The Yowser

External ballistics and bullet drop

You said "...but I do know that this article doesn't tell me what I wanted to know." So what did you want to know? I'm not sure it's practical to include a general purpose bullet drop table (the Speer handloading manual I have has pages and pages of G1 model charts) but if you wanted to see, say, drop charts for a selection of popular calibers, that would be pretty easy to put together. Let me know what you want, and I'll see what I can do about adding it to the article. scot (talk) 14:25, 13 June 2008 (UTC)

Well, that is a rather specialized question. How about I work through the answer here, and then we can decide what relevant information can go into the external ballistics article?

First, the basics of air resistance. A ballistic object, that is one moving under only its own inertia, is "powered" by its mass. Take two objects, one twice the mass of the other; the one that is twice as massive will have twice kinetic the energy at any given velocity. This is why bullets are typically made out of lead, because it's cheap and dense, letting you pack more energy into a bullet of a given size. Anti-tank rounds go even denser, with materials like depleted uranium and tungsten, with nearly twice the density of lead, letting them carry even more energy for a given size and shape.

To move through the air, or for that matter any fluid (and at high enough impact speeds, even tank armor splashes like a fluid), the projectile must push the fluid out of the way, and this takes energy. If you take two objects of equal mass and velocity, one a sphere of radius 10 and one a long, thin cylinder of radius 1, they will have the same kinetic energy. However, the sphere will have to push much more fluid out of the way to traverse the fluid; 100 times as much, since it has 100 times as much frontal surface area. This is where sectional density comes in; it's the ratio of mass to frontal surface area, and when penetration is desired, a greater sectional density is good. When penetration is to be limited, then a lower sectional density is good--this is why expanding bullets exist, to greatly increase their frontal surface area upon impact and limit penetration by displacing more fluid. Also note that to move at twice the velocity, twice as much fluid per unit time must be moved.

Not only does the projectile have to move the air, but it has to move it quickly enough to let the projectile pass through. Compare two projectiles of equal mass, velocity, and frontal surface; one with a flat face, the other with a long, slender taper. The flat projectile will have to accelerate the fluid nearly instantly from rest to the projectile's velocity, pushing it forward and outwards. The tapered projectile will gradually accelerate the fluid slightly forward but mostly to the sides, accelerating it far more gradually. Since f=ma, the force required to accelerate the air quickly is far greater than the force required to accelerate it gradually. Again, double the projectile velocity, and you double the fluid acceleration required. The shape of the back also has some impact, as the low pressure behind the projectile pulls fluid along behind it (at least in the air) and this also takes energy; this is why boat-tailed bullets provide lower drag than flat based bullets, by reducing the low pressure void and the resulting fluid mass it moves. Combine the shape with the sectional density, and you get a single factor called a "ballistic coefficient", which describes how well a ballistic object moves through a fluid compared to a standardized object. A high ballistic coefficient means less velocity loss; increasing the sectional density or streamlining the shape gives you a higher BC, decreasing the sectional density or blunting the shape gives you a lower BC. BCs are not constant across all velocities, but rather change slightly, but usually they are averaged across the expected velocity range and presented as a single value. One note of interest is that when you scale a projectile diameter up by a factor of 2, holding shape and material density constant, the frontal surface goes up by a factor of 4, and the volume and thus mass by a factor of 8, which yields an overall BC increase of 2.

Now combine the quantity of air to move with the acceleration required, and you get an air resistance that is proportional to the velocity squared; the exact exponent is not v^2, but the v^2 or v^3 curves are both close enough to match experimental results with an appropriate scaling factor.

Once you get into the supersonic realm, things change a bit, but not too greatly. Since you're now trying to accelerate the fluid particles faster than their average molecular velocity (that's what the speed of sound is based on) they tend to build up in front of the projectile, and require more force to accelerate. That doesn't change the essential exponential nature of the curve, but it does change the scaling factor you use to fit the a given exponential curve to the projectile path. I wrote a simple ballistic matching program that did a curve fit to the ballistic charts listed in my reloading manual; I used two different "fudge factors" to make my exponential curves fit the curves given by the charts, based on whether the projectile was subsonic or supersonic, and I got a very good match to the charts with this simple program. I tried v^2 and v^3, and ended up settling on v^3 as giving me the best fit over the extent of the data I was fitting to.

