User talk:Dolphin51/Archive 3

Thanks for the welcome

I realize it was a while ago now, but I just wanted to say thank you for the welcoming message you left on my talk page. Regards, Seashorewiki (talk) 04:23, 4 April 2010 (UTC)

Thanks for acknowledging it! Happy editing. Dolphin51 (talk) 12:24, 5 April 2010 (UTC)

Same from me - sorry for the late reply, but thanks! Gnathan87 (talk) 13:30, 12 February 2011 (UTC)

Thanks for the acknowledgement. No problem about a late reply - no deadlines on Wikipedia! Dolphin (t) 04:13, 13 February 2011 (UTC)

Something out of a code of conduct?

"Respect for a request made by another User sounds like something out of a code of conduct. I doubt [M] has an expectation that any of us should be observing a code of conduct" may be accurate, but it's not so long ago that you had a dispute with M. --Philcha (talk) 07:46, 12 April 2010 (UTC)

Hi Phil. All that you have written is correct. I object to Ceranthor's implication that PeeJay should respect M's wishes. M and some of his friends are boastful about their contempt for the Wikipedia code of conduct so there must be no implication that other Users should observe this code of conduct in their dealings with M. M has abandoned the code of conduct for his dealings with some Users so he cannot rely on its protection when others are dealing with him. Ceranthor is oblivious to this. A code of conduct is a two-way street. Dolphin (talk) 12:40, 12 April 2010 (UTC)

Moral philosophy or logic just aren't your strong suits, are they Dolphin. If you believe in a code of conduct, then you must strive to live by it, not pick and choose to whom it applies and to whom it doesn't. I am not aware that I am relying on the "protection" of anything, especially not the ludicrous "civility" policy, which empowers its crusaders to be as incivil as they like to whomever they take a dislike to, so long as they don't use any naughty words in doing it. Malleus Fatuorum 15:58, 12 April 2010 (UTC)

G'day Malleus! My view is that we all live by a code of conduct, including you and me. I acknowledge the legitimacy of the Wikipedia code of conduct, and I accept that if I want to play on Wikipedia then I must abide by it. (If I objected to it I would be obliged to get it changed or play elsewhere.) I am not aware of me applying the Wikipedia code of conduct unevenly - please let me know if you see an example. The code of conduct you display is one devised by yourself. For example, you object to what you consider stupid edits on Wikipedia, and when you see one you sometimes punish the editor with insults, abuse and so on. Your system of expectations, likes and dislikes, and your system of punishments, constitute a private code of conduct, although I am sure you have never thought of it as such. Your private code of conduct is grossly unfair - it was devised by you, you are the Police Constable, the Chief Prosecutor, the Judge and the Sheriff. All ranks are held by you alone. Your private code of conduct is secret so people know nothing about it until they see they have been punished. Your private code of conduct confers great power and privilege on you and, occasionally, on some of your friends. I object to individuals striving to win great privilege for themselves, at the expense of the community. If you see examples of Administrators who are uncivil, why manifest your frustration on others who are not being uncivil? Dolphin (talk) 12:42, 13 April 2010 (UTC)

Just because one user is uncivil does not give another user the right to be equally uncivil; both should be treated the same. Malleus – if you're still reading this – if you believe that the "Civility Police" are giving another user preferential treatment, why not just raise the topic? I'm sure people will listen if you highlight a flaw in the system. – PeeJay 20:59, 12 April 2010 (UTC)

Re: Greetings from Australia

Hi Dolphin, thanks for your message. I'm glad to have expanded your horizons a little. At least something good came from this business with Malleus Fatuorum! Hope you're well, and keep editing :-) – PeeJay 12:33, 15 April 2010 (UTC)

Acknowledged! Dolphin (talk) 12:38, 15 April 2010 (UTC)

Vortices and Vorticity

Hello Dolphin,
Thank you for your conscientious attention to this article. The following responses address your questions about my edits.
1. The mathematical definition of vorticity is the curl, or (excuse my rusty LaTeX here) $\nabla \times$, of the velocity vector, as already mentioned in the article, or $\nabla \times v$. An ideal free vortex has a $v_{\theta }={\tfrac {a}{r}}$, where $\textstyle a$ is the constant ${\tfrac {\Gamma }{2\pi }}$ and the other components ($\textstyle v_{r}$ and $\textstyle v_{z}$) = 0, as also mentioned in the article. The $\textstyle r$ and $\textstyle \theta$ components of the curl ($\nabla \times$) of this vector are both zero. The $\textstyle z$ component is ${\tfrac {1}{r}}{\tfrac {\partial }{\partial r}}\left(rv_{\theta }\right)-{\tfrac {1}{r}}{\tfrac {\partial v_{r}}{\partial \theta }}$. Since $\textstyle v_{\theta }$ is ${\tfrac {\Gamma }{2\pi r}}$, making the first derivative zero, and since $\textstyle v_{r}$ does not depend on $\textstyle \theta$ (is, in fact, zero everywhere), all three components of the curl are zero, making the vorticity zero, except at the center singular point. I am not sure if this needs a reference as it follows directly from the math, most of which is already in the article, but I can find one if you think it helps. This is a well-established property of free vortices. Indeed, many common vortices are much closer to free vortices than forced vortices, including those usually found when water or air form natural circulating flows (drains, tornados, etc). It is true, and perhaps surprising as I mentioned, that vorticity can be zero even though the fluid is moving in an obviously circulating pattern. The circulation is not zero, but that is because it is the integral along a closed flow path of a constant velocity or, if you use Stokes theorem, the surface integral of vorticity over a bounding surface. Since all bounding surfaces in the latter case include the central singular point, and since the surface integral over such a point is non-zero, the circulation is finite even though the vorticity is everywhere, except at the center singular point, zero.
2. see 1. above
The leaf example in the article is a good indication of what vorticity really represents. It is the tendency of fluid to circulate about itself at a point, and is not related to the bulk flow pattern. Since, in a free vortex, fluid does not circulate about itself locally the leaf always points in the same direction with respect to the laboratory reference frame, i.e, always points north, for example. The forced vortex, which has vorticity, rotates the leaf. The leaf discussion is very good, but the underlying stream lines are not accurate. They should be evenly spaced in the radial direction for the free vortex and have decreased spacing with increasing r in the case of the forced vortex.
3. The velocity of a free vortex increases much faster than that of a forced vortex as you approach the center, becoming infinitely high in the ideal limit at the center. The velocity in a forced vortex is zero (all three components) at the center. So Bernoulli's equation would say the pressure is much lower at the center of the free vortex than the forced vortex (which is why, by the way, that free vortices of the type formed in draining basins form such deep slender holes). Indeed, since the velocity approaches infinity at the center, the pressure should approach zero. However, Bernoulli's equation is not a reliable indicator of the flow in a forced vortex since one of the explicit assumptions in deriving it is that the flow has no vorticity. Forced vortices have finite vorticity everywhere. That is why Bernoulli's equation suggests the pressure in a forced vortex should decrease with increasing distance from the center, since the velocity is increasing with increasing distance from the center, whereas the actual behavior is the opposite. The pressure is lowest in the center in a forced vortex, but it never approaches zero. The article would be improved it if either pointed out this shortcoming of Bernoulli's equation or deleted the reference to it. These behaviors can be appreciated by considering the surface of water in solid body rotation (such as water in a bowl in which both the bowl and water are rotating at the same speeds) and a free vortex, such as water draining from a basin. The water surface is a line of constant pressure (atmospheric pressure to be precise). It forms a relatively gentle and mathematically parabolic shape in the case of solid body rotation and a much steeper decrease near the center in a free vortex, the latter being mathematically proportional to ${\tfrac {1}{r^{2}}}$.
Please feel free to send any corrections or comments.

Larrybaxter (talk) 04:10, 16 April 2010 (UTC)

Larry, many thanks for your careful and rigorous explanation. It is now clear to me that we are both in agreement that, in a free vortex, vorticity is zero everywhere except at the center singular point. This is the nub of the issue.

In your 11 April edit of Vortex you added the statement The vorticity of a free vortex is zero ... My submission is that the notion that vorticity is zero everywhere except at the center singular point cannot be accurately summarised by writing The vorticity of a free vortex is zero ... If it was zero it would not be necessary to add except at the center singular point. Dolphin (t) 06:19, 16 April 2010 (UTC)

Perhaps we are splitting hairs here, but since the center singular point of free vortex is unattainable (infinite velocities, zero pressure, etc.), the vorticity in any real flow that behaves like a free vortex is, in fact, zero everywhere. No real vortex can be described as a free vortex near the center, so the exclusion of the center singular point is unnecessary for any real application, but perhaps important from a theoretical or mathematical point of veiw.

