TECHNICAL SPECIFICATIONS
Length w/o main blades: 1,148 mm
Overall height: 315 mm
Frame width: 206 mm
Frame weight: 1,500 g
Main shaft diameter: 10 mm
Feathering shaft diameter: 8 mm
Main gear: 170 T
Pinion gear：22T（20T Optional）
Main gear ratio：7.7（8.5 Optional）
Tail ratio: 4.615 （5 Optional）
Fuel tank capacity: 345 cc
Recommended blade length: 550 – 580 mm
Engine class: .50 – .55 nitro
Power system: Nitro (requires engine, pipe, servos, and gyro)
All-New Compact Nitro Clutch System
The new system features multiple engineering upgrades over the previous version:
🧩 All-new pre-balanced clutch assembly — factory balanced to minimize vibration and extend bearing life.
⚙️ Redesigned extended engine shaft — provides higher axial rigidity and smoother transmission, greatly reducing clutch stack distortion under load.
🔧 Refined starter coupling structure — starter cup no longer sits inside the bearing, preventing loosening during operation and improving long-term reliability.
🎯 Improved concentricity — upper clutch bearing alignment has been significantly enhanced for a smoother, more efficient drivetrain.
🧰 Optimized taper angle — allows easier installation and secure clutch engagement without excessive tightening.
🔄 Universal compatibility — fully compatible with both OS and YS engines, requiring no modification.
⚖️ Recommended tightening torque — 16–18 Nm for optimal locking force and reliability.
Together, these upgrades result in a drivetrain that runs quieter, stays cooler, and offers unmatched precision and durability — a true step forward from the original Nimbus 550 Nitro.
Precision
CNC MAIN GEAR ASSEMBLY
With a 7.7 gear ratio, it is perfectly matched to achieve a good rotor RPM while providing enough torque for demanding maneuvers with 550–580mm blades. Optional parts are available to stretch it to a 650-size with an 8.5 gear ratio.
The main gear directly drives the head and has been designed to efficiently transmit rotor torque, producing peak power through extreme rigidity.
Advanced
ROTOR HEAD SYSTEM
Machined from high-strength 7075-grade aluminum, the rigid rotor head provides maximum stability and precise control response. Optimized geometry and high-precision linkage deliver perfectly linear cyclic feedback, while the 1:1 control geometry ensures equal movement in all directions and a consistent, balanced feel — ideal for both aggressive 3D and precise F3C flight.
Modular Structure for
EASY MAINTENANCE
Engine maintenance is also easy, with the ability to remove the engine from the bottom without disturbing other assemblies in a matter of minutes. The engine cooling fan shroud can be independently removed by side and without disassembly of other parts.
Quick-Connect Canopy Lock System
Easy connect canopy locks removing the need for safety pins with a much easier way to remove and mount the canopy.
DAMPENING SYSTEM &
TAIL HUB
Precision CNC-machined from aircraft-grade aluminum for exceptional balance and durability. The teetering tail rotor system, shared with the Nimbus 550 V2 electric version, delivers stronger tail-hold performance, reduced vibration, and improved parts compatibility for easier maintenance and upgrades.
Assembly of the
TAIL HUB
The tail hub uses a tapered collet connection identical to the Specter 700, effectively reducing vibration and simplifying maintenance — in most crash cases, only the tail shaft needs replacement, costing just a few dollars.
servo layout
GEOMETRY
Clean, direct servo placement with optimized linkage geometry delivers mechanical efficiency, equal throw on all axes, and a simplified setup for consistent response throughout the entire flight range. A one-piece 7075 aluminum bearing block and servo mount form the structural backbone of the frame, providing exceptional drivetrain rigidity and stability even during the most aggressive maneuvers.
