Month: August 2022

Second test of 5-blade variable-pitch rotor

Rotor diameter is 410 mm. Revised elastic tailoring.

Results of a second test of the 5-blade variable-pitch rotor
Rotor diameter is 410 mm.

Elastic tailoring is 20% more compliant than in the first test, to give 3 degrees more blade pitch-up at maximum torque.
Elastic elements of different spec. are easily swapped.

This test shows rotor speed levelling out at around 3500 RPM as lift continues to increase with power due to increasing blade pitch.

The batteries hold up better than in the previous test. I don’t know why. Perhaps they needed a rest!

First test of 5-bladed variable-pitch rotor

Ready for first test mounted on measurement rig

See a video of this test at

Test range limited by maximum 190 watts from battery.

The advantages of this design are

1) Extremely quick response. A conventional drone must spin each rotor faster to get more lift, for example to counter a random wind gust.
A drone or aircraft with far quicker response could be used in new ways, such as very close to structures in windy conditions.

2) Low vibration in forward flight. Each lift-rotor blade generates more lift when advancing than when retreating, but in a 5-bladed design, the forces cancel.

3) Low noise. For the same lift and diameter, 5-blades run slower and consequently quieter than 2-blades.

4) Auto-rotation by default. For safety and simplicity, the default blade pitch is negative when not powered. The blade pitch range is readily adjustable to suit application requirements.