Talk:Propeller/Archive 1

Archive 1

Additions requested

Sirs,
A very good article on propellors but two additions should be made to this page.

1. Reversable propellors ( to brake the aircraft ) were developed after the Second World War
2. Early variable-pitch propellors had only two settings, fine for take off and coarse for cruise, and had to be "set" on the ground (with air pressure) and could only move to course once by pilot control. —Preceding unsigned comment added by 216.192.158.129 (talk) 07:15, 8 January 2004

Should the Harvard trainer be mentioned somewhere? The tips of the propeller were supersonic, which made for a great deal of noise, especially to an observer in the plane [pun unintentional!] of the propeller disc. 81.130.91.115 09:52, 16 July 2007 (UTC)

Hmmm. There's a whole lot about aircraft propellers and not much about ships/submarines.

Nojer2 18:45, 19 Feb 2004 (UTC)

Feel free to add to it! which I notice you're doing. —Morven 19:05, 19 Feb 2004 (UTC)

Don't know how wikipedia works too well, but it looks like this article has major terminology problems. Check out nasa (http://history.nasa.gov/SP-367/f78.htm) for the definition of "angle of attack", "helix angle" and "pitch angle". They do not match what is described throughout this article. -Ryan Bavetta —Preceding unsigned comment added by Bavetta (talk • contribs) 06:43, 31 October 2008 (UTC)

Correction to Section 'Propeller Thrust' - if the propeller were a complete screw, it would be a multi-thread screw with n threads (i.e. blades) and the 'ideal' advance rate would be nNP if P is the blade pitch ('thread' to 'thread' axial distance). Is this right? This definition of blade pitch aligns with the 'screw thread pitch' page, but not 'blade pitch' page, which says that blade pitch is an angle not a length. I agree the article is a good start but terminology should be tighter, and the 'analytical' sections more explanatory.LaxeyStu (talk) 13:19, 28 December 2010 (UTC)

Re-write/re-organization needed?

This page is a mess, with a lot of general propeller info in the airplane section, a lot of of historical info in the ship/sub section, and a mish-mash of more and less technical parts. I made a quick pass at improving the introductory paragraph, but could use some help or suggestions to improve the rest of the page in a coherent way.

knotnic 00:15, 7 Aug 2005 (UTC)

A horrible mess, the history section for starters. Archimedes' screw is in no way related to the propeller, nor are sculling, windmills or even the turbine related to the development of the propeller.Jmackaerospace 01:50, 6 September 2006 (UTC)

Mriswith (talk) 02:18, 27 October 2009 (UTC)

This article really is falling part history-wise. There is not a single mention of Bamboo-copter(also known as a "Chinese top"). Which [presumably] predates Da Vinci's and other more well-known designs([1]). Some say that it may even stem from before the Archimedes'_screw(as early as 400BC, but I have no reliable sources on that).

[2] www.aviastar.org/history/index.html

THIS ARTICLE IS TOTALLY BIAS. THERE IS NOT ONE NEUTRAL OR BALANCED WORD IN THIS ARTICLE. SOMEONE SHOULD LEARN SOME DIPLOMACY. —Preceding unsigned comment added by 130.113.32.136 (talk)

Screwed?

The ship's propellor was also affected by the ability to move machinery lower in the hull, which was a factor in naval battle damage. The variable-pitch airscrew is credited to several people; let me pitch for Canadian Wallace R. Turnbull, 7 Feb 1922, at Rothesay, NB. And another Canadian, John Patch (Yarmouth, NS), in 1833 invented a paddle/oar, & in 1849 a double-acting variant that was more efficient than contemporary screws. Trekphiler 05:22, 8 December 2005 (UTC)

"Propellor Walk"

I am thinking that this segment needs to be shortened and simply pointed to the article it refers to. The more I look at it the more it feel out of place. It is more "Seamanship" than a technical item on propellers. I'll think some more and do this in a while. Fiddle Faddle 10:38, 2 May 2006 (UTC)

It is well covered in its own article. Moved to "see also" as a link. Another small step towards clarity Fiddle Faddle 19:57, 8 May 2006 (UTC)

"Wing-axis prop"

I have been looking everywhere for an article on experimental lateral-axis (wing-axis) props. I saw a prototype which had a prop inside the leading edge of the wing, and worked by pushing air over the top of the wing along the wing's length. This system provides lift with zero airspeed, but flies like an airplane. This system shows promise as a VTOL propulsion system, or as part of a "flying car," so is significant.

