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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211 views

Why do electric versions of helicopters need four rotors, or: why are they quad copters? [closed]

Why do electric versions of helicopters need four rotors, or: why are they quad copters? Could it be that their motor do not have enough torque? Then again electric motors have much more torque ...
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What are the guidelines and regulations for building a helipad for multiple aircraft?

Are there any guidelines and regulations governing the ownership and construction of a multiple aircraft type helipad in a) the USA b) Europe?
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Are there disadvantages of coaxial rotor on attack helicopters?

My question stems from the fact that, although this is a very fierce looking, and formidable aircraft with a very powerful engine, Ka-52 Alligator has not seen many export success. Its export is very ...
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356 views

What are the minimum hours required for private instrument fixed-wing plus commercial helicopter?

I want to get my private pilot plus instrument rating in fixed-wing aircraft for personal use. In addition to that I want to get my private and commercial in helicopters to start a career in flying ...
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577 views

Why don't the newest versions of Mi-35Ms have retractable gear?

Older versions of Mi-35 Hind helicopters had wheel boxes so that they could retract their wheels while flying. Why don't the newest versions of Mi-35Ms have wheel boxes?
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How does the V22 Osprey manage such high rotor speeds without shock waves?

I read somewhere that the engineers presented an ingenious solution to the rotor tip shockwave problem, except the article didn't actually explicitly mention it. So, does anybody actually know if ...
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Why does the Apache create much more rotor noise than the A-129?

The AH-64 Apache attack helicopter was upgraded several times after its first flight in 1974. The Apache Longbow was a major upgrade which entered service in 2003. On the other hand, Agusta A-129's ...
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Is there a minimum start altitude for autorotation landings?

If a helicopter is flying relatively low, say for sightseeing, can it still land using autorotation if required? What about if there was an issue during a routine landing? Is there any cutoff point ...
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How practical might it be, to carry military tanks by helicopter(s) to remote areas? [closed]

How practical might it be, to carry military tanks by helicopter(s) to remote areas? Wikipedia lists the M1 A2 Abrams tank at 65 metric tons. HeliPress lists the Russian-made Mi 26 copter as being ...
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How can I deal with insurance requirements for flight hours and training in order to carry passengers?

I just completed a helicopter rating and was excited to take friends for a ride in the R22 and R44. Then I learned that my flight school's insurance requires a total of 100 hours in helicopters and ...
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What are the regulations regarding the safety briefings and harness designs for open-door helicopters?

I'm reading about a helicopter crash that happened yesterday in New York City. The helicopter landed in the East River and apparently inverted. The pilot was able to escape, but all five passengers ...
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How do the Kaman K-225 rotor “planes” work?

I had the opportunity to go to one of the Smithsonian Air and Space museums today and they had a Kaman K-225 on display. For those who don't know, the K-225 is a dual side-by-side helicopter design ...
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What is the relationship between speed, torque and pitch in a helicopter?

Can someone clarify the relationship between aircraft speed, torque, prop length and pitch and how this applies to a helicopter. In addition I want to know if the amount of lift a helicopter ...
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What are the off-airfield rules for private helicopters in New Zealand?

I'm a Switzerland-based private helicopter pilot planning to spend some time in NZ. I'm wondering what are the rules there regarding off-airfield landing. Is it possible at all? Is the land owner ...
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How do helicopters avoid colliding?

When helicopters fly over a city, how do they avoid colliding with each other? For example, after a shooting or accident, both police and news helicopters could head to the same spot.
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Why do helicopter rotors have constant section and angle of attack?

As I understand it helicopter rotor blades keep a constant aerofoil section along their length, and are not twisted. Other rotating aerodynamic devices such as propellors, turbofan fans and wind ...
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What happens when all electrical systems in a helicopter fail?

I was thinking of asking this question at Worldbuilding, because it is for a book I am writing, but I hope this site will fit better. You can migrate this question if you find Worldbuilding more ...
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What is the total lift equation of a helicopter with 3 Flettner rotors?

I'm doing research regarding the possiblity of using Flettner rotors on helicopters. I would like to derive the total lift equation for a helicopter that consist of 3 Flettner rotors. Given that: ...
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Can I land a helicopter by controlling only power, not angle of attack?

With full RPM on my rotor system, can I land my helicopter using only the throttle? That is, by just reducing power rather than reducing the blades' angle of attack?
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Can a helicopter fly without a tail rotor? [duplicate]

Just wondering if a helicopter can fly without a tail rotor?
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What range or variation should we expect from gyroscope in a helicopter?

I need to measure the angular variation of a helicopter. Hence, I am looking for a 3-axis gyroscope? However, what kind of specification the gyroscope should have, like sample rate etc? Therefore, I ...
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198 views

What is the range of amplitude of vibration in a helicopter?

Vibration in helicopter can be caused by many different reasons. I am interested to know what is the range of amplitude of vibration? I am interested to know how amplitude varies with frequency of ...
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Why weren't the rotor tips of the Djinn directly fed from the turbine's exhaust?

The Sud-Ouest Djinn seems to be pretty much the only tip-jet helicopter to have any sort of commercial success. It used a turbine to drive a compressor, which itself fed slightly warm air to pipes in ...
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Are there helicopters with vertically mounted turbines?

On the helicopter representation in this answer, the turbine is horizontal, with gear required to drive the vertical-axis propeller. Are there helicopters where the turbine is vertical and directly ...
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How does a helicopter hover?

