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
105 views

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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1answer
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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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1answer
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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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1answer
63 views

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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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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559 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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128 views

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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134 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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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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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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132 views

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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230 views

Why do the intake of some helicopters have a bump body?

Not all but the intake of many helicopters have a bump body. Why? e.g.
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What is this hole above the intake of engines of Mil helicopters?

Almost all the helicopters designed and manufactured by Mil have a hole above the intake. e.g. What is it for? APU? Other helicopters made by this company:
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1answer
317 views

Why was the Sikorsky Firefly built but never flown?

Sikorsky Firefly is the electric helicopter that has been built but never flown. How do such histories happen? If the design looked so unsafe that there was not enough courage of trying, why this was ...
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Is it possible to build an ultralight helicopter with electric motors as its main engines? [closed]

So I'm trying to make an electric ultralight helicopter, but I'm not sure if it will work. Is it possible to use electric motors to make it fly? If yes, I'm going to need some advice. I'm expecting ...
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1answer
110 views

Per the AIM, Helicopter pilots may fly non-copter approaches at half the published visibility. Where is that in the FAR?

In AIM 10-1-2 Helicopter Instrument Approaches, paragraph a1 says the visibility reduction rule comes from 14 CFR Section 97.3. From what I can see, that section is just definitions. What is the AIM ...
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158 views

Normal tendency of helicopter with counter clockwise rotating main rotors (top view) with force trim off and leaving controls?

Is it normal for the helicopter with CCW rotating main rotors to pitch down and roll left in forward flight, when force trim is turned off and hands off the cyclic? Moreover, when we put the ...
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1answer
347 views

What is rotor damping and how does it affect helicopter stability?

What do we mean by rotor damping (in terms of helicopters)? How is it affected by air density? How does helicopter stability depend on rotor damping?
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Sub-ideal Autorotation in Rotorcraft

I have another AuRo question for you. When a Helicopter autorotates (ideally) it is in the turbulent wake state and there is virtually no flow through the rotor disk (figure of Leishman attached). Now,...
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572 views

What is this helicopter type at a U.S. military base?

This helicopter is on a US military base, shown by Google Maps. I don't recognize the glass windows at the front top.
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Isn't it dangerous for a soldier to sit on the outside of a flying helicopter?

AH-64 during an extraction exercise at Camp Bondsteel, Kosovo in 2007 with a soldier on the avionics bay. I lit upon this image on Wikipedia. I see that the soldier is harnessed fastened to the ...
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1answer
222 views

Why did the pilot in this EC135 crash change the throttle setting after encountering wake turbulence?

I’m confused in this accident why the Eurocopter EC135 pilot decided to manipulate the throttle after encountering wake turbulence - I can’t think of a reason for this. Could someone please explain ...
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What forward airspeed produces maximum rate-of-climb in helicopters?

Lift in a helicopter increases with airspeed (from zero IAS up to some Vmax). But in contrast to fixed-wing aircraft a helicopter can generate lift at zero airspeed. Is there a formula for the ...
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What is the tail rotor rpm for the Sikorsky S58 helicopter?

I need to know the TR rpm for Sikorsky S58. I have tried searching for it and calculating it based on some assumptions I've made. I would like to know the true rpm value and not assume it since this ...
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What is the main and tail rotor speed (RPM) for a Sikorsky S52?

I need the RPMs for the main and tail rotor of a Sikorsky S52 for the research I am doing for my degree. I tried checking flight manuals and other websites, but I don't find concrete numbers, only ...
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Can the lift equation be used for the Ingenuity Mars Helicopter?

I am currently working on a basic simulation of the Mars Helicopter Ingenuity, and I am having trouble interpreting the outputs I am receiving from the lift equation. The equation reads as follows: L =...

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