Drone Motors

5-inch FPV racing motor

EMAX RSIII 2306

A 5-inch racing motor: 2306 stator, titanium alloy shaft, N54SH magnets, 27.8 g without leads, and up to 1,980 g of pull per motor on EMAX’s 6S bench (2100KV).

  • 5-inch racing
  • 6S (1800KV, 2100KV) or 4S (2500KV)
  • 5-inch props
Drawing the 3D model…

The spin is an illustration: the model turns at 1/600 of the no-load speed, and it is a generic 2306 motor drawn from EMAX’s published sizes, not its exact design. No-load speed is KV × 22.2 V, a nominal pack for this version. EMAX’s bench tables for it step by thrust rather than throttle, so they are in the bench data below, not on this readout.

Version

Rated for 3S–6S, for 5-inch props; EMAX tested it at 25.2 V.

Max thrust
1,980 g
HQ 5×4.8×3 prop, 25.2 V
Weight
27.8 g
without leads; 1800KV 27.9 g, 2500KV 27.7 g
Peak current
41.8 A
full throttle
Max power
1,053 W
full throttle

from $19.99a motor at EMAX USA

A set of four: $79.96

Price seen Oct 19, 2026. Plain links: we earn nothing from them.

What you get for $19.99

  • About 2 kg of pull on 6S

    On EMAX’s 25.2 V bench the 2100KV pulled 1,980 g at full throttle on an HQ 5 × 4.8 × 3, drawing 41.8 A.

    Source: EMAX 2100KV payload test

  • 27.8 g

    EMAX lists 27.7–27.9 g without leads, depending on the KV, against 29.3 g for the RSIII 2207.

    Source: EMAX spec sheet, EMAX product page

  • Titanium alloy shaft

    A 4 mm titanium alloy shaft with an M5 prop thread; EMAX USA says titanium is stronger and lighter than steel.

    Source: EMAX USA product page, EMAX product page, EMAX spec sheet

  • Rated for 150 °C

    EMAX pairs N54SH magnets with single-strand wire rated for 240 °C, and rates the motor for 150 °C, with 180 °C as its maximum.

    Source: EMAX USA product page

What to pair it with

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

ESC
EMAX rates the peak current at 34 A (1800KV) and 46 A (2100KV) on 6S, and 43 A (2500KV) on 4S. On its bench the 2100KV drew up to 46.5 A and the 2500KV 47.9 A at full throttle, both on a DALPROP Cyclone 5050. An ESC rated for 50 A covers every prop EMAX tested. (EMAX spec sheet, EMAX 2100KV payload test, EMAX 2500KV payload test)
Props
EMAX lists 5 to 5.5-inch props for the 1800KV and 5-inch props for the 2100KV and 2500KV. On its 6S bench the 2100KV pulled 1,820–1,980 g at full throttle on five props, most on the HQ 5 × 4.8 × 3. (EMAX spec sheet, EMAX 2100KV payload test)
Battery
6S for the 1800KV and 2100KV, 4S for the 2500KV. EMAX rates the first two for 3S–6S and the 2500KV for 3S–4S, and tested them at 25.2 V and 16.8 V. (EMAX spec sheet, EMAX 1800KV payload test, EMAX 2100KV payload test, EMAX 2500KV payload test)
Frame
Four M3 holes on a 16 mm circle (16 × 16 mm). (EMAX spec sheet)

Where to buy

  • EMAX USAthe maker’s US store; one page for the 2207 and 2306, same price for every KV
    $19.99seen Oct 19, 2026
    Visit
  • EMAXthe maker’s global store
    $30.78seen Oct 19, 2026
    Visit
  • GetFPVchoose the KV
    price on the store’s page
    Visit

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

Full specs

SpecValueSource
KV2,100 rpm/V (also 1800KV and 2500KV)EMAX USA product page
Stator23 × 6 mm (2306)EMAX spec sheet
Configuration12N14P (12 stator slots, 14 magnet poles)EMAX spec sheet
Battery3S–6S LiPo (1800KV, 2100KV); 3S–4S (2500KV)EMAX spec sheet
Weight27.8 g (without leads; 1800KV 27.9 g, 2500KV 27.7 g)EMAX spec sheet
Dimensionsφ27.3 × 32 mm (with shaft); 25.1 mm from the bottom of the bell to the shaft tipEMAX spec sheet
ShaftTitanium alloy, M5 thread, protrudes 12.9 mm; 4 mm through the bearingsEMAX spec sheet, EMAX USA product page, EMAX product page
Mounting4 × M3 holes on a 16 mm circle (16 × 16 mm)EMAX spec sheet
Bell7075 aluminiumEMAX USA product page
MagnetsN54SH neodymium magnetsEMAX USA product page
BearingsG1-grade high-speed bearings (EMAX gives no size)EMAX USA product page
WindingSingle-strand, AIW enamelled copper wire rated for 240 °CEMAX USA product page
Internal resistance57 mΩ (1800KV 68 mΩ, 2500KV 43 mΩ)EMAX spec sheet
Idle current1.4 A (at 10 V; 1800KV 1.1 A, 2500KV 1.8 A)EMAX spec sheet
Peak current46 A (on 6S; 1800KV 34 A on 6S, 2500KV 43 A on 4S)EMAX spec sheet
Max power1,160 W (on 6S; 1800KV 860 W on 6S, 2500KV 720 W on 4S)EMAX spec sheet
Leads20 AWG, 120 mmEMAX spec sheet

Bench data

Redrawn from EMAX’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.

