Questions tagged [helicopter]

A helicopter is a type of rotorcraft in which lift and thrust are supplied by rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward, and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft would usually not be able to take off or land.

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1answer
88 views

Helicopter Basics: How does lead-lag of blades actually help in compensating for increase/decrease in speed due to flapping?

I understand the following - Due to dissymmetry of lift, flapping up and down occurs. Since angular momentum has to be conserved, the speed of blade increases/decreases during flapping up/down ...
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What was this helicopter photographed on a Chinese aircraft carrier?

I've read this twit Chinese carrier got photographed by a satellite. On the nose you can find a helicopter and several people around it. What helicopter is that?
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How to say the name of this approach clearance: COPTER RNAV (GPS) 027°

JFK has this approach: https://aeronav.faa.gov/d-tpp/2006/00610COPTERR027.PDF How is this approach said on frequency? Is it the "copter RNAV zero two seven approach" or the "copter RNAV zero two ...
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Was flying a helicopter below building height against FAA regulations? [duplicate]

I'm referring to this incident: https://twitter.com/Dacheslow/status/1267638389421072384 Some people were saying it was illegal under FAA rules to fly that low and close to a crowd, and also to use a ...
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What are the applications, advantages and limitations of Gyrodyne rotorcraft?

Gyrodyne is a VTOL rotorcraft. It has ability to power both rotors and propellers for generating lift and thrust. What makes it of lesser popularity than helicopters. Are there any applications of ...
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What does induced flow exactly means on helicopters flight? How is it different from downward deflection of air?

I believe all airfoils deflect air downwards at an angle at a velocity V. What is the difference between the downward-vertical component of the deflected wind and the induced velocity in Helicopter ...
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How to convert an EASA CPL(H) to FAA CPL Rotorcraft With a Helicopter Class Rating?

I just finished my CPL(H) license and was just wondering if it is difficult to convert your license to an FAA (or TCCA) license. Do you have to do additional exams or check rides? It's hard to find ...
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Is it possible to design a helicopter with fixed rotor blades only (no blade angle/flap/pitch)?

I am not familiar with helicopter rotor design but I wonder if it is possible to build a working/flying helicopter with fixed rotors that cannot change the blade angle, flap, pitch or adjust blades ...
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Helicopter flight: Does the rotor disc plane and hub plane rotate along axis perpendicular to rotational axis?

In many pieces of literature, diagrams as below are shown to explain the directional flight of Helicopter. I have the understanding that the cyclic input will only change the pitch angle of the blades ...
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What is the purpose of a freewheeling unit in an helicopter, if a centrifugal clutch is already present?

Some helicopters such as the Bell 47 are fitted with a centrifugal clutch. Centrifugal clutch will engage only at certain engine RPM. If the engine fails, the engine RPM will reduce and the ...
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What is this long Bar/Rod on the Boeing MH-47G? [duplicate]

This MH-47G has a thick, long rod at the bottom left front. What's the purpose of this thing?
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Helicopter Flight: What is the reason for decrease in Induced drag with increase in speed?

As per the figure the induced drag will decrease only if the AoA of the blade is decreased — But in the forward flight, cyclic input increases and decreases the AoA throughout the blade rotation cycle....
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In helicopters, why not have electric motors controlling blade pitch?

From my related question comes this idea of electrically controlled blade pitch in helicopters. Control linkages in helicopter rotors seem to be pretty complex. This surely incurs a lot of friction, ...
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Why is *vertical* autorotation in a helicopter not recommended?

Helicopters can autorotate back to earth in case of emergency. The FAA recommends a flight profile similar to the following procedure: Notice that in section (2) there is forward speed: vertical ...
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What causes a helicopter to autorotate farther?

Which characteristics improve a helicopters ability to glide a farther distance in autorotation? Do these same characteristics reduce minimum decent speed in autorotation or is that affected ...
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What effect does cold weather have on helicopter performance?

