RC Pit Clock

Quick start guide

RC Pit Clock builds a pit stop plan from the tank endurance and the heat length, then calls the lap on which to come in. This guide covers a full race, from measuring endurance to the flag.

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How it works

The app determines which pass in front of the pits the car must use to refuel.

The calculation rests on two figures you supply: how long one tank lasts on the car, and how long the heat runs. From those it derives the number of stops, the stint length and the lap countdown.

The menu holds four entries:

RUN TIME	Works out tank endurance from a measurement run.
RACE	Plans then runs the race.
TIMER	Practice stopwatch, with no fuel management.
SETTINGS	App settings.

A RESUME entry is added at the top of the list while a race is running. The state is kept for six hours and survives closing the app as well as a battery change.

Setting up a race

Five steps. The first is repeated only when something changes on the car.

Step 1Measure tank endurance

This measurement produces the Run time value, which the number of stops and the stint length both depend on. It takes a run of about five minutes and one reading from a measuring tube.

1. Fill the tank to the brim.
2. Run for a recorded time, five minutes for example, at race pace.
3. Drain the tank into a measuring tube and read the remaining volume in centilitres.
4. Open RUN TIME and enter the values.

Input fields

DRIVEN	Duration of the measurement run.
FUEL	Volume left in the tank after that run, in centilitres.
TANK	Tank capacity. 125 cl by default.
DURATION	Length of the target heat. Used to work out the number of stops shown.

PER TANK shows the resulting endurance. The value is stored in the Run time setting and picked up by the planner.

How often

Repeat the measurement after an engine change, a carburettor adjustment or a change of fuel, and on a track that is noticeably faster or slower. Otherwise one measurement a season is enough.

Step 2Enter the heat length

Open RACE. The first screen offers a list of durations; Custom opens free entry.

Enter the length announced by race control. The number of stops follows directly from it.

Step 3Set the number of stops

The PLANNER screen shows five values:

DURATION	Heat length entered in the previous step.
INTERVAL	Stint length, calculated. Interval between two stops.
RUN TIME	Endurance measured in step 1.
AVG LAP	Reference lap time. Converts seconds into a lap count.
PIT STOPS	Number of stops. The only value editable on this screen.

The up and down keys change PIT STOPS. INTERVAL is recalculated with every change.

Effect of the number of stops

A high stop count shortens the stints: margin on each stint goes up, and so does the total time spent in the pits. A low count lengthens the stints and cuts the margin. The trade-off is a race strategy call and the app does not settle it.

Plan rating before the start

Display	Condition
None	Margin above 10 % of endurance.
TIGHT	Margin below 10 % of endurance. The plan holds if no stop drifts; a few seconds late forces an extra stop mid heat.
OVER	Stint longer than endurance. The car runs dry before the planned stop.

Step 4Drive and mark the passes

START begins the race. During the race, the BACK key marks a pass in front of the pits.

Timing does not have to be continuous. Three or four passes marked before the deadline are enough. Outliers, whether a missed press or a double press, are discarded from the calculation.

What marked passes are for

With no pass marked, the countdown relies on the Avg lap time setting. Marked passes supply the real lap time: the call is then expressed in laps, the unit in which the decision to come in is made.

Step 5Make the pit stop

A buzz precedes each deadline. The top line of the race screen carries the call, in this order:

PIT IN 4 LAPS	Four passes left, including the one coming up.
PIT AT END OF LAP	Come in at the end of the current lap. Ready the fuel gun.
PIT THIS LAP	Come in on this pass.
PIT OVERDUE BY	Deadline passed. The value shows how late.

Press START once refuelling is done. The stop is logged and the countdown restarts for a stint.

Cancelling

A second press on START within two seconds cancels the entry and restores the countdown to its previous value.

Stop out of place

The Adaptive pit plan setting, on by default, redistributes the remaining stops over the remaining race time after each refuel. If the new plan requires one more stop, the app offers it rather than applying it.

Race screen

The screen carries eight readouts.

1. 1Pass call. Number of passes before the stop, including the one coming up.
2. 2Lap gauge. One block per remaining lap; the current block fills.
3. 3Stint countdown. Its colour carries the severity.
4. 4Stint ring. Empties with the tank, in the countdown colour.
5. 5Race bar, flag to flag. One dot per stop: white once made, orange still to come, circled for the next one.
6. 6Time left in the heat.
7. 7Endurance left in the current tank, in minutes. The box marks a state to watch.
8. 8Stops made out of stops planned.

Colour code

The three status colours carry the same meaning on every screen.

Green	Margin sufficient.
Orange	Deadline close, or tank below a fifth.
Red	Stop on this pass, or endurance insufficient to reach the flag.

Two shapes double up on colour: a box for a state to watch, an underline for a favourable condition. Both read without telling the hues apart.

Keys

On five key watches every function is reachable from the buttons; the touchscreen is never required.

1. 1LIGHT Watch backlight. No effect on the app.
2. 2UP Previous page. Scrolls inside lists.
3. 3DOWN Next page. Page order wraps around.
4. 4START Starts the race, then logs a stop.
5. 5BACK Marks a pass during the race. Goes back outside a race.

Vibration alerts

Seven distinct patterns, told apart without looking at the watch.

Event	Pattern
Pass marked	Short pulse.
Best lap	Two pulses, the second longer.
Stop in 30 seconds	Light pulse.
Stop in 10 seconds	Sustained pulse.
Last lap before the stop	Two pulses and a high tone.
Stop on this pass	Two strong pulses.
Deadline passed	Two long pulses and an alarm.

The last lap alert is derived from the measured lap time, not from a fixed countdown.

Secondary pages

Four pages, reached with the up and down keys. The race continues while they are open.

A third page lists the laps, with the best one marked.

Settings

Eleven settings. Five cover ordinary use.

Setting	Function
Run time	Tank endurance. Filled in by the RUN TIME screen, editable directly.
Avg lap time	Reference lap time. Used until a pass has been marked.
Capacity	Tank capacity, in centilitres.
Adaptive pit plan	Redistributes remaining stops after each refuel. On by default.
Screen on	Keeps the screen lit during the race only. Increases battery drain.

Common questions