1800KV on 6S, 25.2 V6 props

PropStepCurrent (A)Thrust (g)Power (W)Efficiency (g/W)
HQ 5×4.8×32.830070.564.25
5.6500141.123.54
9.2700231.843.02
Max34.11,780859.322.07
DALPROP Cyclone 50502.930073.084.11
5.8500146.163.42
9.8700246.962.83
Max33.51,730844.22.05
HQ 5×4.3×32.830070.564.25
5.5500138.63.61
8.9700224.283.12
Max29.81,720750.962.29
DALPROP Cyclone 5046330075.63.97
5.8500146.163.42
9.6700241.922.89
Max32.51,7008192.08
DALPROP Cyclone 50402.930073.084.11
5.6500141.123.54
9700226.83.09
Max27.91,680703.082.39
GF 5045-32.830070.564.25
5.6500141.123.54
9700226.83.09
Max30.61,670771.122.17

Source: EMAX 1800KV payload test

2100KV on 6S, 25.2 V5 props

PropStepCurrent (A)Thrust (g)Power (W)Efficiency (g/W)
HQ 5×4.8×32.930073.084.11
5.9500148.683.36
9.7700244.442.86
Max41.81,9801053.361.88
DALPROP Cyclone 5046330075.63.97
5.9500148.683.36
9.9700249.482.81
Max46.21,9601164.241.68
DALPROP Cyclone 50503.130078.123.84
6.2500156.243.2
10.1700254.522.75
Max46.51,9201171.81.64
GF 5045-3330075.63.97
5.9500148.683.36
9.6700241.922.89
Max37.71,830950.041.93
DALPROP Cyclone 50403.130078.123.84
5.9500148.683.36
9.7700244.442.86
Max36.11,820909.722

Source: EMAX 2100KV payload test

2500KV on 4S, 16.8 V6 props

PropStepCurrent (A)Thrust (g)Power (W)Efficiency (g/W)
DALPROP Cyclone 50504.530075.63.97
9.2500154.563.23
15.2700255.362.74
Max47.91,590804.721.98
DALPROP Cyclone 50464.530075.63.97
8.9500149.523.34
14.3700240.242.91
Max43.11,580724.082.18
HQ 5×4.8×34.430073.924.06
8.7500146.163.42
13.9700233.523
Max41.91,580703.922.24
HQ 5×4.3×34.330072.244.15
8.5500142.83.5
13.4700225.123.11
Max36.51,480613.22.41
GF 5045-34.330072.244.15
8.7500146.163.42
13.7700230.163.04
Max36.81,470618.242.38
DALPROP Cyclone 50404.430073.924.06
8.7500146.163.42
13.6700228.483.06
Max35.11,410589.682.39

Source: EMAX 2500KV payload test

Inside the motor

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

How fast it spins

KV is the motor’s no-load speed per volt. With nothing on the shaft, the 2100KV 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.

BatteryVoltsNo-load rpm (KV × V)Electrical frequencyESC steps per second
4S nominal14.831,0803,626 Hz21,756
4S full16.835,2804,116 Hz24,696
6S nominal22.246,6205,439 Hz32,634
6S full25.252,9206,174 Hz37,044

A 14-pole rotor has 7 pole pairs, so every turn of the shaft is 7 electrical cycles, and a six-step ESC switches the phases 42 times per turn.

About the 3D model

A generic outrunner drawn from EMAX’s published sizes: the 23 × 6 mm stator, 27.3 mm bell, 19.1 mm height, 5 mm shaft, 16 mm mounting circle and 12 teeth and 14 magnets. Anything EMAX 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. EMAX USA: RSIII Brushless FPV Racing Motor (product page for the 2207 and 2306, with its materials list). Retrieved Oct 19, 2026.
  2. EMAX: RSIII 2306 FPV Racing motor, 1800KV 2100KV 2500KV (product page on EMAX’s global store, with EMAX’s RSIII infographics). Retrieved Oct 19, 2026.
  3. EMAX: RSIII-2306 spec sheet (dimension drawing and spec table for each KV; image on EMAX’s product page). Retrieved Oct 19, 2026.
  4. EMAX: RSIII2306 1800KV payload test at 25.2 V, six props (image on EMAX’s product page). Steps of 300, 500 and 700 g, then “Max” at full throttle; EMAX’s rpm column is left out because it has no figure at full throttle.. Retrieved Oct 19, 2026.
  5. EMAX: RSIII2306 2100KV payload test at 25.2 V, five props (image on EMAX’s product page). Steps of 300, 500 and 700 g, then “Max” at full throttle; EMAX’s rpm column is left out because it has no figure at full throttle.. Retrieved Oct 19, 2026.
  6. EMAX: RSIII2306 2500KV payload test at 16.8 V, six props (image on EMAX’s product page). Steps of 300, 500 and 700 g, then “Max” at full throttle; EMAX’s rpm column is left out because it has no figure at full throttle.. Retrieved Oct 19, 2026.