In the modern aviation context, is the word "supercharger" generally assumed to mean a gear-driven system rather than an exhaust-driven system?

At one time the word "supercharger" often was used to encompass both turbosuperchargers (aka turbochargers) which were exhaust-driven, and gear-driven superchargers. But I have seen the word "supercharger" used to specifically mean a gear-driven system as distinct from an exhaust-driven system. Would this usage be generally considered unambigous and good practice in the modern aviation context? Or at least, very common practice in the modern aviation context?

(Include belt-driven along with gear-driven, if such a thing even exists in aviation engines. The question is about exhaust-driven versus mechanically-driven devices, and how these two different sorts of devices map out against the various terminology in current aviation use.)

A supplemental question might be: "Has the word 'turbosupercharger' completely disappeared from modern aviation terminology?"

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    $\begingroup$ Having been in the "tuner" world for a long time, I've never heard of a supercharger being referred to as both a gear driven device and an exhaust driven one. $\endgroup$ – Ron Beyer Oct 31 '19 at 19:27
  • $\begingroup$ Sounds like you are well qualified to answer, perhaps. - Is "tuner" an automotive reference or an aeronautical one? $\endgroup$ – quiet flyer Oct 31 '19 at 19:28
  • $\begingroup$ I'd agree with @RonBeyer. From an automotive perspective, a "turbocharger" is exhaust driven while a "supercharger" is gear/belt driven, and nary the twain shall meet. There are some variations of "twin-charger" (or similar name) which has a supercharger for off-the-line power and a turbocharger for once you're moving. The supercharger saps a lot of horsepower to make even more, while the turbocharger is nearly free power. And yes, "tuner" as in "automotive tuner". $\endgroup$ – FreeMan Oct 31 '19 at 19:33
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    $\begingroup$ A modern top fuel dragster's supercharger can take upwards of 1000HP to drive it. But it returns significantly more. </OT musings> $\endgroup$ – FreeMan Oct 31 '19 at 20:03
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    $\begingroup$ If you want to have fun, look up "turboencabulator" and watch some of the videos. $\endgroup$ – Ron Beyer Nov 1 '19 at 2:32

"Turbosupercharger" was General Electric's official term for their system, probably the first mass produced turbocharging system and was used on a range of US fighters and bombers (the system was very sensitive to back pressure in the turbine outlet which could promote stalling, and so they either had the turbine exposed like on the P-38, or if there was an exhaust duct it was very very short).

Anything that compresses the intake charge is a supercharger. Prior to the GE system, they were all mechanically driven and the mechanical drive naturally had horsepower losses associated with that type of drive. GE added the word turbo to differentiate between the common gear driven or direct driven supercharger and their new and novel system that eliminated most of the energy losses from compressing air.

Move forward into the post war era and the adoption of systems to cars and light aircraft and people get annoyed having to say this pain in the butt 6 syllable word and start to cut out the "super" part, because it doesn't really detract from the meaning, and there you are with "turbocharger" for both cars and airplanes.

Meanwhile, "supercharger" stays as it always was and remains associated with mechanical systems, because the terms, although incomplete technically, don't contradict each other on common usage they continue.

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  • $\begingroup$ Nice answer but I would like to know how early the GE system was introduced, would be a nice addition to the answer. Was it really the earliest turbocharger? I'm sure I've seen photos of turbochargers on aircraft from the '20's. OK you didn't say it was the earliest turbocharger; isn't it possible that "turbosupercharger" was already used for for very early non-GE systems? If so would be worth noting in answer. $\endgroup$ – quiet flyer Oct 31 '19 at 20:40
  • $\begingroup$ As a mass produced production system, yes. Late 30s. I stumbled onto a link to a GE pamphlet and added it at the top. $\endgroup$ – John K Oct 31 '19 at 20:43
  • $\begingroup$ Got it; see slight tweak to comment. $\endgroup$ – quiet flyer Oct 31 '19 at 20:45
  • $\begingroup$ Not aware the details of earlier turbocharger systems, but I refer to "mass production" as something that had become common enough to filter into the public consciousness, as opposed to low volume or experimental systems developed prior. $\endgroup$ – John K Oct 31 '19 at 20:48
  • $\begingroup$ The GE turbosupercharger was developed in 1917 and was the product that moved GE into aviation. From the GE Aviation Blog. $\endgroup$ – Gerry Oct 31 '19 at 21:09

Don't forget turbonormalizer - a turbocharger that only boosts to sealevel pressure. Seen on small planes.



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  • $\begingroup$ And then there's always turbocompound... $\endgroup$ – quiet flyer Oct 31 '19 at 22:49
  • $\begingroup$ Never seen on small planes! $\endgroup$ – quiet flyer Oct 31 '19 at 23:35

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