What you're talking about is, like a vertical axis wind turbine,cyclogyro/cyclocopter ,fanwing, or the Voith-Schneider propeller pic on the article page.. there's a lot of confusion with those types, in all fields they should be called transverse axis- acros the flow, insted of calling is something new making it harder to draw these connections... Also notice that the fanwing is just producing [magnus effect|magnus lift] and that a variable pitch blade on a cyclo-thing really just amounts to flapping like a bird/bug/bat. --Sukisuki 20:44, 27 October 2006 (UTC)

Cavitation Damage

I've added an image of the type of damage that can occur to a propeller operating under cavitating regime. Axda0002 23:03, 20 May 2006 (UTC)

"Aeroplane"

I really do say! "Aeroplane" is not "weird" - it is British! --Profero 18:25, 1 June 2006 (UTC)

"Don't call me Shirley." Trekphiler 12:31, 6 October 2006 (UTC)

Hey! It's not just British. I'm Aussie and I say "aeroplane" too. Dr algorythm 09:12, 9 June 2007 (UTC)

Unscrewed

I deleted this:

"Submariners call the propellers on submarines 'screws'."

It's not limited to sub sailors; navy men around the world do in reference to ship propellors; sonar operators shipboard, heliborne, or submarine will report "screw noise". My problem was how to phrase it; "navy men" seems awkward, "professional sailors" seems to imply civilians aren't. Anybody that can come up with a better way, please rewrite & restore. Trekphiler 12:31, 6 October 2006 (UTC)

... and it's not just the military: TSDY translates to Twin Screw Diesel Yacht. 81.130.91.115 09:52, 16 July 2007 (UTC)

'Screw' is/was the correct technical term for any kind of screw propeller, it's just that the more general term 'propeller' is used more often in non-technical circles. Originally it was 'screw propeller'. That's also why 'SS' in ship designations originally stood for 'Screw Steamer', as opposed to 'PS' for 'Paddle Steamer'. Later 'SS' was taken to mean just 'Steam Ship'.

This is also the reason that aircraft propellers were originally termed 'air screws' such as: The Metal Airscrew Company. — Preceding unsigned comment added by 80.4.57.101 (talk) 13:21, 28 February 2012 (UTC)

Axial speed vs Rotational speed

What's the difference? I know Rotational speed must be RPM; So is axial speed the distance WRT time that a point on the prop covers? Am I the only layman where this required significant contemplation of these terms? :-) —The preceding unsigned comment was added by 59.167.221.55 (talk) 17:34, 10 December 2006 (UTC).

"Feathered position" and "Feathering"

If anyone gets around too revising the section on aviation, it would be great to include a sentence or two about "feathering". I came across a reference to this in the article on the Bay of Pigs Invasion of all places, and was curious about what it meant. The best I could do was find a brief sentence in the disambiguation page for feather. I came to this page and found it mentioned in the caption to the picture of the Hercules props in the aviation section. But the associated text makes no mention of what feathering or the feathered position for props actually is! Dr algorythm 09:12, 9 June 2007 (UTC)

How did we miss that. Photo and text added. Meggar 16:28, 9 June 2007 (UTC)

Sculling

The mention of single-oar sculling in the History section should be explained or qualified. Doesn't this method of propulsion rely mostly on vortex shedding, similar to the way insects such as bumblebees produce lift? The modern aircraft propeller or ship's screw is actually a rotary wing, and produces lift in accordance with Bernoulli's principle. —Quicksilver^{T @} 19:28, 14 August 2007 (UTC)

As someone who single oar sculls, the vortexes seem to be coincidental. Motive force is created by the sweep slicing through the water at an angle, but being held firm by the sculler. Force is transmitted via the sculling notch which drives the boat forward with a much simpler seeming leverage action. Creation of vortices seems to reduce the efficiency of the stroke. This is very similar to, but the opposite of, the draw stroke, used by canoeists and coracle users, the formerto create sideways movement, and the latter to create any movement in the desired direction. Fiddle Faddle 22:15, 30 October 2007 (UTC)

