PIPISTREL SINUS

With 200 km/h at 40% power with the Rotax 912, the Sinus is, together with the Virus, the fastest ultralight with equal power. Its minimum fall rate and record weight for a 15-meter wingspan have an impressive influence on the climb.

DURANDAL-3
Here's how the Durandal 3-blade e props perform on my Pipistrel Sinus.

My Sinus is equipped with a Rotax 72 hp engine (because of the exhaust) with Sodemo injection. The intake pressure values are therefore not comparable with those obtained on engines with carburetors.

To reach 5500 RPM at 2500 ft, I set the blades at 21°8 (2 blades at 21°8 and the 3rd at 21°9 after tightening to 11 Nm). Far from the recommended 25°5. At take-off, I have a maximum speed of 5300 RPM.
I take off in +- 5 sec (runway altitude 400 m). I'll measure the distance on a day with no wind at all.
Tests with 1 person on board and +- 50 liters of fuel.

Rate of climb: 1250 ft/min at 118 km / h and 4880 RPM, i.e. 6.8 m/s, which is slightly higher than the Pipistrel Vario propeller (6.5 m/s) with flaps retracted.
Max speed at 2500 ft : 5520 RPM . speed : 225 km/h ( airspeed indicator ) 233 ( GPS) fuel consumption : 13.5 l/h
Speed at 5100 RPM at 2500 ft : 209 airspeed indicator , 219 GPS 10.5 l/h
At 4000 ft rate of climb decreases to 1000 ft/mn. 4850 RPM 113 km/h flaps retracted.

At FL 45 here are some examples of speeds and RPM:
4910 RPM 185 km/h airspeed indicator 205 km/h GPS consumption 9 l / h
4800 RPM 190 airspeed indicator 184 km/f GPS fuel consumption 8.5 l / h
4620 RPM 184 airspeed indicator 199 km/h GPS fuel consumption 7.5 l / h
5120 RPM 197 airspeed indicator 190 km/h GPS fuel consumption 10 l / h

Sink rate with engine off, flaps smooth at 98 km/h: +- 300 ft / mn or 1.65 m / sec.
Of course, this is not as good as with the vario Pipistrel (0.9 to 1 m/sec.), but quite honestly I was expecting much worse, especially with a 3-blade propeller !

Overall, the Durandal propeller's performance is close to that of the original variable-pitch propeller (sometimes even better!), which is extraordinary! And all this without any mechanism, while saving 3 kg (the Vario Pipistrel weighs 6 kg excluding variable pitch system). The Durandal is maintenance-free, whereas the Vario requires you to change the bearings every 200 to 300 hours.

So I'm very happy with the Durandal propeller !
J.M. (2023-06-21)

DURANDAL-2
Just to tell you how satisfied I am with my propeller.
No vibration and good performance 235 Km/h at 5200 RPM and for 28/29 RPM.
with extra 800/4 wheels!
J.B. (2018-06-21)