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Why Rotor, not Propellor?

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Why Rotor, not Propellor?

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Old 12th Feb 2017, 03:22
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Why Rotor, not Propellor?

A propeller is defined as "a device having a revolving hub with radiating blades, for propelling an airplane, ship, etc.", whereas a rotor can refer to many, many disparate things, contained within electric motors to gyros.

How did the helicopter come to have the word "rotor" applied, rather than "propeller"?

The earliest reference to "helicopter rotor" in the aviation press I could find was this article dated 1915.

https://www.flightglobal.com/pdfarch...0-%200266.html

Esoteric I know, and only anorak wearers would be interested.
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Old 12th Feb 2017, 05:27
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Probably the distinction might be that rotor blades are flexible, as opposed to propeller blades which are (mostly) stiff and better fit the description of a gyro that id so often used.

Phil
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Old 12th Feb 2017, 05:44
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The "auto gyro" was the first flying fling wing, and that was 100+ yrs ago.( january 9th, 1923 )
Many earlier attempts were bogged down trying to understand the dynamics etc, then "teetering" was discovered. The rest is history.

From gyro's bigger things grew.......helicopters were the next step.
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Old 12th Feb 2017, 06:03
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A helicopter is a "rotary wing" aircraft. Hence rotor.
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Old 12th Feb 2017, 06:05
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technically, "rotor" is a set of rotating wings. The propelling effect is a by product of an imbalance force component of the "rotating wings"
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Old 12th Feb 2017, 06:18
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technically, "rotor" is a set of rotating wings
But so is a propeller.
A helicopter is a "rotary wing" aircraft
Understood, but what is the etymology of the term?
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Old 12th Feb 2017, 06:55
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Propeller is fixed or variable pitch blade bolted onto a Stiff-Wing ......a Rotor on a Rotor-Craft is lump of metal/plastic thingamabob that can cyclically tilt the disc in a desired direction with the Cyclic Shtick & also have the pitch angle of attack collectively changed by the Collective lever/club (apparently)

Last edited by Vertical Freedom; 12th Feb 2017 at 07:07.
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Old 12th Feb 2017, 08:37
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Originally Posted by megan
But so is a propeller. Understood, but what is the etymology of the term?
The propelling effect is a by product of an imbalance force component of the "rotating wings"
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Old 12th Feb 2017, 09:17
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The etymology is the irregular shortening of "rotator".
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Old 12th Feb 2017, 09:32
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Originally Posted by megan
But so is a propeller.
A rotor (wing) produces lift, a prop(ellor) produces thrust, non?
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Old 12th Feb 2017, 09:48
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Er or Or, either spelling appears to be correct.

I say potayto you say potarto
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Old 12th Feb 2017, 10:06
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The "auto gyro" was the first flying fling wing, and that was 100+ yrs ago.( january 9th, 1923 )
Have I just had a long sleep, or something?
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Old 12th Feb 2017, 10:23
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a propeller is locked on his axis only ..... The rotor can move around
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Old 12th Feb 2017, 11:31
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So at the rear we have the tail propeller 😁

R
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Old 12th Feb 2017, 14:47
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Tail Rotor

Originally Posted by RINKER
So at the rear we have the tail propeller 😁

R
The "Tail Rotor" resists the torque of the main rotor.
It does not contribute to the forward thrust of the machine.
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Old 12th Feb 2017, 15:17
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For what it's worth...

I seem to recall the following:

Back when "aeroplanes" were being developed, those of the nautical majority had extreme power. Hence the use of a number of nautical terms in aviation: ballast, engine deck, waterline, propeller, and el piloto. After all, these insignificant aircraft were to support naval dominance.

Fast forward and by the time Igor was making headway developers were free to use other terms based on function rather than nautical legacy.

On the flip side, I've read somewhere that a "propeller" provides thrust parallel to the fixed longitudinal axis of a vessel/aircraft and any other thrust provider is not a "propeller."

Lastly, I think this version came from a helicopter design white paper that a "aerodynamic rotor" was an assembly of field removable components and a propeller was a single component.

It is what it is. I'm just glad they didn't go with the word "fan" like some engine people did with the turbojet vs. turbofan.

W1
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Old 12th Feb 2017, 15:25
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It does not contribute to the forward thrust of the machine.
Unless its going sideways.
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Old 12th Feb 2017, 15:48
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Latin Origin

propellare to drive forward

rotare to turn
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Old 12th Feb 2017, 17:05
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Originally Posted by TURIN
Unless its going sideways.
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Old 12th Feb 2017, 17:33
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Flight Controls Perspective

Working as an engineer in both flight controls and propulsion I have used this discriminator:

If it's primary purpose is solely for propulsion and it dose not have a means for high frequency blade pitch control it is a propeller.

If it's primary purpose is either solely flight control or equally flight control and propulsion, plus it is equipped with a means for high frequency blade pitch control it is a rotor.

Note that on small quad copters that use variable rpm they are called propellers. But on quad copters with collective pitch control they are called rotors.

CTR
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