## PSN-L Email List Message

Subject: Verticals
From: "Ted Channel" tchannel@............
Date: Sun, 27 Dec 2009 06:59:50 -0700

```Hi Folks,  I have downloaded Bob McClure's great program SpringCalc.exe. =
I have put in some numbers and see it calculates very long periods =
under certain conditions, periods of >20.

My question is can long periods like these really be achieved?    I have =
build several models and some working sensors using this approach, but I =
have never gotten more than about 3x the springs natural frequency.   A =
spring of .5 second, just hanging vertically, resulted in a sensor of =
1.5 seconds.   I guess the AS1 is another example.   The design of the =
AS1 is widely used and am I correct that it is operating at about 1.5 =
seconds?   In theory, is this shape, capable >10 seconds?

I hope to use Bob's program to construct another vertical, but I am =
confused, about my results.    I know there are methods for extending =
the period, but here I am just asking about the physical results of =
using     a spring-supported pendulum constrained to move in a vertical =
plane.   Perhaps these calculated long periods would only be possible =
under the best of conditions, where all factors were perfect.    I seem =
to get a period of  around x3  that of the spring hanging vertical with =
a mass.    I have tried many different springs and the result were very =
similar in achieving only x3.

Hi Folks,  I have downloaded Bob =
McClure's=20
great program SpringCalc.exe.    I have put in some =
numbers and=20
see it calculates very long periods under certain conditions, periods of =

>20.

My question is can long periods like =
these really=20
be achieved?    I have build several models and some =
working=20
sensors using this approach, but I have never gotten more than about 3x =
the=20
springs natural frequency.   A spring of .5 second, just =
hanging=20
vertically, resulted in a sensor of 1.5 seconds.   I guess the =
AS1 is=20
another example.   The design of the AS1 is widely used and am =
I=20
correct that it is operating at about 1.5 seconds?   In =
theory, is=20
this shape, capable >10 seconds?

I hope to use Bob's program to =
construct another=20
vertical, but I am confused, about my results.    I know =
there=20
are methods for extending the period, but here I am just asking about =
the=20
physical results of using     a =
spring-supported=20
pendulum constrained to move in a vertical plane.  =20
Perhaps these calculated long periods would only be =
possible under=20
the best of conditions, where all factors were =
perfect.    I seem=20
to get a period of  around x3  that of the spring hanging =
vertical=20
with a mass.    I have tried many different springs and =
the=20
result were very similar in achieving only x3.

Thanks, Ted
```

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