OK, this is a fundamental but common misunderstanding common to Wright Stuff too. People see a really good helicopter or plane fly slow think this is somehow the secret to long flight. That's just backwards.bwy wrote:<SNIP>I'm just wondering, if you reduced the friction, wouldn't the rotors spin faster? I thought slower rotors were better (as long as they can still keep the helicopter flying, of course) since they unwind the rubber band slower and thus the helicopter flies longer. That was what I saw at states, at least.
Making it efficient is the secret to long flight, slow is just a side effect of efficiency!! If you have an efficient helicopter (or airplane), it means you get more lift for less effort. That means the rotors can turn slower to provide the same lift as an inefficient one, and take less torque to do so. Allowing thinner rubber, which means longer, which means more winds, which means a longer flight.
Note, efficiency is NOT a side effect of slowness. If you slow things down by creating useless drag you just need more torque for the same lift, fatter rubber, which means shorter, which means less winds, which means a shorter flight.
So, if you reduce friction and don't change the motor, yes the rotor will spin faster. You'll also get more lift. You don't need more lift than to hold the copter up, so use thinner rubber, slow down the prop, and fly longer.
Note, this was specifically addressed to forms of drag unrelated to lift. Now lift inherently creates drag and that's unavoidable, but someone already mentioned the key concept there and that's the lift/drag ratio and the need to maximize it. That's where concepts like pitch/diameter ratio, curved ribs, elliptical plan form, etc come in. And again high lift/drag allows slower speeds, it doesn't COME from lower speeds.
So, you all have heard me harp on weight, weight, weight. That's because I first want to get you flying. To those who want to win guess I should add, reduce drag, reduce drag, reduce drag!! Course that's the really hard part, but that's the end goal of what you are trying to do.
Jeff Anderson
Livonia, MI