Jet Engine Component; Counter-Rotating Propeller, Pitch Changeable

Pistons and turboprop engines rotate propellers for propulsion.
In that case, anti-torque is generated on the aircraft, which affects the maneuvering.
One of the countermeasures is a Counter-Rotating Propeller.
The Wright brothers, who succeeded in mankind's first powered flight, dealt with this problem by rotating the propellers placed on the left and right in the reverse direction with a chain. (Refer my model "Wright Flyer 1903, Power Plant")
Since then, many studies and prototypes have been made, but the coaxial Counter-Rotating Propeller has not been adopted in practical aircrafts except Russia.
The weight increase due to the complexity of the counter-rotating structure, the maintenance cost increase, and the noise due to the interference of the front and rear propellers cannot be solved, and the anti-torque is left to the countermeasures on the aircraft side.
However, as a future engine, it is one of the technologies related to the “Propfan” engine being researched and has a very interesting structure, and this time I made a pitch-changeable counter-rotating propeller function model.
A. Components and Features of this model
　① Planetary gear + Coaxial counter-rotating gear device・・Motor drive possible
　② Rack and pinion pitch change mechanism, Counter-rotating propeller (4 blades x 2)
　③ Push / pull pitch change structure assuming hydraulic piston and cylinder
　④ Air intake cowling assuming a turboprop engine

[Video] https://youtu.be/rG3PaHKxKeA

B. Assembly Manual (PDF format, total 27 pages)
　The detail assembly manual including "Parts-List", "After printing treatment" and "Assembly procedure" are prepared based on "Standard Skill (Filing, Drilling, Tapping, gluing and tightening)".

C. files includes;
- files: STL Files (61 items)
STL file name: "ws" of last 2 digits means "With " which special designed.

D. Purchase Parts Information; (See Assembly Manual)
1. Metal Bearing; Ball Bearing WBC6-12ZZ (6x12x4) ; For Pitch Change Mechanism
　　 Steel Ball (φ3) ; as Rack & pinion Bearing
　2. AL Pipe; φ4, 5, 6 and 8
3. Drill and Tap
　　My design hole diameter is considerably smaller than the finish hole diameter in order to ensure the wall thickness at the time of printing.
　　Drill : φ1, 1.5, 2, 2.5, 6.2 Tap : M1.4, M2, M3, M6
　　For M1.4 Screw; No need “Tapping” for PLA material. (φ1.0 drill required). But “Mandatory” for AL Pipe.

E.Total Net Print Time: Approx. 84HR
- (Estimated as case of PLA, 0.4mm Nozzle, 0.2mm Layer Height, 40% infill and No raft and )

F. 3D printing settings (Raft, , Layer Height, Infill)
　　When at actual print, each parameter may be adjusted by your experience.
　　But for parts having gear teeth, 100% infill is recommended.

I do hope you enjoy making!!

See above