Larrybaxter (talk) 22:38, 17 April 2010 (UTC)

Hi Larry. I don’t agree that our discussion is merely splitting hairs. Vortex can mean at least two things – it can mean a circular motion in a real fluid, with viscosity and turbulence and secondary flows. Alternatively, it can mean a mathematical model with curl and vorticity and circulation. At Vortex#Dynamics it says Vorticity is a mathematical concept used in fluid dynamics, so when we are talking about vorticity we should be talking primarily about the mathematical concept.

At Vortex#Free (irrotational) vortex it says the vorticity is zero everywhere (except for a singularity at the center-line). I agree with this description of a free vortex. Your 11 April edit added the statement The vorticity of a free vortex is zero whereas the vorticity of forced vortices is non-zero. As a result, Wikipedia is now contradictory on the question of whether the mathematical model of a free vortex has zero vorticity everywhere, or vorticity only at the center (where there is a singular point).

The solution seems clear. If your statement were to be amended as follows, I think my objections would disappear: The vorticity of a free vortex is zero everywhere except at the center, whereas the vorticity of a forced vortex is non-zero. Dolphin (t) 05:10, 18 April 2010 (UTC)

Larry has not responded after nine days so I will edit the pertinent sentence so that it matches the wording in italics in my final para above. Dolphin (t) 06:09, 27 April 2010 (UTC)

Sorry for the belated response - work gets in the way of checking on these things. I have no overwhelming objection to the edit. However, I will point out that the center of free vortex is a singular point (infinite velocities, etc.) that will never relate to any real flow. The finite vorticity and all other behaviors there are more mathematical aberrations than any behavior realized in the physical world. In the physical world, the vortex ceases to be a free vortex near the center precisely because this anomalous limit. I suspect there is no disagreement on this point. The most useful statement, I feel, is that near-free vortices observed in the real world (flow down drains, tornados, and the like) exhibit nearly zero vorticity everywhere except near the center, which is sometimes closer to forced vortex structure (drains) and sometimes far more complex (tornados) but is never close to free vortex flow. Larrybaxter (talk) 1 May 2010 (UTC)

Delta wing article

Hi, hope you are well. Please can you check the point that I made in the discussion of "delta wings", I do not think that the information in the article is correct...

Thanks,Jez 006 (talk) 14:36, 17 April 2010 (UTC)

Thanks for alerting me to the problem at Delta wing. I agree with you that the current statement is incorrect, and I have said so on the Talk page. The current statement is not only incorrect, it is completely unsourced so it is almost certainly just someone's original research. You are at liberty to delete the offending sentence(s). Regards, Dolphin (t) 05:04, 18 April 2010 (UTC)

Thanks for the quick reply. I'm currently working on a project based around delta wings so I have a lot of material discussing the flow characteristics over different types of delta wing. I would like to edit the page appropriately, but the journals I am reading have been accessed through science direct from the university. For example I would like to reference "I. Gursul, Z. Wang, E. Vardaki - Review of flow control mechanisms of leading-edge vortices", which gives a clear explanatation as to why double delta wings and wings with canards display superior characteristics to pure delta wings. It also shows flow visualisation which really helps explain it. Can I reference this journal even if it cannot be accessed by the general public? And can I upload photos from it? I'm guessing no for the second point, which makes the write up a bit trickier!

Best regards, Jez 006 (talk) 11:15, 18 April 2010 (UTC)

You are free to go ahead and add new text, citing whatever suitable sources you are using. The fact that some of these sources may not be readily accessible to the public is not a problem. WP:SOURCEACCESS includes the following advice: The principle of verifiability implies nothing about ease of access to sources: some online sources may require payment, while some print sources may be available only in university libraries.

There is also some very good advice about primary, secondary and tertiary sources at WP:PSTS

I agree that the images are unlikely to be freely available for use in Wikipedia. Dolphin (t) 06:13, 19 April 2010 (UTC)

I have read through the entire page, looking at my notes and journals and there is a lot of other material that I disagree with too. Please can you check over the extra comments I have added on the discussion page?

Best regards, Jez 006 (talk) 12:01, 18 April 2010 (UTC)

I have read your latest comments at Talk:Delta wing. If you see errors in what is written in the article you are at liberty to correct the errors. I can suggest three different ways of doing this, depending on the size and extent of the changes:

• Simply make your changes, either sequentially or in one big bang!
• Discuss your proposed changes on the Talk page. If anyone wants to discuss them, or challenge them, you can do so and gauge the right time to insert your changes in the main article.
• Establish a personal sandbox. Copy the contents of Delta wing and paste into your sandbox. You can then use your sandbox to work on your changes over a period of time without any risk that others will object or interfere with your work. You can see my personal sandbox (which I use for this purpose) at User:Dolphin51/Sandbox. When you have finished your re-work of the article you can use Talk:Delta wing to announce the availability of the re-work and invite interested Users to visit your sandbox and comment on your new version. After a few days, or when the discussion has died down, you can copy the new version in your sandbox and paste it into the article.

To start your own personal sandbox, go into your User:Jez 006 page and, somewhere there, type [[/Sandbox]] and then save your edit. It will appear as a red-link. Double click on the red-link and it will open a new personal sandbox for you, called User:Jez 006/Sandbox. See WP:USERSUBPAGE if you have any questions about the process. Dolphin (t) 06:13, 19 April 2010 (UTC)

Sounds good. I'm slowly writing up this project at the moment, and have exams after that but I'll get round to it in the next few months hopefully!

Thanks for the help,

Jez 006 (talk) 13:56, 20 April 2010 (UTC)

Uncivil Users

I appreciate the mesage. But my experience has been unpleasant because of 2 uncivil users, complaints against which I have launched. Also, I want to change my user name or close my account but these things are not allowed so I ontend to laucnch complaints against Wikipedia with the BBB and other agencies concerning this matter.--BlueRider12 17:46, 25 April 2010 (UTC)

Thank you for your message. Changing your user name should be possible through WP:Changing username. Best regards. Dolphin (t) 11:20, 26 April 2010 (UTC)

Speedy deletion nomination of Lift (force)/Comments

A tag has been placed on Lift (force)/Comments requesting that it be speedily deleted from Wikipedia. This has been done under section A3 of the criteria for speedy deletion, because it is an article with no content whatsoever, or whose contents consist only of external links, a "See also" section, book references, category tags, template tags, interwiki links, a rephrasing of the title, or an attempt to contact the subject of the article. Please see Wikipedia:Stub for our minimum information standards for short articles. Also please note that articles must be on notable subjects and should provide references to reliable sources that verify their content. You may wish to consider using a Wizard to help you create articles - see the Article Wizard.

If you think that this notice was placed here in error, you may contest the deletion by adding {{hangon}} to the top of the page that has been nominated for deletion (just below the existing speedy deletion or "db" tag), coupled with adding a note on the talk page explaining your position, but be aware that once tagged for speedy deletion, if the page meets the criterion, it may be deleted without delay. Please do not remove the speedy deletion tag yourself, but don't hesitate to add information to the page that would render it more in conformance with Wikipedia's policies and guidelines. Lastly, please note that if the page does get deleted, you can contact one of these admins to request that they userfy the page or have a copy emailed to you. Cnilep (talk) 15:39, 28 April 2010 (UTC)

Wing design then and now...707 vs 777 Question

Hello Dolphin 51

I saw your participation on Wiki's Fluid Dynamics Task Force and wondered if when you have time you can give me an answer to a long sought question regarding early jet airliner wings than what we see today.

My main observation was that with the exception of the Convair 990, the 707,727, DC8, DC9 and DC10 all had clean underwing designs (the DC9 and DC10 had one small flap guide each). The Convair had anti-shock bodies on top of the wings. Starting with the 747, large flap track fairings were incorporated under the wings and have been a main design feature on all following Boeing aircraft and are found on Airbus aircraft.

The Wiki article on anti-shock bodies indicates that the Flap Track Fairings are also used as Anti-shock bodies.

1. My question is why were/are the 707, 727 and DC9-10 series not designed with any anti-shock bodies? They have a basically clean underwing.

2. Another question I have always wondered about is if these airaft did not have flap track fairings, was the internal wing structure more robust to handle the flaps? I assume that having the flap track fairings portruding from the wing requires less structure/weight for the wing even though the flap track fairing increase drag to some extent? Is it true that the flap track fairings are anti-shock bodies?

Just wondering.

Thanks

guinflyer Guinflyer (talk) 02:52, 2 May 2010 (UTC)

Hello Guinflyer. Thanks for your questions. I have no authoritative information about this aspect of the design of any aircraft, but I'm prepared to consider your questions from first principles and see where it leads.

