“As machines become more and more efficient and perfect,
so it will become clear that imperfection is the greatness of man”
This year marks the 50th anniversary of the first rotary engine that Mazda produced and doggedly continued to champion until a mixture of increasingly onerous legislation and the design’s own particular quirks saw it finally consigned to history in 2012.
The rotary engine has a reputation for being complex, temperamental, unreliable and hard to maintain but the reality is that nothing could be further from the truth! Sure, it’s unconventional but, with a modicum of knowledge, a little bit of care and a willingness to get your hands a tiny bit dirty every once in a while, you can be rewarded with years of trouble free driving and a unique experience that only a free-revving rotary engine can give you.
So,what is a rotary engine and how does it work?
Well, very simply is the answer!
The engine follows the basic principles of intake, compression, power and exhaust (or suck, squeeze, bang blow) as the diagram above shows.
As you can see however, there are some fundamental differences which do warrant a brief explanation. Firstly, there is a startling lack of pistons involved – what you have instead is a rotor (the ‘triangl-y’ bit) which rotates around a shaft, inside a housing. This design means that you can dispense with a large number of moving parts and reduce it down to, in essence, the rotor, the housing, the shaft, a few gears and some seals which keep everything air, water and oil tight* – that’s pretty much it really – now, what’s so complicated about that??
*(in reality, you’ll have to multiply the above parts by two as pretty much every rotary engine you’re likely to encounter has two rotors, one behind the other).
The next difference requires a tiny bit of visualisation – unlike a piston engine where the 4 cycles (suck, squeeze, bang, blow) need to be completed before the next phase begins, the rotary engine design is much closer to the concept of perpetual motion. If you look closely at the diagram above, you may be able to see that as the top of the rotor is in its ‘suck’ phase, the right hand section is in its ‘bang’ phase and the bottom is in its ‘blow’ phase, no matter where the rotor sits at any given point, there are three of the four phases happening simultaneously. What this means in practice is that the engine never takes a breather, it’s a constant ball of motion and energy, creating heat and power at a frenetic rate that piston engines simply could never match.
The fact that the eccentric shaft of the engine runs through the centre of the rotors an housing means that it can rotate at a much higher speed, much more smoothly without adding excessive stress, and it’s this design that allows the rotary engine to run up to 10,000 rpm very happily and extremely smoothly whilst still producing maximum power – in short, it simply doesn’t let up.
So, a simple engine that has few moving parts, that generates power ‘all the way up to 11’ and delivers it with unrivalled smoothness – sounds perfect right? Well, not quite if I’m 100% honest. There are some inherent faults which, through a mixture of misunderstanding and bad timing, have ultimately led to the sad demise of the rotary engine.
Firstly, the tips of the rotors are sealed to the housings by thin strips of metal known as apex seals, these are seated on springs which constantly push them against the housings, maintaining compression in the chambers. As you can imagine, metal rubbing on metal at speeds of up to 10,000 rpm will not last too long without some kind of cooling and lubrication so the engine uses a metering pump to spray engine oil into the chamber to keep everything running smoothly. Using the incorrect oil, allowing the oil to run low or a failure of the oil metering pump or feeding lines can all lead to the apex seals wearing down or breaking, in turn leading to loss of compression.
Thirdly, the only thing a rotary loves better than being revved beyond oblivion is petrol! These are definitely not cars for hyper-milers or those commuting long distances, or, for that matter, those who do lots of traffic driving, nor those who are concerned (in any way shape or form) about the environment, neither for those who consider fuel economy when purchasing a car at all really. They are thirsty cars which need to be revved in order to deliver power and, whilst technically, they may be 1.3 litre engines, they will go through as much fuel as a 3.1 litre – and then some.
As mentioned earlier though, there are some simple steps that can be taken to address these potential problems (see the next blog post) and, if done with a reasonable degree of diligence, there is no reason at all that any rotary engined car will not deliver you years of trouble free driving.
That driving, by the way, is guaranteed to be a completely different experience that you will ever get from a piston powered car. With excellent chassis’ that grip for days, high power to weight ratios and 50:50 weight distribution, the way a rotary car handles is simply unrivalled. Add to that the sound of twin rotors screaming up to the red line and the constant linear delivery of power and what you are left with is an intoxicating mix of involvement, connection to the road and, quite frankly sheer joy which is nothing short of exhilarating. It’s definitely something that all drivers need to consider at least once in their lifetime.
In a world where Instagram filters, duck faces and social media streams are constant and unbroken feeds of people desperate to show us their ‘perfect’ lives, sometimes it’s a relief to realise that true perfection lies in the flawed beauty that surrounds us and reminds us all that we are all human and never blemish free. To have accomplished what they did in a short period of time and as a single company battling convention, Mazda should be applauded – and I shiver to think what could have been if the mainstream had thrown their collective efforts, knowledge and finances behind developing the technology on a world-wide scale!
In todays’ age of self-driving, lane assisted, electronically controlled marvels of refined engineering, the rotary cars produced by Mazda over the past 50 years are a perfect example of how beautiful flaws can be – the weathered face that stands out in a room of pretty banality, the one you are drawn too because you know it has a story you want to hear. To quote Marilyn Monroe;
“Imperfection is beauty, madness is genius and it’s better to be absolutely
ridiculous than absolutely boring”
If you can embrace this, you very soon realise just how right Mazda got things with the rotary cars – yes they are ridiculous in ways, yes they are far, far, from perfect but, you know what – that imperfection is what makes them a perfect machine and an essential experience for those who still like to live life one analogue mile at a time – at least occasionally.