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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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Why in helicopter autorotation phase the opposing torque is eliminated?

As you many know, according to Newton's 3rd law for every action there is an equal and opposite reaction, as the main rotor of a helicopter turns in one direction, the fuselage tends to rotate in ...
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Compressive strength of helicopter reject runway [closed]

What is the compressive strength (psi or N)
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1answer
204 views

Can you help me ID these two helicopters?

Hey folks! Desperate to find what these two helicopters are. Any help greatly appreciated!! A
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139 views

Why is the rotor system of an aircraft and the rotor system of a helicopter different? [closed]

Both aircraft with propeller(variable pitch) and helicopter rotor system can change pitch. Of course, for helicopter, there is not only collective pitch control but also cyclic control. The aircraft ...
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1answer
100 views

What happens if full collective pitch is suddenly commanded on most modern helicopters?

Related, but not the same: What happens when you apply full cyclic + collective? If the pilot suddenly applies full collective pitch on a turbine powered helicopter, will the engine stall? It seems ...
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1answer
186 views

Twin engine helicopters: is the throttle controlled separately for each engine or together?

There is usually a twist throttle on the collective for a single engine helicopter. On twin engine helicopters, does the twist throttle control it for both engines, or just for one?
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275 views

In what emergency situations would a pilot bail out of a helicopter?

The Hiller UH-12 POH actually mentions “Emergency Exit in Flight” as an emergency procedure. What emergencies would make the pilot do this and why don’t other helicopter POH’s mention this?
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1answer
38 views

Advance ratio formula for drone propeller in vertical climb

According to this wikipedia article. There are two expressions for advance ratio: For propellers: $$J = {V_\infty \over nD} \tag{1}$$ For helicopters: $$\mu = {V_\infty \over \Omega r} \tag{2}$$ We ...
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103 views

How does a circulation control helicopter work

This essay describes that this helicopter uses circulation control of the rotor for cyclic and collective control, but not how circulation control works. https://ntrs.nasa.gov/archive/nasa/casi.ntrs....
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Is autorotation possible in a tandem rotored helicopter?

I just wonder, whether a synchronized autorotation is possible in case of turbine failure (one or both gas turbine engines). All Gearboxes obviously must turn not to desynchronize -> lethal
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110 views

What happens when you apply full cyclic + collective?

Can a helicopter apply full cyclic and then full collective at the same time? Would'nt the blades on one side (opposite of the intended tilt direction) have already maxed their aoa, resulting in a net ...
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36 views

Will Thrust on Rotor (Main) increase with altitude?

Can some one please let me know,if the thrust required on the rotor head increases with the increase in altitude in an Helicopter or decreases with increase in Altitude?. Thanks in advance, Pawan
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Phoenix Area Helicopter ATC: What is “Hee-lah” (Gila?) One, and what is the 101 transition?

I've been listening to the Phoenix Tower LiveATC feed, and I hear references to "Hee-lah" (Gila?) One and the 101 transition with helicopters (see audio files below): Angel-Five TV-3 TV-15 Does ...
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Are there attempts at fly-by-wire servo flap controlled rotor?

Reading this question and then this document about servo flap controlled rotor I was wondering if there has been any attempt at building one fixed hub helicopter with twistable blades hosting at 75% ...
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2answers
176 views

Are helicopter searchlights fixed or movable?

Can the helicopter crew move the helicopter searchlights or are they always fixed at a specific location on the helicopter? They are used by rescue helicopters mostly but I am not sure if crew can ...
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1answer
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Does the commercial helicopter training in 61.129(c)(3)(i) require a CFII?

For the commercial ticket in a helicopter you need 5 hours of hood time. Can any CFI provide this training or does it require a CFII? 14 CFR 61.129(c)(3)(i): Five hours on the control and ...
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How is static droop achieved in mechanical governors

The Bendix power turbine governor in the Bell 206 is just simple flyweight arrangement which controls a pneumatic signal to the FCU. How is static droop achieved in this type of system?
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1answer
150 views

What do I need to get my pilot license? [closed]

I am thinking of getting my pilot license, I would love to fly a helicopter or a small plane, but I don't know where to start. What do I need to get a pilot's license? Things like: How much does it ...
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1answer
58 views

Does the HAL LCH have fly-by-wire?

