E-Props adjustment on Rotax series 9 engines

The ground adjustable pitch E-Props have a strong ESR effect. Their behavior is similar to that of an inflight variable pitch propeller: high efficiency of the engine-propeller combination over the whole speed range of your aircraft.

⇒ To obtain this ESR effect, the adjustment of the blade pitch must be subtle and precise

IMPORTANT: The measurement of the ideal engine rpm is done in flight and not on the ground.
For ground adjustable pitch E-Props models, which have a strong ESR effect, static rpm measurement is not a significant data, because they are designed to reach their full traction or thrust just after the start of the take-off roll, not in static. In static, the blades of the E-Props are slightly stalled.

On Rotax 9xx series 4-stroke engines (912, 912S, 912iS, 914, 915iS), the pitch at which the E-PROPS propeller will give the best performance over the whole speed range of the aircraft is obtained :

5,500 rpm at full throttle level flight (at altitude 2500 ft)

PROCEDURE:
1/  Adjust the pitch as recommended on the Propeller Identification Sheet (sent with the propeller), or on the description of the propeller on our catalog, or ask our team.

2/ On the ground, put full power on brakes or chocks.
✗  If you have between 5.000 and 5.800 rpm, you can go on with the flight tests.
✗  If this is not the case, adjust the blade pitch to have between 5.000 and 5.800 rpm on the ground.
Increasing the pitch by 0,6° reduces the rotation speed by 100 rpm.
Decreasing the pitch by 0,6° increases the rotation speed by 100 rpm.

3/ In flight, level off at an altitude of about 2500 ft.
✗  Apply full throttle.
✗  Note the number of rpm that appears on your tachometer.
✗  If you have 5.500 rpm (+/- 50 rpm), your setting is perfect.
✗  If not, land and redo the setting.

Example: in full throttle, the engine is running at 5,700 rpm, while the target is 5,500 rpm. The difference is 2 x 100 rpm, so the pitch must be increased by 2 x 0.6° = 1.2°
If you get this value of 5,500 rpm full throttle, then your propeller is optimally set for the full speed range of your aircraft. 😀