FlyFish Flash 2004

What it pulls

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

What you get for $16.90

• 888 g from 16.6 g

  On FlyFishRC’s 4S bench the 2900KV pulled 887.9 g at full throttle on an HQ T5125, drawing 26.01 A; on 6S the 1800KV pulled 837.2 g on the same prop at 14.95 A.

  Source: FlyFishRC spec sheet

• Three kinds of build

  FlyFishRC suggests it for a 3.5-inch carrying a GoPro, a long-range 4-inch, or a very light 5-inch.

  Source: FlyFishRC product page

• One-piece 7075 bell

  FlyFishRC’s Uni-Bell in 7075 aluminium, in black; it says the design adds crash resistance.

  Source: FlyFishRC product page

• NMB bearings, N52SH magnets

  NMB bearings, N52SH magnets, a steel shaft, and copper wire rated to 220 °C.

  Source: FlyFishRC product page

What to pair it with

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

ESC

FlyFishRC gives 10-second peaks of 14.95 A for the 1800KV on 6S and 26.01 A for the 2900KV on 4S. A 20 A ESC covers the 1800KV; the 2900KV needs 30 A. (FlyFishRC spec sheet)

Props

4 to 5-inch props on a 1.5 mm shaft. On 6S the 1800KV pulled 568.5 g on an HQ T4 × 2.5 × 2 and 837.2 g on an HQ T5125; on 4S the 2900KV pulled 887.9 g on the HQ T5125 and 856.6 g on an HQ T5020. The top has four M2 holes on a 5 mm circle. (FlyFishRC spec sheet)

Battery

6S for the 1800KV, 4S for the 2900KV. (FlyFishRC product page)

Frame

Four M2 holes on a 12 mm circle (12 × 12 mm) and 150 mm 22 AWG leads. (FlyFishRC product page, FlyFishRC spec sheet)

Where to buy

• FlyFishRCthe maker’s store; same price for both KVs
  $16.90seen 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 FlyFish’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. One piece of 7075 aluminium (FlyFishRC’s Uni-Bell), φ26 mm, in black, with four M2 holes on a 5 mm circle in the top. (FlyFishRC product page, FlyFishRC spec sheet)
• Shaft. 1.5 mm steel, standing 3 mm above the bell. (FlyFishRC product page, FlyFishRC spec sheet)
• Magnets. N52SH, which FlyFishRC describes as heat resistant. (FlyFishRC product page)
• Stator. 20 × 4 mm with 12 slots, wound with copper wire rated to 220 °C. (FlyFishRC product page)
• Bearings. NMB. (FlyFishRC product page)
• Base. Thickened, with four M2 holes on a 12 mm circle. (FlyFishRC product page, FlyFishRC spec sheet)

How fast it spins

KV is the motor’s no-load speed per volt. With nothing on the shaft, the 1800KV 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 FlyFish’s published sizes: the 20 × 4 mm stator, 26 mm bell, 13.5 mm height, 1.5 mm shaft, 12 mm mounting circle and 12 teeth and 14 magnets. Anything FlyFish 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. FlyFishRC: Flash 2004 1800KV 2900KV FPV Motor (product page). Retrieved Oct 19, 2026.
2. FlyFishRC: Flash 2004 Motor (Black) spec sheet: spec table, dimension drawing and test report for the 1800KV at 25.2 V and the 2900KV at 16.8 V (image on the product page). The measured voltage in the test report runs from about 24.1 V down to 23.9 V for the 1800KV and from 16.05 V to 15.67 V for the 2900KV.. Retrieved Oct 19, 2026.