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
80 views

Is an additional rotor useful on a coaxial rotor configuration?

I can understand coaxial rotors cancelling the need for a tail rotor, however, I am curious as to if the second rotor is needed to actually maintain the same pitch or could be just used to offload the ...
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2answers
256 views

How much force does a helicopter's tail rotor counteract?

How much force does a helicopters tail rotor counteract? What are the formulas for determining this? How much rotational torque is produced by spinning the blades?
4
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1answer
111 views

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 ...
4
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3answers
459 views

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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1answer
140 views

Are Helicopters allowed near busy airports? [closed]

Are Helicopters allowed near busy airports or any airports at all and if not why not
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1answer
7k views

Do the Mt. Everest rescue helicopters have modified engines to operate at high altitudes?

There are so many climbers on Mt. Everest today that there is now a helicopter rescue service there. They operate rescue up to 21,000 + ft. Because this is essentially stationary service it seems that ...
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1answer
99 views

From Aerodynamic view, what is the advantage/disadvantage of the Akagi Kaman K-Max Helicopter?

Here is a video showing the helicopter, the rotors are perfectly synchronized. As there are not many such design helicopter, then my question are, is any aerodynamic weakness? What is its advantage/...
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1answer
249 views

Can helicopters have engines running while rotor blade stays stationary?

So, I was skiing sometime ago, and unfortunately, another skier got injured. So, a heli was flown up to get the injured skier. The rotor blades were stationary, but I still heard some sort of engine ...
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0answers
79 views

What's the difference between hover power and maximum continuous power?

What's the difference between hover power and maximum continuous power? Is a pilot clear to fly when its hover power is more than maximum continuous power calculated by table?
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1answer
63 views

How are performance classes for helicopters/rotorcraft defined?

In helicopter/rotocraft literature, such as ICAO Annex 14 Volume II (how to design heliports), there's constant references to performance classes. How can I tell what performance class a helicopter is ...
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1answer
157 views

Which Inlet Barrier Filter (IBF) is used in Airbus H145?

Inlet barrier filter (IBF) is an optional equipment in H145 / MBB-BK 117 / EC145 helicopters, which company Inlet Barrier Filters are used on them Donaldson, Aerometals etc.. The H145 Helionix / ...
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1answer
168 views

Do ducted fans have a future in forward flight aircraft? Can they be made more efficient than open rotors?

I'm fascinated by how ducted fans have the ability to be more efficient than open propellers of equal diameter in vertical flight through the use of tight tolerances, lightweight duct material, proper ...
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0answers
101 views

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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1answer
163 views

Is the Mil Mi-2 still in production?

I have read conflicting reports that this Russian helicopter is out of production, yet others say otherwise. Could anyone confirm?
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4answers
6k views

Is it allowed to let the engine of an aircraft idle without a pilot in the plane. (For both helicopters and aeroplanes)

Is it allowed to let the engine of an aircraft idle without a pilot in the plane. (For both helicopters and aircr). Would there be a difference between a C172 and a 737?
6
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2answers
197 views

In a helicopter does forward flight produce a rolling moment?

In forward flight the advancing blade will produce more lift than the retreating blade. It seems this would produce a rolling moment. If so, does the pilot have to move the cyclic to compensate for ...
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3answers
299 views

Why the pitch control of helicopter is named Collective Control? And why does it located at the left side of the pilot seat?

This is probably a very trivial for some of you. But sometimes a name not representing the function become a question, just like this Collective Control, which its function is to pitch up the blade ...
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0answers
76 views

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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2answers
154 views

How does the noise of a 2-to-4-seat helicopter compare with that of a similarly-sized fixed-wing aircraft?

We are considering allowing helicopters on our private airstrip (2600 ft strip). Noise on the ground (and approach) is the concern from the community. Does anyone know approximate dB ratings for a ...
4
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2answers
119 views

How is lift transferred from rotor to chassis (or weight, the other way around)?

I am trying to find out how a helicopter rotor's lift is transferred to the chassis. Equivalently, how is the weight of the helicopter transferred to the rotor blades? While looking for this online, ...
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0answers
233 views

Why are Western helicopters more expensive, yet smaller in size, but Russian helicopters are way less expensive, and larger in size?

So, I was looking around for prices of the Bell 412, Blackhawk and Mil Mi 8/17 prices, and the Bell 412, despite being a lot smaller than the Mi8, was US$2mil more than the Mi8.
5
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1answer
118 views

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, ...
5
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1answer
108 views

Is a retreating blade stall a problem that can be overcome on dual-rotor helicopters?

I know that regular main+tail rotor helicopters stall at higher speeds as the relative airspeed of the retreating blade approaches zero. I'm curious if coaxial or intermeshing dual-rotor helicopters ...
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2answers
7k views

What is the loud noise of a helicopter when the rotors are not yet moving?

What is the loud noise when a helicopter is ready to start flying, but the rotor is not yet rotating? For example at Trump's "chopper talk", when he is intercepted by reporters on the way to Marine ...
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1answer
236 views

Does a turboshaft's exhaust provide any thrust?

See the below figure. Does the exhaust gas coming out through the nozzle have any force? If the exhaust gas has force then how is it controlled by the helicopter?
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139 views

Closest RL Match for Fictional Helicopter Design?

Erm, not sure if this is the best place to post this but it seems like the best place to get a pretty straight answer thus far in my search. So yeah, this helicopter is obviously from a cartoon – but ...
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3answers
342 views

Why do some helicopters have such complicated flight control mixers?

