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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79
votes
18answers
158k views

Why haven't quadcopters been scaled up yet?

Why are quadcopters not flown by human pilots yet? Wouldn't they be more stable and easier to control than helicopters?
27
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2answers
27k views

How can a helicopter be designed without a tail rotor?

How will the main rotor torque be balanced if a helicopter doesn't have a tail rotor?
13
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4answers
2k views

Is an “atmospheric geostationary satellite” feasible with current technology?

Meaning by "atmospheric geostationary satellite" a vehicle capable of hovering 30 km above Earth surface, hence insde atmosphere, for unlimited time, making use of air propellers, solar panels and ...
28
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2answers
6k views

What happens when a helicopter loses an engine?

It seems like at this point it would be game over, since the spinning rotor is the only thing keeping it in the air. Is there any way to land a helicopter in this condition without crashing?
35
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3answers
7k views

Why would a helicopter climb in a spiral?

I was just watching the James May's Toy Stories Christmas Special Flight Club*, and in it he commented that the helicopter was making a spiral climb to 8,000'. Why would the pilot spiral, not just ...
16
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2answers
4k views

Why are three-bladed helicopters relatively rare?

I admit that this observation is entirely subjective, but it seems to me that there three-bladed rotors are significantly less popular than two or four. Factors that I'm guessing contribute - ...
24
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2answers
15k views

Can I land a helicopter anywhere?

If I own a helicopter and am appropriately rated, can I land the helicopter anywhere that isn't private property, and is a safe place to land (clear of obstructions, appropriate surface, etc.)? My ...
19
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2answers
10k views

How does a helicopter pilot execute an auto-rotation landing?

What are the critical steps a pilot follows to perform an auto-rotation landing?
13
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2answers
7k views

What is “settling with power” and how does it differ from vortex ring state?

I've always heard these terms used interchangeably. I figured that "settling with power" was what the pilot did to cause the vortex ring state (VRS). But comments on another question indicate that ...
28
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9answers
24k views

If a helicopter's tail rotor fails, is it possible to perform an emergency landing?

In the event of a total failure of the tail rotor, is it possible to maneuver a helicopter to an emergency landing spot that is within, say, 30 minutes flying time? What are the maneuvers required ...
27
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5answers
9k views

Why is the PIC position for helicopters the right seat, rather than the left seat as in airplanes?

So far as I am aware, in a fixed wing aircraft having side-by-side seating and dual controls but only a single set of instruments, those instruments are always positioned in front of the left seat. ...
26
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6answers
4k views

Why not simplified fly by wire helicopter controls?

I was discussing helicopter control with relatives over the holidays, particularly regarding how difficult it is to fly one and how changing any control requires adjusting the other two main controls. ...
20
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4answers
4k views

How do modern helicopters tackle Vortex Ring State?

According to the wikipedia page : Air vortices can form around the main rotor of a helicopter, causing a dangerous condition known as vortex ring state (VRS) or "settling with power". In this ...
12
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2answers
2k views

Do rotorcrafts like helicopters have autopilots?

Years ago, I had the opportunity to board a Bell 407 for a long distance flight and put every question related to helicopters that crossed my mind to the pilot when we were forced to land due to ...
20
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3answers
5k views

Why does a helicopter need cyclic control rather than just tilting the whole main rotor?

Helicopters use a cyclic control to tilt each blade differently through the rotor's revolution. This is quite a complex mechanism. What is the advantage of this vs tilting the whole rotor plane? This ...
8
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8answers
5k views

Is it possible to design a helicopter with fixed rotor blades only (no blade angle/flap/pitch)?

I am not familiar with helicopter rotor design but I wonder if it is possible to build a working/flying helicopter with fixed rotors that cannot change the blade angle, flap, pitch or adjust blades ...
28
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2answers
8k views

Why don't helicopters always takeoff from a hover out of ground-effect?

I've read enough crash reports to see that helicopters discovering too late in takeoff that they lack the power to fly out of ground-effect is a serious problem. I am wondering why the following isn'...
14
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2answers
4k views

Can a helicopter stall?

Imagine that a helicopter raises its nose up and then there is a loss in speed. Can it enter a stall? If so, how do you recover from the stall?
14
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3answers
7k views

What is the name of the maximum altitude at which a helicopter can fly?

What is the name of the maximum altitude at which a helicopter can fly? I recall it as "vertical limit", but I can't find a Wikipedia page for it other than a movie of the same title, which seems to ...
8
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1answer
1k views

Should helicopters fly when they the lack power for vertical climb out of ground effect?

Following up on this question: If a helicopter lacks power to climb vertically (i.e., with no translational movement) out of ground effect, is it ever considered safe to fly? If so, under what ...
12
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5answers
2k views

Has there ever been a diesel-electric helicopter?

Occasionally I come across the diesel-electric (DE) design for submarines and freight trains. They say something like "a diesel engine powering an electric drive lets the two operate at their most ...
3
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3answers
8k views

Under what conditions would a helicopter be allowed to fly at low altitude over populated areas?

Yesterday, the Department of Energy was flying a military helicopter at low altitudes over Boston and the surrounding area as part of an experiment of some type to measure radiation. I saw one of ...
11
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1answer
1k views

How does the energy and weight efficiency compare between a battery/electrical propulsion and combustion engine?

For the same total energy and power output would a battery powered vehicle be lighter than one which uses a fuel burning engine (Currently)? This question is intended for helicopters.
11
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3answers
3k views

Would it be more effective to increase the length or chord of a rotor blade for better performance?

Would it be more effective to increase the length or chord of a helicopter rotor blade for better performance? (Say, 10%?)
11
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7answers
6k views

What limits the lifespan of helicopters?