Anti-shock bodies assist an aircraft design to conform well to the area rule. They raise the critical Mach number. However, at speeds slower than the critical Mach number they increase drag compared with a similar aircraft with a clean wing-trailing-edge.

It is my guess that Boeing and Airbus don't consider their flap-track fairings primarily as anti-shock bodies. Primarily they are aerodynamic fairings over the flap operating mechanism and are intended to reduce parasite drag at all speeds. They may raise the critical Mach number a very small amount, and they may confer a small reduction in drag at cruising speed. If so, these designers are entitled to say their flap-track fairings are anti-shock bodies. Alternatively, the designer might translate the transonic benefit of the fairings into slightly less sweep-back on the wing and retain the same critical Mach number. Sweep-back is very expensive in terms of the weight and complexity of the wing.

This raises the question about why have flap-track fairings on the Boeing 747 and Airbus aircraft when they weren't used on earlier aircraft. It is likely that flap tracks of a given strength can be lighter in weight, or cause less confusion inside the wing, if they are partly outside the wing section. Perhaps in the design of the wings of Boeing 737 and earlier aircraft the flap tracks were contained within the wing, thereby leading to a clean trailing edge. Perhaps in the design of the 747 and later aircraft they located the flap tracks partly outside the wing section to allow less weight, and to allow greater space inside the wing for fuel tanks. Perhaps the added drag that would inevitably occur with flap tracks partly outside the wing section is partly mitigated by well-designed fairings.

Another possible consideration is fuel price and cruising speed. I think the B737 and earlier aircraft were designed for a slightly higher cruising speed than later designs. It is plausible that external flap-tracks might be economical at slightly slower cruising speeds, but not quite economical at slightly faster cruising speeds.

I am sceptical that these fairings are significant in raising the critical Mach number, which is what true anti-shock bodies are for. I think their primary effect in reducing drag is due to their streamlining effect and so is effective at all speeds but does not raise the critical Mach number.

If you are interested in pursuing a more authoritative answer, or some alternative answers, you could try WP:WikiProject Aircraft. Best regards, Dolphin (t) 12:40, 2 May 2010 (UTC)

Welcome

Thanks for your welcome dolphin51. The subject 'energy' on the discussion page of 'Energy' continues... Knoxjohnson (talk) 07:54, 19 May 2010 (UTC)

Yes, I have Energy on my Watchlist so I see the debate is continuing. Unfortunately it has reached a philosophical level at which I am unable to comprehend, let alone contribute! Dolphin (t) 12:16, 19 May 2010 (UTC)

Thanks for your welcome. --Ricvelozo (talk) 19:31, 19 June 2010 (UTC) My pleasure! Dolphin (t) 12:58, 20 June 2010 (UTC)

Comments on nuclear force

Answered on TALK:nuclear force page. Thanks. SBHarris 18:29, 22 June 2010 (UTC)

Thanks for that. Putting it on the discussion page is good because it allows others to join the debate. Dolphin (t) 22:57, 22 June 2010 (UTC)

Thanks for picking that up

Thanks for picking up the consequence of my minimal approach to changing the text supporting the lead image at fixed-wing aircraft! That's what comes of knowing nothing about the article subject... hamiltonstone (talk) 00:15, 28 June 2010 (UTC)

I'm pleased to be able to help. Dolphin (t) 03:02, 28 June 2010 (UTC)

Thank you

Hi Dolphin51,

Thank you for moving my question to the Mathematic's desk instead. That is of course where it belonged. I was not even aware there was a matehematics help desk. Earlier, when I have had questions, they have been of a scientific character for which the science help desk has been the right place, and I had gotten into the habit of not even considering there existed anything else ;-) I appreciate the replies I have received for the question, and they give me some new subjects to understand, but now I am at least not stuck. Best wishes --Slaunger (talk) 07:00, 1 July 2010 (UTC)

I am pleased to be able to help! Dolphin (t) 13:13, 1 July 2010 (UTC)

Recent Changes Camp Canberra Aug 11, 2010

I saw you're listed in the ACT Wikipedian page and thought, by chance, you might like to come to this:

RecentChangesCamp, Canberra is being held at the University of Canberra, Building 7, Room 7XC37 on 11 August 2010.
ABOUT | REGISTRATION | SCHEDULE

Hope we'll see you and friends there, but please register so we can prepare lunch. Leighblackall (talk) 01:41, 21 July 2010 (UTC)

"Leading capitals" on Ref-desk pages

Is there some guideline for making that change? Seems like its main result is breaking anchored links to the sections. DMacks (talk) 06:18, 22 July 2010 (UTC)

On the various Reference Desks, most new Section headings are correctly written with a leading capital and all subsequent characters in lower case, except for proper nouns. However, I have noticed that every few days there is a spate of headings without capitalization. It seems that many people posting questions copy the capitalization of preceding questions. I thought that if inappropriate capitalization was corrected promptly it might prevent these periodic epidemics of inappropriate capitalization.

On the matter of capitalization of Section headings, at WP:Headings the fifth bullet states Capitalize the first letter of the first word and any proper nouns in headings, but leave the rest in lower case ... The same thing is stated at Wikipedia:Manual of Style (capital letters)#Section headings.

I'm not aware of any regular occurrence of links to questions at Reference Desks. The only example I can think of is where one User might write to another User mentioning a question at one of the Reference Desks, and providing an active link. Dolphin (t) 12:33, 22 July 2010 (UTC)

Reference Desk

What "large number of Users"? You are the only person thus far who has made any issue with it. Please read WP:NOTCENSORED, the question is appropriate and asking for references, which the reference desk is for. Stop removing it because you personally have some issue with the questions subject 95.78.69.25 (talk) 23:23, 25 August 2010 (UTC)

Hi

I did not know you can't write such "crime" thing on RD, I thought the only taboos were Medical & Legal Advice. However now I know better ''Jon Ascton~Talk

Center of Pressure Historical Usage

Dolphin 51, I re-read Historical Usage and it seems like we should just get rid of it. What center of pressure is talking about? I assume the air and not the combined air and water pressure fields. It just seems confusing and useless. Skimaniac —Preceding unsigned comment added by Skimaniac (talk • contribs) 20:44, 3 September 2010 (UTC)

Hi Skimaniac. I agree that the section has some serious problems. It is completely unsourced; and the final sentence looks incorrect - I suspect that for stability of a sailboat the center of pressure on the sail needs to be forward of some particular point analogous to a neutral point rather than the center of mass. However, seeing the article presently has one section devoted to aircraft and another to missiles, I think there should be a section devoted to nautical applications of center of pressure. I will look for a group of Users who works in the field of sailing or marine architecture and ask that they have a look at the offending section with a view to re-writing it and providing some references to suitable sources. Dolphin (t) 05:57, 4 September 2010 (UTC)

I have posted a request with the good people at WikiProject Ships. See diff. Dolphin (t) 06:16, 4 September 2010 (UTC)

More Center of Pressure

It seems like at one time someone had added discussion of center of pressure for hydrostatic forces. Much like in statics class when you are computing tipping moments on dams. I would think we ought to have something along this line to cover the center of pressure folks see in statics class. any objections if I give it a try? Skimaniac (talk) 03:37, 5 September 2010 (UTC)

Good point. I have no objection. Go for it. Dolphin (t) 03:55, 5 September 2010 (UTC)

Reference Desk Removal

May I ask why you removed the question about long-haired wool from the Reference Desk: [1]? You included the edit summary DNFT, which I assume means "Do Not Feed Trolls". However, the question appeared legitimate to me, and in fact, I was looking forward to finding out the answer. Is there something about this particular IP address that makes you assume it is a troll question? In any case, I'd appreciate a note on the Reference Desk talk page letting people know what you've done so that we don't have to dig through the history to find out where the question went. Thank You. Buddy431 (talk) 16:13, 5 September 2010 (UTC)

Hello Buddy. Thanks for your enquiry.

The question Long haired wool was first posted by 88.104.91.35. For reasons I will explain shortly, this question was promptly deleted by User:TenOfAllTrades, an Administrator. See DELETION

The same question was then re-posted by 88.104.92.244 and I deleted it.

TenOfAllTrades has done a lot of good detective work to uncover the fact that a banned former User called User:Light current now operates as a troll using IP addresses in the series 88.104.xx.yy. TenOfAllTrades has established that all postings from 88.104.xx.yy have been from this banned User. TenOfAllTrades has asked all Wikipedia Users to delete (on sight!) any posting to a Reference Desk from IP 88.104.xx.yy. See HERE 1 and HERE 2

Here are some examples of questions posted from IP 88.104.xx.yy and promptly deleted by virtue of DNFT:diff 1, diff 2, diff 3, diff 4

There would be no objection to you asking the question about long-haired wool.

