It's so much fun to Wonder with you, Jason! We agree, Jauquin! We bet it took a great deal of hard work, planning and determination to build that helicopter! It's pretty awesome to see it flying with the help of the pilots!
We really liked today's Wonder, too, Azhir! We think the students and the pilots worked together like a team to reach their goal! We learned so much from today's Wonder and we're glad to hear that you did too! We Wonder if you will create something like a human-powered helicopter in the future!?
We certainly agree, Pablo! We bet it takes a great deal of determination to succeed- we hope those students and the pilots win! These students and pilots have really tried their hardest, great point, Kamaria! We hope they are successful and win the prize for their awesome invention! We bet they are working hard to create a safe, soft landing for the helicopter and the pilot!
Wasn't that an amazing Wonder video, Henry!? Collin and Henry must be very powerful to get the helicopter so high off the ground! Great point, Carla! We hope that Collin is okay, but we bet he jumped right back in the helicopter after they repaired it! Very cool! You've got a great idea of how a helicopter works, Aniyah!
Thanks for sharing your comment with us! We bet you'd LOVE the Wonder video today-- it shows a group of engineers who are working on a human-powered helicopter!
Thanks for stopping by Wonderopolis today! Great Wonder, Mrs. Reasor's Class! We bet you'll enjoy checking out this site that explains the original helicopter designed by Igor Sikorsky!
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We sent you SMS, for complete subscription please reply. Follow Twitter Instagram Facebook. How do helicopters work? What can helicopters do that airplanes cannot? What are some of the special jobs helicopters can do? Wonder What's Next? Tomorrow's Wonder of the Day has ears, but it can't hear a thing! Be sure to grab a friend or family member to help you explore the following activities: Want to make your own helicopter? First, you'll need some basic things to get started. A powerful engine would be a good place to start.
Then you'll need several hundred pounds of high-strength steel…What? Don't have those things around the garage? Not to worry! Here's a simpler version you can try instead. With just a few common items, you can make a paper toy that behaves just like a mini-helicopter!
If you could fly anywhere in the world, where would it be? The North Pole? The South Pole? A Caribbean island? Once you've settled on a destination, give some thought to HOW you'd like to fly there. Would you rather fly on an airplane or a helicopter?
Make a list of pros and cons of both airplanes and helicopters. Share your list with a friend or family member. Do they agree with you? Why or why not? What is the largest helicopter? How about the fastest helicopter?
Do your own independent Internet research about helicopters. Try to find the answers to these and any other interesting helicopter-related questions you can think of. Share what you learn with a friend. Did you get it? Test your knowledge. What are you wondering? Wonder Words aircraft sleek incite blade rotor hover capability military ambulance mobility aeronautical engineer amaze bulky lift troops runway prototype Take the Wonder Word Challenge.
Join the Discussion. Dec 2, Sounds like you need to dig a little deeper by taking a Wonder Journey, simon! May 29, That's a great question. Like the collective control, these cyclic stick movements correspond to the directional movement of the helicopter; moving the cyclic stick forward makes the helicopter fly forwards while bringing the stick back slows the helicopter and even makes it fly backwards.
Moving the stick to the left or right makes the helicopter roll in these directions. The cyclic control works by tilting the swashplate and increasing the pitch angle of a rotor blade at a given point in the rotation, while decreasing the angle when the blade has moved through degrees around the rotor disc. As the pitch angle changes, so the lift generated by each blade changes and as a result the helicopter becomes 'unbalanced' and so tips towards whichever side is experiencing the lesser amount of lift.
The illustrations below show the effect of this cyclic control on the swashplate and rotor blades. As the swashplate is tilted, the opposing rods move in opposite directions.
The position of the rods - and hence the pitch of the individual blades - is different at any given point of rotation, thus generating different amounts of lift around the rotor disc. To understand cyclic control another way is to picture the aforementioned rotor disc , the imaginary circle created by the spinning blade tips , and to think of a dinner plate sat flat on top of the cyclic stick.
As the stick is leaned over in any direction, so the angle of the plate changes very slightly. This change of angle corresponds directly to what is happening to the rotor disc at the same time i. Above: the approximate layout of helicopter controls in relation to the pilot's seat.
At the very rear of the helicopter's tail boom is the tail rotor - a vertically mounted rotor consisting of two or more blades, similar to an airplane propeller. This tail rotor is used to control the yaw , or rotation, of the helicopter i. Torque is a natural reactive force caused by any turning object. In a helicopter it is caused by the engine turning the main rotor blades; when the blades are spinning then the natural reaction to that is for the fuselage of the helicopter to start spinning in the opposite direction to the rotors.
If this torque isn't controlled, the helicopter would just spin round wildly out of control. When the main rotor disk is tilted, the horizontal component of thrust moves the helicopter in the tilt direction. Figure 20 shows the conventional main rotor collective and cyclic controls. The controls use a swash plate. The collective control applies the same pitch angle to all blades and is the main tool for direct lift or thrust rotor control. Cyclic is more complicated and can be fully appreciated only when the rotor is rotating.
The cyclic operates through a swash plate Figure 20 , which has non-rotating and rotating plates, the latter attached to the blades with pitch link rods, and the former to the control actuators [ 7 ]. Rotor control through a swash plate. Two anti-torque pedals are provided to counteract the torque effect of the main rotor.
This is done by increasing or decreasing the thrust of the tail rotor Figures 19 and The torque varies with changes in main rotor power; therefore, the tail rotor thrust is necessary to change too.
The pedals are connected to the pitch change device on the tail rotor gearbox and enable the pitch angle of the tail rotor blades to increase or decrease [ 2 ]. Tail rotor pitch angle and thrust in relation to pedal positions during cruising flight. It is very important to determine what maximum weight the helicopter can carry before take-off, if the helicopter can safely hover at a given altitude and temperature, what distance is needed to climb above the obstacles, and what is the maximum climb rate [ 2 ].
