Rubber convo was, Re: source for scales

From: jabiruchick <jabiruchick_at_yahoo.com>
Date: Wed, 28 Apr 2010 22:45:29 -0000

Thanks Ray, that's the answer I was looking for-- a "how to." Not that I can do it without mooching off of someone else's rubber stripper... So really, it's an attempt to consistently quantify a thing that's variable by nature for repeatable results. Engineering the Unengineerable... Flying on instruments vs. seat-of-the-pants? Herding cats??

Who knew "toy" airplanes could be so interesting... !

 

--- In Indoor_Construction_at_yahoogroups.com, "Mark F1diddler" <f1diddler@...> wrote:
>
>
>
> --- In Indoor_Construction_at_yahoogroups.com, "ray_harlan" <rbharlan@> wrote:
>
> the
> answer always comes out .085, or such. As Bill Gowen points out, it depends on
> the batch. Not because of different densities, but because of different
> thicknesses.>>
>
> Fully agree, Ray. I only mentioned density because it played a part in how I arrived at my 1.57 "thickness normalization" factor (but also the number had to be slightly adjusted according to the tension of my reworked depth gauge spring.) The important item is that thickness often varies more than a well sliced width, and therefore width is not the whole story for communication, even to self.
>
> Anyhow, I hate having to use precious flying time to strip rubber. So I carry 12-15 ft coils of virtually every size I may need (and twice that in some sizes.) If I cut a *motor* sized piece off a coil labeled, say, .032g/in, and if the smaller motor piece is also close enough to .032g/in, I know that this would be .050" rubber IF it were .042" thick. If per (wholly unnecessary) gauge check it happens to be more than .042" thick, then I already know it's less than .050" wide by measure, but no matter, that's not a difference in cross section. In brain, it's still .050" rubber, with thickness normalized.
>
> The flaw here is that my labeled g/in, whether from a big wad or of motor strand, is only an average value. But another salvation sometimes occurs. Suppose the factory thickness tapers fairly uniformly such as .041" at one end of strand to .044" (or whatever) at other end of strand. Tie a knot, put the knot at rear hook as usual, and then the thicknesses "meet in the middle," averaging out perfectly all along. This could also work with an unfortunate tapering width, of course.
> Mark F1diddler
>
Received on Wed Apr 28 2010 - 15:47:40 CEST