RC helicopter (1)

Today I am going to make a brief introduction about RC helicopters. I will use my own RE helicopter for demonstration and some pictures from Wikipedia. I hope after reading this, you can have a wide range of view to helicopters. You know, helicopters really are a great invention.

A mini RC helicopter

Thanks to its hover feature, one helicopter can be used in many situations and distant places where it is not accessible by land vehicles. Things like saving injured personnel at a cliff, or searching a person in a wide range of field like open water requires the capability of helicopters which can hover for a very long time. The drawback of helicopters is the flying speed. On the vertical view, helicopter is very fast, far faster than airplanes. It can take off within less a minute, compared to airplanes which may need two or three minutes. However, the terminal speed of helicopters is slower than most of airplanes. Helicopters just cannot be supersonic, a modern standard required for most of fighters. Still, helicopters maintain their own glory for the unique feature that no one can reach.

The important components on helicopters must be the blades and the tail rotors. Most people may not think that much on how helicopters make their movement. They may think the blades are rotating so it just flies! But hey, how do helicopters move forward? What is the mechanism behind this? The following will introduce a component that I think is really important and revolutionary for the development of helicopters.

The lower blue part is called swashplate.

1 Non-rotating outer ring (blue)
2 Turning inner ring (silver)
3 Ball joint
4 Control (pitch) preventing turning of outer ring
5 Control (roll)
6 Linkages (silver) to the rotor blades

So here is how it works. The whole swashplate is linked to the main blades. The rotating part is the silver ring above the blue ring. When the blades rotate, only the whole part above the blue ring will follow the main blades rotation. The pivot, which is the 4th, and 5th part on the above picture, can control the direction of the blue ring. So when the rotation begins and you turn the blue ring into a 30 degree angle, the 6th part on the picture is linked to the blades, so when it follows the blades rotation, it will also be affected by the blue ring. This will cause the vertical movement of the linkage that will change the angle of the blades thus to change the wind direction and make the helicopter move forward.

A lucid demonstration of swashplate

A swashplate that tilt to a specific angle.
You can see how the linkage is affected by the lower part of  the plate.

So now you know how it works. Next post will focus on the Anti-torque system. Oh, just let you know the blades on helicopter are not fixed. You can actually move the blades part up and down like this.

You see the angle of the entire blades is 30 degree to the right. 

The blades is now tilted to the upper left.