Design of helicopters, although fixed, is irreplaceable in many niches.
Helicopters have resisted the addition of wings, without which they can still GLIDE.
As can airplanes, to extent engine-failure is more survivable in singles than in twins…
… except in commercial ops, which are dominated by engine-failure training.
Substitution of multiple motors for a large single rotor is thus seductive…
… but specious, as loss of power is less the issue than controlling what remains.
Nascent eVTOL solution has therefore been to add more motors: 16, 18, 32…
… or else wings to restore gliding ability, assuming no glitches in the hover.
Yet 99% of the world’s drones are quads, yet they’re not falling from the sky.
So is it safer to feel vulnerable with fewer motors, or invulnerable with more?
Are so many PAVs vaporware because motors provide only an illusion of safety?
Will that be addressed by automation and AI?
Did PCs ever crash?
For a while it appeared the main rotor, fruit of decades of evolution and operation, could be readily displaced by a motors, batteries and circuitry as costs fell. Rotorcraft and fixed-wing types have always been able to recover from engine failures, given the capacity to glide. Absent that capacity and fail-safe redundancy becomes an issue of adding so many power-plants that the capital-cost savings are obviated, or relying on automation to replace pilots... so what looks easy at the outset turns out not to be.
