Description
A quadcopter is only as rigid as the arms that carry its motors. Every flex the frame absorbs is an oscillation the flight controller must then fight, and every fight costs the pilot a clean line through a gate.
The AeroFlex arm is a replacement pressed from 3K carbon fiber in a twill laminate. Carbon is used here for three properties that matter at this size: it is stiff along the length of the arm, it is close to weightless, and it does not conduct, so a snapped prop or a wet landing never turns the airframe into a circuit. The laminate runs the full length of the arm and the motor plate is left flat, so a standard four-hole motor pattern sits flush without shimming.
Three lengths cover the common racing and freestyle classes, five, six and seven inch, and each is supplied as a single spare, a matched pair or a full four-piece set. Crashes are part of how these machines are flown, and a replacement should be something kept in the field box rather than something waited on. A spare arm is a re-flight, not a rebuild.
Carbon does not apologise for a bad landing. It simply asks that the next arm be laminated, not printed.
Airframe Notes
- ✦ 3K carbon fiber arm in a twill laminate - stiff, light and non-conductive
- ✦ Sized for 5 inch, 6 inch and 7 inch FPV frames
- ✦ Available as a single spare, a matched pair or a four-piece set
- ✦ Flat motor plate accepts a standard four-hole motor mount
- ✦ Matte laminate finish hides scuffs and resists edge fraying
- ✦ Non-metallic airframe - no antenna interference and no shorting risk
- ✦ Field-replaceable, so a hard crash becomes a five-minute repair
Laminate Specification
- Material: 3K carbon fiber, twill weave laminate
- Frame Class: 5 inch, 6 inch and 7 inch FPV builds
- Pack Options: 1 pc, 2 pcs, 4 pcs
- Motor Mount: Flat plate, standard four-hole pattern
- Finish: Matte laminate
- Geometry: Straight arm with symmetrical motor plate
- Hardware: Reuses the original frame screws (not included)
- Role: Replacement or spare arm
- Construction: Fiber laminate, no metal inserts
- Inspection: Check motor-mount edges after hard impacts
Where Arms Break
Racers carry spare arms because the arm is the part that meets a gate on a bad lap. Freestyle pilots bend theirs on concrete and rooftop landings. Builders starting a new 5 inch or 7 inch frame order a four-piece set so the airframe is matched from the first screw. In each case the arm is the cheapest part of the machine to keep on hand and the most expensive part to be missing on race day.
Against the Alternatives
Printed nylon arms are the obvious alternative and they have their place on a practice frame, because they flex instead of shattering and a replacement costs nothing but filament time. What they do not do is hold a motor plate flat under load, which is precisely when jello and a drifting gyro appear. Aluminium sits between the two: stiffer than polymer but heavier at the tip, which is the worst place to add weight, and conductive at the point where an ESC and a wet field meet. Carbon laminate is the material the racing class settled on for the same reason the frames these arms replace are built from it. The AeroFlex is that material in spare form, so a broken arm ends a lap rather than a weekend.
Builder Questions
Q: What does 3K refer to?
A: 3K describes the carbon tow - roughly 3,000 filaments per strand. It is the standard laminate for FPV frames because it balances stiffness against impact toughness.
Q: Will these fit my frame?
A: The arms use a common straight-arm geometry and a standard four-hole motor plate. Compare your frame's arm mounting pattern and motor bolt spacing with the product photos before ordering.
Q: Is carbon fiber conductive?
A: Carbon itself conducts. In practice the laminate is bonded with epoxy and isolated by the mounting hardware, but keep exposed ends away from bare powered contacts.
Q: Do I need new screws?
A: No. Reuse the screws from the arm being replaced, provided they are straight and the heads are intact.
Q: Can I order different lengths together?
A: Yes. The 5, 6 and 7 inch arms are separate options and can be combined in one order, though each frame should run a matched set.
Q: Are the mounting holes pre-drilled?
A: Yes. The motor plate and frame holes are drilled during manufacture; no cutting or drilling is required.
Q: Can I use these on a cinewhoop?
A: Only if the frame uses the same straight-arm mounting pattern. Ducted cinewhoops normally use a different arm geometry.
Q: What thickness are the arms?
A: They are supplied as replacement arms for the frame class named. Compare the plate spacing and stack height with your existing arm before ordering.
Q: Do they include the motor mount plate?
A: The arm includes its integrated motor plate. Motors and screws are not included.
Q: How many spares should I keep?
A: Racers tend to carry two arms and a full set in the toolbox. If you are ordering once, the four-piece set is the better value.
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