Talk:Windlass

Chesterfield's Crooked Spire church

There were thousands of buildings constructed using windlasses in the Middle Ages- why is Chesterfield's Crooked Spire church specifically mentioned? — Preceding unsigned comment added by 174.20.111.117 (talk) 03:43, 3 December 2012 (UTC)

Chesterfield's Crooked Spire church is mentioned specifically in the reference given, is a useful and generally quite interesting example of a large building built by windlass, and it has a Wikipedia page, so it helps prevent the page from becoming a 'stub'. You can suggest other buildings if you like and they can be added, or, suggest how the section could be improved. James463 (talk) 22:06, 3 December 2012 (UTC)

Chinese windlass

Chinese windlass redirects here, but the article does not discuss Chinese windlasses. In a Chinese windlass, there are two drums of different radii mounted on a single axle. The rope winds up on oneand you turn it drum and unwinds simultaneously from the other one. If the difference in the two drums radii is d, then each turn of the drums raises (or lowers) the attached weight by d. By making d small, extremely large mechanical advantages can be achieved. -- —Dominus (talk) 19:20, 3 February 2009 (UTC)

• Fixed. Philly jawn (talk) 21:00, 14 June 2009 (UTC)

I'm no engineer, but I don't think it's correct that Since each turn of the crank raises the pulley and attached weight by only 2π(r − r'), very large mechanical advantages can be obtained. Turning the crank will shorten the bight by 2πr, and it will lengthen the bight by 2πr', for a net shortening of 2π(r − r'). But the bight is a doubled-over section of line, so wouldn't we have to divide that figure in half to find out how much the pulley is raised? That would give us a lifting of π(r − r') for each turn of the pulley. Somebody check my math, please--I don't feel confident enough in it to make the revision immediately. 206.208.105.129 (talk) 19:02, 15 September 2010 (UTC)

Philly jawn, I agree with you. I was just about to make this same comment. I also find this comment very confusing {"...there are two coaxial drums of different diameters r and r'."] If the writer here is talking about diameters, why does he/she use r and r' when these would normally refer to radii. Again I agree with you and your formula π(r − r') where r and r' are radii. As you say the block in the bight divides by two. —Preceding unsigned comment added by 184.99.210.92 (talk) 20:33, 20 December 2010 (UTC)

I've changed "diameters" to "radii" (nice catch!) and removed the "2" from the formula. If this revision is wrong, no doubt someone more knowledgable will come along and revert it. 206.208.105.129 (talk) 15:38, 21 December 2010 (UTC)

I'm not sure if the current formula is right for how much the pulley is raised per turn of the crank. From what I understand, and what is written here before, I think it should be (2π(r - r'))/2 = π(r - r'). First the difference giving how much the length of the rope hanging from the drums is changed, and then dividing that by 2 since it goes through the pulley. The current formula is divided by 2 an extra time it seems. 84.202.41.5 (talk) 21:55, 8 April 2011 (UTC)

Merge?

This does not seem distinct from a wheel and axle--عبد المؤمن (talk) 23:47, 9 September 2014 (UTC)