A Wankel engine uses a three-flank rotor moving planetarily in a two-lobed housing, with the rotor turning at one third of main-shaft speed. This calculator is a timing and event-count calculation only.
Related Resources for Actuator Projects
For separate actuator-driven fixtures or automation projects, compare stroke, linkage angle and peak force through the full travel. These resources concern actuator selection; they do not describe the Wankel engine drive.
For press, clamp, or fixture motion, verify the actuator cannot overload tooling or create an unguarded pinch point. The control circuit should define the safe state after a jam or power loss.
If the application needs synchronized motion, feedback should be treated as a requirement rather than an accessory. Two open-loop actuators wired together can drift apart when friction, load, or mounting geometry differs between sides.
- Map actuator stroke to the actual output travel before choosing a model.
- Check for binding, changing leverage, and peak load near the ends of travel.
- Decide whether timed motion is acceptable or position feedback is required.
For a FIRGELLI design review, calculate the load case with the FIRGELLI actuator force calculator and plan the switching or controller arrangement with the linear actuator wiring diagram generator. If an actuator or cylinder is already installed, the linear actuator replacement finder helps keep the comparison tied to real dimensions.
Wankel Rotary Engine Interactive Calculator
Enter shaft period and rotor count. Outputs assume a fixed 3:1 shaft-to-rotor speed ratio and one counted power event per shaft revolution per rotor—not combustion quality, torque, power or engine performance.
Equation Used
- Shaft period is entered and treated as constant.
- Rotor speed is exactly one third of shaft speed.
- Rotor count is an integer from one to four.
- One ideal power event per shaft revolution per rotor is counted.
- Housing/rotor dimensions, eccentricity, chambers, ports, ignition, pressure, torque, power, efficiency, sealing, cooling, lubrication, emissions, vibration, limits and durability are omitted.
Three-Flank Rotor and Fixed Speed Ratio
Mazda Technical Review 2003, figures 1–5 illustrates the production Wankel rotor, two-lobed housing and stationary-gear relationship. EP Patent 3,056,661 describes the three-flank rotor at one third main-shaft speed; U.S. Patent 3,724,427 describes the two-lobed epitrochoid housing.
What This Calculator Represents
The tool converts one entered shaft period to rpm, applies the fixed 3:1 ratio to rotor period and speed, and multiplies shaft rpm by rotor count for an ideal event frequency.
Timing and Event-Count calculation
Trotor=3Tshaft
Nrotor=Nshaft/3
events/min=Nshaft × rotor count
Counted events are not delivered power.
Worked Timing Example
For a 3.000 s shaft period and one rotor, shaft speed is 20 rpm, rotor period is 9.0 s/rev, rotor speed is 6.67 rpm and the ideal count is 20 events/min.
Assumptions and Limits
- Calculated: frequency/period conversions, fixed 3:1 ratio and ideal event count.
- Illustrated: three-flank rotor in a generic two-lobed housing.
- Not calculated: chamber volume, combustion, pressure, torque, power, efficiency, sealing, cooling, emissions or durability.
Frequently Asked Questions
Does event count equal power output?
No.
Why is rotor speed one third of shaft speed?
That is the fixed planetary relationship assumed for the Wankel topology.
Are misfires included?
No.
Are chamber volumes calculated?
No.
Does rotor count change shaft rpm?
No; it only scales the event count here.
Can this size or rate an engine?
No.
References
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