Now for the Me 163 versus the 30mm shell (the article states it was a low velocity, 30mm MK 108 cannon). I'm assuming a ballistic coefficient of 1.0; the G1 drag model is based on a 1 inch bullet, and the 30mm shell is going to suffer a bit since it's less dense, being full of explosive or incendiary mix. The glider, under power, will do about 600 mph, which is 880 f/s, and that gets added to the 1770 f/s of the cannon shell. Assuming a constant speed of 600 mph for the Me 163, it's going to catch up with the shell after about 23 seconds, nearly 4 miles past the firing point; the shell have slowed to about 500 f/s forwards, also 500 f/s downwards, and will have dropped over 7000 feet. Note that the plane would need to immediately vector downwards to reach the point where the bullet will be, or aim slightly upwards, and that's going to mean it travels more than the 4 miles quoted. I would need to do some iterative calculations to figure out where the interception point would have to be (probably add another half mile or so), but the results from this simulation show that the bullet is going to be moving at a much steeper angle than the plane when the paths cross, and that's going to make the odds of an impact astronomical. scot (talk) 17:42, 18 June 2008 (UTC)

Live Steam gauges

You can't have everything in one article, see Rail_transport_modelling_scales, this is in the "See Also" section in the Live Steam article... ;)

Speedy deletion nomination of Tang Sao Dao

Please refrain from introducing inappropriate pages, such as Tang Sao Dao, to Wikipedia. Doing so is not in accordance with our policies. If you would like to experiment, please use the sandbox.

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 - if no such tag exists then the page is no longer a speedy delete candidate and adding a hangon tag is unnecessary), 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. — Timneu22 · talk 15:07, 6 August 2010 (UTC)

What's going on? I can't see anything about what I put on line to make it qualify for speedy deletion. It was a stub but I included a reference to a page that verified all the information. The Yowser (talk) 13:33, 16 August 2010 (UTC)

Simply verifying the existence of a subject is not sufficient. Wikipedia is not an indiscriminate collection of information. Subjects must be demonstrated to be notable by indicating they have received significant coverage in independent sources. I hope this clears up your confusion. WikiDan61^ChatMe!_ReadMe!! 16:09, 27 August 2010 (UTC)

Speedy deletion nomination of Wufoo

If this is the first article that you have created, you may want to read the guide to writing your first article.

You may want to consider using the Article Wizard to help you create articles.

A tag has been placed on Wufoo requesting that it be speedily deleted from Wikipedia. This has been done under section A7 of the criteria for speedy deletion, because the article appears to be about an organization or company, but it does not indicate how or why the subject is important or significant: that is, why an article about that subject should be included in an encyclopedia. Under the criteria for speedy deletion, such articles may be deleted at any time. Please see the guidelines for what is generally accepted as notable.

If you think that this notice was placed here in error, contest the deletion by clicking on the button labelled "Click here to contest this speedy deletion". Doing so will take you to the talk page where you will find a pre-formatted place for you to explain why you believe the page should not be deleted. You can also visit the the page's talk page directly to give your reasons, 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. If the page is deleted, you can contact one of these administrators to request that the administrator userfy the page or email a copy to you. andy (talk) 15:16, 18 August 2011 (UTC)

Nomination of Obfuscation on Wikipedia for deletion

A discussion is taking place as to whether the article Obfuscation on Wikipedia is suitable for inclusion in Wikipedia according to Wikipedia's policies and guidelines or whether it should be deleted.

The article will be discussed at Wikipedia:Articles for deletion/Obfuscation on Wikipedia until a consensus is reached, and anyone is welcome to contribute to the discussion. The nomination will explain the policies and guidelines which are of concern. The discussion focuses on good quality evidence, and our policies and guidelines.

Users may edit the article during the discussion, including to improve the article to address concerns raised in the discussion. However, do not remove the article-for-deletion template from the top of the article. Cameron Scott (talk) 09:33, 7 September 2011 (UTC)

Please don't put personal reflections in article space. --Cameron Scott (talk) 09:33, 7 September 2011 (UTC)

It needs an admin to move it into your personal space - let me see what I can do. --Cameron Scott (talk) 09:37, 7 September 2011 (UTC)

The article text is now at User:The Yowser/Obfuscation on Wikipedia. The mainspace article has been deleted by move without redirect. - Smerdis of Tlön - killing the human spirit since 2003! 14:47, 7 September 2011 (UTC)

Write Once Read Many

ROM was already mentioned at the end of this article. It is only tangentially related to WORM, as the end-user can't write it even once. Also, ROM is still "ubiquitous" in computers; it provides the code that reads in the operating system, though you're right that originally it sometimes contained the complete operating system. I'll move your paragraph to the end of the article and truncate it. I think that how ROM is programmed belongs in its own article. Spike-from-NH (talk) 20:06, 1 November 2011 (UTC)

Disambiguation link notification

Hi. When you recently edited Park Hall Nature Reserve, you added links pointing to the disambiguation pages Bluebells, M6 and Wildlife Trust (check to confirm | fix with Dab solver). Such links are almost always unintended, since a disambiguation page is merely a list of "Did you mean..." article titles. Read the FAQ • Join us at the DPL WikiProject.

