CH-47 Chinook: One fast helicopter

WAIT WAIT WAIT!!!!! Before all of you go berserk with rage saying that the Eurocopter X3 is the fastest helicopter around, I have 3 issues with it that prevent me from labelling it as the fastest helicopter in the world. 1) It is experimental, and that means I want to save it for another post. 2) It doesn't officially hold the record, so I am really not comfortable giving it the title of fastest helicopter in the world. 3) I'm not sure it is a 'helicopter' per se. While the craft looks like an unconventional helicopter on the ground, when in flight it really isn't a helicopter at all, so I don't want to call it the fastest helicopter in the world. With that out of the way, lets talk about the CH-47 Chinook

What is it?

The Boeing CH-47 Chinook is a heavy transport helicopter that is in the service of the US Army, the Japanese Ground Self-Defence Force and the Indian Air Force. Its primary use is to ferry heavy cargo and troops to important areas quickly. What makes it special is the unique design that allows it to achieve high speeds.

The design

It uses two very large rotors that are placed on top of the craft to keep itself flying. The rotors spin in opposite to ensure that there is total stability of the craft. Because the two rotors are situated on top of the craft, there is double the force pushing it forward and keeping it in the air. But hold on, why do helicopters even have 2 rotors? I mean, most of the time the secondary rotor doesn't even seem to produce any lift at all is spinning sideways for no reason whatsoever. Well, there is a very good reason why helicopters have tail rotors, as without them, the helicopter could crash before liftoff.

The Tail Rotor concept

This is all to do with Newton's third law of motion, which states that "Every action as an equal and opposite reaction." In terms of helicopters, this applies to the massive main rotor on top of the craft. The rotor spins so fast and violently, the helicopter below will be sent spinning in the opposite direction. But the spinning can be prevented with some rather simple physics.

The main rotor exerts a turning force on the helicopter, so we need another turning force to counteract this. That is the purpose the tail rotor serves: to provide an opposing turning force preventing the helicopter from spinning out of control, which you can see in the diagram to the left. So the tail rotor at the end spins in the opposite direction to the main rotor to push the helicopter in the opposite direction to the main rotor spins the helicopter in. But why is it so far out on a very long tail?

That is to do with a concept of physics called torque. Torque is defined as a force that causes rotation, and can be calculated very simply with the formula: T= F*r where T represents torque, F represents the perpendicular force in newtons and r is the distance from the point you are trying to turn. The equation also shows that you can increase torque in 2 different ways: 1) Increase the force you apply, or 2) increase the distance from the point you are trying to turn. That is why the tail rotor is so far behind the main rotor, it can use less fuel and energy while keeping the helicopter stable, as shown in the diagram. That is the basic concept of a tail rotor, but as I am sure you are aware, there is no tail rotor on the CH-47 Chinook. It just has two very big rotors on top.

Why doesn't the Chinook have a tail rotor?

This is because it honestly doesn't need one. The way it is designed, a tail rotor would simply waste fuel and potentially send it spinning out of control. The reason is that the two main rotors are spinning in opposite directions. This means the rotors exert two opposing turning forces on the helicopter, which both cancel out, so the helicopter will be stable most of the time. There is no danger of spinning out of control in a Chinook, so a tail rotor is not necessary for this craft. And the two main rotors also do something else that is advantageous for the Chinook, they do provide more thrust.

The secret to the Chinook's speed

The top speed of the Chinook is an amazing speed of 302 km/h, which is roughly 187 mph. This is faster than most helicopters because in the Chinook, both rotors provide lift and thrust, whereas a conventional helicopter only has one rotor that gives it thrust. This means that the Chinook can fly at a more aggressive angle, without a danger of losing lift. Helicopters can only angle down a little to generate forward thrust because the main rotors have to lift the thing up as well as give it forward thrust. So if the helicopter is angled too far forward, they will lose lift and crash. This 'angle of no return' is what limits the top speed of helicopters and is also the reason helicopters will never be as fast as a plane. But that should be enough about how helicopters work. Now, back to the Chinook itself.

The Chinook's service record

Well, it is very long. I mean, the helicopter was first introduced during the Cold War. And no, not the late Cold War, I mean the early Cold War. Hell, this damn thing was first flown in 1962!! It is almost 60 years old! So let me just say it is successful. It was in an active role in the Vietnam wart, the Iran-Iraq War, the Libyan Wars, the Falklands War and the Afghanistan and Iraq Wars as well. In all those conflicts it served its role as a transport craft more than adequately. It is one of the most successful helicopters in current service, and I doubt it will be retired anytime soon. I mean, this helicopter can carry 33-55 troops to a combat zone in places most other transports can't reach and can carry a

maximum payload of around 24,000 lbs. With that level of payload, it can transport heavy artillery into some really tricky positions and can easily supply said artillery with enough ammunition to last forever. I don't think any helicopter can match the speed of the Chinook at the moment. Even if one is invented that is faster than the Chinook, there is no way in hell it would be able to carry the same payload the Chinook can.

If it is so amazing, why haven't we heard more about it?

Good question. I think honestly, it has to do with the fact that is was introduced in 1962. The world had more things to worry about. This was the year Yuri Gagarin became the first man in space in Sputnik 1 and it was also the year the Soviet Union put operational nuclear missiles on the island of Cuba. When you compare the CH-47 Chinook to an apocalyptic even and a milestone in the evolution of human scientific capability, it is very easy to forget that the CH-47 even existed. Only if you went looking for advancements in helicopter technology would you find the CH-47. I personally believe that the only reason is existence is ignored is because it was overshadowed by other achievements and problems the world was given at the time. Because of that, I really didn't know much about it, but I am glad I did the research. The Chinook is one of the amazing things humans created that somehow went unnoticed. It deserves recognition, and I am glad I could give it some. This 58-year old veteran will land in the Hall of Fame, one way or another.