Manifold Data
Posted: May 26th, 2010, 12:13 am
Linked here are an Excel spreadsheet, and images of the individual worksheets from the spreadsheet that contain the manifold data that the committee received from FV drivers and engine builders, manifold makers, etc. A Word document is also linked that explains each measurement.
Download the Excel spreadsheet and the (Word Document) description of the measurements as they were requested in the letter to the FV community here: http://docs.google.com/leaf?id=0B9_s9jA ... NmVj&hl=en
You can view the Word Doc online or download it. The Excel spreadsheet loses it's formatting (which is important) when converted to a Google Doc so I'm making you download the actual file and open it in Excel.
If you don’t have Excel, download the images of the charts and a snapshot of the data from the spreadsheet here:
http://picasaweb.google.com/cendiv37v/D ... directlink
Understanding the spreadsheet:
The first tab is labeled Manifold Data and includes the actual measurement data summarized in a form that hopefully makes it understandable. Each row contains the measurements from a single manifold. The columns each contain a different piece of data for each manifold as labeled at the top of the sheet. “Largest OD in Bend” is the largest diameter found in either bend of the manifold. “Largest Avg OD in Bend” is the larger of a single average OD taken from each bend of the manifold (1-2 side or 3-4 side). This is calculated by averaging the largest OD found on that side with the smallest OD measured at that same location along the tubing. See the linked Word document for a fuller description of what this means. The data is sorted from low to high for the “Largest OD in Bend” column which puts most of the “largest” manifolds at the bottom.
In green cells below the data itself are the dimensional limits that could be used to limit further manifold development. Once you load up the spreadsheet in Excel, you can change the values in the green cells. Just select the cell, type a new number and press enter. When you do so, the formatting of the data will change to highlight the out of spec. manifolds for that dimension. That is, if you set "Minimum Bend2Bend" at 18.5, all Bend2Bend measurements less than 18.5 will become red. In addition, the word Disallowed will appear in the column to the left of the data for each manifold that becomes no-compliant for this measurement. Playing with the all of the numbers in green allows you look at the effect of different possible limits.
Directly below the green cells are two cells containing the total number of manifolds (in red) that would be disallowed for any given set of new dimensional controls. The first one (labeled at its left) assumes a no-go system would be used in the bend OD with the limit as set in cell B136. The next cell (below) is an estimate (usually correct) of the number of manifolds that would be disallowed if an average OD (two measurements) was used to determine compliance with the limit set as in cell B137. This allows you to compare no-go limits vs. an average limit. Note that this average is NOT the same as a multiple measurement average in the bend as has been proposed by the manifold makers. It is however, the only “average” type data we have on real manifolds and is therefore our only way to compare the two options.
The cells to the right of those contain the number of manifolds out of compliance by measurement type (column label at the top of the sheet). Note that a manifold is counted as disallowed only once if it violates more than one dimensional limit. Therefore the total disallowed is not equal to the total of the numbers to the right if them.
All of the worksheets are locked so you can only change the numbers in the green cells. If you want to really mess around, you can unlock any of the sheets. If you try to change a locked cell, it will give you a warning. Within the warning are directions as to how to unlock the worksheet. The password is “fv” (no quotes). I suggest you make a back-up copy of the spreadsheet before you do this!
The other tabs (sheet) contain histograms for each data type (Bend2Bend, Carb Flange Height, etc.) These allow you to look at the distribution of the data. The blue columns represent the number (Frequency) of manifolds in that range. The pink line is the accumulated percentage of manifolds to the left of the measurement. For instance it shows that there are very few manifolds that measure less than 18” from bend to bend but that there are a bunch that are right at 18 inches bend to bend. These graphs help you get a visual feel of how the data is distributed.
I hope this helps you understand how the committee evaluated the data we received and maybe helps you understand why we have chosen the limits we have proposed to the FSR/C and CRB. As stated in our earlier minutes, the greatest difficulty we had was in determining what "Current State of the Art" really means.
