# Best D.I.Y. effort of 2009: the guy who built his own helicopter

2 pictures

20-year-old Wu Zhongyuan from China demonstrates his home-made helicopter. View gallery (2 images)

And to think I crack a self-satisfied beer after fixing the lawnmower... Wu Zhongyuan, a 20-year-old farmer from China, cobbled this working helicopter together out of a pile of steel pipe, some Elm wood and a 150cc scooter engine using his high-school physics knowledge and researching the rest on the Web via his mobile phone. I don't know whether to line this kid up for a Nobel Prize or a Darwin Award. This article comes with two Christmas bonuses: Bonus 1: a quick lesson on how to fly a helicopter. Bonus 2: five short videos demonstrating exactly what happens when helicopter dynamics go just a tiny bit wrong.

Helicopters are an incredibly versatile means of transport - and also probably the most complicated type of aircraft to fly. To understand the scope of this 20-year-old's achievement in building a working helicopter, let's take a look at exactly what he's had to build.

When you strip a heli down to its most basic control components, here's what you get:

### How to fly a helicopter

- The pilot's left hand works the 'Collective Control Stick' - this has a twistgrip throttle on the end of it that controls the speed of the rotor blades. You can also pull the stick up and down like a car's handbrake; this motion controls the angle of all the blades on the main rotor. If all the blades are level with the ground, there's virtually no lift. If all the blades are angled hard into the wind, then they produce a large amount of lift, provided the rotor's spinning at a good speed.

- The pilot's right hand works a joystick-like "Cyclic Control Stick" to effectively control the tilt of the aircraft in any direction. This is achieved by changing the angle of the main rotor's blades depending on where they are in their rotation - so you can create an area in the main rotor's rotation where the blades angle up a little steeper and you get extra lift just on that side.

- The pilot's feet work a pair of pedals that control the angle of the blades on the tail rotor. The primary job of the tail rotor is to balance out the torque effect of the main rotor - which would spin the cabin along with it if there was nothing to counter it. By manipulating the pedals, the pilot is able to produce or reduce thrust at the tail of the aircraft, and control its rotation.

All these inputs work in concert to produce a complex and constantly changing flight dynamic that requires total concentration and focus from the pilot.

And it's a good insight into why Wu Zhongyuan is probably a decent contender for the 2009 "giant brass cojones" award as well as the D.I.Y. crown. Because there's not a chance in hell you'd get me airborne in the thing.

From its three supermarket trolley caster wheels (one broken - hey, it's a tradition among supermarket trollies) to its welded steel tube frame, to its precariously mounted 150cc motorcycle engine, to its wooden rotors, which appear in one shot to be stabilized with string, it's clear you're not dealing with the world's most refined aircraft.

Furthermore, it's unclear how, or even whether, Wu has managed to implement a tilting mechanism on the main rotor, or that all-important cyclic tilt control.

The 20-year-old is confident that his home-made chopper, which cost him two months of work and about US\$1600 in parts, will take him as high as 2600 feet. The Chinese government, like us, isn't so sure, and has grounded the machine, at least for the time being.

That's possibly for the best - here's a selection of short videos showing how quickly and comprehensively things can go wrong, even in commercially built and flight-approved helicopters with trained pilots.

## 5 short helicopter crash videos

#1: I wouldn't want to be the guy that falls out at 0:16

#2: New chopper owner doesn't wait for his flying instructor

#3: Why you need an effective tail rotor

#4: Twin rotor fails to land on carrier deck

#5: Terrifying accident, with a very lucky ending for all involved

## Editors Choice

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