Engines that use rotational output (Turboprop, Turboshaft) incorporate the torque meter system that uses the opposite torque of the engine output.
There are various methods, but in engines in which the engine and reduction gear are integrated, the one utilizing engine oil is often used.
By replacing the anti-torque with axial movement and adjusting the opening of the valve, it balances the pressure in the piston and cylinder with the anti-torque axial force.
Then, this pressure is displayed on the cockpit panel as the torque meter and used to control the engine.
As the method to generate that axial movement;
【Ⅰ】Planetary gear used spur gears (carrier shaft is as the output shaft)
Add the helical spline around the ring gear and use the axial force generated in the ring gear.
This method provides a relatively large piston area, so engine oil pressure can be used.
【Ⅱ】Planetary gear used helical gears (ring gear is as the output shaft)
Use axial force generated on carrier gear (s)
This method requires a higher pressure pump for torque meter because each piston area is narrow.
【Ⅲ】Reduction gear with the helical gear train (mainly for turboshaft engines)
Use axial force generated on the intermediate gear. (Model of this method will be later)
【Ⅳ】Others
Some engine use the difference in torsion between two or one shaft (hydraulic or electrical).

This model reproduces the【Ⅰ】method as the cutaway model.

A. The components of this model are:
① Sun Gear
② Carrier gear
③ Ring gear (with helical spline on outer diameter) (move in axial direction)
④ Housing with helical spline (fixed)
⑤ Piston and cylinder (with piston and ring) - Piston working dimension is about 3 mm.
⑥ Control valve
⑦ Oil passage (engine oil, torque meter oil, bleed)
⑧ Brake adjustment screw for operation reproduction and Handle (tool)

By reproducing the anti-torque with the screw and turning the handle, you can see the movement of the ring gear, piston and valve.
In order to operate without oil, the gap between each part is enlarged. (Example: Piston ring, control valve etc.)
A sponge piece is used instead of a spring to allow the control valve to follow the piston.?

B. Assembly Manual (PDF format, total 14 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. Purchase Parts
1. Screws
M1.4x3.5L, M2x6L, M2x8L, M3x8L, M3x15L, M4x35L
2. Others φ6 ABS Pipe, φ6x25L AL Pipe, φ5x10L Spring

D. STL file
Total STL files are 26 items including the stand and tools.
Almost of parts are re-designed to this purpose.
“ws” of last 2 digits of file name means “With Support” special designed.

E. Total Net Print Time: Approx. 51HR
- (Estimated as case of PLA, 0.4mm Nozzle, 0.2mm Layer Height, 40% infill and No raft and support)
Note: When at actual print, each parameter may be adjusted by your experience.

F. Printing settings
Raft, Support, Layer Height, Infill: Depending on your experience.
My models were printed by "idbox" using with 0.4 nozzle, 1.75 PLA.

I do hope your success!!