Re: Re: Rubber energy spreadsheet

From: Bill Gowen <b.gowen_at_earthlink.net>
Date: Sat, 28 Apr 2007 15:02:48 -0400

Thanks Eric!

The test I wanted to enter went to 110 wt. I divided this by 14 and got 7.85. I put 8 in the C2 block. Does the program adjust the last block so you'll come out at zero? The good news (if I did this right) is that the motor tested to 4277 ft-lbs/lb. Another test due today. Hopefully I can get another one done without breaking the motor.

  ----- Original Message -----
  From: ewmonda
  To: Indoor_Construction_at_yahoogroups.com
  Sent: Saturday, April 28, 2007 2:33 PM
  Subject: [Indoor_Construction] Re: Rubber energy spreadsheet


  Bill,

  I hope Fred won't mind if I field this question. After Mark's post
  I dissassembled the spread sheet to see what it was doing.

  The spreadsheet should have =A2/14 entered in cell C2. It is
  entered like that in subsequent examples, (C8). In A2, the number
  of winder turns (not rubber turns) is entered. B2 is the weight of
  the rubber motor in grams. Once A2 and C2 are filled in, row 4 is
  populated with the number of motor turns (not winder turns) where
  the torque should be read in in-oz and entered in row 5. The sheet
  then uses the Composite Simpson's Rule method of numerically
  integrating the area under the curve (for you math geeks out
  there). If you want to use a 5 to 1 winder, you'd have to change
  the coefficients in the equation.

  You are correct that the 40 to 1 is a typo. The coefficients in the
  equations require it to be a 20 to 1 winder. Comment on the 10 to 1
  spreadsheet is correct.

  Eric Monda

  --- In Indoor_Construction_at_yahoogroups.com, "Bill Gowen"
  <b.gowen_at_...> wrote:
>
> Fred
> Can you post some instructions on how to use the energy
  spreadsheet? I
> tried to enter some data and get all kinds of different results if
  I do
> it different ways. I think what I need is some simple step-by-step
> instructions for filling out each box.
>
> For instance, how do you determine the unwinding increment? Do you
  have
> to select an increment so you come out at zero winds at the end?
  do you
> put the maximum torque reading in the first box?
>
> If I use an increment of 5 winder turns I get an energy that is
  double
> what I get if I use 10 winder turns for the increment.
>
> Also the blank sheet says it is for a 40 to 1 winder which seems
  to be
> a typo.
>
> Confused in Decatur.
>



   

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Received on Sat Apr 28 2007 - 12:10:34 CEST