[R-390] Cosmos PTO, spring-loaded linearizing core?

[Jim M.]

If I recall correctly, and it has been a while, the core of the linearizing 
coil is spring loaded inside in some fashion so that it moves in and out as 
the adjustment screw heads push against the slide (I dont have better names 
for these parts).  I dont recall if there was a lot of tension or not but 
when you push on the little "nub" the coil core should go in slightly, and 
then spring back when you release the pressure.   The pressurization inside 
the can (if there ever was any) has nothing to do with it.  What is going on 
that you think this coild may be the problem?

The only adjustable coil I know of with screw threads is the end point 
adjustment coil right next to the linearizing coil.  There shouldn't be any 
wiggling threads.  I have only opened one Cosmos PTO (the one on the URL) so 
I don't know what you may have there.  If it doesn;t look like what's 
pictured on the URL inside, then maybe it is something different or it has 
been modified sometime in its life.

Jim M.
----- Original Message ----- 
From: "Tim Shoppa" <shoppa_r390a at trailing-edge.com>
To: <r-390 at mailman.qth.net>
Sent: Sunday, February 26, 2006 7:52 PM
Subject: Re: [R-390] Cosmos PTO, spring-loaded linearizing core?


> Jim recommended:
>> Fix the wife some chicken soup, clean up the kitchen and get the kids
>> under control first.
>
> OK, made that much progress :-).
>
> But now I have more time to write my real question:
>
> How the heck is the linearization screws/plate/core/inductor supposed
> to work in real life?
>
> "In principle" it's a spring loaded thing such that the core follows
> the 40-some linearizing screws through the rotation.
>
> But this is what I find in my Cosmos:
>
> The linearizing inductor has a core in it.
> The core is on a leadscrew.
> The leadscrew goes through a threaded hole in the metal base of the
>  inductor.
> On the other side of the leadscrew is a plastic nub that, I presume,
>  is supposed to follow the 40-some screws.
>
> What I don't see:
>
> Any way for the nub to move the core in and out of the little linearizing
>  inductor.
>
> There's no spring. Nothing slides.
>
> Maybe, just maybe, the nub compresses/flexes the metal base such that
> the tiny corrections are made. But it doesn't seem likely.
>
> Maybe, just maybe, the pressurized nitrogen in the PTO provides the
> restoring force and the sliding is just the screw wiggling in its
> threads. But that doesn't seem likely either.
>
> Obviously my knowledge of how the linearizing is supposed to work has
> a huge gap in it, because I don't see how the screws move the nub
> or how the nub moves the little core.
>
> Can anyone PLEASE correct my mistaken reasoning here?
>
> Tim.
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>