Happy editing! Dolphin (t) 23:28, 5 September 2010 (UTC)

Thank you very much. Buddy431 (talk) 23:41, 5 September 2010 (UTC)

81.44 edits

Honestly? I'm almost certain that that isn't one of our regular socks. The other contributions don't look right, and the IP address is from Spain. He may still be a troll, but as far as I know he's a new troll. TenOfAllTrades(talk) 03:29, 6 September 2010 (UTC)

Userboxes

You may be interested in the discussion at Wikipedia:Miscellany for deletion/User:BillCJ/UBX/atheism Is Harmful, as it potentially relates to the use of a userbox on your userpage. - BilCat (talk) 11:18, 8 September 2010 (UTC)

Welcome (from Barcelona)

Hi Dolphin51. Thanks for the welcome. I am a Wiki beginner and not really fluent in English. I am publishing some articles in Catalan language : sailing, horse colours, engines, medieval history, thermodynamics, ... If you like sailing, do you know the "Patí de vela" or "Catalan Patí"? A very old catamaran ...ruderless. From BarcelonaRoger Liart (talk) 17:01, 14 September 2010 (UTC)

Hi Roger. Your English looks very fluent to me! I'm afraid I don't know much about sailing. Best wishes. Dolphin (t) 04:27, 15 September 2010 (UTC)

BLP problem at WT:Signatures

Just to let you know, I issued an additional warning to 66.168.55.5 (talk · contribs) for the content you reverted at WT:Signatures since it was a pretty severe BLP violation as it was extremely contentious or defamatory and was unreferenced. Thanks for removing the content, but it seems you missed the bigger picture there: it was irrelevant to the signatures talk page, but it was also a pretty serious violation of WP:BLP. Just thought I'd let you know. GiftigerWunsch [TALK] 12:31, 26 September 2010 (UTC)

Thanks for that. I agree the edit was a serious violation of BLP and it was appropriate that the offender receive a warning. Dolphin (t) 05:20, 27 September 2010 (UTC)

Quite an odd place to post a rant like that. The Mike Vick page must be protected. - BilCat (talk) 05:40, 27 September 2010 (UTC)

Yes, Michael Vick is semi-protected. The IP address probably tried the article, and when that failed, set out to try anything that looked vaguely useful. Dolphin (t) 05:58, 27 September 2010 (UTC)

Talk:Lift (force)

Hi Dolphin51, shouldn't that be reference frame attached to the wing/airfoil instead of reference frame attached to the atmosphere? Then I would fully agree with you. Cheers, Crowsnest (talk) 23:04, 27 October 2010 (UTC)

Hello Crowsnest. It is wonderful to hear from you again after such a long time.

If a wing/airfoil is not accelerating and not changing direction, then the reference frame attached to that wing/airfoil would be an inertial reference frame. However, relative to that inertial reference frame the velocity of the wing/airfoil would be zero.

The conventional definition of lift is that it is the component of the aerodynamic force that is perpendicular to the velocity vector. This begs the question - velocity in what reference frame? My view is that it is the reference frame attached to the atmosphere, otherwise to determine lift would require knowledge of the velocity of the atmosphere relative to the reference frame (eg wind speed and direction.)

It is interesting to consider an aircraft climbing at constant speed and in a constant direction. The aircraft's gravitational potential energy is increasing showing that the weight of the aircraft is doing negative work. However, the aircraft's kinetic energy is not changing, showing that the negative work done by the weight is offset by positive work done by some other force. If we use the reference frame attached to the atmosphere, lift does no work (because it is perpendicular to the velocity vector) so it is the excess thrust (the amount by which thrust exceeds drag) that does positive work to offset the negative work done by the weight.

However, if we use a different reference frame, such as the one attached to the ground, the situation changes. The negative work done by the weight is the same as in the previous example, but the source of the positive work is different. It is the same amount of positive work, but it is partly work done by the excess thrust and partly work done by the lift. With a different reference frame, lift does work because it is no longer perpendicular to the velocity vector.

We can imagine the infinite number of inertial reference frames. There is only one such reference frame in which the lift on an airfoil does no work regardless of the velocity of the airfoil, and that is the reference frame attached to the remote free stream in which the airfoil is moving. In the case of an aircraft, this is the reference frame attached to the atmosphere.

I hope this makes sense. Best regards. Dolphin (t) 02:54, 28 October 2010 (UTC)

I have just realized that what you have in mind might be that the airfoil is stationary and the fluid is flowing past it. In that case, I would say lift is still the component of aerodynamic force perpendicular to the velocity vector, but the vector is the one representing the flow of fluid past the airfoil. In either case, it is the direction of the vector that is important and it is the direction of the relative motion of fluid and airfoil. Dolphin (t) 04:39, 28 October 2010 (UTC)

Hi Dolphin51, I was thinking about the work performed on the airfoil. Work equals force times velocity (inner product of force vector and velocity vector, velocity is the velocity of the wing in the considered reference frame). There always is the lift force, and in "real" fluid there is always drag. So the forces are nonzero (apart from the trivial case of zero relative speed between air and wing). Therefore, the only frame of reference in which the air does not provide work on the wing is in the frame of reference where the velocity is zero, i.e. attached to the wing. This is of course a non-inertial frame of reference when turning or other speed changes. -- Crowsnest (talk) 10:11, 28 October 2010 (UTC)

Hi Crowsnest. You have written about the air performing work on an airfoil. You have also written that in a viscous fluid there will be drag, and the drag will perform work on an airfoil. I agree with what you have written.

When an airfoil is moving through a fluid there will be an aerodynamic force, and I agree that the work performed by the aerodynamic force is the inner product of aerodynamic force vector and velocity vector.

Where our views differ is as follows: I am resolving the aerodynamic force into two components – lift and drag. Drag is the component parallel to the vector representing the relative velocity between airfoil and atmosphere. The drag force and the velocity are parallel so the drag force does work (negative work) on the airfoil. Lift is the component perpendicular to the vector representing the relative velocity between airfoil and atmosphere. When considering the work done on an airfoil, providing the reference frame is attached to the atmosphere, the lift force does zero work.

You might ask when would an airfoil be considered using a reference frame that is not the reference frame attached to the atmosphere? My answer is that in some situations the motion of an aircraft or airfoil is considered in the reference frame attached to the ground. In this situation some of the work done on the aircraft or airfoil is done by the lift force. Dolphin (t) 03:25, 29 October 2010 (UTC)

Hi Dolphin51, this is really becoming very interesting. At least I note that above I am meddling with the work performed by the wing and the work performed by the air. At least two things are important to consider: 1. the energy changes in which system with which system boundaries are to be determined and 2. the influence of the frame of reference. I will be away until Tuesday, and cannot reply before Tuesday. But I have time to think about it. Best regards, Crowsnest (talk) 06:34, 29 October 2010 (UTC)

Yes, please think about it. A word of advice - work is done BY a force, not by a body. Work is done ON a body. Regards.— Preceding unsigned comment added by Dolphin51 (talk • contribs) 07:23, 29 October 2010

Thanks! I am also having a look in my fluid dynamics books. I have to go now, and will come back on it next week. Kind regards, Crowsnest (talk) 11:59, 29 October 2010 (UTC)

Hello Dolphin51, isn't it most useful to work with the relative velocity V_rel=u−v? Where u is the free-stream fluid velocity and v is the wing velocity (both in the same frame of reference). Then the lift force is perpendicular to that V_rel [2]. Force is independent of the frame of reference (provided it is inertial). So that would make the work the same in any inertial frame of reference. Best regards, Crowsnest (talk) 09:18, 5 March 2011 (UTC)

Hello Crowsnest. I agree that the aerodynamic force on an airfoil is proportional to the relative velocity between the airfoil and the remote free stream.

Force (and mass and acceleration) are independent of frame of reference, providing it is an inertial frame of reference. In contrast, displacements and velocities are dependent on the frame of reference. Work is the scalar product of force and displacement so work is dependent on the choice of frame of reference, because of the influence of displacement. The work done by a force will be different in different frames of reference; and the kinetic energy at initial and final states will also be different in different frames of reference; but regardless of the frame of reference the work done will always be equal to the change in kinetic energy (Work-Energy Theorem).

