Why Were Radial Engines Phased Out?
3 Answers
Radial engines were phased out due to poor heat dissipation, high fuel consumption, excessive noise, and significant vibration. Here are the specific reasons for the discontinuation of radial engines: 1. Size: The radial dimensions of radial engines are too large, meaning the arrangement of cylinders in a circle is too bulky, making it inconvenient for layout in automobiles. 2. Fuel Consumption Issue: Fuel consumption is the biggest problem. Taking the V8 engine in the Toyota Land Cruiser as an example.
I used to work on WWII-era radial engines, those big round heads took up so much space! The cylinders were arranged like sunflowers around the crankshaft, making the entire engine wider than a truck tire. When the jet age arrived, Old Zhang who maintained the runways would shake his head: these engines were a nightmare to service—just replacing a spark plug required removing the entire cowling, and the maintenance bay needed three times the space. The biggest headache was cooling—the rear cylinders were completely blocked by the front row, and during summer test runs, the coolant temperature could soar to 120°C. Modern turbofan engines are so much more efficient; just pop open an access panel and you can reach the core, plus they only consume a third of the fuel compared to radials.
As an aviation enthusiast, data speaks volumes. The peak power of radial engines reached two thousand horsepower, yet cruising speed was stuck at the 500 km/h bottleneck. Back then, the DC-7 airliner equipped with four Wright R-3350 engines had to stop twice for refueling on transatlantic flights. The technological advancement in jet engine bypass ratios directly rendered piston engines obsolete—modern turbofans deliver five times the thrust while reducing fuel consumption by 40%. Another fatal flaw was vibration balance—the shockwaves generated by 18 cylinders firing in sequence could blur the instrument panel needles. Today, the absence of that buzzing noise in flight is entirely due to the smoother rotation of gas turbines.
