RC Glider Motor: How to Choose a Motor, Prop and ESC for an Electric Glider
An electric glider motor only has to climb the glider to height; then it’s switched off and the prop folds. So you want a light, efficient brushless motor with enough power for a confident climb, a folding propeller, and an ESC with a brake that stops the prop so the blades fold back. Small gliders use direct-drive outrunners; larger and competition gliders often use inrunners with a gearbox that turn a large prop slowly and efficiently. A common target is roughly 100–150 W per kg for a relaxed climb, more for fast climbs.
By Kyle HilsonUpdated: October 20264 min read
Motor types
| Type | Pros | Typical use |
|---|---|---|
| Outrunner, direct drive | Simple, light, cheap | Foam and small sport gliders |
| Inrunner + gearbox | Large prop, high efficiency, slim nose | Composite gliders, competition |
| Brushed (old) | Cheap | Older and toy gliders; replace with brushless |
How much power
Power is often expressed in watts per kilogram of flying weight:
- About 100–150 W/kg: relaxed climbs for thermal gliders.
- 150–250 W/kg: brisk climbs, light aerobatics.
- Over 300 W/kg: rocket climbs for competition (F5J and similar classes use altitude limits and specific rules).
A 2 kg glider wanting a steady climb therefore needs roughly 200–300 W from the battery. Motor basics such as kV and can size are in RC electric motors for airplanes.
kV, prop and battery
Gliders like large, slow-turning props for efficient climbs. That means lower kV for direct-drive outrunners, or a gearbox for inrunners. Choose the cell count first (often 3S for medium gliders), then pick a motor kV and folding prop that draw a sensible current; check the result with a watt meter on the ground. Too much current overheats the motor and ESC; too little gives a weak climb.
The ESC
- Brake on: stops the prop so the blades fold; essential.
- Soft start: protects gearboxes and folding hubs.
- Current rating: at least 20–30% above the measured maximum.
- BEC: enough for the servos, or use a separate BEC on bigger gliders.
- Cutoff: soft cutoff that leaves enough for a glide home.
Installation tips
- Match the spinner diameter to the fuselage nose for a clean transition.
- Set down- and side-thrust as the kit specifies to prevent pitching during climbs.
- Make sure the folded blades lie flat against the fuselage.
- Provide cooling air in and out, even in slim noses.
- Balance the CG after fitting the motor; a heavier motor may need the battery moved back.
Using the motor well
Climb steeply to your planned height, cut power, and let the prop fold before you start searching for lift. Use a timer or altitude telemetry to track motor use. If you find rising air, you can stay up long after the climb; if not, a second climb is easy. Many pilots set a throttle-cut switch for safety on the ground. Soaring technique is in RC gliders and sailplanes.
Upgrading an old glider
Older brushed gliders can be converted to brushless for better climbs and longer flights, often with less weight. Measure the nose space and the old mount, pick a motor that fits, and use a modern ESC with brake. Check the CG after the change.
Choosing checklist
- Glider weight and target W/kg known.
- Battery cell count chosen.
- Motor fits nose diameter and mount.
- Folding prop and spinner sized together.
- ESC with brake and enough current reserve.
FAQ
Brushed or brushless for a glider?
Brushless: lighter, more efficient and more powerful.
Why does my folding prop not fold?
The ESC brake is off, or the hinges are too tight.
How much power does a glider need?
Roughly 100–150 W per kg for a relaxed climb.
Do I need a gearbox?
Not for most sport gliders; it helps for large props in slim noses.
More on this topic: the complete RC Basics guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