Recently I was flying around my RC helicopter on a 40 $^\circ$F (4$^\circ$C). At some point in the flight the rotor just stopped moving in mid-air and then I regained control back at ground level. I ...
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What are the most maintenance-intensive parts of a helicopter?

Which components of a helicopter are the "driving" ones that require most regular attention and down-time, and how often do they last between inspection or overhaul? I don't have a specific model in ...
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With helicopters, is normal landing or auto-rotation landing any different when landing on water?

I noticed something from investigating my other answer to a not-really-related question. A wiki article here says: The "water bird" emergency landing is a technique developed by the Canadian ...
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101 views

Is it possible to start another engine of Mil Mi 8 with one engine started and APU off?

In the 737NG, it is possible to start the other engine without APU if one engine is already started, by routing air from the started engine to the other one. Is this possible in the Mil Mi 8 ...
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129 views

How are pitching and rolling moments transferred from rotor to the body?

When a rotorcraft pilot moves pushes on the cyclic control stick, the swashplate tilts so that angle of attack of the retreating blades increase and of the advancing blades decrease, which creates ...
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In helicopter's forward motion, how is the forward pitching moment taken care off?

When the rotor disk is in the position shown by the dashed lines, the net Lift is at an angle. It should produce a forward pitching moment about CG (Center of gravity). That can cause the helicopter ...
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Can a helicopter operate continuously in a small, enclosed, sealed environment?

Many years ago I had an interesting discussion with a friend (while drinking). We were discussing what would happen if a helicopter was placed into a sphere of some size (slightly larger than the ...
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What angle of deflection / pitch on the rotor blades can the controls generate?

I was wondering, if a pilot uses full input on cyclic and collective, what pitch angle can be achieved for the rotor blades? Is there a mechanical stop to prevent extreme angles of attack? And how ...
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Are there any helicopters with tail rotors where slip-skid ball may be centered even when fuselage is streamlined to the airflow in cruising flight?

In a related answer, I stated "The tail rotor of a helicopter also generates an aerodynamic sideforce. Again, just as with the twin-engine airplane with one failed engine, when the fuselage is ...
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What methods are used for calculating maximum takeoff windspeed of a helicopter?

I would like to calculate the maximum windspeed in which a helicopter may safely take off and safely land, assuming a theoretical wind environment with constant wind direction and no gusts. I ...
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Can you use a home built helicopter for solo hours?

I'm curious to know if anyone has heard of or has any knowledge of using a kit helicopter for the FAA required minimum solo hours of flight training.
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Are helicopter with coaxial rotors equiped with blade flapping mechanism?

Helicopters with coaxial rotors such as the Ka-27 don't need mechanisms to overcome dissymmetry of lift as there is advancing blades on both sides of the helicopter. A common mechanism to overcome the ...
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Do tower-controlled helipads have a standard naming convention?

Just wondering if anyone knows, or if it just depends on the airport. Edit: This question is different than How does the FAA determine which format of location identifier to assign to an airport?. ...
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What exactly happens when I try to maintain the flare when coming to a hover?

I've been considering this question. I believe myself to be an average pilot but I'm embarrassed to say that I could not figure out the answer to the following question: I flare and use power to ...
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Why is ground effect greater over smooth hard surfaces?

Helicopter Flying Handbook: Ground effect is the increased efficiency of the rotor system caused by interference of the airflow when near the ground. The air pressure or density is increased, ...
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If a helicopter's tail rotor fails, is it possible to perform an emergency landing?

In the event of a total failure of the tail rotor, is it possible to maneuver a helicopter to an emergency landing spot that is within, say, 30 minutes flying time? What are the maneuvers required ...
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How is rotor airfoil analysis different than fixed wing airfoil analysis?

What the is difference between rotor airfoil analysis and fixed-wing airfoil analysis? Intuitively, it seems that the airspeed at the tip of a rotor blade would be more than that at its root. Wouldn'...
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Does a dual-rotor helicoptor like the Chinook transition from hover to forward flight differently than a single rotor helicopter?

