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An aviation expert reminded me that a propeller is a wing.

While I understand that propellers use similar principles to generate force, it muddied the definition of a rotary wing aircraft vs a fixed wing aircraft. If the propeller of a fixed wing aircraft is considered a wing, what is the distinction between the two? Is it how much surface area each type of wing works on? Is it the direction of force?

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maybe you should either rephrase the title or the question since the title states that you want to know whether a propeller is a wing or not, and the first sentence says that an aviation expert reminded you that it was. ;-) –  flyingfisch Mar 7 at 22:03
    
It depends what you mean by 'is'. Is a tomato a fruit? –  AakashM Mar 11 at 13:01

5 Answers 5

up vote 12 down vote accepted

I think most people would say the answer is no. Consider the dictionary.com definition as it relates to Aeronautics:

9. Aeronautics . a. one of a pair of airfoils attached transversely to the fuselage of an aircraft and providing lift. b. both airfoils, taken collectively.

The wings are the big airfoils which are responsible for generating most of the vertical lift.

A colloquial test of this definition would be to grab a CFI and ask him/her to "point out the wings on this airplane to me." They won't point out the propeller. (Not a scientific experiment)

However, both wings and propellers are airfoils (and so are the other wing-like surfaces such as the vertical and horizontal stabilizers). You might get some disagreement about whether those other surfaces are wings, but I believe the answer is still no. There is nothing to be gained by calling them wings, and only leads to ambiguity. We already have a word which describes lifting surfaces in-general, and again, it's airfoil.

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What about helicopters, which are commonly referred to as "rotary-wing aircraft"? Just because the airfoils are not attached to the fuselage doesn't mean they aren't wings. –  egid Mar 7 at 23:26
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@egid Well, I've never heard rotary-wings simply referred to as wings before, but it's possible. People call them rotors or rotorwings. Again, the word "wing" already has an understood meaning which we apply to airfoils intended for vertical lift. So my point was that I don't see any advantage in making the word "wing" ambiguous when we already have the word "airfoil" for that purpose. However, we are ultimately arguing over definitions which is perhaps too opinionated for the site anyway. –  Bret Copeland Mar 8 at 0:21

Is a propeller a wing? Maybe. It depends on how pedantic you feel like being about your definitions.

A propeller is certainly an airfoil (usually several of them - each blade is an airfoil, and you can have one blade, two, three, four, or more attached to a hub).

A wing is also an airfoil.

Aerodynamically a wing and a propeller function the same way: Air moves over the surface of the airfoil(s), producing "lift". In the case of the wing the lift is mainly vertical and we call it "lift", while in the case of a propeller it's mainly horizontal and we call the resulting force "thrust" instead.


My two cents, ignoring all the dictionary pedantry? A propeller is an airfoil, but it is not a wing.

Why? Simple:

If I'm flying along and my propeller magically vanishes I'm now flying a really inefficient glider.
My day is ruined and when I catch the guy with the genie-in-a-lamp who wished my propeller away I'll probably beat them up, but I have a fair chance of putting the aircraft on the ground without killing myself or anyone else.

If I'm flying along and my right wing magically vanishes the genie-posessing miscreant is safe as I'm almost certainly going to die. All the lift from the remaining wing is going to try to flip the aircraft over, and I'm nowhere near skilled enough to keep control with a missing wing and land safely.

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Regarding the "mud" this may throw on the definition of rotorcraft, bear in mind that rotorcraft are already pretty muddy (and I still personally believe that helicopters fly by black magic). A helicopter losing its entire rotor (all of the blades) is like an airplane that lost both wings (i.e. "A ballistic projectile."). One that loses a single blade is like an airplane that lost a propeller blade ("Probably going to tear itself apart from the unbalanced forces, becoming multiple ballistic projectiles"). A decidedly hybrid situation. –  voretaq7 Mar 8 at 0:30
    
You ought to be flying a superb glider instead, anyway :D –  yankeekilo Mar 8 at 17:10

An aviation expert reminded me that a propeller is a wing.

This is not false- a wing generates lift by creating a pressure difference, in the same way a propeller does. Wing typically refers to the structure lifting the main weight of the aircraft, while a propeller generates thrust, so from definition it's probably incorrect, from a theoretical standpoint it's the same principle.

While I understand that propellers use similar principles to generate force, it muddied the definition of a rotary wing aircraft vs a fixed wing aircraft.

A fixed wing aircraft will move at speed to generate sufficient lift to get airborne. A helicopter will be able to lift off vertically by spinning the blades quickly enough, which will have the same effect as moving forward.

If the propeller of a fixed wing aircraft is considered a wing, what is the distinction between the two? Is it how much surface area each type of wing works on? Is it the direction of force?

Propeller thrust is directed forwards. In level flight it contributes very little to lifting the plane up- that's left to the wings to do.

Rotary wing aircraft's blades do really work as a propeller: By increasing the angle of attack on one side, you generate more thrust, and the helicopter flies in the direction you want it to, since there's a force vector in that direction.

heli

Distinction between the two: Rotorcraft generate the thrust to lift off themselves. A propeller generates the thrust (and in turn speed) necessary to create lift over fixed surfaces.

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Since no one else mentioned this, I thought I would. Wilbur Wright, of the Wright brothers, said that a propeller was nothing more than a twisted wing.

If you accept his analogy, then the twisted wings that compose a propeller are clearly specialized wings, but they do generate a differential in air pressure above/in front of and below/behind as the surface moves through the air. That is what a wing does.

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After doing a little more research, I have come to the conclusion that the answer is probably no. Since wings produce lift, I would argue that a propeller is not a wing since it does not produce lift, but thrust.

Since thrust is pretty much always perpendicular to lift, I can't see how the propeller would ever actually produce lift.

lift,thrust

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A propeller does generate lift. A propeller can even stall depending on its angle of attack just like any airfoil. Thrust is simply a direction of the force, not the cause of it. In the case of a propeller-driven aircraft, the thrust comes from the forward lift generated by the propeller. In the case of a jet or rocket engine, thrust would come from expelling hot matter at a high velocity. –  Bret Copeland Mar 8 at 0:26
    
@BretCopeland eh, I beg to differ. Why do fighter pilots talk about their lift vector, which is usually perpendicular to the wing? –  flyingfisch Mar 8 at 0:29
    
In a typical airplane the propellers are perpendicular to the normal wings, so the "lift" direction of that propeller blade is aimed towards the front of the plane, perpendicular to the "lift" direction of the fixed wing. –  Peteris Mar 8 at 0:59
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@flyingfisch You are using all the wrong analogies. Consider a propeller driven aircraft climbing vertically. Is the lift generated by the wings now opposing the weight? Where is the "lift vector"? –  Simon Mar 8 at 17:58

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