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
107 views

What is the name of the unequal lift distribution across a helicopter rotor blade?

A helicopter rotor blade will generate more lift at the fast-moving tip than at the slow-moving root, unless it is twisted or tapered. Wikipedia calls this "asymmetry of lift", however I ...
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Why do smaller RC helicopters have visible twist in their rotors, and slightly bigger ones do not?

Smaller, cheap, RC helicopters generally have very pronounced twist in their blades, and also vary their chord - slightly larger, slightly more expensive RC helicopters have no visible twist or chord ...
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Is any of the Ingenuity helicopter's special design attributes helpful in improving helicopters flying in Earth's atmosphere?

According to Wikipedia, the Ingenuity helicopter is an astonishing piece of engineering having some attributes beyond the equivalent of the classical helicopters: The lower gravity of Mars (..) only ...
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What are the design principles that result in thin, long-span, narrow chord main rotor blades?

Regardless of the overall design configuration of a helicopter, it appears that helicopters have main rotor blades that all fall into the class of ultrahigh aspect-ratio wing design: that is, you ...
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107 views

What impact had the removal of the horizontal stabilizer end plate on the H135?

In the last update of the H135 helicopter line (EC135 T2 -> EC135 T3) Airbus removed the end plate at the horizontal stabilizer on the tail. I heard from some some people that they had aerodynamic ...
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Why would "hot gases" from a volcano damage helicopter rotors?

In the ongoing story about someone trying to rescue dogs from a volcano with a drone, I keep seeing variations of this claim repeated: Spanish authorities have dropped food down to the dogs with ...
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200 views

How do ultralight helicopter like mosquito manage to fly without a swash plate?

It doesn't seem to have a swash plate. Does pilot shift his weight like in a hang glider?
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1answer
247 views

How a takeoff decision point(TDP) for vertical takeoff vehicle is defined?

For a vertical takeoff vehicle like a helicopter, how the takeoff decision point is defined or computed? Look at the snapshot below, seems the height of TDP is related to the rejected takeoff distance?...
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Hover Performance in Helicopter dynamics

What do we mean by “good” hover performance in Rotor dynamics? If I want to analyse hover performance of a helicopter, then What parameters should I monitor?
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Can I fly part 91 a German certified and registered helicopter in the USA? [duplicate]

Can I fly part 91 a German certified and registered helicopter in the USA?
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Private Helicopter landing on Private land [duplicate]

Can I land a helicopter on my property in Palm Beach County? The property is 6 acres along the Loxahatchee River in Unincorporated Jupiter / Palm Beach County. What is the pertinent FAA or County ...
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Do any RAF helicopters have skids instead of wheels?

Are there any current, or Cold War-era, Royal Air Force helicopters fitted with skids as standard? I seem to recall hearing, when I served, that RAF helicopters only ever had wheels, whereas skids ...
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How do Private Helipads Work regarding Airspace?

For executive helipads or helipads run by a private company but not within airport airspace (tourism or shuttle helicopters for example), how do they work from a regulations standpoint? Do pilots just ...
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Why there is a descent segment during helicopter takeoff?

I am reading some regulations about vertical takeoff vehicles like a helicopter and there is some takeoff path is defined as below, and I am curious why there is a descent segment in its takeoff path? ...
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Can you identify this helicopter?

I saw this helicopter in Hungary. It might be an Airbus H225M, but I'm not sure. Can you confirm or identify it correctly? Unknown helicopter seen in Hungary What is the red spot on the side, under ...
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How can I calculate the torque of a helicopter's main rotor?

Might be a simple answer that I am overlooking but... I am attempting to determine the torque of a helicopter main rotor so that I can design an anti-torque rotor to counteract it. Anyone aware of of ...
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What’s the difference between the MD 500E and MD 530F helicopters?

What’s the difference between the MD 500E and MD 530F helicopters? They look almost the same outwardly, and I can’t tell the difference. I would assume parts of the 530F are more modern, but what ...
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Can any helicopters use negative collective to descend rapidly?

