Such propellers were in use around 1911 (see also The Gallery). They did work just fine, and today one has to go to extremes in order to gain a few percents in efficiency.
The Ariane V5 propeller: In order to save weight, we used a small, high RPM motor. The prop noise was loud and sounded like an air raid siren. A scimitar blade shape is required here because the blade tips are operating in the transsonic range already. The propeller has a diameter of 250 mm (9.8") and a mean pitch of 160 mm (6.3"). The design operating point is 19,000 rpm, 1130 W and 40 m/s (90 mph) with a calculated efficiency of 80.5 %.
CAD wireframe model of the negative mold lower half. | |
CAD shaded 6 side view. | |
Milled mold. | |
Propeller complete with HP355/25 motor. | |
Top view of propeller and spinner. |
One of several propellers designed for the Ariane V6 and Ariane V7; this one has a diameter of 406 mm (16") and a mean pitch of 410 mm (16.1"). The design operating point is 7700 rpm, 1150 W and 50 m/s (112 mph) with a calculated efficiency of 89.1 %.
CAD wireframe model of the propeller blade. | |
Laminated carbon propeller blade. | |
Propeller complete with motor. | |
Top view of propeller and spinner. |
Some other propellers:
CAD shaded picture of the injection mold for a pretty well known propeller. | |
CAD shaded picture of a folding prop with spinner and fuse. | |
CAD shaded picture of a three blade propeller. |