Comment by tofof | Hacker News Reader

Comment by tofof | Hacker News Reader

My uncle worked at Estes, the hobby rocket company, for many years. He was always a stickler about calling the black powder propellant sources "motors" and indeed older motors are labeled such. [1] He insisted they were not engines as they had no moving parts and would always correct me when I said "rocket engine." He eventually explained that rocket engines exist, but they are engines with valves and pumps and use liquid fuel (e.g. the Saturn V's F-1 engines), while solid rockets (e.g. Estes' products, or the shuttle's SRBs) are simply motors since they merely consist of burning propellant and a nozzle. Indeed the wiki pages for the F-1 and the SRB are consistent in calling the former engine and the latter motor.

However, at some point since he retired, Estes transitioned to calling them Engine/Motors [2], and now, the primary labelling Estes uses calls them Engines, though Engine/Motor is still printed on the cardboard casing itself. [3]

Interestingly, the Spanish, French and German on the motors still use motor, as Motor, Moteur-Fusee and Raketenmotor, respectively.

Because of that upbringing, I have since treated the words to mean that a motor is something that provides force of motion (thrust or rotation) - it may or may not also be an engine, as in the rocketry examples. An engine is a contraption with moving/interacting parts that uses energy to accomplish some goal - that goal may (F-1, car engine) or may not (cotton gin, search engine) be the propulsion of the contraption itself and what it's attached to.

That said, as a child I made no such distinction, hence the frequent corrections. I am happy to recognize that in common vernacular they are usually synonymous, though it would still sound strange, I think, to call something a 'search motor' (edit: however, see comment by yau8edq12i !) or a 'graphics motor' just as it would be jarring to encounter 'servoengine'.

1: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi...

2: https://www.apogeerockets.com/bmz_cache/f/f8ecac9604d017a5c7...

3: https://estesrockets.com/products/b6-4-engines

A friend who studied engineering at MIT made a similar distinction, and it's where I expected the article to go, being hosted there.

The notion was that the development of engines, as opposed to simpler motors and mechanical systems, had required a net set of skills that led to a recognizably different discipline. More systematic, more concerned with dynamics and feedbacks, cross-disciplinary to materials and machining techniques, more data driven, more advanced mathematic and analytic techniques in support of these. The sense was simpler mechanical systems were more linear and engines were highly non-linear, and required a different mindset to approach.

I like the distinction and appreciate the different terms.

Electric motors have moving parts and at least where I am nobody would call one an electric engine.

Automobiles generally have engines, but motor isn't uncommon for (internal combustion) engines there either. Motor car is something I remember my grandfather saying although I guess that's not really used anymore, but motorbike certainly is. So is motorsports. "Blown motor" is a pretty common phrase for an IC engine that has stopped working due to damage.

Engine has some exclusive cases where motor does not substitute. Jet engine and steam engine come to mind.

Depends on what you consider part of the motor. Linear electric motors directly apply force to something else like a train car without themselves having moving parts.

>Electric motors have moving parts and at least where I am nobody would call one an electric engine.

Second this. In photography, the little electric drive motors inside camera lenses are never called engines, though they definitely do have small moving parts.

Yes, but in the marine realm they are consistently called outboard motors and not outboard engines.

French uses "Moteur" because it doesn't have a word for "engine". The closest is "engin", but that means "contraption" and generally applies to the entire class of "large mechanical devices that move".

Both Motor and Engine are generally translated into french as "Moteur"

Same in all latin languages I think. One word for both motor and engine. In spite of having a word for 'engineer'.

Same in Dutch (a Germanic language).

Then again, we colloquially call both a motorcycle and its engine “motor”.

Interesting, I was surprised to learn this fact from you!

"engineer" in French is ingénieure (feminine) and ingénieur (masculine).

And putting "ingen" into google translate returns.. engineer.

Edit: @euroderf: Lol

So how do these relate to ingénue ?

The word in Germanic that is used closest to "engine" would be maschine/maskin/ ... and so on.

It is called motor with respect to its effect, and machine with respect to how it works. A machine is called motor to denote it is connected to wheels or propellers, but service or repairs are technically performed on the machine.

This distinction can sound a little old-fashioned now.

As for German, there isn't really an equivalent for engine, even combustion engines are called (Verbrennungs)Motor.

Rocket and jet engines are sometimes called Raketentriebwerk and Turbinentriebwerk respectively.

But this has the meaning of something providing propulsion.

A steam engine is called Dampfmaschine (steam machine), though more recent designs are called Dampfmotor (steam motor) instead.

It also has to do with the "heat engine," and particularly the Stirling engine, and the related carnot cycle. An engine transforms heat to extract work.

A rocket motor has the expansion part of a heat engine in an obvious way. An electric motor produces motion, but isn't an engine.

Out of curiosity, what do you think your uncle would have said that the magazine Motor Trend (first published 1949 according to wikipedia) is about, or what types of vehicles use a motorway, or what the going concern of the Ford Motor Company is?

Or was it more one-directional, such that engines can be called motors but motors should not be called engines?

So, the disciplines are called engineering and motoring, and the practitioners are called engineers and motorers? ;)

Reply on news.ycombinator.com