Wikipedia:Reference desk/Archives/Science/2015 May 12

= May 12 =

Large wheels trailed behind early British tanks
In photos and film of British tanks dating from the First World War a pair of large "wagon wheels" can often be seen attached to the back of the tanks. What was the purpose of those wheels? Roger (Dodger67) (talk) 14:18, 12 May 2015 (UTC)


 * Tanks like the Little Willie and the Mark I tank had optional "steering tail" wheels, which apparently were intended to allow the tank to make tighter turns. They seem to have been pretty fragile and the idea didn't survive, replaced by better gearboxes for the treads. -- Finlay McWalterᚠTalk 14:27, 12 May 2015 (UTC)


 * ...Illustrated and briefly described in British heavy tanks of World War I. Many of these tanks also came fitted with pigeon escape hatches as standard communication devices.--Shantavira|feed me 16:00, 12 May 2015 (UTC)


 * Thanks! So we have a few passing mentions but no details on how the steering tail worked. Roger (Dodger67) (talk) 10:57, 13 May 2015 (UTC)


 * @ User:Dodger67, a bit late in the day, but I found these (slightly contradictory) accounts:-
 * "For slight turns, the driver could use the steering tail: an enormous contraption dragged behind the tank consisting of two large wheels, each of which could be blocked by pulling a steel cable causing the whole vehicle to slide in the same direction." Breverton's First World War Curiosities by Terry Breverton
 * "The two wheels had linked track-rods, so they could be steered to left or right, moving like the front wheels of a car. The track-rod was turned by cables passing round a bobbin on the driver's steering-wheel. It was thought that these wheels would help in normal steering - minor corrections to left or right when the tank was moving forward with both tracks turning. 16 large springs kept the wheels in contact with the ground and there was a hydraulic jack system which could raise them as required, such as when the tank wanted to turn on its own axis, which was achieved by putting one track into neutral and letting the other turn. In the field, it was discovered that minor corrections could be achieved simply by use of the brakes and I think this is why the wheels were abandoned in later models. Great War Forum
 * "The 'steering tail' was intended to help with modest turns; the driver could turn the trailing wheels, using them like a rudder to influence the direction of the tank". Article on The Ultimate History Project by Benjamin L Apt.  Alansplodge (talk) 17:07, 14 May 2015 (UTC)

UL Recognized Component Mark
Is the logo UL_(safety_organization) a backwards italic UR or a backwards italic LR? Do the letters stand for anything (perhaps it is "Ul Recognised"?). -- SGBailey (talk) 15:48, 12 May 2015 (UTC)


 * Here, the UL refers to the one just for Canada as a "The C-UR Mark." Unfortunately, a few sentences later, they refer to "The optional C-UL-US Component Recognition Mark" -- which I think is a typo, based on the previous reference, and of course the way the mark looks, and I believe the previous quote should read "C-UR-US Mark". That page doesn't say so specifically, but "UL Recognized" seems to be the reasonable and implied interpretation. SemanticMantis (talk) 16:05, 12 May 2015 (UTC)

Upside down J
Where I live, one city has plenty of water and another city doesn't have enough. After years of debate. the city with plenty of water has agreed to sell water to the city that doesn't have enough, if necessary. This is a very expensive project and there are big pipes all along the road between the two cities, some of which have finally been put underground. I don't know if this is just true there, but there are several yellow upside down Js above ground near the existing water system from which the pipes are soon to be running. Any idea what these might be?— Vchimpanzee  •  talk  •  contributions  •  18:37, 12 May 2015 (UTC)
 * Sounds like a casing vent marker, . This marks the location of the pipeline and vents the outer steel casing around the pipeline.  For once, we don't seem to have an article on that.  --Amble (talk) 19:18, 12 May 2015 (UTC)
 * Okay, thanks. Doesn't sound like something I'll be writing about either.— Vchimpanzee  •  talk  •  contributions  •  19:20, 12 May 2015 (UTC)
 * This BBC article might be a useful starting point for anyone interested in the subject. Tevildo (talk) 19:42, 12 May 2015 (UTC)
 * I've added a paragraph to Pipeline_transport. --Heron (talk) 19:34, 13 May 2015 (UTC)

Power outage cycles
An email at work said that the site experienced a power drop of 35% for 8 cycles. The cycles bit, would that be 8 cycles out of the 60 during every second? Dismas |(talk) 22:49, 12 May 2015 (UTC)
 * I'd guess so, but only your hairdresser employer knows for sure. Short Brigade Harvester Boris (talk) 23:59, 12 May 2015 (UTC)


 * Voltage sag might be helpful. Dolphin  ( t ) 00:43, 13 May 2015 (UTC)

Ahklun Mountains highest point
Hi, USGS data for Ahklun shows that Wood River Mountains is not a subrange of Ahklun Mountains, therefore the highest point may be Atshichlut Mountain a 3,530 feet peak. thx --YB ✍ 15:41, 12 May 2015 (UTC)


 * And your question is ...?
 * I'm guessing you are referring to something in one of our 4 million articles. If you think something can be improved in a Wikipedia article, then please either fix it yourself, or post a suggestion on the article's talk page. --ColinFine (talk) 16:57, 13 May 2015 (UTC)