Image source Some helicopters have a very complicated set-up that mixes flight control inputs to many or all of the swashplate actuators, like in the picture above for the S-76. Why are all the ...
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1answer
221 views

On coaxial helicopters, how exactly does the yaw mechanism work?

This question asks how coaxial helicopters achieve yaw. The accepted answer correctly states that this is done by increasing pitch on one rotor while decreasing pitch on the other rotor, which leaves ...
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1answer
150 views

How to convert an EASA CPL(H) to FAA CPL(H)?

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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5answers
8k views

Why is the UH-60 tail rotor canted?

The Sikorsky UH-60 (S-70) has a tail rotor that is canted 20 degrees upwards. Why is that? Picture source
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1answer
116 views

Could helicopters use a rear wing to get more lift from the rotor vortex?

Could a wing be added to the rear of a helicopter to catch the vortex from a helicopter for more lift? How would that affect transitional lift while in forward flight? Source: https://www.danubewings....
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1answer
186 views

Could a rotor head wing be plausible?

Could a helicopter support a detachable wing with no controls on top of the rotor head in place of a radar dome? Could the rotor head be made to support more weight? Would it be more fuel efficient at ...
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3answers
222 views

How Helicopters Change Attitude (Gyroscopic Precession or Thrust Vector Tilt)

I am trying to determine how helicopters pitch and roll (i.e. change attitude). I have heard two explanations. 1) Pitch/roll change is achieved by tilting the tip path plane and therefor tilting the ...
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3answers
185 views

Do helicopters need a class B entry clearance when air / hover taxiing?

You're a helicopter pilot at a class B airport. You'd like to taxi to another parking spot. The ground controller could either give you a hover taxi clearance or an air taxi clearance, depending on ...
5
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1answer
354 views

Are there any helicopter blades that fold in the middle?

Let's assume that, for some arbitrary reason, helicopter blades are too long for transport or storage. Folding them at the rotor hub, as is done with conventional folding helicopter blades, would ...
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3answers
704 views

Would a Chinook helicopter fly better with contra-rotating along with counter-rotating propellers?

Would a Chinook perform better or have any advantage with dual contra-rotating propellers over a Chinook with just normal counter-rotating propellers?
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1answer
129 views

What is the inner dashed line on this helicopter chart?

Inside the delta for KSGR is another blue dashed circle. What is this?
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1answer
940 views

Why do some helicopters have wheels instead of skids?

I have noticed that Black Hawk helicopters have tires, but I have not seen one take off like a plane. When would a helicopter need to use a running take off or landing? When is it determined ...
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1answer
138 views

What is the definition of “airport boundary”?

While flying in to KBTR in a helicopter, I called tower and stated “10 west, landing south ramp with information Mike”. They responded “proceed to the airport boundary”. When I was closer I got the ...
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1answer
89 views

Does shutting down the engine affect the rate of rotation during autorotation?

If a helicopter's tail rotor shears off while flying then the helicopter's fuselage will start rotating in the direction opposite to the main rotor's rotation direction. During autorotation, if I ...
6
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1answer
202 views

Helicopter tail horizontal stabilizer angle

In helicopters what factors decide the horizontal tail stabilizer angle? By angle I mean that in some helicopter they are -6 deg relative to tail boom while in some -3 deg. These angle were remain ...
2
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1answer
414 views

Could this helicopter's body be a flying wing?

This question: Could a helicopter fly like a plane this way? asks if a helicopter can turn sideways using additional wings to tip forward to allow the rotor blades to act as a propeller. The tail-...
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5answers
544 views

Could a helicopter fly like a plane this way?

Could a wing be added to a helicopter to allow the entire craft to tip 90 degrees forward allowing it to fly faster like a plane using a fixed wing and leaning into the wing for lift? I understand ...
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3answers
985 views

How does this RC helicopter keep itself upright?

I have this (cheap, beginner-level) RC helicopter: It has 3 controls: one for climbing and descending (collective throttle), one for yawing (differential throttle), and one for pitching (the tail ...
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0answers
157 views

How low can a helicopter fly above a residence if the helicopter is an air ambulance landing?

Two medical helicopters just located directly across the street from my home. Their landing pad is less than 500 feet from my property. When they land, the helicopter is only 100 to 200 feet above ...
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4answers
10k views

Can a helicopter mask itself from radar?

I have read somewhere that if a helicopter is traveling under 100 km/h and below 5 meters AGL then most radars will ignore it. From what I understand of this process, the radars can pick up things ...
2
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3answers
157 views

How is rotor pitch best managed in helicopter autorotation?

In a recent stack exchange question writers were comparing autorotation to an aircraft engine out rotation prop when something rather startling occured to me: In an engine out the airflow will ...
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2answers
232 views

What are the differences between PC and professional simulators?

It looks like there are a differences between the models used in the schools and the simulators you can run in a PC . I'm curious to know the differences and price of both type of simulators. I ...
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3answers
312 views

Why does an increase of airspeed result in a decrease of angle of attack?

In Chapter 02: Aerodynamics of Flight of Helicopter Flying Handbook, on page 10, it says: Induced flow velocity is increased, resulting in a decrease in AOA. I don't understand how airspeed can ...
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3answers
232 views

How useful is skyscrapers and high buildings lighting to get a visual reference for pilots by night? (not obstruction lights, just general lights)

I would like to know how useful is skyscrapers and high buildings lighting to get a visual reference for helicopter and small planes pilots by night in cities like New York. This is different from ...