I watched this video of an RAF Chinook taking off vertically and transitioning to forward flight. I'm curious if the method for increasing lift to move forward, controlled by the cyclic in a single ...
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Are a gyrodyne and a compound helicopter the same thing?

Both the gyrodyne and the compound helicopter are typically rotorcraft with driven rotor, additional stub wings and thrust provision. Are they two terms for the same thing or do they differ in some ...
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Rotor Tip Speed vs Forward Airspeed - IAS or TAS?

I created this graph to illustrate how the tip speed of the advancing and retreating blades vary with forward airspeed but am confused as to what would be the most correct way to label the x-axis: ...
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How does a Delta-3 hinge on a helicopter tail rotor work?

I am trying to understand how adding offset hinges would provide a self-feathering force. Does anyone have more information on Delta hinges on helicopters? I am a bit confused with the information I ...
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What type of aircraft would fly with an orange light at night?

I know planes usually fly with red lights which seem small in the sky, but last night i saw a bright orange blinking light traveling through the sky; it was bigger then a star but was orange. I ...
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Why there is a helicopter sitting north of madras, OR, , above the warm springs reservation every single night? [closed]

Every night I see a helicopter light above the reservation sitting in a spot above my house, but way up that I can't see it closely, just the light. Has to be a helicopter since it sits in one spot.
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How do “tip jet” helicopters cancel the torque effect of the main rotor?

Some helicopters use "tip jet" on the rotor blades tips such as the McDonnell XH-20 Little Henry and Hiller YH-32 Hornet. How do they cancel the rotor torque (often canceled by the tail rotor)?
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Why do intermeshing helicopters use asymmetric airfoils?

I am referring to the Kaman K-max and the Kaman Huskie here. They both use NACA 23012, which is an asymmetric airfoil. Any reason as to why this is? Is there a different mechanic in play when ...
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Helicopter or Airplane, which is the most difficult to fly? [duplicate]

I know it varies from aircraft to aircraft, but I want to know in general, which would be the most difficult aircraft to fly even after years of experience. Helicopter or Airplane ? I tried to fly a ...
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How does flying a helicopter compare with flying a fixed wing plane?

There has been a lot of interest in the ease of flying a helicopter recently, and questions have arisen on how easy it is to control a helicopter in less than ideal circumstances such as low ...
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What fuel would a Bell Huey helicopter use in 1964?

What type fuel would a Bell Huey have used in 1964? If that matters, let's say for a medical evacuation situation
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Why does the UH-1 Huey have a hump at the rear of the cabin?

Why does the Huey have this weird hump as shown in the picture? For some system? Why not remove it? https://www.helis.com/h2/uh-1h_seats.jpg
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Why are there no stealth helicopters?

There aren't exactly an abundance of stealth planes, but most highly developed countries own one. Why are there no stealth helicopters? If there are, why are they so obscure?
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Under what conditions would a helicopter be allowed to fly at low altitude over populated areas?

Yesterday, the Department of Energy was flying a military helicopter at low altitudes over Boston and the surrounding area as part of an experiment of some type to measure radiation. I saw one of ...
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Can helicopters create contrails?

Can some or all helicopters have contrails? If only some, why only those? If not, why can they not? Pictures would be really helpful. I do know that turboprops and piston props can leave contrails, ...
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Buy an aircraft to train first or after? [duplicate]

I'm thinking about learning to fly. Is it worth buying an R22/S300 or C172/Cherokee to train in then fly afterwards?
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What is this helicopter (and probe) in the film “Act of Valor”?

In the film Act of Valor, two helicopters are used to airdrop troops and their boats onto a river. (Clip here.) Firstly can you identify the aircraft? Second, what is the extremely long probe on the ...
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How significant is the static buildup on the blades of the main rotor? And some questions related to this [duplicate]

1) Usually, a static charge is built on the helicopter when it flies through the air. If a person touches the helicopter before it touches the ground can that person get electrocuted because of the ...

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