Technically, unless a helicopter's centre of gravity and centre of lift (centre of the rotor) are in perfect alignment, it would generate a pitching moment which would make it unstable. So, how does ...
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Why does AH-64 Apache have its radar over its rotors? [duplicate]

The targeting radar is above the rotor assembly ! But why ?
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What are the airflow patterns of a helicopter when operating in ground effect?

When operating in the air cushion region of approximately 8 inches and below to the ground what pattern does the downward flow of air flow?
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What is the range of frequencies of vibration in a helicopter due to the main rotor alone?

Vibration in helicopter can be caused by many different reasons. I am interested to know what is the range of frequencies of vibration due to the main rotor alone? I understand that it would depend ...
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Do pilots land a helicopter sideways for improved visibility of the landing area?

When flying helicopters in the PC-based game Arma 3 (not a flight simulator), some of the cockpit have a large instrument panel directly in front of the pilot, obscuring the view of the ground ahead ...
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What approvals do I need for a helicopter landing?

I have a horrible conflict; my sons are graduating on the same day at about the same time in different states. One in East Greenbush NY the other in Beverly MA. I am interested in hiring a ...
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Could a helicopter perform a forward inversion (front flip)?

This is inspired by a previous question What would happen if I bank a helicopter then pull hard on the cyclic? I've seen some pretty radical videos of piloting by Chuck Aaron, but I've not seen a ...
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Are fully electric helicopters suitable for military operations?

I read this question about diesel-electric (DE) helicopters, which sparked the following question: Are fully electric helicopters suitable for military operations? They are more silent, and electric ...
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How does a student pilot learn the process of pre-flighting a Robinson R22?

I've watched a few youtube videos on pre-flighting a Robinson R22 helicopter, and I'm always impressed by the way the pilot methodically does the external checks and the internal pre-start, start-up ...
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How can a helicopter show up at 29000ft, 547kts at Flightradar24?

Today I observed a strange flight on Flightradar24, a helicopter departing HAM and traveling at altitudes up to 29000ft and speeds up to 547kts which seems to be way beyond the specifications of a ...
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How does the rotor blade material affect aircraft performance?

Helicopter rotor blades in newer helicopter designs are made from composite materials. This results in improved performance. Is this simply because they are lighter or is there another reason behind ...
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What type of helicopter is shown in Star Wars The Last Jedi featurette?

There is a nice featurette about the new Star Wars movie The Last Jedi. One shot (1:32) shows a helicopter in the background. What is it?
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How can I calculate the thrust of a fan given the diameter of the blade?

How do I calculate the thrust of a multicopter fan blade from its diameter? I am searching for a multicopter blade that can provide a thrust of 15 - 20N. Being someone who doesn't have any ...
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What is the typcial descent rate of a helicopter?

I'm not a pilot, just asking out of curiosity. What is the typical descent rate for a helicopter when landing? I found the answer of 300 feet per minute on the web, but I want to confirm this. If this ...
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Do helicopter rotor blades speed up and down during the rotation?

Does the inertia force change the angular velocity due to increase-decrease in the radius when the blade travels up? Does this cause an excessive bending moment?
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Do intermeshing rotor helicopters have a swasplate? If no, then how do cyclic and collective controls work?

Looking at the Kaman K-Max and H-43 Huskie, it looks like they rely entirely on rotor flaps. How are they controlled?
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How to keep a helicopter steady when close to the ground?

I understand the ground effect and the air cushion of approximately 3-6 inches when the helicopter is close to the ground. With that in mind, my questions are: Why does the helicopter become ...
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Is a clearance needed to depart a helipad in class B airspace?

I have noticed statements like the following on sectionals: This would seem to suggest that a clearance is needed to "depart" any helipad, even if you are staying under the wedding cake. Is that true?...
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Are there any problems opening a helipad close to an airport?

I am looking at the possibility of installing a helipad at my house which is within 1.5 miles of a Class D airport. The location is not in the approach to any of the runways, however. I am not a ...
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Do helicopters have automatic tail rotor compensation for anti-spin?

Helicopter pilots need to push on the pedals constantly to compensate for the main rotor torque, so that the helicopter does not start an unintended spin. But it would be annoying to indefinetly put ...
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Why do helicopters not roll over when flying forwards?

Related to this answer: with velocities so different at forward going and rearward going blade, why does the helicopter not roll over? The higher airspeed at the forward going blade should cause more ...
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Could a quadrotor use a main gas powered rotor with small electric rotors for attitude control?

Here is my idea of heavy lifting quadcopter. (Although it is not a quad copter anymore because of the center rotor) Have a big coaxial fixed pitch rotor at the center. The rotor is gasoline fueled. ...
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How do I compute thrust of a rotor disk and the necessary power to drive it??

as it seems, this question has been asked a few times here so please forgive me for asking again. If I have 50 BHP shaft power available at 5000 RPM and 106 N.m torque, then can I convert it to 200 ...
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How do active blades work on helicopters?

Can someone throw some light on 'active blades' as used in helicopters? I'm mostly interested in the use of piezoelectric material and actuators. How are the actuators able to sense the change of ...
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Do helicopters use more fuel when hovering?

This answer says A helicopter uses a LOT more fuel hovering than it does in forward flight. Is this correct? Why?
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Does a helicopter's boundary layer have different properties that are caused by the rotation? How does this affect stability of the helicopter?

I recently got introduced to the boundary layer theory of an airfoil, and I couldn't stop thinking of how it would be affected by rotation as well as the varying speeds of rotation.

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