User talk:Mangogirl2

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Welcome!

Hello, Mangogirl2, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or ask your question and then place {{helpme}} after the question on your talk page. Again, welcome!  Mak (talk) 03:57, 21 March 2007 (UTC)

Contents

[edit] The Military history WikiProject Newsletter: Issue XIII - March 2007

The March 2007 issue of the Military history WikiProject newsletter has been published. You may read the newsletter, change the format in which future issues will be delivered to you, or unsubscribe from this notification by following the link. Thank you.

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[edit] The Military history WikiProject Newsletter: Issue XIV (April 2007)

The April 2007 issue of the Military history WikiProject newsletter has been published. You may read the newsletter, change the format in which future issues will be delivered to you, or unsubscribe from this notification by following the link. Thank you.

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[edit] Pulsed rocket motors

Good job getting the refs for the article. It is easy to format a simple ref like that, just type it in like this:

<*ref>put the ref text here</ref>

Don't actually enter the asterisk (*) that I put in the first expression, that's only there to keep everything visible, otherwise it collapses into an actual ref like this:

[1]

You can always go to the article and click on "Edit this page" to see exactly how it should look when you type it in. Good luck, and feel free to contact me if you have any questions. Doc Tropics 21:12, 22 May 2007 (UTC)

[edit] The Military history WikiProject Newsletter: Issue XV (May 2007)

The May 2007 issue of the Military history WikiProject newsletter has been published. You may read the newsletter, change the format in which future issues will be delivered to you, or unsubscribe from this notification by following the link. Thank you.

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[edit] The Military history WikiProject Newsletter: Issue XVI (June 2007)

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[edit] King George Elementary School

King George Elementary School has been proposed for deletion. An editor felt the subject might not be notable enough for an article. Please review Wikipedia:What Wikipedia is not and Wikipedia:Notability for the relevant guidelines. If you can improve the article to address these concerns, please do so.

If no one objects to the deletion within five days by removing the "prod" notice, the article may be deleted without further discussion. If you remove the prod notice, the deletion process will stop, but if an editor is still not satisfied that the article meets Wikipedia guidelines, it may be sent to Wikipedia:Articles for deletion for consensus. NickelShoe (Talk) 00:04, 12 July 2007 (UTC)

The fact that a category exists doesn't mean anything that fits in the category belongs in an encyclopedia. There is, for instance, a Category:1983 births, but that doesn't mean I need an article just because I've been born. What you most need are secondary sources, not only to demonstrate notability, but also to comply with Wikipedia:No original research. 23:27, 17 July 2007 (UTC)

[edit] KIng George Elementary School

A few points here...

  • When you leave someone a message, please do it at the bottom rather than the top of their page. (but that's not important)
  • A topic need to establish some form of notability in order to have notability. For instance, I could fling a rubber band held with my toes at my cat. My friends could start doing it as well. Maybe our whole little town is doing it. But a person in San Diego doesn't need to know about it.
  • My school is in AR and the PTA as well. It doesn't have an article. It doesn't need one. It lives on in the hearts and mids of the 400 or so people who attend it. It might even help it if weren't your school.

†Ðanieltiger45† Talk to meas 15:42, 17 July 2007 (UTC)

[edit] Military history WikiProject coordinator selection

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[edit] Military history WikiProject coordinator election

The Military history WikiProject coordinator election has begun. We will be selecting nine coordinators from a pool of fourteen candidates to serve for the next six months. Please vote here by August 28! Kirill 17:43, 18 August 2007 (UTC)

[edit] The Military history WikiProject Newsletter : Issue XVIII (August 2007)

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[edit] The Military history WikiProject Newsletter : Issue XIX (September 2007)

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[edit] The Military history WikiProject Newsletter : Issue XX (October 2007)

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[edit] The Military history WikiProject Newsletter : Issue XXI (November 2007)

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[edit] Neutral point

Dear Mangogirl2. Many thanks for your enquiry (to my Talk page) on the subject of Neutral point. When I first visited Center of pressure I saw a number of errors. The worst was "The center of pressure must lie behind the center of gravity for a positive static margin and static stability." This is incorrect because the center of pressure of an airfoil moves as angle of attack changes. Up until 7 July 2007 there was a sentence that captured that sentiment. Under "Historical useage", it said "... the center of pressure may be located an infinite distance forward or behind the airfoil."

The center of pressure on the main wing of an aircraft can lie behind the aircraft! On 15 November I rectified the 7 July deletion by inserting a few paragraphs to explain the movement of the center of pressure.

The article on Center of pressure actually talks about the center of pressure of an aircraft, not just an airfoil. This is odd because, providing thrust and drag act through a common point, the center of pressure on an aircraft in straight, level flight will always be located exactly at the center of gravity. (This statement comes from consideration of basic statics. In straight, level flight weight is equal but opposite to the lift on the whole aircraft.) Otherwise the aircraft would be accelerating nose-up or nose-down! It is not valid to say the center of gravity must lie ahead of the center of pressure of the aircraft. In straight, level flight the contribution of the horizontal stabilizer will always act to bring the center of pressure of the whole aircraft in line with the center of gravity.

