3–3.5-inch FPV motor
T-Motor Pacer P1604
An 11.6 g one-piece-bell motor for sub-250 g 3.5-inch freestyle, with a 1.5 mm T-mount shaft: 3800KV for 4S, 2850KV for 6S.
- 3.5-inch freestyle under 250 g
- 4S (3800KV) or 6S (2850KV)
- T-mount 3–3.5-inch props
The spin is an illustration: the model turns at 1/600 of the no-load speed, and it is a generic 1604 motor drawn from T-Motor’s published sizes, not its exact design. Thrust, current and power are T-Motor’s bench figures for the GF3520-3 prop at 16.8 V, read straight across between its throttle steps. Its data starts at 20% throttle.
- Max thrust
- 514 g
- GF3520-3 prop, 16.8 V
- Weight
- 11.6 g
- with leads; the same for both KVs
- Peak current
- 16.8 A
- full throttle
- Max power
- 278 W
- full throttle
from $19.90a motor at T-Motor
A set of four: $79.60
Price seen Oct 19, 2026. Plain links: we earn nothing from them.
What it pulls
T-Motor’s own bench test, one line per prop. Drag across the chart to move the throttle; the model above follows.
At 60% with the GF3520-3: 292 g of thrust, 7.7 A, 128 W, 2.29 g per watt.
On your quad
3.2 : 1
Thrust to weight at full throttle: four motors pull 2,056 g with the GF3520-3 at 16.8 V.
At 60% throttle they pull 1,170 g, 1.8 times the quad’s weight.
All-up weight is the quad ready to fly, with its battery and camera. The thrust is the maker’s static bench figure; in the air it is lower.
What you get for $19.90
One-piece bell
The Pacer line's Unibell, which T-Motor says is more durable.
Source: T-Motor product page
11.6 g
11.6 g with its 120 mm leads, for sub-250 g 3.5-inch freestyle builds.
Source: T-Motor product page
T-mount, 9 × 9 base
A 1.5 mm shaft with T-mount prop holes in the top, and a 9 × 9 mm base that T-Motor says suits more props and frames.
Source: T-Motor product page
Bench data
Both KVs on the Gemfan 3520 three-blade: 618.8 g at full throttle for the 2850KV at 25.2 V, 514.1 g for the 3800KV at 16.8 V.
Source: T-Motor specs and test report
What to pair it with
Our reading of T-Motor’s numbers, so your build matches what the motor was tested with.
- ESC
- Peak current over 10 s is 16.8 A for the 3800KV and 15.8 A for the 2850KV, so a 20 A ESC per motor leaves room. (T-Motor specs and test report)
- Props
- T-Motor benched both KVs on the GF3520-3 (3.5-inch three-blade). T-Hobby suggests three-blades from 3 to 4 inches. (T-Motor specs and test report, T-Hobby product page)
- Battery
- 4S for the 3800KV, 6S for the 2850KV. (T-Motor product page)
- Frame
- 3.5-inch freestyle frames under 250 g. Four M2 holes, opposite holes 9 mm apart. (T-Motor product page, T-Motor drawing)
Where to buy
- T-Motorthe maker's store (Tmotorhobby)$19.90seen Oct 19, 2026Visit
- T-HobbyT-Motor's hobby-brand store; price shown for 2850KV$19.90seen Oct 19, 2026Visit
- RaceDayQuads3800KVprice on the store’s pageVisit
- RaceDayQuads2850KVprice on the store’s pageVisit
- Pyrodrone3800KVprice on the store’s pageVisit
- WREKD2850KVprice on the store’s pageVisit
Plain links, not affiliate links. Prices change; the store’s page has the current one.
Full specs
| Spec | Value | Source |
|---|---|---|
| KV | 3,800 rpm/V (also 2850KV) | T-Motor specs and test report |
| Stator | 16 × 4 mm (1604) | T-Hobby product page |
| Configuration | 12N14P (12 stator slots, 14 magnet poles) | T-Motor specs and test report |
| Battery | 4S LiPo (2850KV: 6S) | T-Motor product page |
| Weight | 11.6 g (with leads; the same for both KVs) | T-Motor specs and test report |
| Dimensions | Φ20.8 × 15.5 mm (15.5 mm is the full length, shaft included) | T-Motor drawing |
| Shaft | 1.5 mm, protrudes 2.9 mm, for T-mount props (four M2 holes on a 5 mm circle in the top); 2 mm inside the motor (T-Motor's spec table gives 2 mm) | T-Motor drawing |
| Mounting | 4 × M2 holes, opposite holes 9 mm apart (9 × 9) (T-Hobby's text says 12 × 12; T-Motor's drawing and its feature image both say 9 × 9) | T-Motor drawing |
| Bell | one piece (Unibell) | T-Motor product page |
| Idle current | 0.8 A (at 10 V; 0.4 A for 2850KV) | T-Motor specs and test report |
| Peak current | 16.8 A (for 10 s; 15.8 A for 2850KV) | T-Motor specs and test report |
| Max power | 277.8 W (for 10 s; 394.6 W for 2850KV) | T-Motor specs and test report |
| Leads | 24 AWG, 120 mm | T-Motor specs and test report |
| In the box | 1 × motor, 1 × parts bag | T-Hobby product page |
Bench data
Redrawn from T-Motor’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.
