Time-Speed Rally Overview

An overseas reader of this website saw my recent post about the 2016 Rally Round The Erie Canal and was curious about how Time-Speed rallies work.  In this post I will try to provide a brief overview using some examples from the 2016 Rally Round The Erie Canal.

I have included a sample instruction page from the rally course following instructions.  At the top of the page I have written down that our current speed based on Instruction #30 on the previous page is 35 miles per hour (mph).  Instruction #31 means that once we see the sign shown we are to continue doing 35 mph for 20 seconds and then accelerate to 50 mph.  As we continue on to Instruction #32, when we see the “Speed Zone Ahead” sign we are to slow down to 40 mph.  At the “Stop Ahead” sign we are to change our speed to 35 mph.  Instruction #34 we come to a Stop Sign, we stop for 15 seconds, turn right, and accelerate to 35 mph. And so on through the instructions. The location of the timing controls are not known in advance.  When we reach a control, you don’t stop as your end time for one leg is the start of the next leg measured to the second.  Sample Instruction Page

Sample Instruction Sheet

As you can see, no distances are provided and no odometers are allowed.  As we were competing in the PRO Class we were able to use a calibratable speedometer with 1 mph markings.  Our speedometer is the round black instrument held onto the dash by a short rope and a bungee cord.  (this was a day-of-the-rally decision to use this car) The speedometer directly reads to 50 mph around the circumference, but there is no stopper so 60 mph is indicated as 10 mph.  We rotated the speedometer to have the 30 mph position in the vertical position.

Digital time-of-day clocks are not allowed, so we used my large diameter “Sawtooth Clock” which has each second marked i.e. “47, 48, 49…”, that way I don’t have to count second markers, I just read the clock.  The clock is shown mounted in the center of the car.  For timing maneuvers a digital stop watch is allowed, but I prefer to use a mechanical stop watch which I have placed on the dash by Velcro.  Directly in front of me, I have fixed a clipboard which holds the performance chart that we were using for this rally.  A calculator and some pencils complete my navigator tools.  I use all of my own timing/navigation equipment no matter what car I’m navigating in, because I want to have the proper equipment and with familiar equipment which I know exactly how it works.


Timing Equipment For A Time-Speed Rally

If you look back at the instruction sheet, then you can see some scribbles that I made to fine tune the timing.  For example in Instruction #34, we are to travel 0 mph for 15 seconds.  However it is impossible to travel 35 mph right up to the stop sign, instantaneously stop, wait 15 seconds then immediately do 30 mph.  Because of time lost decelerating from 35 mph to 0 mph, then accelerating from 0 to 30 mph, we were only stopped for 12.8 seconds.  All through the rally, the navigators must take into account the time lost or time gained with every maneuver.  The key to taking this into account is the performance chart.  Each car has its own performance chart which has to be prepared by the rally team before the event.  A sample performance chart is shown below.

Sample Performance Chart

A Sample Performance Chart

A sample use of the performance chart would be the time lost to accelerate from 0 to 30 mph.  When a car starts from a standing start and accelerates to 30 mph, the car does not immediately go 30 mph, but forward progress is being made, so not all time is lost.  In the case shown above the time lost from 0 to 30 mph is 2.4 seconds.  Therefore if a car’s start time was 9:58:00 , the actual time to leave and accelerate to 30 mph for this car would be 9:57:55.6.  This 2.4 seconds head start is equivalent to starting instantly at 9:58:00.  The time lost or gained for speed changes can be determined from the performance chart.

I posted a technique to prepare a performance chart for a car on this website on October 11, 2014.

Our score sheet for a day’s rallying in the 2016 Rally Round The Erie Canal is shown below.

Our Saturday Scores

A Sample Individual Score Sheet

On this day, there were 6 legs in the rally and our scores (timing errors) at each control or leg were 2, 7, 14, 5, 4, and 3 seconds for a day’s total of 35 seconds.  Some of duration of the true times are misleading as we had some transits included in the true time.  Leg 4 did not have a transit, so it had a rally time duration of almost 30 minutes or 1800 seconds.  Our error from the perfect time was 5 seconds, which while a good score, others did a little better.  However to beat the top teams this is level of performance that a team needs to achieve.

This is illustrated in the Saturday score sheet shown below.

Saturday Score Sheet

Score Sheet From The First Day Of The 2016 Rally Round The Erie Canal

Our total score of 35 seconds was good for 4th place, but the top three teams had total timing errors of 26, 26, and 42 seconds.  You might wonder how a car with a 42 second error was in the third position, while we had an error of 35 seconds, but was in the 4th position.  This is because the older cars get an error reduction factor based on the age of the car.  This is because, in general, their cars have less power and lesser brakes.  This factor allows for well-driven/navigated cars from the early part of the 20th century to often be found at the top of the scoring sheets.

The scoring sheet shows the typical results that can be expected from a day of a Time-Speed rally.

I have only touched the surface of these type of rallies, so if you have any comments or questions either leave a comment below or send me a private email at the following address: shanna12 at comcast dot com


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