Combustion engines power a wide range of vehicles, large and small, and scale models are capable of powering RC cars. This little engineering marvel features many of the same parts and processes as a typical car engine, but it’s not a complete powertrain. A new video from JohnnyQ90 on YouTube shows the process of manufacturing a special three-speed manual transmission paired with such a small engine.
Working manual gearbox connected with a Howin L4-172 Nitro RC four-cylinder engine. The four-stroke, 17.2 cubic centimeter engine has a single overhead cam, produces 2.27 horsepower (1.69 kilowatts), and features a powerful, functioning water pump. It weighs 2.6 pounds (1,200 grams) and is intricate, with a reinforced crankshaft, precision-engined rocker arm and camshaft, and is finished in silver and black.
The build process begins by modifying the engine flywheel to accommodate the clutch. The 3D-printed transmission case houses the gears, hiding them from view. However, the case was later modified in the video to reveal it. A servo was added to operate the throttle and gearshift via remote control, and everything was then hooked up for testing.
It takes a little while to start the engine, but it offers great throttle response once it’s started. There is a small cooler link which is easy to fix. It’s also high idle, at around 6,500 rpm, but hits over 14,000 at full speed.
However, the transmission was not perfect. During the test, the third gear dog ring broke, causing the part to be rebuilt with longer teeth. However, that’s not the only mechanical problem with the gearbox. The second tooth dog ring broke the tooth, but that didn’t hinder the operation. It continues to work without problems.
The JohnnyQ90 channel is filled with videos about scale model machines, and this isn’t the first time we’ve covered them. He previously made a two-rotor Wankel engine and a 1/10 scale model with a V8 carburetor. Car culture goes far beyond the new metal on the showroom floor, and that includes RC cars and their elaborate real-world powertrains.