The web site you quoted contains a statement that In order to meet at the trailing edge at the same time, the flow’s velocity on the upper camber is higher than the flow’s velocity on the lower camber which is the notorious equal transit time fallacy and shouldn't be used by any University. Regards. Dolphin (t) 11:30, 7 March 2011 (UTC)

Hello Dolphin51. Oops: I was not focussed on and did not notice the 'equal transit time fallacy' in the quoted web site, but that should indeed not be taught at a university. Also for the rest I agree with you. -- Crowsnest (talk) 22:31, 7 March 2011 (UTC)

User:Gloryjeans

I've given this user a welcome, with a request in the edit summary to read the linked pages. Hopefully, once they have read the linked pages the disruption will stop. Failing that, escalate the warning. For the moment, I'm AGF that their editing is misguided rather that deliberate vandalism. Mjroots (talk) 08:10, 3 November 2010 (UTC)

Thanks for your message. Regards. Dolphin (t) 11:08, 3 November 2010 (UTC)

Transparent metals

Is there anything that you can do for me here ? After a couple of weeks of hard work and doing everything that I have been asked to do by the interested editor, I seem to have reached an impasse. Please advise. Thanks ! logger9 (talk) 03:09, 11 December 2010 (UTC)

Nevermind...I think I have the situation under control now. logger9 (talk) 03:51, 11 December 2010 (UTC)

Flight dynamics (satellites)

Thanks for your discussion on Flight dynamics (aircraft) Talk page.

There is related discussion going on at Talk:Flight dynamics (satellites), on several related topics. Would appreciate your input on any or all of them. (as well, of course, with making improvements to the article.) Cheers. N2e (talk) 17:54, 13 December 2010 (UTC)

Thanks. I will take a look in the next day or two. Dolphin (t) 21:29, 13 December 2010 (UTC)

MfD nomination of User:Logger9

User:Logger9, a page you substantially contributed to, has been nominated for deletion. Your opinions on the matter are welcome; please participate in the discussion by adding your comments at Wikipedia:Miscellany for deletion/User:Logger9 and please be sure to sign your comments with four tildes (~~~~). You are free to edit the content of User:Logger9 during the discussion but should not remove the miscellany for deletion template from the top of the page; such a removal will not end the deletion discussion. Thank you. Chester Markel (talk) 07:16, 23 December 2010 (UTC)

Thanks for notifying me. I have left my comment at Wikipedia:Miscellany for deletion/User:Logger9. The deletion process cannot be used against a User. If a User offends repeatedly it is possible to take action to have that User blocked, but the deletion proces is only applicable to articles and some project pages. Dolphin (t) 11:49, 23 December 2010 (UTC)

2000 Australia Beechcraft King Air crash

Hey there. Thanks a lot for the copy-edit of the article, it's helped readability a lot. With regards to the points you mentioned,

• I've re-written the first part of the lede to clarify where the aircraft crashed.
• I've removed the note about the registration number in the lede, but kept it in the background; to maximise readability of the lede for those unfamiliar with terminology. Unfortunately (and it irritates me too) the "tail number" in the infobox is a parameter which is part of the template (the same problem occurs on all aviation accidents in Australia, for example Ansett Airlines Flight 232 and Trans Australia Airlines Flight 538. The only way around this would be to actually change the formatting of the template.
• I've removed the image.

During the copy-edit you seem to have made the article slightly longer, and it has now been 5x expanded, so I will nominate it at DYK with you as a co-nominator. Thanks again for the excellent copy-edit! wackywace 10:18, 9 January 2011 (UTC)

Happy to help out by being named as a co-nominator. I see what you mean about tail number in the template. I will think about raising this as a technical problem somewhere appropriate. Rgds. Dolphin (t) 10:23, 9 January 2011 (UTC)

Invite

You may be interested to come to the Wikipedia celebration on 15 January in Canberra. see http://ten.wikipedia.org/wiki/Canberra . Graeme Bartlett (talk) 05:47, 10 January 2011 (UTC)

Thanks for the invite. I will investigate my commitments for Saturday 15th. Dolphin (t) 07:07, 10 January 2011 (UTC)

DYK nomination of 2000 Australia Beechcraft King Air crash

Hello! Your submission of 2000 Australia Beechcraft King Air crash at the Did You Know nominations page has been reviewed, and there still are some issues that may need to be clarified. Please review the comment(s) underneath your nomination's entry and respond there as soon as possible. Thank you for contributing to Did You Know! _{Piotr Konieczny aka Prokonsul Piotrus| talk} 20:42, 10 January 2011 (UTC)

DYK for 2000 Australia Beechcraft King Air crash

HJ Mitchell | Penny for your thoughts? 12:03, 17 January 2011 (UTC)

Angle of attack

All the verifcations to my article are in the information above. Self referencing is out. Therefore it is not original research. Aero engineers have a tendency to make simple concepts complilcated so my article is a way of countering that. Neither is it an instruction manual, rather a simple explanation of why something happens. Not sure if this is the right place to answer an querry but I can't find anywhere else to do this. Flags33. — Preceding unsigned comment added by Flags33 (talk • contribs) 01:54, 27 January 2011 (UTC)

Do you really think that what I have written could in any way be original research? Please, be reasonable. I wrote the article because people have a habit of making simple things complicated by using terms that most people don't understand. Any references required are in the article above what I wrote.

Most people in the avaiation industry have no idea why a wing stalls so I have endeavoured to enlighten them. Having been a pilot myself I do know what I am talking about. I have also done enough edits on Wiki to know the rules.

I do not think so called "super editors" such as yourself should cut somebody else's contribution unless it is factually wrong, or is a political rant, or it is a personal position. We know these should not be on Wiki. The whole point of Wiki is that various people add to articles based on their information or what they have available and help to expand everybody's knowledge. That way everyone gains. If you cut then everyone misses out.

Cheers Flags33 — Preceding unsigned comment added by Flags33 (talk • contribs) 04:21, 28 January 2011

On Wikipedia, the expression original research has a special meaning. Its meaning here isn't simply what people generally understand by it, or what a dictionary might say it means. There is a whole document devoted to Wikipedia's policy of No original research. Please read WP:No original research very carefully. The second paragraph of this policy document ends with the following advice:

If no source exists for something you want to add to Wikipedia, it is "original research". To demonstrate that you are not adding original research, you must be able to cite reliable published sources that are both directly related to the topic of the article, and that directly support the material as presented.

So on Wikipedia, if some information is challenged, and there is no source for that information shown in an in-line citation or reference, Wikipedia considers it to be original research. Wikipedia doesn't divide all unsourced information into categories of unsourced information and original research - it simply says it is all original research and therefore violates the policy of No original research. There are many policy documents on Wikipedia, and banners used at the top of articles, saying that unsourced information is considered to be original research and may be removed.

It is easy to place new material on Wikipedia, based on stuff we know to be true. It becomes much more difficult when we have to find a published source to allow independent verification of that new material. Many Users don't like that policy and so leave Wikipedia - they like just writing stuff they know to be true without having to find published sources and provide them as in-line citations. Wikipedia is an encyclopedia, just like any other encyclopedia. It isn't a guide book or instruction manual. If you like writing stuff about aviation you might find a blog site dedicated to aviation topics more to your liking. Happy editing! Dolphin (t) 07:07, 28 January 2011 (UTC)

Thanks

Thanks, if I need any help I will ask you. :) --Rattakorn c (talk) 11:29, 15 February 2011 (UTC)

Hi Rattakorn c! Yes, please do that. Dolphin (t) 11:32, 15 February 2011 (UTC)

Yea on abortion, bottommost, there is a rating bar. I've never seen it before on any other articles and when I clicked edit I can't see any codes behind it. Do you have any links to explanation for this (perhaps) new feature of Wikipedia? --Rattakorn c (talk) 15:06, 15 February 2011 (UTC)

Good question! I have never seen the rating bar before and I haven't been able to find anything in the short time I have been looking. I suggest you post your question at the WP:Help desk, just asking for a link to some background information. You will find someone will post an answer within half an hour or so, perhaps less. Dolphin (t) 20:37, 15 February 2011 (UTC)

I've got an answer now. It's automatic feedback tool and the with this feature are only the US state policy articles. Thanks for advice. --Rattakorn c (talk) 04:02, 16 February 2011 (UTC)

The Help desk worked really well! Your first answer after only four minutes. Thanks for letting me know. Dolphin (t) 05:03, 16 February 2011 (UTC)

Science Desk question edit

Hi Dolphin51, you may want to see the discussion related to your edit. While your change was undoubtedly a good-faith effort to improve the quality of this "question," other regular editors on the reference desk do not think it is a good idea to modify the original form of the question - even in this case. Nimur (talk) 19:03, 19 February 2011 (UTC)

Thanks very much for alerting me to the discussion. I have added my own thoughts at the relevant thread on WT:Reference desk. Dolphin (t) 06:11, 20 February 2011 (UTC)

Thanks for the welcome

Thanks.

glad to join in. I'll look through those links. Those acronyms are university departments. I've filled them out. Getting the hang of things here, gradually.

