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Match Air Budget

How many times you can fire before the tanks are spent, and whether anything is left when it matters. Two 200 ml tanks is less air than it sounds.

Inputs

One row per pneumatic mechanism. Count a fire as one full out-and-back cycle. If a mechanism goes out in autonomous and stays out, count it as half by entering it once and halving the number.

1
2
3
psi

100 psi is the rule limit and there is no reason to start lower.

psi

Below this a cylinder still moves but may not hold. Everything under it is unusable air.

%

Air held for the end of the match, when it usually matters most.

Results

Does it last the match?

—

Air the match needs

—ml

Free air, at atmospheric.

Usable air on board

—ml

Left at the buzzer

—ml

Spare fires of the thirstiest

—

Uses the most air

—

Autonomous takes

—%

Air per full cycle, all mechanisms

—ml

Air used, against what the tanks hold—

Everything past the end of the bar is a mechanism that stops working before the match does.

Watch the tank go down

Watch the tank go down
0%

The tank as the match runs, with the air your mechanisms ask for taken out evenly. The dashed line is the reserve you said you wanted left; the bar turns when the air left drops below it. Air is not like a battery: it goes in gulps, and the tank does not warn you first.

Mechanism by mechanism

MechanismCylindersStrokePer cycleFiresTotal airShare

How this is calculated

Air in a tank is compressed, so a 200 ml tank holds far more than 200 ml of usable air. Everything here is converted into free air, the volume it would occupy at atmospheric pressure, because that is the only way to compare what the tanks hold with what the cylinders swallow.

free air in tank = tank volume × (gauge pressure + 14.7) ÷ 14.7 usable air = free air at charge − free air at your pressure floor air per stroke = cylinder volume × (working pressure + 14.7) ÷ 14.7

A dual acting cylinder fills on the way out and again on the way back, so one full cycle costs roughly twice one stroke.

Stroke costs more than bore

All VEX cylinders share a 10 mm bore, so the only thing you control is stroke. A 75 mm cylinder uses three times the air of a 25 mm one for every single actuation.

That makes stroke the first thing to look at when the budget does not fit. A mechanism that only needs 25 mm of travel and was built with a 75 mm cylinder because it was the one on the shelf is quietly spending triple.

Fire count beats everything

The other lever is how often a driver fires. A clamp toggled fifteen times in a match costs fifteen cycles whether or not the extra ten did anything. If the budget is tight, the cheapest fix is usually a driver habit rather than a hardware change.

Why the sums come out tight

Two full tanks hold roughly six liters of free air. That sounds enormous next to a cylinder that swallows a few millilitres per stroke, until you multiply by the pressure ratio: air delivered at100 psi costs almost eight times its own volume out of the tank. This is why teams run out, and why the honest answer is usually fewer, shorter cylinders rather than another tank you are not allowed to add.

Sources & assumptions

Bore (10 mm), strokes (25, 50, 75 mm), tank volume (200 ml) and the100 psi charge limit are VEX published figures. The limit of 2 reservoirs is a game manual rule and, like all rules here, is worth checking against the current manual.

Retract force on a dual acting cylinder is lower than extend force, because the rod takes up part of the piston area. VEX does not publish the rod diameter, so this tool does not model the difference and treats both directions as using a full bore of air, which is slightly pessimistic on air and optimistic on retract force.

Assumes air is delivered at the working pressure you set and that temperature does not change. Real systems also lose air to fittings and leaks, none of which is modeled, so treat the answer as an optimistic ceiling.

Every source the site uses, and when it was checked

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                                Comes after

                                Pneumatic or Motor?fills in your air pressure hereCylinder Force Calculatorgives you your air pressureCylinder Pivot & Lever Forcegives you your cylinder strokeCylinder Mount Findergives you your cylinder strokePneumatic Mechanism Reliabilitygives you your air pressure

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                                Match Air Budget Calculator

                                Where your answer goes

                                Pneumatic Mechanism Reliabilitysee how much reliability you lose as pressure falls to that flooruses your air pressure againCylinder Force Calculatorcheck the force you still get at the lowest pressure you trustuses your air pressure againPneumatic or Motor?put the thirstiest mechanism on a motor if the air runs outbrings your air pressure with it

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