RCinPower SmooX 1404 Plus

What it pulls

RCinPower’s own bench test, one line per prop. Drag across the chart to move the throttle; the model above follows.

What you get

• Made for ultralight quads

  RCinPower recommends it for 2.5- to 4-inch ultralight quads, and says a 4-inch long-range build can fly for more than 20 minutes.

  Source: RCinPower product page, RCinPower page image

• 9 g

  9 g with 3 cm leads in all three spec tables; the scale photo on the page shows 8.88 g.

  Source: RCinPower page image

• Prop mount on the bell

  A 1.5 mm shaft end with four M2 holes in the top of the bell (opposite holes 5 mm apart) to bolt the prop on.

  Source: RCinPower page image

• Bench data on 2.5- to 4-inch props

  Gemfan and HQProp props from 2.5 to 4 inches at two voltages per KV, with the temperature after 3 s at full throttle.

  Source: RCinPower page image

What to pair it with

Our reading of RCinPower’s numbers, so your build matches what the motor was tested with.

ESC

The 6000KV drew up to 15.8 A at full throttle on 3S (Gemfan 4 × 2 × 2, 85 °C, which RCinPower marks hot); the 3750KV up to 9.6 A on 4S and the 2750KV up to 6.9 A on 6S. A 20 A ESC covers all three. (RCinPower page image)

Props

Tested with a Gemfan 2.5 × 4 × 3, HQProp 3 × 2.5 × 3 and 3 × 3 × 3, and a Gemfan 4 × 2 × 2 two-blade. The most thrust in the tests: 474 g (6000KV, Gemfan 4 × 2 × 2 on 3S), 405 g (2750KV, HQProp 3 × 3 × 3 on 6S) and 401 g (3750KV, HQProp 3 × 3 × 3 on 4S). (RCinPower page image)

Battery

2S–3S for the 6000KV, 3S–4S for the 3750KV, 4S–6S for the 2750KV. (RCinPower page image)

Frame

Four M2 screws, opposite holes 9 mm apart. (RCinPower page image)

Where to buy

• WREKDchoose KV and colour
  price on the store’s page
  Visit

Plain links, not affiliate links. Prices change; the store’s page has the current one.

Full specs

Bench data

Redrawn from RCinPower’s test reports. Thrust is static pull on a bench, more than you get in flight. Power is volts × amps; efficiency is thrust divided by power.

Inside the motor

A brushless outrunner: the coils stand still in the middle and the magnets spin around them. From the top down:

• Shaft. 2 mm inside the motor, 1.5 mm where it leaves the bell, protruding 3.8 mm. (RCinPower page image)
• Stator. The coils are wound on a stack of thin steel laminations: 14 × 4 mm (1404, from the name) (RCinPower's three spec tables give the stator diameter as 12 mm, which does not match the 1404 name; the 4 mm length agrees). (RCinPower page image)
• Base. 4 × M2 holes, opposite holes 9 mm apart (9 × 9); the bell's top has 4 × M2 holes for the prop, opposite holes 5 mm apart. (RCinPower page image)

How fast it spins

KV is the motor’s no-load speed per volt. With nothing on the shaft, the 3750KV version reaches about these speeds; a prop loads the motor and brings it down, typically to around 70–75% of these figures at full throttle.

A 12-pole rotor has 6 pole pairs, so every turn of the shaft is 6 electrical cycles, and a six-step ESC switches the phases 36 times per turn.

About the 3D model

A generic outrunner drawn from RCinPower’s published sizes: the 1404 stator, 19.2 mm bell, 13.1 mm height, 1.5 mm shaft, 9 mm mounting circle and 9 teeth and 12 magnets. Anything RCinPower doesn’t publish is typical for a motor this size, and the bell’s spoked top, the base and the inside are a generic design, not this motor’s. The colours are read off the maker’s product photos. There are no logos or markings: it is our drawing, not the maker’s.

Sources

1. RCinPower: SmooX 1404 Plus (product page; its content is one long image). Retrieved Oct 19, 2026.
2. RCinPower: SmooX 1404 Plus page image: what it is recommended for (in Chinese), photos including one on a scale (8.88 g), and the 2750KV, 3750KV and 6000KV spec sheets with dimension drawings and bench tables (temperatures after 3 s at full throttle). Retrieved Oct 19, 2026.