Another Wankel rotary myth. Just like any other engine, the cost of a unit is primarily driven by its raw material costs, its complexity and most importantly the manufacturing volume. Wankel rotary engines are less complicated and require less raw material to manufacture, and therefore, if the quantities were equal to those of piston engines, would have a lower cost to produce.
So if we consider the vast range of piston engines available, you can buy a highly sophisticated modern piston engine from a major OEM for a few thousand pounds (because they make them in the millions). But you can also purchase high-performance, highly tuned piston engines from specialist companies (for automotive racing or aerospace) for tens of thousands of pounds; you pay more because these are hand assembled and batch machined, and no one blinks at this and just accepts this is how it is.
At the moment, most rotary engines fall into the latter category: manufactured for specific specialist applications, produced in low volumes and hand built, so they cost accordingly. Mazda though has proved that once you start to assemble rotary engines in tens of thousands of units per year, they do compete on cost with pistons produced in much higher volumes; there is no inherent cost penalty in utilising Wankel technology, just the usual economies of scale of different applications and markets.
Simultaneous 5 Axis port Machining a 650S engine rotor housing on our in house Mazak i500, absolutely amazing pic.twitter.com/xly5SMkhGP
— AIEUK (@aieukltd) March 17, 2016
Simultaneous 5 Axis port machining an AIE 650S engine rotor housing at AIE
AIE’s engines have scalability and low cost of manufacture designed into them as a primary goal. We do not use any “unobtainium” in our engines or utilise any manufacturing processes that are typically reserved only for the unlimited budgets of F1 teams or space programs.
This article is part of a question and answer series which can be found at: Ten inaccurate preconceptions about Wankel rotary engines discussed.