Timekeeping

[D-Type]

I hope I'm posting this query in the right forum.
 
 I'm trying to sort out early Land Speed Record speeds (every source differs marginally).  One approach I'm trying is that  "a mile (or km) in 24 seconds is 150mph while a mile in 23.99 is 150.0625 mph and in 24.01 is 149.9375" so a record can only be set at one of these speeds and not in between.
 
 A key element of this approach is the accuracy of the timing.  Broadly speaking I would expect that pre WW1 it was hand timing to 0.1 sec, inter war it was by timing wire accurate to 0.01 sec, from 1930 (or so) to about 1960 it was photoelectric still accurate to 0.01 sec, then from about 1980 this improved to an accuracy of 0.001 sec.
 
 Can anyone tell me what timing accuracy was achievable at different times?

[ddahlgren]

breaking a 150 mph record by 0.0625 MPH is just a little bit trivial isn't it?
 FWIW I believe  the last time I really took a hard look at a time slip it went to 0.001 seconds but it might be better than that and just rounded for printing or i may be wrong..
 Dave

[Malcolm UK]

The accuracy of timing equipment and the number of decimal places then used to calculate speeds is set down in the rules of the organisations who recognise land speed records.  
 
 Unfortunately there will not be many people if any alive who have the knowledge themselves going back to the earliest dates.  There will be sources of reports about reciord attempts that may assist.
 
 Nowadays most of the errors are eliminated and do not forget that for many two runs are averaged - whether it is time or speed - and so you go from .001 to .0005 increments of time.

[D-Type]

Originally posted by Malcolm UK:
  The accuracy of timing equipment and the number of decimal places then used to calculate speeds is set down in the rules of the organisations who recognise land speed records.
 ~
 Nowadays most of the errors are eliminated and do not forget that for many two runs are averaged - whether it is time or speed - and so you go from .001 to .0005 increments of time.

Unfortunately the FIA consider themselves far too important to answer queries from mere members of the public.
 
 I'd missed the point about the average of the two runs muddying the waters.  Thanks for pointing that out.
 
 With successive roundings, misreporting, conversion from kmh to mph and vice versa, every listing of records contains slightly different values.  I hoped that by establishing the accuracy of the timekeeping, I could say that the time must have been (say) either 18.001 or 18.002 seconds so a speed corresponding to one of these times is more likely to be correct than one corresponding to 18.001377 seconds and set the record straight.
 
 I'll have to see if I can think of a way to tackle 2-way runs where I don't know the speed in each direction.

[JackD]

World Speeed records over a Kilo or Mile are expressed in time and the rules direct the degree of precision. The 2 way average is required and the final expression that everybody looks for is MPH or KPH.
 The more you measure the time past the decimal, the more it will drift the final result.

[Malcolm UK]

The current FIA rules for timekeeping are on their website - www.fia.com; FIA Sport; regulations; records; Appendix D.  
 
 The MotorSports Association in the UK may be able to assist with historical FIA timing methods as Britain has used the FIA rules consistently.  You may find a senior timekeeper would have some historical data too.  
 
 If not, then Burdette Martin in the USA as the Chair of the Records Commission (ACCUS/FIA) and former President of the Sporting Authority in the US may answer questions.

[LittleLiner]

Published reports indicate the Nick Craw of Denver will be (or already is) the replacement for the retiring Burdette Martin.  Also it appears that the ACCUS office will be moving to Denver as well.  Craw is a former BMW racer, former head of the SCCA and former head of US Sailing as well as a former head of the Peace Corps.   Perhaps all this LSR record business can be resolved by contacting the new guy.
 
 For Malcolm  - if you are able to make that visit to Maxton I would enjoy meeting you.  Art

[Malcolm UK]

Art
 
 I am told that Burdette will remain the Chairman of the records commission of the FIA through 2005 but it is not clear if it would pass to the new ACCUS boss.
 
 I am working hard to get to Maxton and then on to Wendover in late April/early May, confirmation still awaited at this end.  East and West coast so I can be flamed at both and no fire suit!