In the previous part we talked about how they interact with the flight control surfaces control the helicopter. In this part we will talk about piston engines used for helicopters, small, mostly for school activities, reconnaissance and shedding sostanze.Si These motor units to the public in general aviation: an example is in the Hughes 300, using the Lycoming HIO 360 (H = I = injection helicopter O = opposed, since the drive unit configuration using a 4-cylinder boxer, with double switch). This engine is almost onniprsente: cessna 172, PARTENAVIA P68, Piper Seneca, and many others. The difference between the models mounted on helicopters and those mounted on aircraft consists mainly in the cooling system (for air because we think the propeller, the helicopter is designed for a forced air system). Returning to the helicopter and the dynamic operation of the airplane, the acceleration of the engine behind a demand for power can be done in two ways: manual or via "governor". In manual mode the pilot to increase or decrease the speed of the engine by manually by rotating the knob of the gas. E 'instinctive, try this: put your left arm vertically with the closed fist. Pretend to challenge the collective and rotated by lifting the wrist to the knuckles approach to the seat. Conversely, when lowered, rotate the wrist to the outside, removing the knuckles. So, in summary: If I have to raise the helicopter, I must raise the collective pitch lever, collectively, by varying the pitch of all pale.Aumenteranno then the angle of incidence of the blades and the torque of my overall rotor. In short, as if with a car going into the mountains. Then I'll have to balance the power demand (increased resistance) with an opening of the throttle (power increase). Conversely, if I have to lose altitude, my collective will subside, and my throttle will rotate toward the minimum. This is where my helicopter piston has no "governor." If our helicopter is equipped with this device, I do not moves with the throttle, we automatically think about a series of levers and mechanisms. We are talking about piston engines, and for the referral of power we will talk about MAP, that is, Manifold Air Pressure: The air pressure in the intake manifold of the engine.
In figure (taken from a simulator, but fair enough) we can distinguish:
1) An instrument MAP (top left, in inches of mercury);
2) A double-lap, where the long hand lower, with the inscription "E" screen occupies the outer scale from 0 to 3500 rpm and the short hand of the rotor speed is on, bearing the letter R and its values range from 0 to 600 rpm. Note that the green band (the indicator has two rounds, but the lower to the ground and is valid at least) is very narrow? Well, to stay in the air, you have to stand in principle that the hands spazio.Questo idea was to make the in flight is a little more complicated affair, especially given the need to coordinate the hands, feet, wrists and head . Many drivers say it's like riding a bicycle understood the trick is not that difficult.
