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Wright Flyer -> Components of elec heli (5/27/2003 2:03:13 PM)
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Hi,
I've got a Hyperfly and it is NOT a real helicopter because, like Jeff says, it has no tail rotor and it cannot hover (or rather it can only appear to hover like a plane can if you fly it forward into wind that is blowing the other way at the same speed the plane is flying).
Don't be taken in by it thinking it is a real helicopter (I was when I first started in R/C). These days I have a "real" model helicopter - the Litemachines Corona 120 which is the PERFECT beginners helicopter as it can be bashed to pieces (bound to happen!) and it still flies - most other helis shatter into a 1,000 pieces and cost loads to repair after such an "event".
As for the "bits" in a heli. Pretty much everything (in a simple, fixed pitch, beginners heli) is the same as a plane only in a different place. While on a plane you have a servo for left/right control that operates the rudder or ailerons on a heli there's one servo that tilts the main rotating "dish" left/right. In a plane for up/down you have another servo on the elevator. This tilts the plane up/down so it points in the direction you want to go. On a heli the up/down is actually controlled by the throttle - the faster the blades spin the more lift they give. However you also need to be able to tilt the rotor disk forwards/backwards to make the heli "lurch" in the direction you want to go so there's a second servo (besides left/right) on the disk that tilts it fore/aft. Finally, because of Newtons third law (to every action there's a reaction...) if you had the main rotors spinning then the body of the heli would tend to rotate in the other direction, so you have another mini "propeller" at the back end of the tail that blows agains this tendency to keep the nose always pointing in the direction you want to go. The blades on the tail have variable picth and there's a servo that controls how much they "blow" and whether it tries to move the tail/nose left or right. However only the most skilled pilots can handle making the correct tail control inputs to keep the nose pointing where you want it to go, as the main rotor speeds up/slows down there's a tendency for the tail to move left/right so most people add an electronic gyroscope which can detect a tendency to turn and then applies opposite tail rotor pict to keep the tail steady. Some such gyros are simple "rate gyros" that help to dampen tail movement but don't stop it all together. More advanced, heading hold gyros, will just keep the nose/tail locked in exactly the last position the pilot commanded whatever happens (variation of rotor speed, wind gust making the tail try to "weathercock", whatever).
Flying helis is perhaps twice as complicated at flying a plane because you are trying to co-ordinate four inter-linked controls at once (throttle for up/down, for/aft+left/right cyclic to make the wohle thing fly in the right direction and finally tail rotor control to keep the nose pointed the right way). The best idea for anyone starting out is to get an r/c sim - both FMS and [url]www.preflightsim.com[/url] are FREE to download and have heli simulation though the ones in FMS are too "easy" to fly but at least you get to try out the basic controls.
Cliff
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