Computing MPH

[Flanagan, Steve]

SO what would the formula look like?

mph = |G dt  ( the | means integral)

assuming different G (G1 -> Gn) values for all time intervals I think I
would get the following

MPH = G1^2/2 * t from t0 --> t1 + G2^2/2 * t from t1 --> t2 + G3^2/2 * t
from t2 --> t3 +
  ... Gn^2/2 * t from t(n-1) -> tn.


How do we scale G's to MPH?  The following does not look correct to me at
first glance:

1 G = (32 Ft / sec^2) * (1 Mile / 5280 Ft) * (3600^2 sec ^ 2) / Hr ^ 2 =
78545 Mile / Hr^2

Now I have G's represented as Mile / Hours (Squared), and when multiplying
each piece of the formula by the time in Hrs) the answer should be left in
MPH?

Is this correct?

Thanks

steve

-----Original Message-----
From: bearbvd at cmn.net [mailto:bearbvd at cmn.net]
Sent: Monday, August 27, 2001 12:05 PM
To: diy_efi at diy-efi.org; gmecm at diy-efi.org
Subject: Re: Computing MPH


At 10:43 AM 8/27/01, Steve.Flanagan at VerizonWireless.com wrote:
>I was at the track this weekend and pitted next to Victor Cagnazzi (#10 on
>the Pro-Stock Truck circuit).  Look for him in Indy this weekend, Great
guy,
>gave us some clutch tuning tips and other.
>
>He is using the RacePac data logger and it has a channel that shows MPH.
>This is not based off the Drive Shaft or other but it uses the G sensor.
>
>I have a data logger that shows G's but does not compute MPH.
>
>How would I go about figuring out MPH relative to G's?
>
>I know how to compute relative to Drive Shaft.  This is not what I am
>asking.
>
>What is the mathematics involved.  And does the Sampling rate of the G
>sensor make a difference or are we just concerned about the average G's and
>the time?

You basically need to integrate G over time to arrive at velocity (MPH).
The quicker the sampling rate, the more accurate the result.

You can do the same thing--integrate V over time to get distance.

Trident missile subs do this (in all six degrees of freedom, and to an
astounding degree of accuracy) in their inertial navigation systems----

Greg
>
>Thanks
>
>Steve F
>
>
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