BrotherHobby VY 2004

What it pulls

BrotherHobby’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 sub-250 g 5-inch

  BrotherHobby designed it for sub-250 g 5-inch racing quads; it weighs 14.9 g with short leads.

  Source: BrotherHobby product page, BrotherHobby title image, BrotherHobby spec and drawing

• About 1 kg per motor

  The 3150KV pulled 1,036 g at full throttle on a GF T-mount 51 × 25 × 3 at 15.8 V, drawing 32.5 A; the 1950KV pulled 977 g at 18.8 A on 23.9 V.

  Source: BrotherHobby 1950KV test report, BrotherHobby 3150KV test report

• Hard-anodised 7075

  Bell cap and base in 7075 aluminium with a hard-anodised finish, which BrotherHobby says takes light scrapes without marking, on a heat-treated titanium-alloy shaft.

  Source: BrotherHobby product page, BrotherHobby build image

• 260 °C winding

  BrotherHobby rates the winding wire to 260 °C, for long runs at full throttle.

  Source: BrotherHobby spec and drawing, BrotherHobby winding image

• NMB bearings

  Japanese NMB 7 × 3 × 3 mm bearings, which BrotherHobby says run smooth and quiet.

  Source: BrotherHobby product page, BrotherHobby build image

What to pair it with

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

ESC

BrotherHobby’s test reports list a 6S 15 A ESC for the 1700KV and 6S 20 A for the 1950KV, and 4S 15 A for the 2100KV and 4S 35 A for the 3150KV; full-throttle currents were 14.1 A, 18.8 A, 13.4 A and 32.5 A. (BrotherHobby 1700KV test report, BrotherHobby 1950KV test report, BrotherHobby 2100KV test report, BrotherHobby 3150KV test report)

Props

5-inch T-mount props: BrotherHobby tested every KV on a GF T-mount 51 × 25 × 3, held by two M2×7 screws in the bell’s top. (BrotherHobby spec and drawing, BrotherHobby load tests, BrotherHobby 1700KV test report)

Battery

6S for the 1700KV and 1950KV, 4S for the 2100KV and 3150KV. (BrotherHobby product page, BrotherHobby spec and drawing)

Frame

Four M2 holes on a 12 × 12 mm pattern, with four M2×6 titanium screws in the box. (BrotherHobby product page, BrotherHobby spec and drawing, BrotherHobby load tests)

Where to buy

• BrotherHobbythe maker’s store; $21.99, down from $24.99, for any KV, with every KV listed as out of stock
  $21.99seen Oct 19, 2026
  Visit

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

Full specs

Bench data

Redrawn from BrotherHobby’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:

• Bell. 7075 aluminium, φ24.6 mm, hard anodised, with a four-spoke top that carries the prop on M2 screws. (BrotherHobby product page, BrotherHobby spec and drawing, BrotherHobby build image, BrotherHobby top photo)
• Shaft. Heat-treated titanium alloy, Ø1.5 mm, standing 4 mm above the bell. (BrotherHobby spec and drawing, BrotherHobby build image)
• Stator. 20 × 4 mm with 12 slots, in 0.15 mm Nippon Steel silicon steel, wound with wire rated to 260 °C. (BrotherHobby product page, BrotherHobby 1700KV test report)
• Magnets. N52H arc magnets, 14 poles. (BrotherHobby product page, BrotherHobby spec and drawing)
• Bearings. NMB, 7 × 3 × 3 mm. (BrotherHobby product page)
• Base. 7075 aluminium, with four M2 holes on a 12 mm circle and 24 AWG leads 16 cm long. (BrotherHobby product page, BrotherHobby spec and drawing)

How fast it spins

KV is the motor’s no-load speed per volt. With nothing on the shaft, the 1950KV 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 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 BrotherHobby’s published sizes: the 20 × 4 mm stator, 24.6 mm bell, 12.4 mm height, 1.5 mm shaft, 12 mm mounting circle and 12 teeth and 14 magnets. Anything BrotherHobby 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. BrotherHobby: VY 2004 Ultralight Motor (CW) (product page on BrotherHobby’s store, with its spec list, photos and Tech Specs tab). Retrieved Oct 19, 2026.
2. BrotherHobby: VY 2004 title image, “design for sub-250g 5” racing”, with each KV’s full-throttle figures (image on the Description tab). Retrieved Oct 19, 2026.
3. BrotherHobby: VY 2004 specification and drawing (image on the Description tab). Its cell count reads 4S; the page’s spec list gives 4/6S.. Retrieved Oct 19, 2026.
4. BrotherHobby: VY 2004 load test data for all four KVs, with the packing list (image on the Description tab). It repeats the four test reports’ tables.. Retrieved Oct 19, 2026.
5. BrotherHobby: VY 2004 1700KV test report, 18 June 2020 (drawing, spec table and load test on a GF T-mount 51 × 25 × 3 at 24 V; image on the Tech Specs tab). The copper temperature is after two minutes at full throttle.. Retrieved Oct 19, 2026.
6. BrotherHobby: VY 2004 1950KV test report, 30 April 2020 (load test on a GF T-mount 51 × 25 × 3 at 24 V; image on the Tech Specs tab). Retrieved Oct 19, 2026.
7. BrotherHobby: VY 2004 2100KV test report, 18 June 2020 (load test on a GF T-mount 51 × 25 × 3 at 16 V; image on the Tech Specs tab). Retrieved Oct 19, 2026.
8. BrotherHobby: VY 2004 3150KV test report, 28 April 2020 (load test on a GF T-mount 51 × 25 × 3 at 16 V; image on the Tech Specs tab). Retrieved Oct 19, 2026.
9. BrotherHobby: VY 2004 “Solid shape” and “Smooth inside” image: 7075 aluminium, hard anodising, heat-treated titanium shaft, NMB bearings (image on the Description tab). Retrieved Oct 19, 2026.
10. BrotherHobby: VY 2004 winding, steel and magnet image (image on the Description tab). Retrieved Oct 19, 2026.
11. BrotherHobby: VY 2004 product photo (first gallery image on the product page). Retrieved Oct 19, 2026.
12. BrotherHobby: VY 2004 from above, showing the four-spoke top (gallery image). Retrieved Oct 19, 2026.