Is Automatic Flight Control System (AFCS) the same as Fly-by-wire? If not what's the difference? India’s Hindustan Aeronautics Limited (HAL) has carried out the first flight of a Light Combat ...
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Wheel or skid? Which advantages does each one have when used as the landing gear system compared to the other one?

I would like to discuss this topic in depth, as I have not found a clear answer yet. Which are the advantages of using skids instead of wheels (or viceversa) for the following considerations?: -As ...
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Where can I find official information about a recent crash in Mexico?

I have heard about a helicopter crash involving an Agusta A 109 in Mexico, that seems to be causing some turmoil due to the deaths of a newly-elected governor and her husband. Is there any info about ...
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3answers
125 views

From which rating would it be easier to transition to an Osprey? Fixed-wing or rotary-wing?

If the future of flight was to be on aircraft that were a hybrid of fixed-wing and rotary-wing (for example the Osprey), assuming they had similar technical abilities and the same number of flight ...
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1answer
122 views

How can you calculate the vertical speed of an helicopter during auto-rotation?

How can I calculate velocity of a helicopter when it falls with autorotation when the engine fails, given all the parameters such as mass , height , wing size etc.
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774 views

Black aircraft at night no lights with helicopter following - is this a stealth aircraft? [closed]

I have just seen a dark long aircraft fly over my car followed by a long helicopter. I am not an expert at this but it is 8pm, i am on a hill with a few houses, there is a little street light on the ...
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1answer
214 views

Do Military Turboshaft engines have a distinctly different sound from Civilian ones?

I live in India, and near an airbase so there are a moderate amount of helicopters flying overhead. My friend claims that he can distinguish between a civilian helicopter or a military one based on ...
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How is the inflow velocity distributed of a tilted and trimmed rotor in hover?

I'm wondering of how the inflow velocities per blade look during one revolution of a real-life helicopter in hover (no inflow velocity into the rotor plane) with a tilted rotor plane about 20 deg. Is ...
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1answer
242 views

Why are autorotations to a full touchdown not practised any more?

What is the history behind a decision to discontinue helicopter autorotations all the way to ground contact? In the 1960s, our Army flight program directed full ground contact for any and all ...
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1answer
144 views

How do typical ground marshaling signals differ for helicopters?

There are common hand signals used by ground crew for fixed wing aircraft like 'taxi forward', 'spin up engine #1', 'turn right', or 'stop', for example: At most airports, general helicopter traffic ...
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1answer
513 views

What is the name of this vintage helicopter trainer?

I am curious about the tiny training helicopters that can be seen from the second 0:10 in this vintage video about the Cuatro Vientos helicopter school, near Madrid. ...
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198 views

What is the heaviest payload ever carried by a single main rotor helicopter?

What is the most heavy payload ever carried by a single main rotor Helicopter?
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1answer
177 views

Would increasing rotor disc diameter increase efficiency in a helicopter by reducing disc loading?

Despite the obvious drawbacks of a larger rotor diameter would the reduced disc loading increase efficiency during hover and forward flight?
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In an articulated hub rotor craft, what could cause the blade to flap negatively?

For example in forward flight what could cause the blade to flap lower than parallel to the CF at the front of the aircraft ?
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2answers
210 views

Benefit of a deswirl vane for a turboshaft helicopter engine

I am trying to understand the benefit of deswirl vanes on a turboshaft helicopter engine. For these type of engines, the kinetic energy of the exhaust stream is essentially wasted energy. Also, ...
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61 views

Where to find information on weight breakdown for helicopters?

