… that’s not true. By far. ☺️
Feb. 25, 2025 – Hartzell Propeller is launching the Kestrel, a lightweight carbon fiber constant speed prop and the first in its new Falcon composite propeller series, specifically designed for aircraft powered by Rotax 916 engines. The Kestrel propeller has received ASTM approval, with FAA certification expected later this year.
In their PRESS RELEASE, they wrote that: Kestrel is “The Lightest Constant Speed Propeller for Rotax 916 Engines”.
So, according to its data sheet, this 76-inch-diameter 3-blade propeller weighs 9.89 kg with its spinner. Without pitch control and spacer.
It’s very far from the weight of our 3-blade CS propeller Glorieuse for Rotax 916iS !
4 kg all-inclusive : 3-blade diameter 69, 75 or 83 inch, spacer, spinner, governor and regulator.
Let’s compare Moments of Inertia:
– 8370 kg.cm² for Kestrel
– 3000 kg.cm² for Glorieuse
It means that the Kestrel’s MOI is very close to the high limit of Rotax 916iS (9000 kg.cm²), and not authorized for Rotax 915iS (7500 kg.cm²). Poor gearboxes…
The Kestrel is heavy because of the hub in aluminium (beware of cracks !). Glorieuse is full carbon, hub + blades, and the blades have a Titanium leading edge protection – top technology.
Hartzell is not the first propeller to claim to be the lightest. Duc Helices also claimed that for its Swirlblack-3.
If Hartzell, Duc and the others claim that each of their models is the lightest, it’s because this data is extremely important to obtain the best possible performance… At E-Props, we have always been convinced of this, and we fight every day to offer ultra-light and high-performance propellers.
The complete set of Glorieuse propeller with its spinner, spacer and all the screws (3,5 kg) + governor and regulator (0.5 kg) = 4 kg
E-Props Glorieuse is on the market since September 2021. Several hundred have already been sold around the world, equipping numerous aircraft, with pilots delighted by their performance.
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