Some RC parts are decorative. This is not one of them.
This is an original E-flite EFLH1213 Outer Shaft & Main Gear Set, produced for the Blade CX family of coaxial electric helicopters. The assembly combines the long metal outer rotor shaft with its installed molded main gear, providing one of the central mechanical links between the helicopter’s motor system and counter-rotating rotor arrangement.
It is the kind of replacement part that may sit unused in a toolbox for years—right up until a worn gear, bent shaft, rough bearing fit, or crash-damaged rotor assembly puts an otherwise complete helicopter on the shelf.
For an owner maintaining an older Blade CX, CX2, or CX3, having the correct original part number matters.
The Blade CX-series helicopters use a coaxial rotor system. Instead of one main rotor and a separate tail rotor, they use two main rotor sets mounted on the same vertical axis and rotating in opposite directions.
That arrangement helps cancel the torque that would otherwise make the fuselage spin in the opposite direction from the rotor. It was one of the reasons the Blade CX family became popular with pilots learning to hover and fly indoors.
The two rotor systems require separate concentric shafts:
This listing is for the outer shaft and attached main gear assembly.
The metal shaft runs through the helicopter’s central bearing structure, while the main gear meshes with the appropriate motor pinion. As the motor turns, the gear transmits rotation into the outer shaft and then into the corresponding rotor head.
Because the shaft is part of the rotating system, straightness matters. Because the gear carries motor power, clean and complete teeth matter. This is why replacing a compromised assembly is often preferable to trying to continue flying with a bent shaft or damaged gear.
A Blade CX-series helicopter may require an outer shaft and main gear after:
Not every vibration problem is caused by the outer shaft. Blades, rotor heads, flybars, bearings, inner shafts, retaining collars, gears, and motor pinions can all contribute. However, the outer shaft is one of the components that should be inspected when the lower rotor system does not rotate cleanly or concentrically.
Legacy RC helicopters often have several parts that look similar in photographs but are not interchangeable.
This assembly should be matched by the printed part number:
EFLH1213
That is more dependable than buying an unmarked shaft based only on approximate length or gear diameter.
The packaging identifies it as:
Outer Shaft & Main Gear Set: BCX
Original Blade CX-family documentation also associates EFLH1213 with the Blade CX-series coaxial helicopters.
Owners should still compare the existing assembly, helicopter manual, gear dimensions, shaft length, mounting holes, and original part number before installation. Production revisions and previous owner modifications can complicate compatibility on older RC equipment.
The shaft is a long, hollow metal tube with a machined opening near one end.
Its design allows it to surround the inner shaft while rotating independently. That concentric arrangement is the mechanical heart of the coaxial rotor system: two separate shafts occupying the same central axis but driving different rotor assemblies.
Visible features include:
The cross-drilled opening is part of the shaft’s attachment and alignment system. It is not damage.
The molded main gear is installed at one end of the outer shaft.
Its job is to receive power from the motor pinion and transfer it into the shaft. Gear condition is important because even one damaged section can create:
When installing any replacement gear, the motor-pinion mesh should be checked carefully. A mesh that is excessively tight can create drag and premature wear. A mesh that is too loose can allow skipping, damaged teeth, or inconsistent power transfer.
This listing does not include motors, motor pinions, bearings, retaining collars, rotor heads, blades, or installation hardware beyond what is visibly attached to the assembly.
The Blade CX platform belongs to an important period in hobby-grade electric helicopter development.
It helped make stable indoor helicopter flight more accessible by combining:
Unlike disposable toy helicopters, the Blade CX family was designed around replaceable service parts. Motors, shafts, gears, blades, rotor heads, bearings, frames, electronics, and linkages could be individually repaired.
That repairable construction is exactly why original parts such as EFLH1213 still matter. A mechanically complete older helicopter may only need one correct component to return to service.
Installation should be performed by someone familiar with small coaxial RC helicopters.
A typical service process may involve removing portions of the rotor assembly, retaining hardware, collars, bearings, gears, or frame components. Exact procedures vary by model and configuration.
Before final assembly:
Do not force the shaft through a bearing. Do not pry directly against the gear teeth. Do not hammer the shaft into place.
If the helicopter still vibrates after installation, stop and inspect the remainder of the rotor system before continuing to fly.
This is a new old stock replacement part in its original E-flite retail packaging.
The outer shaft and main gear appear unused and uninstalled. The gear teeth appear present, and the metal shaft appears straight in the photographs.
The retail card and clear bag show storage and handling wear, including creasing, surface marks, wrinkles, an older price area that has been marked over, and general cosmetic aging. The packaging is not mint.
The assembly has not been installed or operated by us. Functional performance after installation depends on correct compatibility, proper installation, drivetrain adjustment, and the condition of the receiving helicopter.
Please examine every photograph closely. The photographs show the exact assembly and packaging included.
Professionally packed & shipped with care — Protecting the fun every step of the way.
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