[TowerTalk] Rotator specs?

[gdaught6 at stanford.edu]

Steve, K7LXC wrote,

> Howdy, TowerTalkians --
>  
>     I'm trying to compare rotator specs and Alfa Radio  just threw me a 
> curve. Everything I'd been reading was in in-lbs until I came to  the AR website 
> that listed the specs in Lb-ins. I couldn't find an online  conversion program 
> to convert the Lb-ins to in-lbs. I would say that the 2 specs  are different. 
> Am I wrong? Do you know of a conversion site that'll do it? 
>  
>     I'm not even close to being an engineer so just  looking for a little 
> clarification. Tnx. And excuse my ignorance.

I'm not very close to being an engineer, either, but I'm a physicist by training, so I'll 
have a go at the question.

Quick answer :  no difference.

When one applies a force on the end of a lever in order to "twist" or rotate something, 
[like tightening or loosening a bolt, or keeping your Porsche's chassis off the ground,]  
the mathematical product of the force applied and the length of the lever arm is called 
"torque".  So, a 10 pound force on a 12" lever gives a torque of 120 inch-pounds, or 
120 pound inches.  You get your choice of which order, because we are talking about 
a number system where the order of multiplication doesn't affect the answer... [the 
commutative law]  i.e. 10x12=12x10... either way you get 120, and inches x pounds 
= pounds x inches.  

It's been almost 50 years, [I can't believe it!] but I believe that's all OK.

73,

George T Daughters, K6GT
CU in the California QSO Party (CQP)
October 3-4, 2009