Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin (Account/Technical Issues)  |  Contact Global Moderator
September 17, 2021, 11:35:11 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: 1 [2]   Go Down
Print
Author Topic: FAI sidewinder vs Gizmo winder  (Read 2030 times)
0 Members and 1 Guest are viewing this topic.
lincoln
Titanium Member
*******

Kudos: 38
Offline Offline

United States United States

Posts: 2,518



Ignore
« Reply #25 on: April 29, 2012, 12:06:47 AM »

Elasticity and strength are two different things!* The modulus of elasticity of steels is all very similar (so is the density). The strength can be all over the map. If someone says piano wire is "soft", they're talking about the strength, not the stiffness. Or else they're full of baloney. OTOH, you need to know the DIAMETER of the wire to a pretty close tolerance if you want to calculate the stiffness of the wire correctly. I forget if it's the fourth power of the diameter or what.

To calibrate your meter, all you need is a lever and a weight. If you have a 10 inch lever and a one ounce weight, then, surprise surprise, that's 10 inch ounces!

*Think peanut brittle vs. polyethylene (as in a plastic milk bottle), for instance.  Or fiberglass vs carbon fiber, which are both of similar strength, but the carbon is maybe 3 or 4 times stiffer. Or a cookie (the kind you eat) vs. a piece of gristle.
snip
One of the links you kindly provided contained a formula where one of the figures was "Torsional Modulus of elasticity of music wire" Shocked This reminded me of a discussion awhile ago, either here or on another forum, talking about the variability of piano (music) wire. Some was described as "soft as butter", while other samples were as good as the stuff we used in our 'yoof'. I realise that calibration by hanging weights from a lever should take this into account, but it's time I'd rather spend building and/or flying Grin Grin

snip
Cheers

Peter
Logged
lincoln
Titanium Member
*******

Kudos: 38
Offline Offline

United States United States

Posts: 2,518



Ignore
« Reply #26 on: April 29, 2012, 12:09:51 AM »

P.S. I made a winder out of an old electric drill, and a counter out of a calculator. The winder is something like 8.3 to 1, so the calculator is a good way to go. Wired a reed switch to the equals key and enter 8.3+. Or is it +8.3? Works well. The drill is very robust, and there's no doubt which one is mine. Ergonomics could be better, probably needs a handle.
Logged
Pages: 1 [2]   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!