Engines have always been a mystery to me. They are strange boxes under the hood or wrapped in a cowl. I’ve never worked on one, and most of my life I’ve had only the vaguest notion of how they actually function. But now that we’re an airplane-owning family, some knowledge of how engines work is mandatory.
My mechanic has been patient with me. Showing me parts and reminding me, time and time again, what their names are. Slowly, ever so slowly, I’m beginning to understand. But as a visual learner, I have a hard time grasping things that I can’t see. And of course, the more of your engine you can see, the more your maintenance bill is going to be!
Rio to the rescue.
During a recent outing to a hobby store, Rio encountered a plastic see-thru engine model kit made by Haynes, who is also apparently the leading publisher of engine how-to-repair handbooks in the real world. The model kit was a hair pricy, but he was keen on it, and I had a flash of inspiration that this might finally give me the look inside an engine that I needed to really understand, not just the nuts and bolts, but how the parts relate to each other; and more importantly, how they dance with each other in a living, breathing engine.
The model came home with us.
It’s a replica of a simple “straight four” internal combustion engine, not very airplane-like, but this is internal combustion kindergarten for us, so we judged it to be good enough. The model took us the better part of a day to build, but it wasn’t overly difficult. All the parts either snapped or screwed on. No glue and no paint!
The manual, which includes a six-page essay called, “How an Engine Works,” was nearly as educational as the model itself, always referring to the parts of the model as if they were real engine components. Pistons, connecting rods, a crankshaft, a sump pan, valve stems, rocker arms, a cam shaft and cams, even a cylinder head gasket!
Of course, beyond “piston,” this was all Greek to me.
Well, not quite Greek. All of these are words I’ve heard before in my life, but like incantations in some ancient magical tongue, they had no substance, no reality for me.
As the model started to come together I was amazed at the detail. The model’s designer must have had a real love affair with engines. There was even a dipstick for the oil level. But there’s more. The motor actually works. Well, in a simulated way. It’s battery powered, and when fired up all the parts of the engine move and run in concert with each other the way they would in a real engine. Electric lights flash in sequence to simulate spark plugs igniting, forcing the pistons downwards, rotating the crankshaft. The valves atop the pistons actually open and close as they would during the intake and exhaust strokes. It’s amazing.
Watching it in action, I was stunned. The internal combustion engine is so simple, and yet so mind-numbingly complex in the same breath. How on earth did humans ever develop such a thing in the first place? As you see it run, it all starts to make sense, but to develop this myriad of systems from scratch?
As I watched the plastic pistons ride up and down through the clear walls of the cylinder block, I envisioned the processes inside Tessie’s old Continental C-85. She too has a four cylinder engine, but of a very different design. Her cylinders, each a separate entity rather than all in one “block” lie flat, two on each side, and each is powered not by one spark plug, but two.
But each cylinder has two valves, just like our model, and her pistons connect to—and drive—her crankshaft, just like our model. Still, I was left wondering, as I watched the flickering lights simulating the sparkplugs on the model kit, what’s the firing order under Tess’s cowl?
I guess I’ll look for a model of an airplane engine…