Bruce
PS: I have tried explain this adequately in this post, however, I expect questions and will answer them as best I can as they come up.
Download the Excel spreadsheet and the (Word Document) description of the measurements as they were requested in the letter to the FV community here: http://docs.google.com/leaf?id=0B9_s9jA ... NmVj&hl=en
You can view the Word Doc online or download it. The Excel spreadsheet loses it's formatting (which is important) when converted to a Google Doc so I'm making you download the actual file and open it in Excel.
If you don’t have Excel, download the images of the charts and a snapshot of the data from the spreadsheet here:
http://picasaweb.google.com/cendiv37v/D ... directlink
Understanding the spreadsheet:
The first tab is labeled Manifold Data and includes the actual measurement data summarized in a form that hopefully makes it understandable. Each row contains the measurements from a single manifold. The columns each contain a different piece of data for each manifold as labeled at the top of the sheet. “Largest OD in Bend” is the largest diameter found in either bend of the manifold. “Largest Avg OD in Bend” is the larger of a single average OD taken from each bend of the manifold (1-2 side or 3-4 side). This is calculated by averaging the largest OD found on that side with the smallest OD measured at that same location along the tubing. See the linked Word document for a fuller description of what this means. The data is sorted from low to high for the “Largest OD in Bend” column which puts most of the “largest” manifolds at the bottom.
In green cells below the data itself are the dimensional limits that could be used to limit further manifold development. Once you load up the spreadsheet in Excel, you can change the values in the green cells. Just select the cell, type a new number and press enter. When you do so, the formatting of the data will change to highlight the out of spec. manifolds for that dimension. That is, if you set "Minimum Bend2Bend" at 18.5, all Bend2Bend measurements less than 18.5 will become red. In addition, the word Disallowed will appear in the column to the left of the data for each manifold that becomes no-compliant for this measurement. Playing with the all of the numbers in green allows you look at the effect of different possible limits.
Directly below the green cells are two cells containing the total number of manifolds (in red) that would be disallowed for any given set of new dimensional controls. The first one (labeled at its left) assumes a no-go system would be used in the bend OD with the limit as set in cell B136. The next cell (below) is an estimate (usually correct) of the number of manifolds that would be disallowed if an average OD (two measurements) was used to determine compliance with the limit set as in cell B137. This allows you to compare no-go limits vs. an average limit. Note that this average is NOT the same as a multiple measurement average in the bend as has been proposed by the manifold makers. It is however, the only “average” type data we have on real manifolds and is therefore our only way to compare the two options.
The cells to the right of those contain the number of manifolds out of compliance by measurement type (column label at the top of the sheet). Note that a manifold is counted as disallowed only once if it violates more than one dimensional limit. Therefore the total disallowed is not equal to the total of the numbers to the right if them.
All of the worksheets are locked so you can only change the numbers in the green cells. If you want to really mess around, you can unlock any of the sheets. If you try to change a locked cell, it will give you a warning. Within the warning are directions as to how to unlock the worksheet. The password is “fv” (no quotes). I suggest you make a back-up copy of the spreadsheet before you do this!
The other tabs (sheet) contain histograms for each data type (Bend2Bend, Carb Flange Height, etc.) These allow you to look at the distribution of the data. The blue columns represent the number (Frequency) of manifolds in that range. The pink line is the accumulated percentage of manifolds to the left of the measurement. For instance it shows that there are very few manifolds that measure less than 18” from bend to bend but that there are a bunch that are right at 18 inches bend to bend. These graphs help you get a visual feel of how the data is distributed.
I hope this helps you understand how the committee evaluated the data we received and maybe helps you understand why we have chosen the limits we have proposed to the FSR/C and CRB. As stated in our earlier minutes, the greatest difficulty we had was in determining what "Current State of the Art" really means.
Bruce
PS: I have tried explain this adequately in this post, however, I expect questions and will answer them as best I can as they come up.