It is reasonable to talk about the center of pressure of an airfoil, but not the center of pressure of an aircraft. The true value of an understanding of the center of pressure on an airfoil is that it leads to an understanding of aerodynamic center, and it is the aerodynamic center that is of fundamental significance in a study of longitudinal stability. For stability in a tailless aircraft, the center of gravity must not lie behind the aerodynamic center. In a conventional aircraft with a horizontal stabilizer, the stabilizer adds to the stability of the aircraft so that the most aft position of the center of gravity lies behind the aerodynamic center by an amount that is proportional to the tail volume - the planform area of the stabilizer multiplied by the moment arm of the stabilizer about the aerodynamic center. So the location of the center of gravity for neutral static stability in a conventional aircraft is a small distance aft of the aerodynamic center. That point is known as the neutral point. (For longitudinal dynamic stability, the most aft point is known as the maneuver point.)

You have convinced me that, at present, neutral point is something of an orphan. In the near future, I will enhance the information on the subject so it is not so much of an orphan.

There is already some good information at Pitching moment although it is a bit too long on mathematics and short on information for the non-mathetician.

Feel free to write to me again. Best regards. Dolphin51 03:08, 4 December 2007 (UTC)


Hi again. I will begin by moving Neutral point out of Center of pressure and creating an article of its own. It sounds as though the use of center of pressure in missile engineering is specialised and significantly different to aircraft engineering. (Perhaps a missile behaves like a symmetrical airfoil - there are no cambered missiles!) It will then be desirable to sub-divide Center of pressure into "Aircraft" and "Missiles" so readers can see the two different applications. If you agree feel free to create a new sub-heading devoted to missiles, and I will do the same for aircraft. The revised "Center of pressure" could provide links to "Static margin", "Aerodynamic center" and "Neutral point". What is epsilon angle of attack? Dolphin51 (talk) 20:33, 5 December 2007 (UTC)

Hi again. I have created a new article called "Longitudinal static stability". I transferred a lot of material on this subject out of "Pitching moment". I also transferred the material on neutral point out of "Center of pressure". Feel free to develop "Center of pressure" by creating a sub-heading devoted to missiles and the significance of center of pressure in analysing those vehicles. Regards Dolphin51 (talk) 10:57, 10 December 2007 (UTC)

Hi again. If you visit Longitudinal static stability, then go to para 5.2 Static stability, you will find a definition of static margin h. Someone has written "h is known as the static margin. For stability it must be negative." For consistency within Wikipedia I have written that positive stability is associated with a negative static margin, and vice versa. In the next week I hope to add some references to the article on Longitudinal static stability. While I am checking those references I will look for confirmation of the above. Best regards. Dolphin51 (talk) 11:21, 13 December 2007 (UTC)

And again. I have added three references to Longitudinal static stability. Irving defines the static margin as -dCmg/dCL. He states (page 31) that the negative sign is to ensure a positive static margin accompanies positive static stability. He also says this criterion for static margin "is that generally used in British practice." He goes on (page 39) to write about the distance between the neutral point and the CG, and calls it the "c.g. margin". This approach is logical but it is different to what is written in WP under Longitudinal static stability. Aerodynamics for Naval Aviators does not appear to mention static margin. Clancy is consistent with Irving (both British!) although Clancy uses both 'static margin' and 'c.g. margin' as though they are synonymous. Perkins and Hage, (Airplane Performance, Stability and Control) is a respected US book on the subject. I will try to check it out in the coming week to see what it says about static margin, and whether it is conventionally positive for positive stability, or negative. Regards Dolphin51 (talk) 00:55, 14 December 2007 (UTC)


Hi MG2. I have looked at Perkins and Hage. They talk about dCmg/dCL, and hN-h, but without giving them a name. I saw no comment about whether these terms must be negative or positive for stability. I found a very good reference in Aerodynamics, Aeronautics, and Flight Mechanics by McCormick, Barnes W. (1979), John Wiley & Sons Inc., New York NY. McCormick defines the static margin as hN-h where hN is the location of the neutral point and h is the location of the CofG. Defined in this way, static margin is positive when the CofG is ahead of the neutral point and the aircraft has positive stability, which is good. I have not yet seen a reference (other than WP) where static margin is defined in such a way that positive stability requires a negative static margin. Longitudinal static stability makes reference to N.A.V. Piercy's book in the vicinity of the comment about negative static margin for positive stability, so perhaps Piercy is the source. I have access to Piercy's book (Elementary Aerodynamics) so I will check to see if that is so. (Piercy is also British.)