2850KV on 6S, 25.2 V1 prop
| Prop | Throttle | Voltage (V) | Current (A) | RPM | Thrust (g) | Power (W) | Efficiency (g/W) |
|---|---|---|---|---|---|---|---|
| GF3520-3 (Gemfan 3.5 × 2.0, 3-blade) | 20% | 25.2 | 1.4 | 19580.2 | 104.1 | 35.4 | 2.94 |
| 40% | 25.1 | 4.2 | 28436.5 | 235.7 | 105.8 | 2.23 | |
| 60% | 25.1 | 7.2 | 34220.1 | 349.7 | 179.9 | 1.94 | |
| 80% | 25 | 10.4 | 38863.2 | 461.7 | 259.5 | 1.78 | |
| 100% | 24.9 | 15.8 | 44031.6 | 618.8 | 394.6 | 1.57 |
Source: T-Motor specs and test report
3800KV on 4S, 16.8 V1 prop
| Prop | Throttle | Voltage (V) | Current (A) | RPM | Thrust (g) | Power (W) | Efficiency (g/W) |
|---|---|---|---|---|---|---|---|
| GF3520-3 (Gemfan 3.5 × 2.0, 3-blade) | 20% | 16.8 | 1.5 | 17311.1 | 91.2 | 25.9 | 3.52 |
| 40% | 16.7 | 4.6 | 25611.5 | 202.2 | 76.6 | 2.64 | |
| 60% | 16.7 | 7.7 | 30692.7 | 292.4 | 127.6 | 2.29 | |
| 80% | 16.6 | 11 | 35219.6 | 380.5 | 182.5 | 2.08 | |
| 100% | 16.5 | 16.8 | 40750.1 | 514.1 | 277.8 | 1.85 |
Source: T-Motor specs and test report
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, 20.8 mm across, with five spokes in the top that fork into an X at the rim. (T-Motor drawing)
- Shaft. 2 mm inside the motor, 1.5 mm where it leaves the bell, standing 2.9 mm proud, with four M2 holes on a 5 mm circle round it for T-mount props. (T-Motor drawing)
- Stator. 16 mm across and 4 mm tall, 12 slots under 14 magnet poles (12N14P). (T-Hobby product page)
- Base. Four M2 holes, opposite holes 9 mm apart; three 24 AWG leads, 120 mm long. (T-Motor drawing)
How fast it spins
KV is the motor’s no-load speed per volt. With nothing on the shaft, the 3800KV 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.
| Battery | Volts | No-load rpm (KV × V) | Electrical frequency | ESC steps per second |
|---|---|---|---|---|
| 4S nominal | 14.8 | 56,240 | 6,561 Hz | 39,368 |
| 4S full | 16.8 | 63,840 | 7,448 Hz | 44,688 |
| 6S nominal | 22.2 | 84,360 | 9,842 Hz | 59,052 |
| 6S full | 25.2 | 95,760 | 11,172 Hz | 67,032 |
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 T-Motor’s published sizes: the 16 × 4 mm stator, 20.8 mm bell, 12.6 mm height, 1.5 mm shaft, 9 mm mounting circle and 12 teeth and 14 magnets. Anything T-Motor 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
- T-Motor: Pacer P1604 product page on its Tmotorhobby store (price; feature images). Retrieved Oct 19, 2026.
- T-Motor: P1604 spec table and test report on the GF3520-3 prop (image on the T-Hobby page, S4; the report's last row is on the next image). Columns as T-Motor gives them: voltage measured per row, current, RPM, thrust in g, power, efficiency. Retrieved Oct 19, 2026.
- T-Motor: P1604 product drawing (image on the T-Hobby product page, S4). Retrieved Oct 19, 2026.
- T-Hobby (T-Motor's hobby brand): P1604 product page (description, specifications, price). Retrieved Oct 19, 2026.
