovation hasn’t gone away. It has found its niche, energetically branching out into the world of unmanned systems technology. It follows then that, in due course and in future issues of this magazine, you will be learning about the state of the art in UAV rotary engine technology. Of course, that technology hasn’t stood still since the days of Mazda and Norton, and modern developments are fascinating, as we will reveal. Now, here’s a thing “ ” At the moment, around the world there are at least five companies offering rotary engines for use in UAVs