It's OK to remove this message. Also, to stop receiving these messages, follow these opt-out instructions. Thanks, DPL bot (talk) 12:41, 27 January 2012 (UTC)

Disambiguation link notification for February 10

Hi. Thank you for your recent edits. Wikipedia appreciates your help. We noticed though that when you edited Parks and open spaces in Birmingham, you added a link pointing to the disambiguation page Wildlife Trust (check to confirm | fix with Dab solver). Such links are almost always unintended, since a disambiguation page is merely a list of "Did you mean..." article titles. Read the FAQ • Join us at the DPL WikiProject.

It's OK to remove this message. Also, to stop receiving these messages, follow these opt-out instructions. Thanks, DPL bot (talk) 12:06, 10 February 2013 (UTC)

Speedy deletion nomination of Chelyabinsk Meteor shower

Hello The Yowser,

I wanted to let you know that I just tagged Chelyabinsk Meteor shower for deletion, because it appears to duplicate an existing Wikipedia article, [[:{{{article}}}]].

If you feel that the article shouldn't be deleted, you can contest this deletion, but please don't remove the speedy deletion tag from the top.

You can leave a note on my talk page if you have questions. Thanks, YuMaNuMa ^Contrib 09:57, 15 February 2013 (UTC)

File permission problem with File:Protesters at Stubber's Greeb Bog, Walsall.jpg

Thanks for uploading File:Protesters at Stubber's Greeb Bog, Walsall.jpg, which you've attributed to The Wildlife Trust for Birmingham and the Black Country. I noticed that while you provided a valid copyright licensing tag, there is no proof that the creator of the file has agreed to release it under the given license.

If you are the copyright holder for this media entirely yourself but have previously published it elsewhere (especially online), please either

• make a note permitting reuse under the CC-BY-SA or another acceptable free license (see this list) at the site of the original publication; or
• Send an email from an address associated with the original publication to permissions-en@wikimedia.org, stating your ownership of the material and your intention to publish it under a free license. You can find a sample permission letter here. If you take this step, add {{OTRS pending}} to the file description page to prevent premature deletion.

If you did not create it entirely yourself, please ask the person who created the file to take one of the two steps listed above, or if the owner of the file has already given their permission to you via email, please forward that email to permissions-en@wikimedia.org.

If you believe the media meets the criteria at Wikipedia:Non-free content, use a tag such as {{non-free fair use}} or one of the other tags listed at Wikipedia:File copyright tags#Fair use, and add a rationale justifying the file's use on the article or articles where it is included. See Wikipedia:File copyright tags for the full list of copyright tags that you can use.

If you have uploaded other files, consider checking that you have provided evidence that their copyright owners have agreed to license their works under the tags you supplied, too. You can find a list of files you have created in your upload log. Files lacking evidence of permission may be deleted one week after they have been tagged, as described on criteria for speedy deletion. You may wish to read the Wikipedia's image use policy. If you have any questions please ask them at the Media copyright questions page. Thank you. Sfan00 IMG (talk) 17:48, 21 June 2013 (UTC)

Disambiguation link notification for July 2

Hi. Thank you for your recent edits. Wikipedia appreciates your help. We noticed though that when you edited Sky lantern, you added a link pointing to the disambiguation page West Midlands (check to confirm | fix with Dab solver). Such links are almost always unintended, since a disambiguation page is merely a list of "Did you mean..." article titles. Read the FAQ • Join us at the DPL WikiProject.

It's OK to remove this message. Also, to stop receiving these messages, follow these opt-out instructions. Thanks, DPL bot (talk) 13:20, 2 July 2013 (UTC)

ArbCom elections are now open!

Hi,
You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 13:41, 24 November 2015 (UTC)

Nomination of Black Country Urban Park for deletion

A discussion is taking place as to whether the article Black Country Urban Park is suitable for inclusion in Wikipedia according to Wikipedia's policies and guidelines or whether it should be deleted.

The article will be discussed at Wikipedia:Articles for deletion/Black Country Urban Park until a consensus is reached, and anyone, including you, is welcome to contribute to the discussion. The nomination will explain the policies and guidelines which are of concern. The discussion focuses on high-quality evidence and our policies and guidelines.

Users may edit the article during the discussion, including to improve the article to address concerns raised in the discussion. However, do not remove the article-for-deletion notice from the top of the article. Lord Belbury (talk) 18:31, 8 January 2019 (UTC)

Nomination of Capsule speaker for deletion

A discussion is taking place as to whether the article Capsule speaker is suitable for inclusion in Wikipedia according to Wikipedia's policies and guidelines or whether it should be deleted.

The article will be discussed at Wikipedia:Articles for deletion/Capsule speaker until a consensus is reached, and anyone, including you, is welcome to contribute to the discussion. The nomination will explain the policies and guidelines which are of concern. The discussion focuses on high-quality evidence and our policies and guidelines.

Users may edit the article during the discussion, including to improve the article to address concerns raised in the discussion. However, do not remove the article-for-deletion notice from the top of the article. Just Chilling (talk) 02:55, 27 February 2019 (UTC)