Editing Radial engine (section)

==Comparison with inline engines==
[[File:Monaco-Trossi1935.jpg|thumb|The 1935 Monaco-Trossi race car, a rare example of automobile use<ref>{{cite web|title=MONACO - TROSSI mod. da competizione|url=http://www.museoauto.it/website/en/component/content/article/40-monaco-trossi/57-monaco-trossi-mod-da-competizione|work=museoauto.it|access-date=10 November 2016}}</ref>]]

Liquid cooling systems are generally more vulnerable to battle damage. Even minor shrapnel damage can easily result in a loss of coolant and consequent engine overheating, while an air-cooled radial engine may be largely unaffected by minor damage.<ref>{{cite book |last=Thurston|first=David B.|author-link=David Thurston|title=The World's Most Significant and Magnificent Aircraft: Evolution of the Modern Airplane| publisher=SAE| year=2000|page=155| url=https://books.google.com/books?id=7HTPRym0iYIC&pg=PA155| isbn =0-7680-0537-X}}</ref> Radials have shorter and stiffer crankshafts, a single-bank radial engine needing only two crankshaft bearings as opposed to the seven required for a liquid-cooled, six-cylinder, inline engine of similar stiffness.<ref>Some six-cylinder inline engines used as few as three bearings, but at the cost of heavier crankshafts, or crankshaft whipping.</ref>

While a single-bank radial permits all cylinders to be cooled equally, the same is not true for multi-row engines where the rear cylinders can be affected by the heat coming off the front row, and air flow being masked.<ref>{{Cite journal|last=Fedden|first=A.H.R.|author-link=Roy Fedden|title=Air-cooled Engines in Service|journal=Flight|volume=XXI|issue=9|pages=169–173|date=28 February 1929|url=http://www.flightglobal.com/pdfarchive/view/1929/1929%20-%200433.html}}</ref>

A potential disadvantage of radial engines is that having the cylinders exposed to the airflow increases [[drag (physics)|drag]] considerably. The answer was the addition of specially designed cowlings with baffles to force the air between the cylinders. The first effective drag-reducing cowling that didn't impair engine cooling was the British [[Townend ring]] or "drag ring" which formed a narrow band around the engine covering the cylinder heads, reducing drag. The [[National Advisory Committee for Aeronautics]] studied the problem, developing the [[NACA cowling]] which further reduced drag and improved cooling. Nearly all aircraft radial engines since have used NACA-type cowlings.{{refn|group=Note|It has been claimed that the NACA cowling generated extra thrust due to the [[Meredith Effect]], whereby the heat added to the air being forced through the ducts between the cylinders expanded the exhausting cooling air, producing thrust when forced through a nozzle. The Meredith effect requires high airspeed and careful design to generate a suitable high speed exhaust of the heated air – the NACA cowling was not designed to achieve this, nor would the effect have been significant at low airspeeds.<ref name=becker>Becker, J.; [http://www.hq.nasa.gov/pao/History/SP-445/ch5-5.htm ''The high-speed frontier: Case histories of four NACA programs, 1920- SP-445, NASA (1980), Chapter 5: High-speed Cowlings, Air Inlets and Outlets, and Internal-Flow Systems: The ramjet investigation]</ref> The effect ''was'' put to use in the radiators of several mid-1940s aircraft that used liquid-cooled engines such as the [[Supermarine Spitfire|Spitfire]] and [[North American P-51 Mustang|Mustang]],<ref name="document p24">Price 1977, p. 24.</ref> and it offered a minor improvement in later radial-engined aircraft, including the [[Focke-Wulf Fw 190|Fw 190]].}}

While inline liquid-cooled engines continued to be common in new designs until late in [[World War II]], radial engines dominated afterwards until overtaken by jet engines, with the late-war [[Hawker Sea Fury]] and [[Grumman F8F Bearcat]], two of the fastest production piston-engined aircraft ever built, using radial engines.