I would be interested in information on the weight breakdown for the different components of a helicopter. How much of the maximum gross weight is related to the airframe, engine, gearboxes, ...
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1answer
309 views

What are the fins near the tail of a helicopter called?

My young sons are very enthusiastic about helicopters and I am repeatedly asked to name parts of their model aircraft. I would like to do so correctly, but my research has not always given definitive ...
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Why is this type of rotor hub so rare…?

I wonder why is this type of helicopter rotor hub so rare... It is a very simple construction, having no flap or lead-lag hinges. A universal, constant-speed joint leaves the rotor free to find his ...
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1answer
165 views

What is the rod attached to the top of the Bell UH-1N's rotors?

So, I was looking at an image of a Bell UH-1N, and noticed that the top if the rotor has a little stick or rod What is this rod for? I also see this rod on a RC helicopter.
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368 views

Why are helicopters less efficient than planes?

At higher speeds, advancing helicopter blades will operate at velocities approaching mach 1, reducing efficiency. But what about lower speeds? A helicopter is basically a wingless plane with a giant ...
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1answer
406 views

What factors govern the placement of a helicopter's tail rotor (left or right)?

An image search for 'helicopter' indicates that there isn't a consensus on whether to place the tail rotor to the left or the right of the tail boom, although I'm believe there may be a bias for left. ...
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1answer
232 views

How much thrust could a 400 mm EDF produce?

there's a 195mm EDF from Schübeler that produces 25 kg of thrust at a peak power consumption of 15 kW: https://www.schuebeler-jets.de/de/produkte/hst Now, my question is: How much thrust could you ...
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312 views

Who controls airspace and time in my area on helicopters?

I live in Newport Beach which is located in Orange County, California. I recently moved to an area where helicopters fly once in a while at 2-3 am above my house. Since I live on a hill, the sound is ...
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767 views

How to become a helicopter pilot? [closed]

I once had a dream of becoming a helicopter pilot. Then life happened: married young, kids, school, career, etc. I'm working in a good career while finishing a Ph.D. in engineering. But still, I find ...
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1answer
176 views

Is ATC clearance or permission required to fly helicopter routes and transitions in the Los Angeles area?

Skyvector has Los Angeles helicopter charts here and here. Are pilots required to obtain ATC clearance or permission to fly helicopter routes and transitions?
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1answer
229 views

Do military tactical transport flights provide seatbelts for all occupants?

In several movies I have watched recently, the temporary bench style seats of tactical transport aircraft such as the C-130 do not show seat-belts. I would not be surprised that some instances of seat ...
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Are there any reported cases of noise from helicopters causing damage to property?

In the Netherlands, three cases have been reported of Chinook helicopters' rattle noise (low frequency sound) damaging solar panels. The Dutch defense ministry recognises this problem and the lawyer ...
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How does the number of blades affect the static thrust of a propeller? [duplicate]

Since I couldn‘t find an answer to this question I thought I‘d ask you guys! By which factor does the thrust of a propeller increase if I double the number of blades, the motor being powerful enough ...
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2answers
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How do CH-47 pilots lower the tail during a pinnacle landing?

(thedrive.com) Given the recent rescue of a climber on Mt. Hood by a Chinook, how are the pilots able to lower the tail in this situation? Is this just the natural angle during a hover, or are there ...
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1answer
227 views

Why have helicopter top speeds not increased much over time?

With advancements in technology why there isn't much increment in helicopter top speeds from what they were in the 1980s? We have newer designs like the Eurocopter X3 which is a hybrid, but the speed ...
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1answer
751 views

What‘s the thrust of two stacked propellers?

Let‘s say that you have two identical propellers and each is powered by their own motor and together they produce a thrust of 1 kN. How does the thrust change if instead of operating them side on side ...
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391 views

Why don't helicopter change altitude based on variable rotor RPM as opposed to the collective? [duplicate]

AFAIU, helicopter rotors turn at constant RPM and changes lift based on the collective. Why no have a variable RPM heli?