The most important ones are: altitude, including pressure altitude and density altitude, helicopter gross weight, and the wind. One of the most important factors in helicopter performance is the air density, which decreases with a gain in altitude. The effect of altitude is shown in Figure 22a.
Increasing density altitude increases the power required in hover and lower airspeeds. At higher airspeeds, the results of lower air density result in a lower power requirements because of the reduction of parasitic drag.
A higher density altitude also affects the engine power available. The power available at a higher density altitude is less than that at a lower one. As a result there is a decrease in the excess power at any airspeed [ 1 ]. Power required and power available at a different altitudes, and b different weights.
Increases in aircraft gross weight go hand in hand with requirements for higher angles of attack and more power. As shown in Figure 22b , by increasing the weight, the excess power becomes less, but it is particularly affected at lower airspeeds because of induced drag [ 1 ]. High gross weight also affects of the maximum height at which the helicopter can operate in ground effect for a given power available. Under these conditions, the heavier the helicopter is, the lower the maximum hover altitude is [ 3 ].
Wind direction and velocity also affect hovering, takeoff, and climb performance. Translational lift occurs any time when there is relative airflow over the rotor disk. This explains whether the relative airflow is caused by helicopter movement or by the wind. With the increase in the wind speed, the translational lift increases, therefore less power is required in hovering [ 2 ]. Besides the magnitude of wind velocity, its direction is essential. Headwind is the most desirable because it gives the greatest increase in performance.
Strong crosswind and tailwind require the more tail rotor thrust to maintain the directional control. The increased tail rotor thrust takes away a power from the engine, and therefore will have less power available to the main rotor, which produces the required lift.
Some helicopters have a critical wind azimuth limits and the manufacturer presents maximum safe relative wind chart. If the helicopter operates above these limits, it can cause a loss of tail rotor control [ 2 ].
It is supposed that the helicopter is in good operating condition and the engine is able to develop its rated power. It is assumed that the pilot performs normal operating procedures and he has average flying abilities [ 2 ]. With these assumptions, the manufacturer develops performance data for the helicopter taking into account the flight tests.
But the helicopter is not tested under all conditions shown on the performance chart. Instead, an evaluation of the specific data is performed and the remaining data are obtained in mathematical way [ 2 ].
Generally, the charts present graphics related to hover power: in ground effect IGE hover ceiling vs. The exact names of these charts may vary by different helicopter manuals. These are not the only charts, but these charts are perhaps the most important charts in each manual—they help to understand the amount of power which the helicopter have to have under specific operating conditions altitude, gross weight, and temperature.
It has been shown that the performance characteristics can be derived by using simple models as the momentum and blade elements theories. The impact of weight and altitude on the required power and the available power has been presented.
Also, the case when the engine stops in flight and the main rotor performs autorotation is presented. Some elementary analysis of the stability characteristics has been done. The impact of different helicopter parts on the stability has been considered.
Finally, it has been shown how the helicopter can be controlled. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3. Help us write another book on this subject and reach those readers. Login to your personal dashboard for more detailed statistics on your publications. Edited by Konstantin Volkov. We are IntechOpen, the world's leading publisher of Open Access books. Built by scientists, for scientists. Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals.
Downloaded: Abstract This chapter is dedicated to present the principles that constitute the fundamentals of helicopter flight physics, starting from the basics of the main rotor aerodynamics and of the component parts related to flight control. Keywords helicopter aerodynamics induced velocity autorotation ground effect hover. Introduction The helicopter belongs to the flight machine category with the highest operational efficiency because it does not need special take-off and landing grounds with expensive utilities and logistics equipment.
This helicopter did not fly completely free due to its lack of stability; Igor Ivanovitch Sikorsky built a nonpiloted coaxial helicopter prototype; Boris Yuriev tried to build a helicopter with a single main rotor and tail rotor configuration.
He proposed the concept of cyclic pitch for rotor control; the Danish Jen C. The aircraft made several short hops but never made a properly flight; Stephan Petroczy Austrian build and flew a coaxial rotor helicopter; Henry Berliner USA built a counter-rotating coaxial helicopter; Raul Pescara Argentina built a coaxial helicopter; Georges des Bothezat USA designed and built a helicopter for the USA army. He was the first specialist who described the helicopter autorotation; Igor Ivanovitch Sikorsky built the helicopter VS which flew in May 13, Helicopter configurations The helicopter is a complex aircraft that obtains both lift and thrust from blades rotating about a vertical axis.
Vertical climb Considering the helicopter in climb, one can see that the flow enters the stream tube far upstream of the rotor and then passes through the rotor itself, finally passing away from the rotor forming the wake Figure 6.
Main rotor systems The primary way to distinguish between different main rotor systems is represented by the movement of the blade relative to the main rotor hub. Anti-torque system The single rotor helicopters require a separate rotor to overcome the effect of torque reaction, namely the tendency for the helicopter to turn in the opposite direction to that of the main rotor.
Swash plate assembly It has the purpose to transmit cyclic and collective control movements to the main rotor blades and consists of a stationary plate and a rotating plate. Trim The neutral position of the cyclic stick changes as the helicopter moves off from to hover in forward flight.
Collective and cyclic pitch control Collective pitch lever controls the lift produced by the rotor, while the cyclic pitch controls the pitch angle of the rotor blades in their cyclic rotation.
Power required The power required for flight is the second work that must be transmitted to the shaft of the rotor. Power available The power needed to rotate the main rotor transmits to the main rotor from the engine through the transmission Figure Mobile Newsletter banner close.
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