Whoop and Micro Prop Sizes: 31 mm, 35 mm, 40 mm, 45 mm, 65 mm and Shaft Fit

Size is the diameter, in millimetres or inches

Whoop and micro props are sold by diameter. Below 2″ the industry uses millimetres (31 mm, 35 mm, 40 mm, 45 mm, 65 mm); from 2″ up it switches to inches, and the two overlap in listings. The same prop may be labelled both ways:

The frame decides the size: a 65 mm wheelbase clears 31 mm props and nothing larger. If you are not sure, measure motor-centre to motor-centre and read the frame listing — every whoop frame we list carries its prop size.

Shaft and mount — the part that stops a prop fitting

• 0.8 mm shaft — ultralight 0702 motors on sub-20 g whoops. Rare; a 1 mm prop will not push on.
• 1 mm shaft — the whoop standard for 0702, 0802 and 1002 motors, 31–45 mm props. Press fit, no screw.
• 1.5 mm shaft — 1102 to 1404 motors; 2″–3″ props push on, and many 65 mm 2.5″ props come in a 1.5 mm bore.
• T-mount — two M2 screws through the prop into the bell. The 2.5″–3.5″ standard; 1404, 1505 and 2004 motors usually ship with T-mount and a 1.5 mm shaft.
• M5 — threaded shaft and nut from 3.5″ cinewhoop motors (2004, 2105.5) upward; the 90 mm ducted props are sold in both T-mount and M5 bores.

Several props list two mounts (“1 mm / 1.5 mm shaft”, “T-mount, M5 adapters”) because they ship with adapter rings; check the listing, not the photo.

Blade count and pitch

Two-blade props (Gemfan 45 mm 2-blade, 35MMS, HQ 31 mm) are the most efficient — longest flight time, least grip. Three-blade (1219S, 1635, AZI tri-blade) is the all-round default. Four-blade (1220-4, 1636, 1209-4) adds thrust and braking for indoor racing at the cost of a third less flight time. Pitch is the second number in names like 1635 (16 mm diameter class, 3.5 pitch) or 1219S (1.9): higher pitch means more speed per RPM and more current, lower pitch means a calmer, longer flight. On 1S whoops a high-pitch four-blade can pull more than the AIO’s ESC is rated for — stay with what the frame maker ships until you know the motor’s current.

Open vs ducted

Whoops fly inside ducts, so whoop props have squared tips that run close to the duct wall; a prop designed for an open-frame toothpick is less efficient in a duct and vice versa. Cinewhoop props (D51, D63, D75, D90, and DJI Avata sets) are the ducted range from 2″ to 3.5″; micro props are the open-frame 2″–3″ range; whoop props cover 31–45 mm.

Material

Polycarbonate (“PC”) is standard: it bends on impact and springs back. The “Durable” lines from Gemfan and HQProp use a softer blend that survives walls indoors at a small cost in stiffness. Hard nylon props crack on whoops — avoid them below 3″.

Packs and rotation

Whoop props sell in sets of eight — 4 CW + 4 CCW, two crashes’ worth — or sets of four. Rotation matters even though the prop just pushes on: a CW prop on a CCW motor pushes air up. The marking is moulded on the hub (“CW” / “CCW” or “R” / “L”); Betaflight’s default is props-out at the front on the newer whoops, so check your frame’s diagram before pressing them on. A prop tool or small pliers saves the motor bearings when pulling them off.

Where to look

Gemfan and HQProp cover most sizes and bores; NewBeeDrone, BetaFPV and T-Motor fill the 31 mm racing end. Match motors from whoop and micro motors — the listing states the shaft — or start from a bind-and-fly whoop and buy its spare prop set.