I have visited the reference you gave me to the NASA web site. It is very relevant and I now have a better understanding of CofP as applied to missiles. I see that a missile (as opposed to a cruise missile) has no lifting surfaces other than the fins which only generate lift when the body of the missile is not aligned with the relative airflow. I think your recent changes to Center of pressure are very good in that they distinguish between missiles and aircraft, and allow the different applications of center of pressure to be clear. The missile is a symmetrical body and therefore the center of pressure does not move as angle changes. As a result, center of pressure is suitable for use in stability considerations. In contrast, on a cambered airfoil, center of pressure does move significantly as angle of attack changes, so center of pressure is not suitable for use in stability considerations and aerodynamic center is defined. On a missile, it appears to me that center of pressure and aerodynamic center are co-located, so the added complication of aerodynamic center is not necessary. Best wishes for 2008. Dolphin51 (talk) 10:41, 27 December 2007 (UTC)


  • Hi MG2! Thank you for your positive reaction to the work I did in tidying up Static Margin. I'm no expert on Static Margin so I was approaching the article the way I thought a first-time reader would, and trying to anticipate what the first-time reader would be thinking. I must admit that as I made changes I was thinking "I hope MG2 won't mind me changing this".
  • Seeing you are interested in another topic in the aerospace field, I have initiated a debate on Static pressure using the Talk page. Please visit Talk:Static pressure and peruse the various exchanges. I would be very pleased if you would leave a comment, or at least declare which of the two points of view you prefer.
  • I expect to browse through N.A.V. Piercy's book tomorrow. If it says nothing about negative static margin being associated with positive static stability I will be tempted to work through the various articles on WP and eliminate all those confusing references. Best regards. Dolphin51 (talk) 08:40, 8 January 2008 (UTC)


Hi MG2! Thanks for joining the debate on Static pressure. I made a comprehensive re-write of the article about a month ago and so far no-one has challenged any of it, so it can't be too far from the truth.

I went looking for N.A.V. Piercy's book "Aerodynamics" but only found his book "Elementary Aerodynamics". It says little or nothing about static margins. I did find something interesting in "Airplane Aerodynamics" by Dommasch, Sherby and Connolly. On page 447 (4th Ed.) those authors define the static margin as x/c and say "x/c is always negative for a stable airplane." All the other books I have found on the subject define static margin in such a way that it is always positive for a stable airplane. Consequently I am tempted to go back through Wikipedia in the places where it talks about negative static margin for a stable aircraft, change it to positive static margin for a stable aircraft, and acknowledge that at least one author (Dommasch et al) does it differently. What do you think? Dolphin51 (talk) 02:29, 7 February 2008 (UTC)

Hi MG2! Thanks for your message on my Talk page. I left a message for you on your Talk page on 7 February but you didn't respond so I have used that as my excuse for doing nothing in the area of negative static margins. I have been working on Talk:Bernoulli's principle and other articles. When I saw that you had been off the air for all of February I assumed you were taking a vacation up there in the Northern Neck, canoeing and skiing and camping and hunting! I'm pleased you have now created a User page for yourself. We begin to see who you are and your nom-de-plume shows up in blue rather than red.

[edit] The Military history WikiProject Newsletter — Issue XXII (December 2007)

The Military history WikiProject Newsletter
Issue XXII (December 2007)
Project news
Articles of note

New featured articles:

  1. Battle of Albuera
  2. Battle of Dyrrhachium (1081)
  3. Battle of the Gebora
  4. Constantine II of Scotland
  5. Francis Harvey
  6. Vasa (ship)
  7. Wulfhere of Mercia

New A-Class articles:

  1. 1962 South Vietnamese Presidential Palace bombing
  2. Evacuation of East Prussia
Current proposals and discussions
Awards and honors
  • Blnguyen has been awarded the WikiChevrons with Oak Leaves in recognition of his efforts in improving the quality of articles related to Vietnamese military history, including the creation of numerous A-Class articles.
  • Woodym555 has been awarded the WikiChevrons with Oak Leaves in recognition of his outstanding work on topics related to the Victoria Cross, notably including the creation of featured articles, featured lists, and a featured topic.
  • For their outstanding efforts as part of Tag & Assess 2007, Bedford, TomStar81, and Parsival74 have been awarded the gold, silver, and bronze Wikis, respectively.
Tag & Assess 2007

Tag & Assess 2007 is now officially over, with slightly under 68,000 articles processed. The top twenty scores are as follows:

1. Bedford — 7,600
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8. Cromdog — 2,200
9. BrokenSphere — 2000
9. Jacksinterweb — 2,000
9. Maralia — 2,000
12. MBK004 — 1,340
13. JKBrooks85 — 1,250
14. Sniperz11 — 1100
15. Burzmali — 1000
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15. Gimme danger — 1000
15. Raoulduke471000
15. TicketMan — 1000
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15. Blnguyen — 1000

Although the drive is officially closed, existing participants can continue tagging until January 31 if they wish, with the extra tags counting towards their tally for barnstar purposes.

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[edit] The Military history WikiProject Newsletter : Issue XXIII (January 2008)

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[edit] Military history WikiProject coordinator elections

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[edit] The Military history WikiProject Newsletter : Issue XXIV (February 2008)

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[edit] The Military history WikiProject Newsletter : Issue XXVII (May 2008)

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