GTech accelerometer was: Leach headers

From: Jon Steiger (stei0302@cs.fredonia.edu)
Date: Mon Jun 14 1999 - 14:40:30 EDT


On Mon, 14 Jun 1999, Bob Tom wrote:
[...]
> I have not personally used the GTech. I don't know if you have to alter
> the way
> you make a run with it in order to register the effects that the headers
> give at
> the top end. As far as I can tell, the GTech is basically an accelerometer
> which means speed input is still needed since an accelerometer cannot tell the
> difference between acceleration and gravity. As far as the horsepower
> calculation
> is concerned, you would use the acceleration from the accelerometer and the
> speed
> from another sensor... The calculation (mass * velocity * acceleration)
> doesn't care whether the acceleration is due to gravity (going uphill) or
> increase
> in speed.
>
> Someone correct me if I am mistaken.

    Yep, the heart of the GTech is an accelerometer, but you don't need
a speed sensor because velocity can be extrapolated from acceleration.
The type of accelerometer in the GTech is a single axis accelerometer.
(It might be a dual axis if they're also measuring lateral G's, unless
of course they require you to turn the GTech 90 degrees prior to doing
lateral accelleration tests, in which case its just a single axis.) At
any rate, its definitely not a tri-axis accelerometer, which would be
measuring gravity as well; it'll only measure in one axis. Of course,
the assumption is that the accelerometer is perfectly level so that gravity
doesn't throw it off. (Which, in reality, isn't going to happen; there
will always be a little error from gravity because the accelerometer
won't be perfectly level all the time...)

                                              -Jon-

  .--- stei0302@cs.fredonia.edu ----------------------------------------.
  | Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
  | '96 Dodge Dakota v8 SLT CC (14.58@93.55), '96 Kolb FireFly 447 |
  `--------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'



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