It’s back-to-school time in the Okanagan!
Just like our clients, many members of the Valhalla team are thinking again about daily schedules, making lunches (ugh!), and after-school activities. With so many people focusing on academic pursuits, we thought this would be the perfect time for a lesson. Our customers always (always!) ask us this:
How does a helicopter stay up?
Well, grab your notebooks and pencils, everyone! Today, you’re going to learn all about the very cool science that keeps our “birds” up in the beautiful Okanagan skies.
Humans have attempted to build flying machines for ages. In the early 1900’s, several aviation companies put out early designs for helicopters, but none were commercially viable. That changed in 1931, when the now infamous Igor Sikorsky patented his machine; it was in production by 1942. The Sikorsky helicopter is the prototype for almost all commercial helicopters today.
Like all aircraft, helicopters can fly because they have something forcing the air pressure around them to change. Sikorsky and other aeronautical engineers of his era recognized that a successful helicopter needed to combine 2 sets of scientific principles: lift & drag, and thrust & weight.
If the force of the lift is equal to the force of the drag, the helicopter will hover in mid-air.
If the force of the thrust is greater than the force of the weight of the machine, the helicopter will move.
So that’s how Sir Isaac Newton and his laws of physics play into keeping our helicopters in the air, but those aren’t the only important elements.
The body of the helicopter, the fuselage, is made of strong, lightweight materials (usually a composite of fiber-impregnated resins and aluminum or steel). It houses the engines, the gearboxes and controls, the control panel, the communication system and, of course, the seats and safety harnesses. Attached to the outside of the aircraft, you’ll find the hardest-working components!
Helicopters are considered rotary wing aircraft. The blades of the rotor are shaped like the wings of an airplane, slightly curved and exceptionally aerodynamic. Each blade can move individually (controlled by the pilot’s hands and feet), to change the amount of air pressure above and below the body of the heli. At high speed, the curve of the blade forces the air above it to move faster than the air that is passing underneath, which is what creates the change in pressure. As long as the blade is spinning fast enough (and depending upon the angle of each blade), the helicopter can remain aloft!
In order to move forward and backward, side-to-side, or to descend, the pilot needs to adjust the angle of the blade. Increasing and decreasing the pitch of the blades (either individually or collectively) alters the movement and the hover of the entire machine. In order to turn the machine left or right, though, the pilot needs to affect the blades of a different mechanism: the rear rotor.
But why do helicopters have two rotors? The rear rotor creates a resistance force upon the airflow from the first propeller. This aids stabilization, hovering, and most importantly, spin. This counterbalance is what keeps the helicopter from getting into an uncontrollable spiral, and what keeps it from crashing. We are big fans of the rear rotor!