On a helicopter, the collective is used to adjust the attack angle of all the main-rotor blades in the same direction by the same amount, causing the amount of lift generated to increase or decrease ...
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To operate on Mars, how large would a manned helicopter's rotor blades have to be?

I asked this question at https://space.stackexchange.com/questions/53931/manned-helicopter-on-mars but there was disagreement over whether a (now deleted) answer was correct, so I've re-asked it here. ...
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What are those ball-shaped things on some helicopter blades?

I saw these things swinging in a video of a rotor from the blade point of view. I don't know what are they for but I am quite curious. And why some helicopters have it and some don't? Source: alamy ...
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What are the stability criteria of helicopters?

In airplanes, longitudinal stability is maintained if centre of lift lies aft of center of gravity. Like in the airplane shown in the figure below, do helicopters also have stability criteria? They ...
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1answer
218 views

Why do helicopters not flip when using cyclic pitch control to move?

Let's say a helicopter wants to move forward. To do so, cyclic pitch is applied to the blades 90 degrees off which applies a torque on the blades to tilt the craft forward. Once the helicopter is ...
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681 views

Why paint a British roundel on a non-British Lynx?

In recent years, some of the Westland Lynx helicopters of the Portuguese Navy have undergone some form of mid-life update (MLU) in order to have their engines and avionics upgraded. Also, allegedly, a ...
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Could the Mars helicopter Ingenuity have been test-flown outdoors at JPL just for the heck of it? (not that they would)

The Ingenuity helicopter that has flown on Mars is designed for roughly 0.01 bar pressure and a colder atmosphere made of mostly CO2. See links (including video) in this answer to What JPL laboratory ...
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Can we bring a rotorcraft like Ingenuity to an altitude of the same pressure as the one on Mars?

At Perseverance's and Ingenuity's location the atmospheric pressure is about 750 Pa (0.11 psi). On Earth, we find that pressure about 110,000 ft high. If we built a copy of Ingenuity, could we bring ...
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What control inputs are required to perform a "turning-while-in-flight" maneuver in a helicopter?

My question is relatively simple and has to do with the required control inputs to perform a simple turning maneuver over a large area. Suppose a helicopter is traveling in forward flight, straight ...
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How does a hot tip-jet supply fuel to its engines?

Some tip-jets move their rotors by running jet engines on each end of the rotor. Obviously there must be some ways to supply fuel to those engines through a rotating body. How is this accomplished?
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How does helicopter mustering make financial sense?

I've seen and know that helicopter mustering is popular in Australia and what I do not understand is why this works from a business perspective. Helicopters are expensive and dangerous machines so it ...
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What are the spikes on Ingenuity's blades?

I am puzzled by the spikes on Ingenuity's blades (marked by a red box in the image below). What is their function ? Are these special to Ingenuity? Why don't they collide during high RPM? Don't they ...
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What options are there in Canada for treatment of severe depression and anxiety for pilots?

I'm a Canadian commercial helicopter pilot, and I've been struggling with severe depression and anxiety issues since childhood. I'm very good at faking it, well, good enough that I've been able to lie ...
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Helicopter mast bumping in low g condition

The helicopter shown in the concrete pouring video seems to taking off from a hill and descending down in a way which can be classified as low G with low rotor loading. Although, the helicopter is ...
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Why does the UH60 have a titled tail rotor? [duplicate]

I've been looking at helicopter design recently, particularly UK military helicopters. I've noticed that most tail rotors are parallel/flush with the tail of the helicopter in most designs. When ...
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Does anyone know if RHP (assumed to be rotor horse power) is equivalent to SHP (shaft HP)?

I was recently reading a NAVAER aircraft characteristics summary of the proposed XHCH-1 helicopter of 1951. In the engine section it gives the engine power in "Rhp" and later in a 1956 ...
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How does gross weight affect helicopter autorotation?

