Germany-based MT-Propeller has an 11-blade propeller in the works, testing it on a Piper PA31T1 with Pratt & Whitney PT6A-135 turbine engines.
The world’s first 11-bladed propeller recently “took the sky with an impressive noise and sound signature,” company officials said.
“The very promising results in static thrust, 15% increase over the standard certified 5-bladed propeller, and the jet-noise signature showed…what could be possible in the propeller developments,” company officials added.
The propeller system, combined with a low RPM power supply from a turbine or an electric engine, opens new possibilities for performance, efficiency, and noise, MT-Propeller officials noted.
You can see two short videos of test flights below:
In search of :”mine is bigger than yours” ramp appeal. This hits the mark. Wonder about engine out feathered drag?
Well it “Looks” & “Sounds”
Impressive.
So the only real question is whether the performance gains outweigh the added maintenance costs.
Gonna be really a lot more cost to get de-ice and feathering on that prop.
Just install a duct and large diameter turbine
I might speculate that thrust would increase more if the blade were a pusher, and if blade chord were about 50% wider toward the root, tapering toward the tip. I suspect leading edge turbulence event, which normally would clear up, with fewer blades.
15% better performance but twice + the cost and 3 times + higher maintenence does not compute
Looks good but does it improve the reliability and effectiveness?
Congratulations to Muehlbauer in Straubing for this technological achievement . Keep on the good work !
Raimund F. Neuhold
The ol’ Nigel Tufnel propeller. Way better than a propeller with 10 blades.
I’m so glad somebody made a Spinal Tap reference.
Article in Sport Aviation some years ago about a wood prop with a blade cross section resembling a flattened figure 8. Supposedly almost silent, gave good thrust. Never heard anything further about it.
I remember hearing about that and had forgotten about it. Thanks for reminding me. Maybe these guys can look into where that tech disappeared to.
What effect is there on performance? I’m sure the added drag from the extra blades must slow degrade speed substantially.
I remember when they tested MD-80 ship 909, in Mojave, California, with the UDF (un-ducted fan) installed on one pylon. It worked, it flew and it sounded very strange. I recall this happening in the mid to late 80’s. Clearly, advances in theory, technology and efficiency must have driven the need to revisit the concept. Good luck with getting your project across the finish line because it really looks great!
I’m surprised at the only 15% increase in thrust. Disappointing.
Regards/J
I am sure many operators, pilots, bosses, and perhaps wives would do anything for a 15% performance increase.
A better video would have been an overflight at say 2000 feet, what would be more typical with an aircraft on departure or approach over a congested area full of airplane noise critics. And maybe another overflight at 10,000 feet at cruise. What about similar props for piston aircraft. Comparison of 2 / 3 / 4 / 5 / 7 bladed props, measured and perceived noise versus cost. Noise also inside the cabin, not only on the ground. Definitely an important topic, since the aircraft not heard will generally also not be noticed by groundlings.
Die Props sind ziemlich leise.
The props are pretty quiet.