Also in my garage: miniature aircraft engines

Features
 | 1 Mar 2023
Classic & Sports Car – Also in my garage: miniature aircraft engines

You don’t need to convince John Rounce of the beauty of small things.

Not only has the retired engineer owned his MG Midget since 1976, but he’s spent thousands of hours handcrafting tiny engines for model planes.

By day, John maintained radio and radar systems on passenger jets for AirUK (later KLM uk), then spent his evenings attending metalwork and aero-modelling classes.

Classic & Sports Car – Also in my garage: miniature aircraft engines

John Rounce’s MG Midget was in daily use between 1976 and 1981

“It started when I was 14 or 15 and went to a model display at the park,” he recalls. “The engines fascinated me from day one – I loved all the noise.

“I went to evening classes to do metalwork, and most people there were doing some sort of model engineering.

“You start to think, ‘I’m going to get a lathe at home and do more of this.’”

We’re chatting in one of his sheds, and there is indeed a lathe, a milling machine and a bench grinder, the tools required to create the 2.5cc, single-cylinder two-strokes needed to give flight to all the model aircraft dotted about the place.

Classic & Sports Car – Also in my garage: miniature aircraft engines

Railways sets share shed space with John’s tiny engines and model planes

By his mid-20s he had completed his first engine, which ran on a mix of methanol and oil.

“When I was at evening school I did some casting and made five or six crankcases out of what was a Dolomite Sprint cylinder head,” he says.

John pored over magazine articles with titles such as ‘How I Made an Engine’ to help him painstakingly machine small pistons, rings, conrods and carburettors, before running the engine on a testbed.

Classic & Sports Car – Also in my garage: miniature aircraft engines

It takes John about 120 hours to produce each engine

He recalls the feeling of “absolute elation” the first time one of his tiny feats of engineering successfully launched a model into the sky.

“It still is,” he laughs. “When I go to the model field now, start one up and get it to fly I just think: ‘I’ve made all of this.’”

There was much trial and error in the early days, and John points at the blue model he first constructed in the 1990s, Lazy Daze.

“At times it didn’t have enough oomph,” he recalls. “You’d change the cylinder head, increase the compression ratio, modify the port and have another go until it stayed in the air.”

Classic & Sports Car – Also in my garage: miniature aircraft engines

John’s Midget is powered by a modified 1275cc A-series engine

Each engine makes up to half a horsepower and takes about 120 hours of machining, polishing and honing.

“After years and years, you know what will work and what won’t,” says John, now 65 but as committed as ever to both model planes and his ‘round-arch’ 1972 Midget.

The MG was in use between 1976 and 1981, when a slipping clutch consigned it to the garage until a restoration that was finished in 1999.

“I couldn’t sell it,” he says. “I’m quite sentimental. I like to hang on to things, and the longer you’ve had it the less likely you are to get rid of it.”

Classic & Sports Car – Also in my garage: miniature aircraft engines

Mechanical gremlins meant John’s MG Midget spent most of the 1980s and ’90s in a garage

While it was off the road, John turned his attention to something inspired by a project in the pages of Cars and Car Conversions.

The aim was to produce a 1275cc A-series engine for a Mini that was capable of 100bhp at the wheels. Using a donor engine from an Austin 1300 – transverse, like the Mini – he got to work.

“I got to a point where I thought: ‘I’ve got a car sitting in the garage that needs doing, and is the Mini ever going to happen?’ So I decided, ‘No, I’ve got to make this fit the Midget.’”

Classic & Sports Car – Also in my garage: miniature aircraft engines

John in his element: the beauty of making tiny engines is that you can cram in so much other stuff besides…

This meant converting the block from transverse to in-line: “You can do it with a bit of ingenuity.”

He made it fit, and the engine – bored out to take Triumph pistons, with a lengthened stroke and offset crank – is in the Midget to this day.

And does it produce the target 100bhp?

“I can’t imagine I got anywhere near the aims of the project engine,” he smiles. “But it’s all my own work, and that gives me gratification.”

Words: Matt Ware

Images: Simon Finlay

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