Is the piston finally broke?   

Remember the old joke. Man stooped beneath car bonnet. A drunk lurches by. “What’sh the problem?” slurs the drunk. “Piston broke” replies the man, wearily. “Sho am I!” replies the drunk, cheerily.

I reflect on this wisecrack while contemplating the onward march of electric vehicles, now slated to replace their traditional internal combustion powered brethren within a few years, depending on which country and which political party, if any, you listen to. For over two centuries, and thanks to the genius of the British engineer Richard Trevithick and his simple crank mechanism, the lowly piston has done its work countless trillion times a day converting reciprocating movement into rotation. But are its days finally numbered?

Sir Charles with the Prince of Wales during a royal visit to the works in 1923.

Actually, its days were always numbered. From the start, the humble piston was a ‘parvenu’, an interloper invading territory properly occupied by earlier inventions, notable among them the turbine, variously accredited among others to Leonardo da Vinci, Nicolas Copernicus and the Egyptian scientist/philosopher Ptolemy. Why, you might ask, did the piston ever get a look-in?

It’s a good question for which I have only one answer. It’s easier to make a machine which goes backwards and forwards than one which has to go round and round from the start. The reciprocating piston, confined by a simple cylinder, presents no major technical challenges. For the engineer, straight lines and regular circles are much easier to make than things which require complex and continuous changes of shape. All you need is to have something to push your piston backwards and forwards, which is where first steam, then refined petroleum, came in. Gas too has been used to propel our faithful piston on its interminable stop-start journey. In the late 19th century, even my own ancestral saw factory in Glasgow employed a gas engine to power the pulleys and belts which drove the various saw-making appliances.

Pelton motor from Pacific Rural Press September 7, 1889

In contrast, the machines required to generate rotary motion from the beginning were much more complex, because they were mainly composed of the varying shapes which we know as parabolic curves. A parabolic curve is a curve that changes its radius progressively from one edge to the other. The sails of a Dutch windmill did this naturally, thanks to the stretch in the fibres used. But wind is a fickle friend, both in force and direction (Green Brigade, please note). For big, reliable output, you need big reliable input. To impart rotary energy from a direct line of force you need a curve for the force to impact against. It’s the parabolic curve of an aircraft wing, called an aerofoil, which converts the horizontal rush of air into vertical lift. See what happens when you tread on the chamfered edge of a piece of wet Imperial Leather soap. Push down, and the soap shoots out from under at 90 degrees. Get it?

Lester Pelton

It took the genius of two great engineers of the Victorian era to square this circle, or to put into better context, round this out. Britain’s Charles Parsons, using steam for his motive force and applying Boyle’s Law to get the best out of it, devised the mechanisms for manufacturing in quantity the multitudes of curved blades his quite literally revolutionary steam turbines required. Meanwhile, across the Atlantic, the

American Lester Pelton, using water for power, invented the first high efficiency water turbine. Yes, water wheels had existed before, but their crude paddles were slow, inefficient and of little use to the engineers of the late industrial revolution. By employing parabolic curves and complex manufacturing techniques, both Parsons and Pelton devised machinery highly suitable for generating electricity. From that point onwards, the piston’s fate was sealed.

Or was it? Let us not forget the original purpose of the piston, before it was harnessed to Trevithick’s crank, was to pump water. To and fro goes the piston, scooping up the water for each stroke. Not just water: any liquid can be easily pumped using a simple piston and cylinder arrangement. Yet again it was an Englishman who mechanised this. Even before Trevithick, his fellow Cornishman Thomas Newcomen harnessed steam to push the pistons of his pumps back and forth to drain water from the county’s tin mines. It worked then, and it still works now.

Richard Trevithick, locomative pioneer

Consider too, the independence of the simple piston. Yes, Charles Parsons needed steam as an external power source. Lester Pelton needed water. But the piston isn’t fussy. Give it something easily combustible and transportable, such as petrol, and it will set its master free. It carries its power source with it – and there’s a lot of power in a small amount of petrol. If you want proof, just take a gallon or a litre of whatever fuel your car uses and see how far you get on it. Then look at the size of the electric car battery you need to travel an equivalent distance. That battery, a dense sandwich of heavy, rare, and expensive metals, is at least ten times as big and twenty times as heavy than its hydrocarbon equivalents. Need I explain further?

But hang on: how long does it take to charge that massive battery? Thirty minutes, they say. I can fill up my car in five minutes. So, if all the cars are to be electric, we need six times as many charging points as there are petrol pumps. Six times! Has anyone thought of that?

Leonardo da Vinci

Err, and where’s all that electricity going to come from? Britain has roughly sixty gigawatts of generating capacity. If all the vehicles on the road are going to be electric powered, that requirement will double. A major power station generates roughly two gigawatts. So, we need thirty new power stations. What’s going to power the power stations? Coal? Oh no, we don’t like coal. Gas? No, we don’t much like gas either. Nuclear? Oh dear me no, it’s dangerous. So what’s making the electricity? The wind? What if there’s no wind? The sun? What if there’s no sun?

So, should I launch a ‘Power to the Piston’ campaign? Should we be shouting ”Exterminate the electrics”? I don’t think so. Reality coupled with market forces will make the decisions. There will be room for both. But meanwhile, I’m placing my order for the best piston-engine car I can find, while it’s still legal. I’ll bet it will still be there cranking out the power when the green brigade and their batteries of batteries have long since given up.

And for those who didn’t understand the joke, the drunk thought the man under the bonnet said” Pissed and broke”.

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