The factors which affect helicopter autorotational aerodynamics include airspeed, gross weight, rotor RPM, and density altitude. The effects of these factors can be examined during a few phases of the ...
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Why do GPS Copter Approaches require a slower final approach speed than conventional Copter Approaches?

AIM 10-1-2 says helicopter instrument approaches are designed with a maximum speed of 90 KIAS. However, it specifically exempts the final segment on GPS helicopter approaches, saying the maximum speed ...
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How much is a swashplate system more energy efficient than a fixed blade system for the same load

When reading about the lifting capacity of swashplates (as found in helicopters) vs fixed blade systems (as found in e.g. DJI drones), I read a lot of comments about the fact that the bigger rotors of ...
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142 views

Is there a way for the helicopter rotor to get its power half by wind, half by engine?

Imagine a gyroplane, if something happen mid-flight (when the plane is basically an autogyro and the engine provides no power to the helicopter rotor) and just the wind generated by forward flight can ...
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The cost of maintaining VTOL devices

Which device for VTOL flight costs the most to maintain for a given number of flight hours? A tiltwing mechanism? A 2D thrust-vectoring nozzle (vectoring only between VTOL position and cruise ...
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What effect do urban wind conditions have on operating tiltwing aircraft and gyrocopters?

From this research it seems there are quite a lot of strong wind in suburb residential area and around high-rise buildings. High-rise buildings would also create wind tunnel effect and eddy winds. ...
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What descent rate would be a "hard" landing in a Huey or similar helicopter with skids?

I would like to know what vertical descent rate a Huey or other helicopter with skids can land safely at. What would be considered a "hard" landing that would require air frame inspection? ...
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1answer
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Can you mount a net between 2 helicopters for search and rescue?

During situations where multiple people are in danger, I am wondering whether you can have a huge net mounted between 2 helicopters on a device with 2 arms on each helicopter, and when need to rescue, ...
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Do hospitals have radio communications with air ambulances?

Do hospitals have a sort of ATC for incoming medical helicopters? What kind of procedures do helis follow when landing at a hospital to make sure they are cleared to land/takeoff, etc?
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Should the helicopter be washed after any sea mission?

I was seeing this image: The caption of this image says (source): Here a Belgian NH90 NFH returning after a flight over sea. The helicopter is washed by the fire brigade to remove the salt water... ...
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What is this helicopter seen in the Falcon Crest TV series?

My next to last "Falcon Crest" related question for the database I'm programming: Does anyone recognize the make and model of this helicopter from episodes # 160 <7.05> (first screen ...
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Is it possible to stall a stationary helicopter through excessive collective input?

I understand that helicopters can suffer from "retreating blade stall" where the retreating side of the rotor has low airspeed and stalls in a typical way that airplane wings stall. This ...
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On the Ka-50 coaxial helicopter, why does the bottom rotor flap up on the right side instead of in front during forward flight?

In the game DCS World flying the Ka-50, when flying forward at high speeds, the bottom rotor will flap up on the right side of the helicopter (also note that the top rotor is flapping up on the left, ...
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Is axial dynamics important for the helicopter equations of motion?

While analyzing helicopter performance, why do we always ignore the axial dynamics from the equations of motion?
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Why do new helicopters have rotor blades with swept tip? [duplicate]

Many new helicopers have rotor blades with swept tip. Why? Acoustic? e.g.
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126 views

How to do blade element momentum theory analysis for different geometries of airfoil, e.g. NACA airfoils?

I want to analyse NACA airfoils using BEMT. I have only yet done it for basic symmetric airfoils. I would like to know what all assumptions remain same in NACA airfoil analysis and to what degree it ...
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Can a helicopter be stable without moving the control inputs?

I have only flown helicopters in a flight simulator (X-Plane) and I have found it exceedingly hard to fly in certain regimes (especially hovering and close to hovering) because it seems like there is ...

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