The E-PROPS are the world's lightest, strongest and quiestest propellers, and they also give the best efficiency.
special design = the best efficiency
For a paramotor use, the propeller must :
- be exactly adapted to the engine and the RPM
- be ultra-light to be as reactive as possible, and to guarantee a long life to the engine
- give the best thrust
The E-PROPS propellers are very different from the other propellers. They have special profiles, patented designs (for example SCIMITAR), and special position of the blades to reduce the blades drag, so to obtain the best thrust.
The E-PROPS team has developed more than 600 different models (2-, 3-, 4-, 6-blades), for all engines and reducers, with diameters from 115 to 160 cm, with pitch every 0,5°, and in both rotation senses (CW and CCW).
Propulsion efficiency factor is calculated from propeller diameter and engine power. This efficiency factor is the max achievable propeller efficiency. Then, it is up to the propeller designer to come closer to this limit.
The E-PROPS design department consists of 6 technicians and engineers. The head of this department is Jérémie Buiatti, who designs propellers since 2006 and has implemented the internal software LmPTR©.
This complex software performs a detailed aerodynamic flows analysis and a mechanical behavior analysis of the propeller. It is implemented from an advanced language and contains more than 75000 code lines.
This software allows the team to imagine new propellers concepts, by using particular geometries and profiles developed inhouse. That is why E-PROPS propellers are very different from other propellers proposed at present on the market.
When we speak of efficiency, we obviously speak of thrust and also of fuel consumption.
A propeller which has a better efficiency allows to reduce the fuel consumption of the engine.
The E-PROPS propellers have a thin chord (chord = width of the blade). A thin chord generates less drag than a wide chord and leads to a better efficiency of the propeller, a better thrust, makes less noise and reduces fuel consumption.
On average, the use of a E-PROPS propeller allows to save between 6 and 9% of fuel at the same engine RPM (it depends on the blades geometries).
NUMBER OF BLADES
For a paramotor use (it means low speed), for the same diameter, more blades = more efficiency.
A 3-blades has a best efficiency (= a best thrust) than a 2-blades.
Thrust measured with propellers for Vittorazi Moster 185 engine red 2,68, all in diameter 130 cm =>
- 2-blades : 82 kg
- 3-blades : 86 kg
- 4-blades : 90 kg
- 6-blades : 92 kg
=> Please note :
This is true if the blade form is exactly adapted to the configuration : a blade of a 2-blades propeller mounted on a 3-blades or 4-blades hub would not give the best performances.
The "universal" blade for any configuration does not exist. Every propeller has a dedicated blade geometry, or the efficiency would not be the best.
The increase of the diameter is better for the efficiency, because of the improvement of the pusher efficiency. More thrust is obtained with a propeller with a diameter of 150 cm than with a propeller with a diameter of 125 cm.
With the same number of blades, the thrust gap depends on the diameters and on the engine + reducer.
Thrust measured with propellers for Vittorazi Moster 185 engine red 2,68, all 2-blades =>
- diameter 115 cm : 74 kg
- diameter 125 cm : 80 kg
- diameter 130 cm : 82 kg
- diameter 140 cm : 87 kg
- diameter 160 cm : 95 kg
=> Please note :
All sets of engines - reducers can not be equiped with big diameters propellers.
One data has to be verified : the peripherical speed (on tips) must not exceed Mach 0,65
, or the noise would be too high.
Comparative 2-blade / 3-blade :
Some people are saying that the wake of the third blade of a 3-blade propeller is crossing the wake of the 2 other blades, and this phenomenon decreases the efficiency of the propeller.
That's wrong. The wakes of the different blades cannot crossed themselves. It is physically impossible, because the blade's wake is sweeped away by the wind.
here the condensation trails materialize the wakes