"I work on full size production and prototype blades. In dynamics we always seem to get funny looks because we have to hedge answers. At least we know we have to hedge answers... There are only a couple absolutes with helicopters - 1. You cannot…"

"Rob- Very astute observation re efficiency. To the critical engineer, the data often raises as many questions about how to parse data than where to go forward. If you look at the slope of battery depletion maybe you will resolve the power used issue?"

"Won't you need both voltage and current sensors? As the voltage drops the current will go up to maintain hover.
Maybe it won't matter if it's done on quick successive flights."

"I know this sounds terrible to do but if you clean the blades thoroughly, then hover in a dusty area you will see exactly what the airflow looks like over the blades including any flow separation. Microscopic specks can detach laminar flow. Almost…"

"It would be easy to mount a hall effect sensor on the main rotor. They come in biased and unbiased versions. They can be very small and light. Another option would be to do it optically, but I think even two LEDs (TX/RX) would be heavier than a hall…"

"Yaw control in all flight modes has been an issue with coaxials. The rotodyne model used "flappers" at the tips to induce drag and was effective. The Kamov series uses a sliding cam internal to the mast and increases/decreases pitch on one or the…"

"I worked on a drone with a ducted fan and vanes for anti torque. The execution was not elegant and the control was marginal. Actually had an uncontained failure of the fan on this project. Read ugly."

"To FroJoBMX - I'm not certain if pitch loads are the driver on chord length. Practically, I think not. Pitch center migration with angle of attack will drive pitch change loads. So...you end up with the symmetrical blades because they have…"

"Depends on the airspeed. As retreating blade stall is approached the N-per rev increases exponentially before a full blown stall/ rollover pitch up and play dead.
Active control was experimented by Hughes aircraft as HHC (Higher Harmonic Control).…"

"As a dynamics engineer, and working for a company that designs, builds and tests rotor blades, I can assure you there are only a handful of engineers - literally - that have a grasp of what rotor dynamics are all about. I see what some people write…"

"Yes a true dynamic balance is not only possible on a helicopter, it is solved for routinely. The difference for RC is the rigidity of the blades really make them respond more like propeller blades in a horizontal plane. Most balance on a helicopter…"

"This has a bit to do with video - the video is directly impacted by the inherent vibration in the platform compared to the frame refresh rate on the video. Anyone know what the frame rate is on the various video cameras? Im thinking it is around 60…"

"OK, I can only respond to the number of blades issue based on full size helos so it may not be exactly true for scale - More blades are better. The Apache uses 4 blades. The Hind uses 5 the CH-53E uses 7. You just run out of lift with fewer blades…"

"The mass of the blades is not as important as the moment (weight times arm). outright blade weights are no indication the blades will achieve a balance in the dynamic state.
N-per-rev(number of blades times rotor RPM) is aggravated by disc loading,…"

"weight and stiffness are old standbys in the vibration world, but it is also worthwhile to consider soft rubber. Rubber works by displacement and since the shore hardness determines natural frequency it is wise to select different amounts of…"