[Land-speed] British Steam effort 139.843mph

[Malcolm Pittwood]

I am not sure when the need for accuracy chimed in, but as Dave highlights
there will be differences at each venue because of the equipment - however
it is certified.

The wording of the FIA says time 1/1000th of a second (if the SCTA team of
timers go to 7 decimals then they will only need to work with the first
three that they record) and the mph or kph figure quoted to the world is cut
off at the third decimal without rounding.

Average of two times is the correct way to deal with the calculation of the
final average speed when two runs take place.

Malcolm



On Wed, Sep 2, 2009 at 12:50 PM, Dave Dahlgren <ddahlgren at snet.net> wrote:

> You can go to 20 places past the decimal point and not be accurate though
> you might imply it.
> How do the compensate for the length of the wire?
> Dave
> ----- Original Message ----- From: "Kirkwood" <saltfever at comcast.net>
> To: "land-speed" <land-speed at autox.team.net>
> Sent: Wednesday, September 02, 2009 6:02 AM
> Subject: [Land-speed] British Steam effort 139.843mph
>
>
>
> To get 1/1000 of any distance per hour, you have to be able to resolve time
>> to the 0.000277 seconds. However, fundamental metrology requires at least
>> a
>> resolution of 1/10 to the right of the most significant digit to avoid
>> rounding errors. So timing resolution must be at  least 0.000027 seconds.
>> The Bonneville clocks are better than that and report 7 seven places to
>> the
>> right of the decimal!
>>
>>
>>
>> From: Malcolm Pittwood <mbp01 at sky.com>
>>
>> (snip . . . ) "The calcualtion of the average speed . . . . "  All to a
>> timed accuracy of 1/1000th of a second and then expressed to 1/1000th of a
>> mph or kilo per hour.
>> _______________________________________________
>>
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