---

The reference to sculling should be removed, since it really isn't revelent to either the function of a propellor or its origin. A propellor transfers circular "spinnin" motion into horizontal, and even if you scull around in a circle, it is still not spinning motioin, but just a distorted form of side to side linear motion. And there is not any evidence that sculling inspired either the origin of the archimedes screw or the propellor itself. —Preceding unsigned comment added by 66.51.147.97 (talk) 00:32, 27 October 2010 (UTC)

Uses

There needs to be a section on the uses of propellers in aviation. To my understanding, they are used for small planes and huge planes. The article should mention that (if it is true), and explain why. My uneducated guess is that propellers provide greater efficiency but lower speed than jet engines. Whatever the answer, it should be included. Twilight Realm 22:04, 30 October 2007 (UTC)

I don't think there is a size of plane that is inappropriate for a propellor, so I am not wholly sure what direction your thoughts are heading in? If you can clarify somewhat that would help a little more. Fiddle Faddle 22:10, 30 October 2007 (UTC)

Small personal planes have props. Commercial planes have jet engines. Gigantic planes meant for transporting heavy cargo use propellors. Am I right? If so, why? Twilight Realm (talk) 01:39, 27 November 2007 (UTC)

Anyone? Twilight Realm (talk) 22:03, 3 December 2008 (UTC)

Hovercraft, not helicopter

I have looked at the "helicopter" Leonardo Da Vinci invented and it works the same way as a hovercraft, using fan(s) to push air downwards. 122.105.218.141 (talk) 00:28, 24 January 2008 (UTC)

Efficiency of marine propellers

Unlike the aircraft section, that on marine propellers give lots of formulae for calculating efficiency - IMHO too much given the likely readership - but no actual number for a typical modern propeller.

JamesWim (talk) 18:25, 1 February 2008 (UTC)

Request equation cleanup

I'm interested in the section beginning with "Forces acting on an aerofoil", but it's a bit confusing.

Preceding the equation, variables F, A, V, c, and alpha are explained.

The equation, then, introduces f, rho, and R_n, but doesn't use c.

Rho, f, and R_n are not explained in proximity to the equation. Presumably, R_n is Reynold's number, and uppercase C is a coefficient, but lower case c doesn't appear anywhere I can see.

Ve3wtj (talk) 00:01, 20 April 2008 (UTC)

What does the [,,] notation used in

$T=\rho V^{2}D^{2}[f_{1}({\frac {ND}{V_{a}}}),f_{2}({\frac {v}{V_{a}D}}),f_{3}({\frac {gD}{V_{a}^{2}}})]$

mean? It surely can't be a vector?

Also, it doesn't seem like V is defined anywhere (is it pitch speed?). Also, how does $V$ above simply become $V_{a}$ in

$T=\rho V_{a}^{2}D^{2}\times f_{r}({\frac {ND}{V_{a}}})$

and subsequently? —Preceding unsigned comment added by 41.157.12.3 (talk) 18:11, 6 September 2008 (UTC)

Automatic verses Aeromatic

Binksternet, you reverted my changing of "automatic" to "aeromatic". In the process, you also eliminated addition of a much needed citation, as well as edits for clarity and accuracy. I don't think your reasoning is correct anyway. "Aeromatic" is a trademarked name, but it's also a generic since it's the only technology of its type. "Automatic propeller" is a much more generic term that refers to propellers that change pitch to fit changing conditions; this includes constant-speed types. I've changed back to my edit for now. Shreditor (talk) 04:11, 29 June 2009 (UTC)

There were other makers of automatic props than Aeromatic. Even Aeromatic called their product an "automatic propeller," as seen in this photo of the company logo on an early prop. If you must put the company name into this article, say that it is the company. Binksternet (talk) 14:20, 29 June 2009 (UTC)

Again: Automatic propeller is used as a general term for a propeller that adjusts pitch on its own. This includes constant speed types [. I think aeromatic is a more specific term, which is why I used it there. Yes, there were other manufacturers of aeromatic-type propellers, but they're all extinct. In fact, the original Aeromatic company is also gone, and someone else bought up their type certificates. As far as I can tell, "aeromatic" is the only term in English for a propeller that adjusts pitch on its own without any need for pilot control. I'm not related to the company or any way trying to promote their product. I'm just trying to improve the article by providing an accurate history of airplane propellers. Shreditor (talk) 06:07, 30 June 2009 (UTC)

Except that it is not an English word. It is a trademark.