I'll see how I go with this, but I kind of feel like as I'm doing a phd in fluids, I could at least contribute a bit to wikipedia. — Preceding unsigned comment added by Chogg (talk • contribs) 03:21, 24 February 2011 (UTC)

--Chogg (talk) 03:25, 24 February 2011 (UTC)

Chogg (talk) 03:26, 24 February 2011 (UTC)

Ben Chifley Dam

I have updated the dead link on the Ben Chifley Dam article. Thanks - Cartman02au (talk) 10:41, 12 March 2011 (UTC)

Thanks for that. Dolphin (t) 12:06, 12 March 2011 (UTC)

John P. Merrill

By way of introduction, my name is John Coster-Mullen and I’m the author of Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Look me up on the internet. There are literally hundreds of listings for me, including a major cover story in the 12/15/08 issue of The New Yorker. Over the years, literally thousands of people have claimed to have been on the atomic missions. It is widely acknowledged by every historian that 12 men, and only 12 men, were inside the Enola Gay on the August 6, 1945 mission to bomb Hiroshima. These names are written in the history books. All the newspaper accounts from that time list 12 names. Spend some time, go to your local library, and dig out the New York Times microfilms, the Life Magazine collections, Time Magazine, etc. that will show you all the dozens of articles written in August 1945 about what was the most important event of WWII. They have detailed stories about all the crewmembers. John P. Merrill was not mentioned even one time. There were no flight surgeons onboard any of the planes. Indeed, why should there have been?

This is the official listing as shown in my book.

Enola Gay, 45-MO-44-86292, V-82, Strike Aircraft

           Commander                Col. Paul W. Tibbets
           Co-Pilot                       Capt. Robert A. Lewis
           Navigator                    Capt. Theodore J. Van Kirk
           Bombardier                 Maj. Thomas W. Ferebee
           Weaponeer                 Capt. William S. Parsons USN
           Electronics Test Ofc.   2nd Lt. Morris R. Jeppson
           ECM                            1st Lt. Jacob Beser
           Flight Engineer            S/Sgt. Wyatt E. Duzenbury
           Ast. Flight Engineer     Sgt. Robert H. Shumard
           Radar                          Sgt. Joseph A. Stiborik
           Radio                           Pfc. Richard H. Nelson
           Tail Gunner                 S/Sgt. George R. Caron

I’m certain Mr. Merrill was indeed, an important surgeon who made tremendous accomplishments in his field. However, he was not connected in any way with the 509th or the Hiroshima mission. This is a simple historical fact borne out by the full weight of historical evidence. The 1984 NYT article claiming Merrill was in the Enola Gay is false.

As far as who the actual surgeon was who handed Tibbets the pills, that would have been one of the 509th Composite Group members, and only one of the 509th members, and that person was Don Young, a member of the 393rd Bombardment Squadron that made up the core of the 509th. The 509th was an entirely self-contained air group and all had passed intensive security clearances from the FBI. For the most part they did not mingle with the other air groups on Tinian and certainly did not use personnel from these other air groups since they did not possess the same security clearances as the 509th. This security wall was never breached. Many of us have the entire listing of all the men in the 509th and that came primarily from the original 509th “yearbook” published shortly after the war ended. This master list was updated and collated in 1995 by Fred Bock and his wife using not only that original list, but other sources including group photos from 1944-45. Fred was one of the 15 509th airplane commanders and was on the Nagasaki mission commanding the Instrumentation Aircraft The Great Artiste. The name “John P. Merrill” does not show up on any of the listings of the 509th. That is a simple, historical fact not changed by how much dis-information from the notoriously misinformed internet. I can also assure you the Smithsonian National Air and Space Museum (NASM) has the list of those 12 people that were inside the Enola Gay (EG) since it is on permanent display in their Udvar-Hazy building at Dulles Airport in DC. I personally know the man that was in charge of the EG restoration (I’ve been inside the EG for several hours on two occasions) for almost his entire career with the NASM and I can assure you the name John P. Merrill is definitely not on their list.

Paul Tibbets commanded not only the Enola Gay, but also the entire 1,800+ members of the 509th. He was tasked by General Ent with forming this group in late 1944. It was his crowning achievement in WWII. Tibbets own autobiography, in all its various editions, has always stated the following.

---

When we were about to leave the mess hall, flight surgeon Don Young came to my table and slipped me a small cardboard pillbox. “I hope you don’t have to use these,” he said, trying to be cheerful. “Don’t worry. The odds are in our favor,” I replied, slipping the box into a pocket in my coveralls. However casual we tried to be, the subject was grim. The pillbox contained 12 cyanide capsules, one for each member of the Enola Gay crew.

---

I consider this as the definitive primary source for who handed him this box. Quite honestly, these atomic bombings were the most important events of the 20th Century and right from the beginning, everybody wanted to get in on this story. As historians, we have fended off countless thousands of people who have claimed over the last 66 years to have been in the Enola Gay (or one of the six other planes on that mission), flew fighter escort (didn’t happen), were on Tinian, or connected with the 509th in one way or another. The standing joke in the 509th is that if all the men who claimed to have been on Tinian in 1945 were actually there, the island would have sunk to the bottom of the Pacific! Almost all of these claims have proven false. Sometimes these are just claims by family members of a deceased loved one who had been telling a tall tale since he returned home after the war, but other times they have even sadly included members of the 509th themselves, who, as they got on in years, tried to embellish their roles somewhat. As historians, we have struggled to remain objective, relying strictly on the massive amount of historical records relating to these atomic bombings to prove/disprove each claim as they come up. I was one of the people who helped write the official 509th Press Release last year that was instrumental in countering the fallacious clams of Joe Fuoco in the book Last Train From Hiroshima. Fuoco tried to claim he was the Flight Engineer on the Hiroshima Photo Plane

Regards, John Coster-Mullen — Preceding unsigned comment added by Atomicjohn (talk • contribs) 04:01, 18 March 2011 (UTC)

Thank you very much. That is very interesting indeed. I guess it shows that people will believe whatever they want to believe, and just about anything will be accepted as evidence. Regards. Dolphin (t) 05:38, 18 March 2011 (UTC)

Thank you Dolphin for responding. Will Wiki now remove the erroneous information about Dr. Merrill's claimed involvement with the Enola Gay and the Hiroshima mission? This is currently a problem for myself and the other 509th historians since another article about Dr. Merrill is about to be published and this author is citing Wiki, along with the original erroneous NYT obit, as one of his definitive sources to prove Merrill's involvement with the Hiroshima mission. It seems lately we all have been struggling with defending the 509th against such false claims and it has almost become a full-time effort on our part. The only surviving member of the Enola Gay flight crew, the navigator Dutch Van Kirk, has been made aware of this current claim and states emphatically Merrill had nothing to do with the mission, the Enola Gay, and the 509th.

Regards, John Coster-Mullen —Preceding unsigned comment added by 69.217.165.167 (talk) 18:56, 18 March 2011 (UTC)

Thanks John. After examining closely our statement in John P. Merrill it became clear that it went beyond what was stated by Lawrence Altman in his obituary in the New York Times. Wikipedia places great importance on statements being verifiable using reliable published sources, and preferably secondary sources. (See WP:Verifiability.) Seeing you have challenged our statement, and challenged it very persuasively, the statement must be removed. I have done so. Dolphin (t) 04:10, 19 March 2011 (UTC)

Thank you Dolphin51 for your welcome, your kind comments, and your help. Check out my user page.Atomicjohn (talk) 13:23, 21 March 2011 (UTC)

Hi John. I have checked your User page. It looks good! I hope to see more of your work around Wikipedia in the near future! Don't hesitate to ask me for assistance at any time if you think I might be able to help. Dolphin (t) 22:22, 21 March 2011 (UTC)

Please tell me how to add and/or change footnotes and references.Atomicjohn (talk) 20:45, 23 March 2011 (UTC)

Thrust/Torque ratio

Hey, thanks for replying to my post on the reference desk. I had another question: Can you let me know the expression for Thrust/Torque of a propeller? Regards, Yes Michael? •^Talk 11:39, 20 March 2011 (UTC)

i.e: Ratio of Thrust to Torque. Yes Michael? •^Talk 11:47, 20 March 2011 (UTC)

Thrust, torque and thrust-to-torque ratio all vary strongly with advance ratio. (They also vary weakly with Reynolds number and Mach number.) For any given advance ratio, the thrust coefficient, torque coefficient and power coefficient will each be unique for each design of propeller. They can be determined by measurement using the propeller in a wind tunnel or other suitable test equipment. The measurements can then be used to calculate the three coefficients and create a diagram to show the empirical relationships between advance ratio and each of the three coefficients. This is the same as testing an airfoil in a wind tunnel and creating a diagram to show the relationship between angle of attack and lift coefficient and drag coefficient. Dolphin (t) 22:57, 20 March 2011 (UTC)

Have a look at Figure 2 in THIS web article. Dolphin (t) 03:48, 21 March 2011 (UTC)

Thanks for the welcome

and for the nice re-wording of that section. However, I had to correct a minor glitch (hope my English is OK).--Ilevanat (talk) 12:31, 31 March 2011 (UTC)

I agree with your correction. No problem with your English! Best regards. Dolphin (t) 21:18, 31 March 2011 (UTC)

Propeller driven trains

Hi Dolphin51. I reverted your edits to Schienenzeppelin and Land speed record for rail vehicles, as the propeller article is perfectly proper for rail vehicles, which are not aircraft. If you disagree, please discuss it here (I'll watch this page for a while).

