| Dual-rotor also known as coaxial rotors helicopters | | | | also observed that most dual-rotor R/C |
| consist of a pair of rotor rotating in opposite | | | | helicopters have less noise. Conventional R/C |
| directions. One rotor is positioned above the other. | | | | helicopters generate a loud "blowing" noise |
| Coaxial helicopters are popular because of its clear | | | | because of the interaction involving the flow of air |
| stability while in flight making it easier to learn. It is | | | | between main and tail rotors. More and more |
| also considered to be a favorite indoor activity | | | | coaxial helicopters available in the market these |
| compare to the single rotor model. Its | | | | days consume less space making it a more |
| maneuverability makes it ideal and safe even | | | | compact model. |
| within one's home. | | | | Things to consider: The speed of the rotors |
| Underlying Theory: When a helicopter is not in | | | | should be appropriately controlled and maintained. |
| motion its angular momentum is zero. Once the | | | | The stability of a coaxial R/C helicopter greatly |
| engine is started, it produces a significant amount | | | | depends on the 2 rotors' synchronization such |
| of angular momentum that can cause the body | | | | that any deviation may result to damaging |
| of the helicopter to spin around in opposite | | | | effects. Another downside is the possibility of the |
| direction of the rotors. To maintain flight stability, | | | | rotors getting into each other especially during |
| coaxial rotors are used by turning each rotor in | | | | extreme flight maneuvers. |
| opposite directions. This allows the fuselage to | | | | Recently, several R/C helicopters began adopting |
| sustain a zero angular momentum. | | | | a simplified coaxial design. This new model consists |
| How does it work?: Coaxial helicopters do not | | | | of a coaxial unbending rotor system with |
| necessarily need a tail rotor. The torque created | | | | fixed-pitch blades and a swashplate. One thing is |
| by the 2 rotors spinning in opposite directions | | | | clear, dual-rotor R/C helicopters are sure to make |
| cancels each other. This results to a more stable | | | | a wave in the next couple of years. |
| flight and hovering capabilities. Hovering is one of | | | | There is a website that has great information on |
| the main elements in flying a helicopter. When the | | | | RC Helicopters, the website is called: RC |
| pilot slows down or speeds up one of the 2 | | | | Helicopters World, and can be found at this url: |
| rotors, he can control the hover or direction of | | | | By Robert W. Benjamin |
| the helicopter. | | | | You may publish this article in your ezine, |
| Why go for a dual-rotor helicopter?: Coaxial | | | | newsletter, or on your web site as long as it is |
| designs are remarkable because of its ability to | | | | reprinted in its entirety and without modification |
| maximize every available engine power. A tail | | | | except for formatting needs or grammar |
| rotor naturally throws away some of the power | | | | corrections. |
| would have been used in lifting and thrusting. It | | | | |