An accurate history of airplane propellers would include a telling of how Aeromatic (the company) developed their product. Instead of teasing the reader with a link, bring the information here in an encyclopedic way. Binksternet (talk) 14:57, 30 June 2009 (UTC)

I don't care how the company developed their product. That is not yet part of this article. All I'm trying to do is discuss the progression of technology, from one type to another. I wrote how the prop worked, and I cited it by linking to the manufacturer's page which also explains how it works. I'm trying to add a legitimate citation. I really don't understand what your objection is. Shreditor (talk) 17:01, 30 June 2009 (UTC)

And again, I don't understand your objection to using a trademarked name when it is the only name that makes sense. Google "automatic propeller" and you'll get 1,510,000 hits. I looked through the first few pages and most of them are about marine propellers, and ones for flight propellers concern CONSTANT SPEED PROPELLERS. NOT THE SAME THING. Google "aeromatic", and you get the link to exactly what we're talking about here. Aeromatic, trademarked or not, is the only word that is reserved for the particular type of prop we're talking about. Shreditor (talk) 17:17, 30 June 2009 (UTC)

Bernoulli and Incompressibility

"A pressure difference between the forward and rear surfaces of the airfoil-shaped blade is produced and air or water accelerated behind the blade."

Propellers work primarily in Incompressible flow, and lift has nothing to do with pressure differences, so this needs rewording.

This statement implies the ""Popular" explanation (of lift) based on equal transit-time" as described in the page for 'Lift'

I am not, however, sure of how to reword this.

93.97.135.30 (talk) 03:02, 19 October 2009 (UTC)

I polished the syntax by changing the sentence to A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and air or water is accelerated behind the blade.

You say lift has nothing to do with pressure differences. I disagree - lift is the result of the difference in pressure between the two sides of an airfoil or propeller. When there is no pressure difference there is no lift.

I also disagree that this statement implies the equal transit time model. The statement correctly attributes the thrust on a propeller to the pressure difference (explanation based on Bernoulli's principle) and alternatively to acceleration of air or water (explanation based on Newton's Laws of Motion.) Dolphin51 (talk) 03:58, 19 October 2009 (UTC)

H. L. Hunley

The propeller used on the H. L. Hunley submarine was an early ducted fan type http://www.thehunley.com/NEWSLETTER_46_LAST-ARTIFACTS/prop0809_jpg.jpg It didn't use a direct drive from its human powered crankshaft. It had a chain driven flywheel inside the submarine. http://home.att.net/~JVNautilus/Hunley/gear-popup.html —Preceding unsigned comment added by Bizzybody (talk • contribs) 05:43, 25 October 2009 (UTC)

a question!

what is the meaning of a and a' of this article, the article about the propeller? i am rasoolmes a member of wikipedia! —Preceding unsigned comment added by Rasoolmes (talk • contribs) 16:26, 14 November 2009 (UTC)

Manufacture and materials

Really need more on materials and manufacture, the only thing we have is two links to general rather then specific articles in the see also section.KTo288 (talk) 21:30, 15 December 2009 (UTC)

Casing

A section needs to be made regarding propeller casings.

Add

File:Propeller-cased ship with hydrofoils.PNG

File:Propeller-cased ship without hydrofoils.PNG

81.241.109.50 (talk) 11:11, 14 January 2010 (UTC)

No, this looks very much like WP:Original research. Binksternet (talk) 16:20, 26 January 2010 (UTC)

Article split?

Would there be any objections to splitting the aviation specific content off into the redirect, Propeller (aircraft)? Nothing would be lost but there are things missing that need adding. Cheers Nimbus (Cumulus nimbus floats by) 14:15, 26 January 2010 (UTC)

Doing so has been on my list for months. Jump on it if you have the time right now, because I do not. Binksternet (talk) 16:17, 26 January 2010 (UTC)

Ok, I can't see that we have anything to lose, only gains!! Just need to compile a summary to leave behind and a main article link. Nimbus (Cumulus nimbus floats by) 16:53, 26 January 2010 (UTC)

Concur, though my preferred title is Aircraft propellor Aircraft propeller. I'd also like to split off Marine propellor Marine propeller, and leave this article as an overview, and to cover the basics common to both types. - BilCat (talk) 17:03, 26 January 2010 (UTC)