There may be other topics, such as hovercraft, for which the main propeller article is more appropriate than "Propeller (aircraft)". I did have a quick look through the other similar changes you did, but they mostly look like genuine aircraft related articles for which the change is quite proper; I'll leave it to you to revert any others that weren't. Tim PF (talk) 07:10, 5 April 2011 (UTC)

Thanks Tim. I have been working on the principle that if a propeller operates in air the article Propeller (aircraft) is the more appropriate, regardless of whether it is an aircraft; and if a propeller operates in water the article Propeller is the more appropriate, regardless of whether it is a boat, ship, submarine etc. There is substantial commonality to the shape, rotational speed and pitch-changing characteristics of all propellers that operate in gases, and equally substantial commonality to the shape, rotational speed and fixed-pitch characteristics of all propellers that operate in liquids. The reason for this lies in the many differences between aerodynamics and hydrodynamics.

I probably won't revert any changes of the kind you made. If one person considers the Propeller article to be more appropriate there will be many others too, so it won't be a problem and won't be worth my effort changing things - too many genuine aircraft articles to be dealt with! Regards. Dolphin (t) 08:05, 5 April 2011 (UTC)

First I note that Andy Dingley (talk · contribs) re-reverted Schienenzeppelin (Maybe the vehicle isn't an aircraft, but the point is that it did use an airscrew.). I would be happy to go along with that argument if the propeller and propeller (aircraft) articles had a clearer divide between water and air media.

That, would probably mean a considerable change the propeller, possibly with a split to give a propeller (marine) article, with the original article retaining the history and other commonalities, with pointers to propeller (water) and a renamed propeller (air).

This would need more discussion, and a move the article talk page(s). I'm dropping a note to Andy that we're already discussing it here. Tim PF (talk) 10:01, 5 April 2011 (UTC)

I just realised that Andy used the term "airscrew", which is currently a DAB page, but might be a better title for propeller (aircraft) (none of the other links use the term "airscrew" -- windmill refers to Archimedes screws). Tim PF (talk) 10:15, 5 April 2011 (UTC)

I think the most important aspect is the information the reader finds after he selects a blue link. The title of the article is unimportant. So if the application is a propeller in air it is important that the blue link takes the reader to information about propellers operating in air. Whether the article is called Propeller (aircraft) or Airscrew or Propeller (air) is unimportant. Dolphin (t) 12:26, 5 April 2011 (UTC)

• My two-pennorth.
  • Propeller is too big an article. Ideally this should end up (like radiator) as an overall article, more than a disambig, but with most of the content as sub articles, such as propeller (aircraft) and propeller (marine).
  • Schienenzeppelin should use propeller (aircraft), because that's what the real vehicle used. If there's anything missing (which I rather doubt), then fix it. If there's anything better in propeller, then fix that too by editing between propeller] and propeller (aircraft). The Schienenzeppelin used an airscrew, for propulsion through the air. It didn't use some hypothetical "ballast propeller" like those screw-driven snow vehicles, this really was an airscrew, driving purely on the air.
  • Airscrew should be deleted as a disambig and converted to a redirect to a note within Propeller (aircraft). It is an obsolete British term for propeller, which was deliberately removed from RAF service prior to WW2 as it could be confused too easily with "aircrew" (i.e. pilots). None of those other claimed disambigs have any credible history for being described as "airscrews".

Andy Dingley (talk) 13:24, 5 April 2011 (UTC)

That sounds fairly good to me, but I wonder if the devil will be in the detail. Radiator is a good prototype, but the "Heating" section is rather brief), whilst the following "Engine cooling" is about 4 times as long. I can certainly see that, as a default link, there's probably enough meat to save many readers needing to click through to the {{main}} articles.

Both Propeller and propeller (aircraft) have some rather intricate mathematical bits, which may be over the head of the average reader. If the most part of the "Marine" section is moved into Propeller (marine), there will still be a good background article at propeller, and readers can click on the {{main}} links for the finer details.

But that then takes me back to where I came in, with propeller driven trains linked into propeller (aircraft). If Schienenzeppelin were written in the future, and its editor wrote that it was "[[propeller]] driven", the link would give a good background to propellers (both air and sea), and would be quite appropriate.

I can understand that it can sometimes be a fine line as to whether to link to a general article or a more specific article, and I also think it may be hard to see what will work best until the Marine section is split off. I also think that a useful note could be added to propeller that Aviation propellers are used for other vehicles, such as hovercraft and some trains.

I've now set the {{split section}} tag and added that note. Tim PF (talk) 23:27, 8 April 2011 (UTC)

Capacitors in series

As I said in my edit summary, your version is wrong. Consider 1uF/200V and 1uF/400V in series across 600V. Total rating of 600V, but sorry, the 200V capacitor is going to go bang - it has 300V across it. Try 1uF/300V and 2uF/300V - sorry, 1uF goes bang, it has 400V across it. This is not application information, it is basic circuit analysis. It is also necesary to say that calculating voltage division by caapacitance usually fails at DC (or low frequency). This is similar to even basic descriptions of the transformer saying they will not pass DC, even though the ideal transformer in analysis will do so. The division in these circumstances is series resistor division by the capacitor leakage resistance.

I have not reverted you because I am insisting on this staying, but you cannot summarize this in the way you wish. If you think this is a diversion, then it will be neceasary to pretty much remove the whole passage. Although moving it to a more suitable location (capacitor/capacitance?) would be kinder to the original editor. SpinningSpark 07:22, 5 April 2011 (UTC)

Thanks very much for contacting me on my Talk page. Many editors just revert and walk away without any attempt to find a compromise.

I think we agree that off-topic material shouldn't be allowed to remain. It should be moved to a more appropriate place. I have hidden the contentious paragraph so it will still be there in case we decide some part of it should be retained, but it is no longer visible to confuse readers trying to comprehend the basics of series circuits.

I left a sentence saying something about "the voltage across two or more capacitors in series is equal to the sum of the voltages across individual capacitors." If you see an error in this statement, please fix it. Bear in mind this is an introductory article about series and parallel circuits. I'm sure you agree that series and parallel circuits is one of the most basic concepts in the subject of current electricity. To explain this basic concept it is neither necessary nor appropriate to confuse the reader with detail about micro Farads or 400V or 500V.

I have some serious problems with the paragraph I originally removed:

The working voltage of a series combination of identical capacitors is equal to the sum of voltage ratings of individual capacitors. Working voltage has not yet been explained, nor is there any linking to any place that will explain it. This statement is about identical capacitors - what about connection of non-identical capacitors? Voltage rating has not yet been explained, nor is there any linking to any place that will explain it.

This simple relationship only applies if the voltage ratings are equal ... This much of the sentence makes sense. But the words ... as well as the capacitances ... are then attached. What is the meaning of the expression as well as the capacitances when it is attached to the to the end of a perfectly good sentence?

However, the division of DC voltage between the capacitors is dominated by the leakage resistance of the capacitors, rather than their capacitances, and this has considerable variation. I think whoever originally wrote that was trying to display how much he knew about electrical engineering, not trying to write a clear explanation of a very simple concept. And the same can be said for the remainder of the paragraph.

So please now help me. Take the article back to where it was when you found it ("the voltage across capacitances in series etc") and use your obvious knowledge of the subject to turn it into something that is technically correct, clear and easy for a newcomer to the subject to understand. Thanks. Dolphin (t) 07:55, 5 April 2011 (UTC)

There's no point working on it if it is not staying in the article. But note that there is a section on capacitors in series in the capacitor article where it might sit better. To answer some of your specific points:

• I don't think working voltage and voltage rating particularly needs explaining, but the capacitor article has a section on "breakdown voltage" which is the primary limitation to capacitor working voltage.
• Simple addition of voltage ratings only applies to identical capacitors (and perhaps a few other very special arithmetical cases). Examples with non-equal capacitances and ratings I have given already. It is probably easiest to understand this by such examples, but if you want a general formula, it can be expressed in terms of the floor function;

$V_{\mathrm {R} }=\left\lfloor V_{\mathrm {R} n}{\frac {C_{n}}{C_{\mathrm {T} }}}\right\rfloor$

• I think you are right that details of equalising resistors is too detailed for the series and parallel article (but again, could be in capacitor article) but it still needs stating that voltages do not distribute according to capacitance at DC.

