3.5" freestyle has had a hardware problem for years. T-Mount windings strip inside the bell. M2 screws lost in the grass. It works fine for cinematic flying. For freestyle, where you crash every five minutes, it's misery.
One approach we've seen is scaling up a 15xx or 18xx motor with a 5mm prop shaft on top to move past T-Mount. It's a reasonable direction, but the shaft typically steps down to 2mm or 3mm partway through the bell. 5mm where the prop sits, 2mm where the load actually hits. We wanted to take a different route.
So we built what we actually wanted to fly, together with T-Hobby.
A 3mm through-shaft, 5" style
The standard for 3" and 3.5" freestyle has been T-Mount: two M2 screws holding the prop to the bell. It works for cinematic flying. For freestyle, one bad crash and you're stripping threads or hunting M2 screws in the grass.
So we didn't use T-Mount. We took the attachment system from 5" motors, a single threaded shaft with one nut, and scaled it to 3.5". A 3mm titanium shaft runs the full length of the motor, secured with a single M3 nut. No two-screw prop pattern. No M2 inserts to strip. M5 becomes M3, 5mm becomes 3mm. One consistent shaft, top to bottom.
The payoff is simple: prop swaps take seconds. Crashes don't bend the shaft. You don't strip threads. You don't lose tiny screws in the dirt. Hit the ground, hex out, prop on, keep flying.
Running existing 5mm bore props? A shaft adapter is included in the box. Screw them on. Note: the adapter fits standard 5mm bore props only, not T-Mount props.
Unibell 7075, single-screw bottom
The bell is CNC'd from 7075 aluminum as one piece. No seams, no weak points.
And we replaced the c-clip with a single M2 screw on the bottom. Servicing the bearing used to mean fighting a clip that half the time ended up bent, lost, or both. Now it's one screw. 30 seconds. You keep the hardware. You keep flying.
Matched to the Gemfan Bash 3.5 (3525-3)
We co-developed this motor alongside Gemfan's new Bash 3.5 (3525-3) propeller. Pitch and diameter are dialed in for this motor's 3650KV on 4S. If you're building a 3.5" quad, this is the set.
Specs
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Stator: 1604.5
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KV: 3650
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Input Voltage: 4S
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Configuration: 12N14P
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Shaft: 3mm titanium, full through-shaft, M3 nut
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Prop attachment: M3 nut on threaded shaft (not T-Mount)
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Bell: 7075 aluminum, unibell, single M2 bottom screw
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Wire: Silicone
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Mounting pattern: 12x12mm, M2
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Color: Dark gray
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Ideal quad weight: 250-350g
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Ideal propeller: Gemfan Bash 3.5 (3525-3)
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Weight: 13,8gr (including 150mm wire)
Includes
- 1x it's 1604.5 3650KV Motor
- 2x 3mm to 5mm shaft adapter (standard 5mm bore props, non-T-Mount)
- 1x M3 Nylon Nut
- 8x M2 Screws
