Click here for the previous lessons, to learn about: Principle of Airframe; Principles of Aerodynamics; Airfoil Characteristics; Primary Flight Control Surfaces; Description and Operation of Helicopter; Miscellaneous Components of an Aircraft…
Sikorsky and a few of his contemporaries brought a technical rigor to the field that finally made vertical flight safe, practical and reliable. As the flight-crazy Russian continued to refine his helicopter designs, he worked out the fundamental requirements that any such machine needed to have to be successful, including:
a suitable engine with a high power-to-weight ratio,
a mechanism to counteract rotor torque action,
proper controls so the aircraft could be steered confidently and without catastrophic failures,
a lightweight structural frame, and
a means to reduce vibrations.
Many of the basic parts seen on a modern helicopter grew out of the need to address one or more of these basic requirements. Let's look at these components in greater detail:
Main rotor blade —
The main rotor blade performs the same function as an airplane's wings, providing lift as the blades rotate — lift being one of the critical aerodynamic forces that keeps aircraft aloft. A pilot can affect lift by changing the rotor's revolutions per minute (rpm) or its angle of attack, which refers to the angle of the rotary wing in relation to the oncoming wind.
Stabilizer —
The stabilizer bar sits above and across the main rotor blade. Its weight and rotation dampen unwanted vibrations in the main rotor, helping to stabilize the craft in all flight conditions. Arthur Young, the gent who designed the Bell 47 helicopter, is credited with inventing the stabilizer bar.
Rotor mast —
Also known as the rotor shaft, the mast connects the transmission to the rotor assembly. The mast rotates the upper swash plate and the blades.
Transmission —
Just as it does in a motor vehicle, a helicopter's transmission transmits power from the engine to the main and tail rotors. The transmission's main gearbox steps down the speed of the main rotor so it doesn't rotate as rapidly as the engine shaft. A second gearbox does the same for the tail rotor, although the tail rotor, being much smaller, can rotate faster than the main rotor.
Engine —
The engine generates power for the aircraft. Early helicopters relied on reciprocating gasoline engines, but modern helicopters use gas turbine engines like those found in commercial airliners.
The main rotor blade rotates around a central hub (yellow) with an engine beneath it. A single engine powers both the main rotor blade and the tail rotor.
Helicopters use the airfoil principle to generate lift. When the blades rotate relative to the air, the special airfoil shape will generate lift force and make them fly (Fig:2A). The blades derive rotation from an engine, more specifically a turboshaft engine. The compressor sucks the air in and pressurizes it.
How does helicopter power work?
Engine — The engine generates power for the aircraft. Early helicopters relied on reciprocating gasoline engines, but modern helicopters use gas turbine engines like those found in commercial airliners.
What starts a helicopter engine?
Most larger helicopters have an auxiliary power unit (APU). The APU is a smaller, gas turbine engine used to start the main engine(s) and possibly pressurize hydraulic systems, among other things. The APU accelerates the main engine's gas generator (the compressor fans) until it reaches a self-sustaining speed
In many piston engine-powered helicopters, the pilot manipulates the throttle to maintain rotor speed. Turbine engine helicopters, and some piston helicopters, use governors or other electro-mechanical control systems to maintain rotor speed and relieve the pilot of routine responsibility for that task
What keeps a helicopter from spinning?
A: Helicopters do use their tail rotor to prevent themselves from spinning, but they use it to stop spinning in the opposite direction as the main rotor. This is called “torque reaction.” A torque is any force that causes something to spin.
How hard is it to control a helicopter?
Generally speaking, it is understood that helicopters are harder to operate as compared to standard light aircraft. While a pilot may be able to undertake long flights in a standard aeroplane and not be all too tired at the end of it, just a few hours of flying a helicopter may be exhausting for some
Many of the basic parts seen on a modern helicopter grew out of the need to address one or more of these basic requirements. Let's look at these components in greater detail:
Main rotor blade — The main rotor blade performs the same function as an airplane's wings, providing lift as the blades rotate — lift being one of the critical aerodynamic forces that keeps aircraft aloft. A pilot can affect lift by changing the rotor's revolutions per minute (rpm) or its angle of attack, which refers to the angle of the rotary wing in relation to the oncoming wind.
Stabilizer — The stabilizer bar sits above and across the main rotor blade. Its weight and rotation dampen unwanted vibrations in the main rotor, helping to stabilize the craft in all flight conditions. Arthur Young, the gent who designed the Bell 47 helicopter, is credited with inventing the stabilizer bar.
Rotor mast — Also known as the rotor shaft, the mast connects the transmission to the rotor assembly. The mast rotates the upper swash plate and the blades.
Transmission — Just as it does in a motor vehicle, a helicopter's transmission transmits power from the engine to the main and tail rotors. The transmission's main gearbox steps down the speed of the main rotor so it doesn't rotate as rapidly as the engine shaft. A second gearbox does the same for the tail rotor, although the tail rotor, being much smaller, can rotate faster than the main rotor.
Engine — The engine generates power for the aircraft. Early helicopters relied on reciprocating gasoline engines, but modern helicopters use gas turbine engines like those found in commercial airliners.
This is an Aerospace engineering concerned with the development of aircraft and spacecraft, focused on designing aeroplane and space shutlle and it is a study of all the flying wing used within the earth's atmosphere. Also dealing with the Avionic systems that includes communications, navigation, the display and management of multiple systems. Also dealing with Aircraft mishap such as Accident and Serious Incident