SpinningSpark 21:11, 5 April 2011 (UTC)

I have removed all the text previously following the equation about reciprocals of capacitances. Immediately below the heading I have added a link to Capacitor#Networks. New material can now be added to exlain the principle of capacitors in series, and that new material can be monitored by interested Users to ensure it is suitable. To be suitable it should be clearly presented and pitched at a level appropriate to an introductory explanation of series and parallel circuits. Dolphin (t) 23:19, 5 April 2011 (UTC)

Spin page

Thanks for your comments; as you can probably surmise that was my first try at editing a wiki page and I did not intend to step all over someone else's work; I was looking for (but failed to find because it does not exist) the function to "check in my changes as a proposalso that other interested page editors can see them. I will make further comments on the discussion pageChrisOwensBoston (talk) 17:37, 26 April 2011 (UTC)

As a first try at editing a Wiki page you did very well! Most of us don't attempt anything nearly so challenging as your first edit. You will find you are on a steep learning curve and in no time you will feel completely at home. Don't be concerned if your edits are sometimes removed or edited - it happens to all of us, even after a few thousand edits.

I will reply to your comments on the Discussion page.

It is possible to work industriously at improvement of an article without having to finish in one day or have other Users looking over your shoulder. Many of us have a personal sandbox. I am presently using my personal sandbox to develop some improvements to the article on Dynamic pressure - see HERE. When I have finished I will post a message on the Discussion page for Dynamic pressure alerting interested Users to my changes and inviting their comments. If and when there is some sort of consensus I can copy everything in my personal sandbox and paste it into the article. To start your own personal sandbox just type [[/Sandbox]] anywhere on your User page - User:ChrisOwensBoston - and then Save. It will appear on your User page as a red link. Double click on the red link and it will open up as a new blank page ready for you to write or paste whatever you want, and then you can work on it undisturbed by the rest of the world. For more information about starting a personal sandbox see WP:USERSUBPAGE. Dolphin (t) 05:26, 27 April 2011 (UTC)

Replies and Threading

Regarding the issues on the Reference Desk Talk page (replying here to avoid clogging the RefDesk with side chatter), while I've seen the @ convention on other boards (usually those that don't support threaded discussion), my understanding and experience was that Wikipedia talk pages generally use threaded discussion and indentation instead. As Wikipedia:Talk page guidelines#Layout puts it:

• "Use indentation as shown in Help:Using talk pages#Indentation (or, more specifically, Wikipedia:Indentation) to clearly indicate who you are replying to, as with usual threaded discussions."

I thought you were following that convention, which is why I was confused. Cheers. -- 174.31.219.218 (talk) 05:57, 2 May 2011 (UTC)

Understood. Thanks for making use of my Discussion page in this way. I understand you have been contributing to Wikipedia for quite a while, always with an IP address. Please seriously consider registering and editing under a recognisable name. There are many advantages. You will be aware of a number of the Users who regularly inhabit the Reference Desks - Baseball Bugs, Nimur, Wnt, Nil Einne, Jayron32, TenOfAllTrades etc. We quickly develop an understanding of their style, their strengths, their weaknesses and their idiosyncrasies. This assists us to help Wikipedia by taking into account these Users' individual characteristics. In contrast, who memorises the set of ten, eleven or twelve digits for an IP address? We are unable to deal very well on an individual basis with anonymous contributors, and this devalues every contribution they make to a Discussion forum. I often find that my eye goes immediately to the postings from named Users, particularly Users I recognise, whereas my eye skims over postings that come from an IP address. Please seriously consider registering. Many thanks. Dolphin (t) 08:01, 2 May 2011 (UTC)

Hello Dolphin51

After a quick review of the fluid dynamics project page and your talk page it is more than apparent that you and your peers should be the final judge of some work i recently contributed to centrifugal compressor. I am a mechanical engineer with poor mathematical skill. i am not even certain if i am describing my problem correctly. the fundamental analysis section can be written in several ways. vector form or partial differential form; polar or cartesian; abbreviated or expanded. as being in both aviation and fluid dynamics projects, i thought this would be the best place to start. who is available that might be interested in reviewing this contribution?Mkoronowski (talk) 22:08, 24 May 2011 (UTC)

You have done a lot of very good work to improve the Centrifugal compressor. Congratulations on all of that; and thank you for asking me to review it. I will do so progressively over the next few days. So far, I have only looked closely at the introduction and the section about the pioneers.

The second and third paragraphs of the introduction begin In and idealized sense, and In other words. These expressions are colloquial and rarely used in formal written English, such as in an encyclopedia. If they are removed, the sentences will not lose any of their formal meaning so these expressions are most likely redundant and can be deleted.

The section about the pioneers begins The above explanation may seem trivial, but it is actually quite complex. This looks like someone’s opinion. No in-line citation (or reference) is given so I assume this sentence represents your personal view on the subject, rather than a view expressed in a reliable published source. On Wikipedia, any statement that is challenged, or is likely to be challenged, should be supported by an in-line citation to allow independent verification. Wikipedia does not publish original research. If a statement is challenged and it cannot be supported by an in-line citation, that statement is considered original research and is likely to be removed, regardless of whether it is factually correct. See WP:VERIFY.

In the section about the pioneers, the second and third paragraphs are not supported by an in-line citation to allow independent verification that they come from a reliable published source. Are you able to identify a reliable published source, either by inserting an in-line citation or a general reference(s) that applies to the whole article? If so, please insert a reference to identify a suitable source, otherwise readers will assume it is your personal view and therefore original research.

I will look further through the article in the next few days and post my comments here. Dolphin (t) 02:55, 28 May 2011 (UTC)

thankyou, Mkoronowski (talk) 05:27, 2 July 2011 (UTC)

Deletion of Pretoria, Georgia

Someone edited it. Hold on, I'll fix it. Pfft no need to be rude. Violeta123321 (Violeta123321 —Preceding undated comment added 06:32, 5 June 2011 (UTC).

Legalistic Sophistry

Hello Dolphin51: Thanks for your response to Mwalcoff on the help desk talk page. I was drafting something along a very similar line. "Sophistry" was in my draft, also "hairsplitting". "Pedantic" did not come to my mind but it is very apt. I had the identical quote from WP:BLP that you used.

Eventually I concluded than Mwalcoff's decision to bring the redacted name back into the discussion page, not once but three times, and totally unnecessarily, meant that he was interested in defying the policy, not in respecting its "if in doubt err on the side of caution" approach. At that point I abandoned my draft. Thanks for persevering. Wanderer57 (talk) 04:40, 8 June 2011 (UTC)

Thanks for your support, both here and on the Reference Desk Discussion page. I agree. There appears to be a small number of regulars at the Reference Desk Discussion page who regard the questions as sacrosanct, not to be edited in any way and not to be deleted. I sse it differently - asking a question and getting an answer is a privilege, not a right. If a question doesn't conform to Wikipedia's standards then that question should be edited or even deleted. WP:BLP is definitely of higher importance than any question to the Reference Desk, but I think there is a few who see it differently. Best regards. Dolphin (t) 07:34, 8 June 2011 (UTC)

Speedy deletion declined: Debiganj Girls' High School

Hello Dolphin51. I am just letting you know that I declined the speedy deletion of Debiganj Girls' High School, a page you tagged for speedy deletion, because of the following concern: A7 does not apply to schools. Thank you. Courcelles 06:18, 12 June 2011 (UTC)

Speedy deletion declined: Debiganj N.N.Govt.High School

Hello Dolphin51. I am just letting you know that I declined the speedy deletion of Debiganj N.N.Govt.High School, a page you tagged for speedy deletion, because of the following concern: A7 does not apply to schools. Thank you. Courcelles 06:19, 12 June 2011 (UTC)

Speedy deletion declined: Debiganj Riverview Girl's High School

Hello Dolphin51. I am just letting you know that I declined the speedy deletion of Debiganj Riverview Girl's High School, a page you tagged for speedy deletion, because of the following concern: A7 does not apply to schools. Thank you. Courcelles 06:19, 12 June 2011 (UTC) Courcelles is right of course - schools are exempt from A7, but any other CSD can be used if applicable. Kudpung กุดผึ้ง (talk) 06:14, 16 June 2011 (UTC)

I've left a reply for you on my talk page. --Kudpung กุดผึ้ง (talk) 02:22, 17 June 2011 (UTC)

Thank you! Dolphin (t) 07:33, 19 June 2011 (UTC)