Eric Robb RC Eric Robb RC RC Builds · Custom Parts · Backyard Engineering
Quick Answer · Free Tool

How to Match a Motor, ESC, Battery & Prop

Size everything from the wingspan, then make the parts agree: the prop sets how much current the motor pulls, the ESC must be rated above that draw with margin, and the battery needs enough cells and C-rating to deliver it. For a 24–36″ foam plane that's a 2212-class ~1400Kv motor, 30A ESC, 8″ prop, and a 3S 850–1300mAh pack. Tap your wingspan below for the matched set I actually fly.

Matched Sets

Pick your wingspan

Each set is the proven starting point for scratch-built foam planes in that size — the same data behind my Checklist Builder.

👆 Tap a wingspan band to see its matched motor, ESC, prop, battery, and servos.

Starting points, not guarantees — always check your motor's prop chart and your ESC/battery ratings before flying. As an Amazon Associate, I earn from qualifying purchases.

The Full Tool

Want the complete checklist for your exact plane?

This page matches the power system. The Checklist Builder adds plane type, flying style, control surfaces, and your radio brand — and hands back the full buyable electronics list, receiver and all.

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Worked example: the 30-inch trainer's power system

My first-plane build sits in the 24–36″ band: a 2212-class ~1400Kv motor on a 9×6 prop, a 30A ESC, and a 3S 1300mAh pack. Check the agreement: that motor-and-prop combo draws under 20A wide open, the 30A ESC covers it with margin, and the pack at 30C can deliver about 39A (1.3Ah × 30). Every link in the chain is rated above the one before it — that's the whole discipline. Get one link wrong and it's the weakest part that burns, which is exactly what happened on my 30-minute plane: the first motor I grabbed didn't have the thrust for the airframe, and the plane wouldn't stay up until I swapped to a properly sized one.

The most common mistake: sizing up the prop without re-checking amps

The plane flies, but you want more pull, so you bolt on a prop one size bigger. More prop is more load: the motor now pulls more current at full throttle, and nothing else in the chain got upgraded. One prop size can be the difference between a 22A setup on a 30A ESC and a 32A setup on the same ESC — and the ESC is now the fuse. Any time the prop changes, re-check the full-throttle draw against the motor, ESC, and battery ratings. The C-rating calculator makes the battery half of that a ten-second check, and Battery & LiPo Basics explains what those pack numbers actually mean.

Common Questions

Power-system matching, answered

At or above your motor's maximum current draw on the prop you're actually flying, plus margin. A 2212-class motor drawing under 20A wide open pairs with a 30A ESC; when in doubt, size up — an oversized ESC just runs cool, an undersized one overheats and dies.
Check the motor's prop chart, then verify with current: a bigger prop makes the motor pull more amps. If full-throttle draw exceeds what the motor, ESC, or battery is rated for, the prop is too big. The prop is the throttle on the whole system — one size up can push a healthy setup over its ratings.
Capacity comes from the wingspan band — 850–1300mAh for a park flyer, 1300–2200mAh for a 36–48″ trainer — and C-rating × capacity must exceed your full-throttle draw. A 3S 1300mAh 30C pack can deliver about 39A, which comfortably covers a sub-20A trainer setup.
They match the airframe rather than the motor: 9g servos handle most foam-board planes up to about 48″, and metal-gear 9g servos take over on bigger or faster planes where more air pushes on the control surfaces. The BEC in your ESC must supply enough current for all of them.
Yes — that's the cheapest thing about foam-board flying. A matched set for one wingspan band moves between airframes of that size. My 30-inch class electronics have flown in several planes; only the foam changes.
Next in the Eric Robb Builder System

Next: wire it up

Parts matched? See exactly how they connect — in the right order, without frying anything.

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