Torque

Helicopters display alooooot of physics. I can’t actually get my hands on real helicopter, so I used the next best thing—Microsoft Flight Simulator X. Torque is a key component of flight with helicopters. The engine applies torque to the main rotor blade shaft, which in turn causes the rotor blades to rotate and generate lift. Because of Newton’s third law, however, the helicopter also experiences torque from the rotor blades which must be countered with a rear tail rotor which is controlled by anti-torque pedals The pilot of a helicopter can directly control the torque output (displayed on a gauge in the top left as a percentage of maximum torque of a specific helicopter) with a control called the collective. I decided to do a demonstration flight in Flight Simulator in an MD-500 helicopter. If you pay attention to the torque gauge in the video below, you’ll notice that there is actually a significant amount of torque even when the helicopter is resting on the ground. This is because while the helicopter is resting, the rotor blades are still rotating and fighting air resistance. Increasing the torque will cause the rotor blades to generate more lift until finally the force from lift is greater than the force from the helicopters weight (mg), thus allowing the helicopter to accelerate upwards (notice that as I increase torque during takeoff, I must apply slight pedal inputs to keep the helicopter straight because of the increased torque). Also notice that the torque does not always stay constant throughout the flight, during hovers, and especially during landings. During landings such as the one I performed, you may actually notice an increase in torque as the helicopter nears the ground. This increase in torque increases the lift force to allow the aircraft to decelerate vertically and land smoothly on the ground instead of slamming into it.

VIDEO:


NOTE:Sorry the video quality sucks, I have to find better compression software (the original file was 900+mb =/). Its also kinda hard to see the gauge. I will reshoot and upload a higher quality video when time permits.