3 ms·
My experience with computer fans is the smaller ones are much (much) noisier than larger ones moving the same amount of air (because they have to spin faster).
by rwmj 3y ago
My experience with computer fans is the smaller ones are much (much) noisier than larger ones moving the same amount of air (because they have to spin faster). Unclear why these are quieter - is it just the electrical power? From the article it seems like they have better control of the speed so can turn them off on the ground, so perhaps they're only quieter in some situations.
- gambiting 3y agoI thought the article explained it quite well: 1) somewhat counterintuitively, in small helicopters the tail rotor can be actually louder than the main one 2) with traditional design the rear rotor HAS TO spin if the main rotor is spinning 3) with this design the rear rotor can stay still, and actually as the article points out at speed you don't have to use it as the air generates enough force on the tail to keep the helicopter straight so to speak, so the entire machine should be quiter in flight. 4) and finally yes, you can keep the rear rotor still on the ground which is safer for ground crews and quiter at the same time
- bell-cot 3y agoI'd guess you're mostly correct. OTOH, though these fans could easily cost ~1,000X more than a computer fan. And that extra $$$ might unlock some pretty fancy noise-reduction technologies.