[Unified-mailman] Fwd: Re: Note on data reduction

[chipd@MIT.EDU]

Dear Students,

If you are getting reasonable looking outputs from your data reduction, read no 
further and submit what you have.

Quite a few of you have emailed me with concerns about the numbers that you are 
getting out of your data reduction.  Firstly, do not panic.  This is the first 
time that Professor Drela and I went through this lab, and clearly, there have 
been a number of changes over the past couple of days which ideally would not 
have happened as we saw the results of your data reduction.  Howie and I will 
instruct the graders to take this into account.   

Secondly, please note that I messed up and sent out the wrong column switch 
example (see below), and thanks to Mike for picking up on my error.  My 
apologies to those of you who just followed my example and still have 
bad-looking data.  I hope that this will (finally) fix your problems.  Again, 
sorry about the confusion that this must have caused.

-Carl





----- Forwarded message from francis at MIT.EDU -----
    Date: Wed,  3 Mar 2004 23:08:52 -0500
    From: francis at MIT.EDU
Reply-To: francis at MIT.EDU
 Subject: Re: Note on data reduction
      To: Carl C Dietrich <chipd at mit.edu>

Hey, maybe I'm reading this wrong, but if you wanted to fix it with your
calibration matrix, shouldn't it be:
1.7357 0.0094 0.0252 0.0962 -0.0402 -0.0060

This corresponds to Fx Fy Fz Mz Mx My, which is lift drag sideforce pitch yaw
roll, which is how it appears in the spreadsheet.  Let me know if I'm doing
this wrong.
Mike francis
Quoting Carl C Dietrich <chipd at MIT.EDU>:

>
> Be sure that you are careful about which column of raw data
> corresponds to which column of your calibration matrix.
>
> In your Excel file Pitch is the first moment column given, but the
> pitch corresponds to Mz which is the last column of your calibration
> matrix.  This discrepancy can be compensated for by either switching
> the order of your data columns OR switching the columns in the
> calibration matrix (not both).  For example, if you switch the columns
> of the calibration matrix, the first row of your calibration matrix
> should read:
>
> 1.7357 0.0094 0.0252 -0.0060 0.0962 -0.0402
>
> Instead of
> 1.7357 0.0094 0.0252 -0.0402 -0.0060 0.0962
>
>
> -Carl
>




----- End forwarded message -----