Radiator technology
Past and Present

About the Benefits
  • Overview
  • Getting rid of the heat
  • Heat - the top end killer
  • More power per cubic inch
  • Better performance and fuel economy
  • Radiator technology - past and present
  • Shock cooling - Problem solved!
  • The secret to achieving longer TBOs
  • Flying faster on the same power - reducing cooling drag
  • Side benefits - Safer cabin heat
  • Dispelling the Myths

  • Copper and brass
  • Liquid cooled aircraft engines are not new. In fact the very first engine flown by the Wright brothers and many of the earliest aircraft engines were water cooled as well as some famous ones that were used during World War II such as the P-51 Mustang, the P-38 and the Lancaster bomber. So why didn't water cooling work for smaller general aviation aircraft? Well, there are at least a couple of reasons; Weight and reliability. However, in addition, the small piston engines that power GA aircraft today were originally developed under military contract to power forward spotter aircraft. The requirements for such engines had to be ease of maintenance and the ability to survive being shot at. Thankfully today, GA aircraft aren't shot at - so why do we still cling to air cooled engine technology with all of its inherent limitations?

    Back in the old days - well over 50 some years ago and even up to the 1980s most radiators were made from copper and brass. These metals were used because they were easy to work with and could be readily soldered or brazed to form the tubes and fins of the typical radiator. The problem is that copper/brass radiators are both heavy and if you vibrate them enough they tended to crack and leak. These were all issues that made it very difficult to use them in light aircraft. Furthermore the old copper/brass radiators were not very efficient from a thermal standpoint. They required large radiators in order to dissipate the heat generated by high powered engines.

  • Aluminum - Lightweight, Small and Super efficient
  • Aluminum radiator technology has been refined to the point were they are standard on virtually all automobiles manufactured since 1985. New manufacturing techniques have been developed that now make it possible to work with aluminum in such intricate structures as a radiator. An aluminum radiator is up to 60% more thermally efficient than a copper/brass radiator and much more durable. Since aluminum is stronger than copper it has been possible to manufacture radiators with even wider tubes offering greater heat dissipation area than any copper/brass radiator could possibly be made to do.

    Aluminum fins can be made in such a way as to substantially increase the amount of surface area that is in contact with the passing air. The best news is the weight. Aluminum radiators weigh less than half of their copper/brass counterparts. The advancements in aluminum radiators technology is one of principle reasons why liquid cooled aircraft engines are again a viable solution.

    In order to properly cool a 180HP, O-360 engine we have found that a 12"x9" by 2 core (each core is 1.5" deep for a total of 3" deep) radiator is all that is required. This radiator weighs 7.75 lbs, dry. It holds 1.5 quarts of water making the total weight 10.75 lbs.

    Since such small radiators are possible, airframe designers can now be creative about where they might locate a radiator within the airframe or even the wings. It is these types of options that open up to airframe designers that are simply not possible with conventional air-cooled engines. One of the reasons that there may be few pusher type airframe designs is the difficulty on cooling an air-cooled engine located at the back of the airframe. With water cooling such a configuration no longer need be a major headache.

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