Helicopter light painting continues to snuff out physics lesson on your brain

Cool picture, huh? Wait until you see the video footage of this LED-adorned RC helicopter flying on a dark night. But this isn’t an art project. Analyzing the long-exposure photography turns out to be a great way of clearing up some of the physics of flight which otherwise are not at all intuitive. The helicopter used here has different colored lights on the nose and tail, as well as lights on the rotors.

Depending on how the aircraft is moving, different 3D spirography is captured by the camera. When you zoom in on part of the flight path it becomes clear that there are wider arcs on one side of the fuselage than there are on the other. This has to do with the forward progress of the aircraft and the rotation of the blades. The phenomenon is well known by helicopter enthusiasts, and accounted for in the design. But what we didn’t realize is that it actually translates to a theoretical speed limit for the aircraft. Our childhood love of Airwolf — the TV helicopter that could outrun jets — has been deflated.

You should remember the helicopter physics videos featured here last month. This is the latest offering and we’re still wanting more!

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(Model) Helicopter Physics

sideways helicopter

If you’ve ever wondered how a helicopter is able to fly, or would just like to see some awesome RC piloting, the four videos after the break should be just the thing! Although the basic physics of how one works is explained in the last three, one would still be hard pressed to explain how [Carl] is able to fly his RC helo the way he does. The video has to be seen to be believed or even explained, but one of the simpler tricks involved taking off a few feet, doing a forward flip, and flying off backwards and upside-down!

As explained in detail in the other videos, a helicopter is controlled by something called a swash plate on the main rotor, which in short translates a linear action into a rotational one. The same thing is done with the tail rotor, but you’ll have to check out the videos after the break for a full explanation! Really ingenious that someone could come up with this analog control system to use before computers were available.

Of particular interest to physics geeks, an explanation of gyroscopic precession is given in the fourth video. Controlling a helicopter may not work exactly the way you thought!

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