It's in progress, I need to shorten this article next. Nimbus (Cumulus nimbus floats by) 17:42, 26 January 2010 (UTC)

As an American, I like the article title Aircraft propeller, with the er ending. ; ^ )

Binksternet (talk) 17:46, 26 January 2010 (UTC)

'Propeller' is the correct spelling for both sides of the Atlantic isn't it? Nimbus (Cumulus nimbus floats by) 17:55, 26 January 2010 (UTC)

So I'm a bad spellor! - BilCat (talk) 18:27, 26 January 2010 (UTC)

Had me worried there for a minute. Nimbus (Cumulus nimbus floats by) 18:31, 26 January 2010 (UTC)

Propeller is the correct spelling in the southern hemisphere too!

On the question of how much indentation is too much, let's have a look at WP:INDENT Dolphin51 (talk) 22:22, 26 January 2010 (UTC)

I suggest you use {{outdent}} Fiddle Faddle (talk)

I tried to split the article per the long standing split tag and found that the article was virtually all about marine propellers. Therefore, I renamed the article to be about marine propellers and altered the disambiguation page accordingly. I trust this is alright. Op47 (talk) 23:00, 24 January 2012 (UTC)

Propeller sketch naming - trailing/leading edge

I swapped the trailing/leading edges in the description of the propeller sketch to match the image file description. I note that this has been reversed before in the article, so if I the image file description is wrong and article was correct, please fix.MKFI (talk) 14:01, 27 April 2010 (UTC)

The diagram shows (faintly) a curved arrow indicating the direction of rotation of the propeller. Considering the shape of the blades, I think this curved arrow is pointing in the wrong direction. The way you have named the leading and trailing edges is correct relative to the curved arrow.

I think the best solution is for someone with the appropriate skills to reverse the direction of the curved arrow, and then reverse the labeling of leading edge and trailing edge. Dolphin (t) 22:47, 27 April 2010 (UTC)

I believe that the current description is correct. We must remember that we are looking at a "Marine Propeller." For most applications, it is located at the stern of the ship. The naming and the faint curved arrow would show the correct conditions for moving/pushing a ship through the water.138.32.32.166 (talk) 23:57, 5 May 2010 (UTC)

I agree that the description is correct because it matches the faint curved arrow. However, the arrow suggests this is a forward-pointed propeller - the tip of the propeller blade leads the root. I think this is incorrect, even for a marine propeller. I think the tip of any marine propeller blade lags behind the root and therefore the direction of the arrow is incorrect. Dolphin (t) 00:31, 6 May 2010 (UTC)

The leading edge of a propeller is always the edge of the blade that meets the water flow first when in normal rotation. The trailing edge 'trails' behind, hence the name. The usage is the same for aircraft wings and propellers too, which are all aerofoils - the leading edge 'leads' the trailing edge, although if a propeller is run in reverse (i.e., astern) the positions will be temporarily reversed. Generally the leading/trailing edges are specified when running normally, i.e., ahead.

For a marine propeller as the screw pushes rather than pulls, the leading and trailing edges are back-to-front compared with an aeroplane tractor airscrew, i.e., in relation to the hub/boss of the propeller. The leading edge always meets the operating fluid (water or air) first in the normal direction of motion and rotation, and so the leading edge is always the edge nearest the front of the aeroplane or ship when moving forward. — Preceding unsigned comment added by 80.7.147.13 (talk) 12:41, 21 October 2012 (UTC)

Suggested rename

Now that the aircraft propeller section has been made into a separate article, and this article deals almost entirely with marine propellers, I propose that this article be renamed Screw propulsion, which is the usual term applied in marine applications. I would also suggest that the dab page Propeller (disambiguation) be renamed to simply "Propeller", with links to both the aircraft propeller article and this one (as well as the other dab links). I think that makes sense because neither the airscrew or marine propeller can be said to be more important than the other. The "Propeller (aircraft)" article can then simply be renamed "Aircraft propeller" as someone else already suggested. That way we will have a nice logical system. Gatoclass (talk) 20:39, 22 May 2010 (UTC)

Split out of Marine section

I note that this was discussed a year ago when propeller (aircraft) was split out, but it was not actioned. I think it should still be done. Tim PF (talk) 23:23, 8 April 2011 (UTC)