Time Speed Distance Rally Tips: Staying On Course

The first rule of rallying is to stay on course. If you stay on course, you can find the
finish. If you can find the finish, you can find the post-rally party. The second rule of
rallying is to stay on time. If you stay on time, you can win the rally, or at least place
high enough to give you bragging rights at the post-rally party.

This article discusses one method for staying on time, or at least close to it. There are
many methods for staying on time, and this method represents only one of them.
However, it is a simple method and therefore it is a good place to start to learn the art
and science of staying on time in a TSD rally.

Now, if you like to run rallies without regard to speedometers or odometers or
watches, we have no argument. Run the rally, have fun and good luck. We’ll see you
at the party. However, if you want to run a TSD rally in the way it is intended to be
run, please read on.


"TSD" stands for "Time, Speed, Distance,” and it refers to the fact that if you know two
of these three variables, you can calculate the third one. This is the information you
need to stay on time. The basic formula is:

For example:
Distance in miles
Time in seconds

2 miles (D)
240 seconds (T)

x 3600 = Speed in MPH

x 3600 = 30 MPH (S)

It is also true that 3600 divided by any MPH = the number of seconds needed to travel
one mile at that speed.

During a TSD rally, the rally team is required to maintain Assigned Speeds, at least part
of the time. The team that stays closest to these Assigned Speeds over the course of
the entire rally is usually the winner. Now you may say, “Simple! We just watch the
speedometer and keep that needle on the Assigned Speed!” However, the Rally Route
requires that you turn this way and that way, slowing down for curves, stopping for
stop signs, and obeying traffic lights. All of this necessitates speeding up and slowing down.
You will not be able to just keep a steady speed, so you will have to calculate
how fast you really did travel over a given portion of the Rally Route so that you can
then speed up or slow down to try to match the "correct” speed.

To calculate your Speed, you will need Time and Distance. Again, you might think “No
problem!” because most of us wear a watch that will tell us the Time, and most cars
have an odometer that will tell us the Distance. However, in a rally, you don't always
know, in advance, the Distance that you will travel at an Assigned Speed, or how much
Time it will take. You get that information only after you have driven from one
instruction to the next, and have measured the Time and Distance.

So it appears that you have to run each piece of the rally to obtain the Time
and Distance variables, then use our formula to see how close you were to the
Assigned Speed for the section that is now behind you, then tear off on the next
section, trying to speed up or slow down to compensate for how much you were off on
the previous section.

Let's use an example. Let’s say that a TSD section of a rally starts you off at 00.00
mileage and with an Assigned Speed of 30 MPH. You drive off, doing your best to
maintain 30 MPH, and executing the Route Instructions flawlessly, until you see an
instruction that requires you to change speeds. What you should do now is record
your mileage (D=distance) and the time (T=time) that you have spent driving to the
speed-change point. Assume you have gone 4.9 miles (D) and it has taken 10 minutes
and 42 seconds (T). Convert the time to seconds (10 minutes x 60 seconds = 600
seconds + 42 seconds = 642 seconds). According to our formula, you then divide the
miles traveled (D) by these seconds (T) to get "miles per second" (4.9 miles/642
seconds = 0.0076323 miles/sec), then multiply that by the number of seconds in an
hour (3600) to get "miles per hour" (0.0076323 x 3600 = 27.48 MPH).

So you now see that you were slow, averaging 27.48 MPH rather than the assigned 30
MPH. According to our formula, you should have completed that section in 9 minutes
and 48 seconds (588 seconds), but you took 10 minutes and 42 seconds (642 seconds).
So, you need to speed-up during the next section to make up 54 seconds, and make it up as quickly
as possible before you arrive at a checkpoint or passage control where you will be penalized for being
early or late, and by the time you calculate this, you will be well into the next portion of the rally.
And if there are many and/or frequent changes in the Assigned Speed, the navigator will likely always be behind,
and you will likely be carrying large errors until you get to the next speed-change point where you can recalculate how you are doing.
This is not the ideal way to run a rally. Fortunately there is a better way… CONTINUOUS SPEED ADJUSTMENT

Since you don't always know in advance exactly how far the Rally Master is going to
make you travel at each Assigned Speed, you need a way to keep recalculating your
average speed and comparing it to the official Assigned Speed as you go, not just once
it is all behind you. In this manner, you can go faster or slower to compensate for how
badly you are missing the Assigned Speed, making speed adjustments as often as
necessary. The Continuous Speed Adjustment method should allow you to stay close
to the Assigned Speed at all times, and that is how rallies are won.

To accomplish Continuous Speed Adjustment, the rally team needs an odometer, a
watch that shows time to the second (two will come in handy), and a chart showing
MPH in "seconds per mile". The driver usually calls out the miles as they
roll over on the odometer, and the navigator uses his running time piece and a table
to determine their "seconds per mile rate.” The navigator compares the time that it took to
drive the last mile with the reference chart, and notes whether they are fast
(took fewer seconds than they should have) or slow (took more seconds than they should have)
over the mile just completed. Then, as the miles unfold, the navigator can continuously advise the
driver, each mile, to speed up or slow down to maintain perfect speed. Since it is unlikely you
will be off by more than a handful of seconds over the course of a single mile, this simple method
allows you to stay reasonably close to the Assigned Speeds at all times.

For example, let’s say that you begin a TSD section with an Assigned Speed of 30 MPH.
By checking the chart you note that it should take 120 seconds, or 2 minutes and 0 seconds,
to go one mile at 30 MPH. At the designated time, the driver begins the TSD
section, accelerating to a speed that will render an average speed of 30 MPH. Since
acceleration time must be considered, he may choose to leave a few seconds before
the designated start time, and/or he may briefly accelerate past 30 MPH to a speed
that will allow the “acceleration lag” to be made up before dropping back to maintain
30 MPH. As the odometer turns over at the end of one mile, the driver calls out,
“Mile!” and the navigator notes the time it took to drive that mile. Let’s say that in this
case it was 2 minutes and 10 seconds. This indicates that they took 10 second more
than they should have to complete the first mile – they are “10 seconds late.” The
navigator immediately calls out, “Ten seconds late!” and the driver then increases his
speed to make up this time, hopefully within the next mile.

To continue our example, as the odometer turns over at the end of the second mile,
the driver again calls out, “Mile!” and the navigator notes the time it took to drive that
mile. Let’s say that in this case it was 1 minute and 53 seconds. This indicates that they
made up 7 seconds, but they are still 3 seconds late overall. The navigator
immediately calls out, “Three seconds late!” and the driver then adjusts his speed to
make up this time, again, hopefully within the next mile. And so forth. In this way, the
rallyists will know at the end of each mile how well they are doing at staying on time.

Now comes the hard part. The navigator must quickly make these calculations and
advise the driver of the difference between “perfect time” and their time, AND must
be prepared, at the end of each mile, to again calculate how well they have made-up
(or increased) their speed error from the previous section, AND must help navigate,
AND must frequently remind the driver of the next route instruction, AND must help
look for signs and landmarks. No one said that it was easy.

It takes preparation. It takes teamwork. It takes practice. But that’s “the game” of
rallying, and for those who take the trouble to learn and practice the game, the results
can be very satisfying. Fun, even!

Reprinted from the MG Club







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