The lifespan of aircraft is generally limited by metal fatigue. This is true for fixed wing aircraft; is it also true for helicopters? What is the determining factor for helicopter useful life?
2
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2answers
689 views

Why does the Ka-50 (Hokum) have two main rotors, one on top of another?

Why does the Kamov Ka-50 have two main rotors, and is this a better design than a conventional one rotor?
71
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7answers
15k views

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?
27
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2answers
9k views

What helicopter has the most rotor blades?

I have seen 2 rotor blades up to many and wonder when does having more rotor blades become less efficient? What helicopter has the most rotor blades? Related: Why don't helicopters prefer shorter ...
25
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4answers
7k views

How does a coaxial rotor helicopter achieve yaw?

Without a tail rotor, how does a coaxial rotor helicopter achieve yaw control? Does a coax have to bank in order to turn? The link goes to wikipedia's article, and down a ways it says: Rotational ...
15
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3answers
3k views

What are the benefits of a non-orthogonal (scissor) tail-rotor?

Why is the tail-rotor of some helicopters (e.g., Boeing AH-64 Apache) is made of non-orthogonal (scissor) blades? What are the aerodynamic benefits (or any other benefits) compared to the orthogonal ...
10
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3answers
1k views

Can the MH-60 helicopter fly without one or all of the stabilators?

The MH-60R helicopter has a horizontal Stabilator that consists of three subassemblies, RH Stabilator, LH Stabilator, and Center Stabilator. Can the aircraft fly without the RH Stabilator? Can the ...
8
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1answer
3k views

What is the minimum allowed altitude for helicopters over a residential area in the US?

I observed a helicopter hovering over a residential area/houses for more than 20-30 minutes. I would guesstimate about 500 feet altitude or more for the helicopter. The low altitude and long duration ...
23
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6answers
10k views

Why is *vertical* autorotation in a helicopter not recommended?

Helicopters can autorotate back to earth in case of emergency. The FAA recommends a flight profile similar to the following procedure: Notice that in section (2) there is forward speed: vertical ...
17
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4answers
6k views

Do helicopters try to take off and land into the wind?

When helicopters take off and land is it preferable to point the nose into the wind? Since a helicopter is providing its own lift does it matter which direction wind is coming from?
9
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1answer
2k views

What is the purpose of this helicopter fin antenna?

I'm an airplane guy, but I've got a quick helicopter question. I've seen a few helicopters with what seems to be a fin shaped antenna on the middle of the fuselage just above the windshield. I've also ...
2
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4answers
2k views

Why does the helicopter's nose go down when the cyclic is pressed forward (in a hover)?

Helicopters have hinges on top of the rotor mast, allowing the rotor to be tilted longitudinally (forward/aft) or laterally (sideways). Why does the helicopter fuselage tilt up/down when the cyclic ...
13
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1answer
1k views

Will occupants usually survive a decent autorotation?

When I learned to fly helicopters, I of course spent significant time learning about and practicing autorotations. The CFI at my school, who had around 15,000 hrs (that's right, fifteen thousand!) ...
9
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4answers
1k views

Can a free-falling aircraft with no horizontal (or minimal horizontal velocity) start up and fly to safety?

Inspired by this Grand Theft Auto gif, an aircraft with its engines initially idling is dropped from a high altitude (such as from the top of a building) with no or minimal horizontal velocity. Can it ...
9
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1answer
2k views

Do helicopters carry radar equipment? Is so, where is it placed and what type is used?

Do helicopters carry radar equipment and if so, where is it? (e.g. in the nose section like a fixed-wing aircraft). Also what type do they use? (e.g what type of radar would a maritime helicopter ...
5
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4answers
1k views

Why aren't there more helicopter aerobatics at airshows?

I enjoy watching RC helicopter stunts like these. Many RC pilots are very talented, executing barrel rolls and other inversions. How come we don't see these kind of displays at airshows?
5
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1answer
883 views

How is hypothetical max altitude of a helicopter calculated?

How do engineers calculate the hypothetical max altitude of a helicopter if the mass, altitude and length/curvature of blades are known?
2
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2answers
737 views

Why do helicopters typically have blades at the top?

This question has several great answers showing that it's perfectly possible for a helicopter to fly with its blades underneath the rest of the aircraft. There are some obvious issues with having a ...
1
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1answer
1k views

How does wind speed affect helicopter rotor speed?

So on the left it shows wind flowing with the direction of the rotor, yet it represents that it would reduce the rotor speed. I'm wondering how it does this, wouldn't the wind minimally help increase ...
0
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5answers
502 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 ...
31
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1answer
5k views

Are there full scale helicopters capable of sustaining inverted flight?

Background I'm a model aviation enthusiast and really enjoy seeing how far people can push the limits of aerobatics. Model aircraft are able to push the limits well beyond full scale due to their ...
42
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6answers
17k views

Can a helicopter stand on the ground upside down on its rotor head?

From what I understand the rotor head needs to be strong enough to hold the craft weight hanging below it, and sounds pretty strong. The blades however look quite fragile (for a piece of metal). In ...
36
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2answers
4k views

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 ...
28
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5answers
11k views

What would the reason be for this helicopter maneuver?

At 4:30 in this YouTube video, a Chinook traverses the runway on its rear wheels. The text on the video lists "Emergency landing and take-off". Is there any reason for the pilot to do this other than "...
39
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4answers
20k views

Are there any helicopters with ejection seats?

Are there any helicopters with ejection seats? If so, how is the clearance problem with the rotating blades solved?
27
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2answers
19k views

Do helicopters have an auto hover system?

I'm not a helicopter pilot. The way I understand it, helicopter pilots have to constantly make small adjustments to make a helicopter hover steadily at a certain point in space, just like fixed wing ...