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why did we start with main+tail rotor helicopters? Nowadays 4-rotor quadcopters appeared and have taken over The quadcopter advantage is in it's mechanical sim

why did we start with main+tail rotor helicopters? Nowadays 4-rotor quadcopters appeared and have taken over The quadcopter advantage is in it's mechanical simplicity, but having fewer longer blades is better for aerodynamic efficiency(at the expense of max airspeed). This matters less at RC scale, but at full size, even an all-electric helicopter will likely have more range than a quadcopter with the same batteries.

nerdsniper 2mo ago
4 rotors is also a much more difficult “controls” problem. Helicopters actually glide reasonably well if their engine cuts off. They’re not super insanely unstable. Quadcopters are basically obligate fly-by-wire vehicles which necessitate at least pneumatic PID controllers if not computer chips to fly. You can make a helicopter work reasonably well a lot earlier in a pre-computer “tech tree” than you can a quadcopter.
- inigyou 2mo ago
  A helicopter with a broken engine glides well enough to avoid instantly killing everyone on board if the pilot knows what he's doing. I wouldn't call it "reasonably well". Here you go - drops slightly slower than a brick. The pilot has to speed up the descent on purpose so that he can use that stored energy to slow it down just before the crash, thus converting the crash into merely a hard landing. https://youtu.be/05_WFvh9ISk https://youtu.be/05_WFvh9ISk
  - nerdsniper 2mo ago
    That was a shockingly controlled landing for an unpowered vehicle. Very impressive! > Here you go - drops slightly slower than a brick. The glide ratio of a brick, even if it is initially traveling at 80 KIAS is ... 0:1. This is the same glide ratio that an unpowered quadcopter would have. Bell 206B, Robinson R44, and R22 all list their unpowered autorotation glide ratios at 4:1 - that is a mathematically infinite multiplier of performance vs. a brick. https://robinsonstrapistorprod.blob.core.windows.net/uploads/assets/r22_poh_full_book_b79e920713.pdf https://robinsonstrapistorprod.blob.core.windows.net/uploads...
    - ButlerianJihad 2mo ago
      The Space Shuttle orbiter was nicknamed “Flying Brick” in its landing configuration by the astronauts and test pilots, because even for a glider, it had the worst maneuverability they had ever experienced, not to mention the highest approach velocity and catastrophic failure modes. https://en.wikipedia.org/wiki/Shuttle_Training_Aircraft https://en.wikipedia.org/wiki/Shuttle_Training_Aircraft
taneq 2mo ago
Upgrade that 'maybe' to 'definitely'. The disc loading on a helicopter is typically much lower than on a quad (excepting crazy designs like the giant human-powered quad) which makes it significantly more efficient for the same overall size.

nerdsniper 2mo ago

4 rotors is also a much more difficult “controls” problem. Helicopters actually glide reasonably well if their engine cuts off. They’re not super insanely unstable. Quadcopters are basically obligate fly-by-wire vehicles which necessitate at least pneumatic PID controllers if not computer chips to fly. You can make a helicopter work reasonably well a lot earlier in a pre-computer “tech tree” than you can a quadcopter.

inigyou 2mo ago
A helicopter with a broken engine glides well enough to avoid instantly killing everyone on board if the pilot knows what he's doing. I wouldn't call it "reasonably well". Here you go - drops slightly slower than a brick. The pilot has to speed up the descent on purpose so that he can use that stored energy to slow it down just before the crash, thus converting the crash into merely a hard landing. https://youtu.be/05_WFvh9ISk https://youtu.be/05_WFvh9ISk
- nerdsniper 2mo ago
  That was a shockingly controlled landing for an unpowered vehicle. Very impressive! > Here you go - drops slightly slower than a brick. The glide ratio of a brick, even if it is initially traveling at 80 KIAS is ... 0:1. This is the same glide ratio that an unpowered quadcopter would have. Bell 206B, Robinson R44, and R22 all list their unpowered autorotation glide ratios at 4:1 - that is a mathematically infinite multiplier of performance vs. a brick. https://robinsonstrapistorprod.blob.core.windows.net/uploads/assets/r22_poh_full_book_b79e920713.pdf https://robinsonstrapistorprod.blob.core.windows.net/uploads...
  - ButlerianJihad 2mo ago
    The Space Shuttle orbiter was nicknamed “Flying Brick” in its landing configuration by the astronauts and test pilots, because even for a glider, it had the worst maneuverability they had ever experienced, not to mention the highest approach velocity and catastrophic failure modes. https://en.wikipedia.org/wiki/Shuttle_Training_Aircraft https://en.wikipedia.org/wiki/Shuttle_Training_Aircraft

taneq 2mo ago

Upgrade that 'maybe' to 'definitely'. The disc loading on a helicopter is typically much lower than on a quad (excepting crazy designs like the giant human-powered quad) which makes it significantly more efficient for the same overall size.