Air-cooled engines are popular in the aviation industry where greater airflow provides superior cooling negating the need for radiators and coolant.
Car production has featured air-cooled engines over the years with some very successful and reliable designs coming from mainstream and sport car manufacturers alike. Most successful in this area are Porsche who for over thirty years manufactured the 911 using the same basic layout and engine design.
While air-cooled engines can offer weight savings, modern cars need to meet stricter emissions levels something that is easier to achieve with water-cooled engines.
10 Porsche 911 Turbo - Widow-Maker
Up until 1998, all Porsche 911 models featured a variant of the company's famous air-cooled flat 6-cylinder engine, with stricter emissions requirements forcing Porsche to adopt liquid cooling.
Arriving in 1975, as a result of Porsche's racing program, the first 911 Turbo (internally named 930) sported a 3-liter engine delivering 261hp thanks to the addition of the KKK turbocharger. Later models would receive the larger 3.3-liter engine but the 0-60mph time for both would remain the same at 4.9 seconds.
Early 911 Turbos' would earn a bad reputation for oversteer often resulting in accidents gaining the nickname widow-maker.
9 Citroën 2CV - Optional Travel Sickness Tablets Required
Post-war Europe struggling to recover from the financial burdens of war faced a demand for cheap reliable vehicles to help mobilize rural workforces.
With the utilitarian use in mind, Citroen produced the 2CV to be reliable, robust, and cheap to maintain opting for a simple 600cc V2 air-cooled engine producing just 9hp. Adopting the soft torsion suspension setup gave the 2CV its renowned slightly nausea-inducing ride endowing the car with light-off road capabilities.
8 Corvair 500 Sport Coupe - Oversteer In Abundance
Following other designers and adopting a rear-engine layout for the Corvair 500, claiming better passenger ergonimics and improved economy Chevrolet would go on to produce nearly 2 million examples.
Early examples built from 1959 had an air-cooled 2.3-liter flat-six engine producing 80hp, with options of either a 3-speed manual or 2-speed automatic transmission driving the rear wheels. More powerful models were later introduced, but issues with its engine layout and unique suspension setup would attract bad publicity for the poor underload handling issues with oversteer being a major factor.
7 Volkswagen Beetle - Most Successful Peoples Car
Designed before the outbreak of WW2 the Beetle didn't enter into serious production until the late 1940s before deliveries to civilian owners took place. Continuing in production until 2003 over 21.5 million examples had been built in countries around the world.
Early Beetles shipped with 25hp from their air-cooled 1100c engines, with the short stubby exhaust and muffler design responsible for the unique engine note.
On paper the VW Beetle shares many design features with the Porsche 911, both are rear-engined and both are air-cooled, hardly surprising they are the work of Ferdinand Porsche.
6 Trabant 601 - Composite Body and Dated Engine
East Germany's people's car the Trabant launched in 1963, at the time of introduction considered a modern design and would remain in production until 1990.
Filling the need for a cheap reliable and easy to maintain car the Trabant featured a lightweight composite body powered by simple 2-stroke 600cc engine transversely mounted driving the front wheels. Although simple and easy to maintain the engine based on a pre-war design was underpowered with 23hp and quickly became obsolete.
With such a long production life, 2.8 million Trabants were built including the oddly named 2-door coupe officially titled limousine.
5 Porsche 917 - Le Mans Star
One of the most prestigious racing series the Le Mans prototype category has long been one of the fastest racing series in the world.
Constructed on a lightweight tubular space frame chassis, Porsche developed the 917 for the prototype racing series, where excess weight can negatively impact performance. Opting for a mid-engined design the 917 with its air-cooled flat 12-cylinder engine produced 540hp capable of reaching 60mph in 2.5 seconds and reaching a recorded top speed of 225mph - although this figure falls short of the designed 250mph maximum.
Requiring 50 chassis to be built the 917 remains a rare racing car, with the Porsche driven by Steve McQueen in the 1971 Le Mans movie fetching $14 million at auction.
4 Tatra 603 - Quirky Luxury Sedan
Streamlined and uniquely designed, the Tatra 603 continued the company's range of luxury sedans that found popularity among political party members and business leaders.
Early production examples with their unique triple headlight design are easier to differentiate from later models, though all models shared the same air-cooled 2.5-liter V8 engine. Quirky design continues inside the cabin with a separate petrol burning heater residing under the fold-flat front seats.
3 Karmann Ghia - Beetle Mechanicals & Italian Styling
Under the sleek body, the Karmann Ghia shares the same chassis and running gear from VW's series 1 Beetle.
Styling by Ghia and assembled by Karmann from where the car takes its name, designed to supplement VW's product range with a new premium model, launched in 1955. Using the Beetle's 1.2-liter air-cooled engine produced 34hp giving early models a top speed of 75mph, though later models would receive the upgraded 49hp engine.
Produced between 1955-74 VW built 445,000 examples of both the coupe and cabriolet with the former being the more popular choice.
2 Fiat 500 Convertible - First Successful City Car
One of the first small family or city cars ever produced the Fiat 500 arrived in 1957 selling nearly 4 million examples before production ended in 1975
Rear-engined and air-cooled the Fiat's tiny 500c engine produced 22hp coupled with a manual 4-speed transmission, gearing ideally suited for hilly environments reflecting its maximum speed of 59mph. Internally designed to seat four passengers, and even featuring a basic fabric roll-back roof rear seat access is restricted.
1 Morgan Three Wheeler Euro 3 - 21st Century Retro Car
Casual onlookers would assume the Morgan is a restored classic car from the 1940s or 1950s but arrived on the market in 2012.
Despite the modernization of the design Morgan utilize a wooden frame to which they fit a coach-built aluminum body helping to keep weight under 525kgs. Mechanically a more modern approach is used, sourcing the 5-speed transmission from Mazda while power comes from a 2-liter air-cooled S&S engine producing 82hp.
While not particularly powerful the rear-wheel-drive three-wheeler can reach 62mph in six seconds and has a top speed of 115mph.