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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What are the main changes in CAP437 rev 9 from a Helideck Monitoring perspective?
CAP437 rev 9 was first published Edition 9 February 2023. In particular, what should a Heliops operator conducting operations on a "moving" helideck be made aware of. What training would an ...
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How does a helicopter rotor keep spinning in the same direction when autorotating without reversing the pitch
I have read that if helicopter's engine fails, you set the pitch to minimum but not reverse pitch. The rotor would have to be tilted back to provide an angle of attack on the blades so it glides like ...
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Deriving Accurate Exit air velocity of rotor
My goal is to derive the equation for exit air velocity as a function of:
Pitch angle
RPM
Rotor Radius
Constants like ρ
Assumptions:
Vc is relative velocity of air upstream, and is = 0
Inflow is ...
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Is blade flapping "fully automatic"?
I have a rather simple question just to "double check" if I understood blade flapping right. So, I understand that a helicopter, in forward flight faces an asymmetric lift. Blade flapping is ...
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Why are there no helicopters with the rotor mounted on the bottom?
Downwash from the rotor of a helicopter creates drag on the helicopter body acting against the lift force of the rotor.
Why are there no helicopters with the rotor under the main body of the ...
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Why is there variation in helicopter autorotation maneuvers?
Why are there some different autorotation techniques?
For example, on light helicopters, like the Airbus Helicopters H125 or Aérospatiale Gazelle, you do not flare too much: at 70-100ft AGL adjust ...
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What are the effects of whiteout (snow) and brownout (sand/dust) on helos?
Is there any other effect besides low visibility?
Both seem to show very similar conditions.
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For transporting 4000kg of cargo via Mi-17 helicopter for 54 km, how much maintenance cost per flight hour will be incurred?
In a disaster response case study, I am using Mi-17 helicopters for relief supplies transportation in a challenging logistics environment.
Regarding this, I want to check my estimates with the actual ...
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How much fuel cost will be incurred for transporting 4000kg of cargo via Mi-17 helicopter for 54 km?
I am working on a logistics case study in which I am using Mi-17 helicopters for transportation of relief to the affected areas in a disaster.
In this regard, I want to check my estimates with the ...
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What differences would a helicopter designed to withstand many negative Gs have compared with a normal one?
There are a few helicopters that are able to take negative G's, and to this day only one can actually perform aerobatics (ie. Chuck Aaron's BO-105). The BO 105 is a rigid rotor helicopter that has ...
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What type of helicopter is this?
Wondering what kind of aircraft this is. Military or commercial? Photographed nearing island HK (possibly near Wanchai) an hour or two ago.
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Humidity and its effect
We know that humidity degrades engine performance. Is there any charts or tables which quantify effect on engine performance due humidity?
The question is specific to helicopters.
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Can vortex ring state (VRS) be solved by shaping the blades so that the vortexes they produce are weak enough not to form a vortex ring?
Vortex Ring State is one of the hazardous states a helicopter can find itself into. VRS happens when a helicopter has low airspeed (and usually hovering OGE) and is descending. If the helicpoter is ...
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Helicopter V speeds explanation
I am reading Cat A heli procedures, and there is Vtoss speed, so what is the difference between Vx(best angle of climb speed) and Vtoss(take off safety speed) ?
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Can the use of wide-chord supercritical airfoil blades in a helicopter with coaxial counter-rotating rotors solve retreating blade stall?
The problem with retreating blade stall is that it limits the VNE and the overall top speed of helicopters. Retreating blade stall is basically the tip of the retreating blade having too much AoA at a ...
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Helicopter autopilot
Is there any video or explanation how parallel actuators work on 4 axis helicopter autopilot ?
I am familiar with beep trim and trim release buttons, but want to know how it all works in the ...
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Rotor system Weight of a Helicopter
I was wondering whether there is a "rule of thumb" or some kind of estimate (ideally with a source) that states how heavy a rotor system (blades, swash disk, actuators) typically is as a ...
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accelerated turns in helicopter
In flight Manual of Russian Mi-17 helicopter, it is give that ”max bank permitted in accelerated turns is 45 deg up to 1km altitude”. At the same time it also mention max bank permitted is 30 deg up ...
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Does the CH-47 Chinook generate differential yaw as a side effect of generating differential lift?
I have been reading up on the controls of the CH-47 Chinook. I understand how yaw movement is created not by counter torque but by opposite cyclic on the front and back rotors. What I'm wondering ...
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Adding fixed wing CFII SEL to helicopter CFII rating
I am a CFII, and have just been asked to assist a Helicopter pilot who has FIH (CFFII-Helicopter) and a Commercial fixed wing (SEL) certificates to obtain a CFII SEL rating.
My research to date ...
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How much power and lift margin do helicopters have for hover?
Suppose you are designing a helicopter and trying to size the rotor system for hover and flight. Your helicopter has a certain gross weight at sea level, standard atmosphere. How much additional lift ...
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Helicopter induced velocity
I found this on one book I am now reading, and I dont uderstand how induced velocity is decreasing whyle climbing? And what is the difference between induced velocity and inflow velocity ?
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Does a cyclic in a helicopter essentially control rotor attitude?
So the basics of helicopter control as I understand it, at least, in terms of roll and pitch, are as follows:
A helicopter is caused to move through space by means of tilting the main rotor disc, ...
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Why is the helicopter rotor brake easily accessible?
According to this article, a rotor brake is dangerous to use in-flight, yet it's easily accessible and the pilot's reaction indicates that it would've deployed mid-flight. Why is the brake so easily ...
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What, if anything, could actually cause one helicopter blade to be more eroded than the others?
Does this scenario in which one blade is more eroded then the others commonly occur with real helicopters? Even if it does, Julio's explanation is obviously wrong; what actually causes it?
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Why phase lag on helicopter blade is sometimes 90°, and sometimes less?
On semi rigid rotor head, phase lag is 90°, and also the advance angle between pitch link and coresponding blade. But of fully articulated rotor the phase lag is less then 90°, and also the advance ...
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Helicopter blades flapping with the cyclic – can you help with the explanation?
I am now reading books about helicopter aerodynamics. And I have one question about blades flapping.
If you push forward on the cyclic, the swashplate will tilt forward and will set the maximum pitch ...
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Would military aircraft jam TV signals?
Various military aircraft just flew overhead on their way to the Trooping of the Colour in London.
At the same time, my Television's signal went completely dead, and then restored once they had gone. (...
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What is the approximate lifespan of H125 helicopter
What is the lifespan of the Airbus H125 helicopter used by law enforcement agencies?
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Why do heli PC2 operations require highest obstacle clearance
In designing a helipad I notice that the Australian requirements (AC139.R-01) for obstacle clear gradients specify that the slope category (12.5% slope) generally applies to PC2 operations, whereas ...
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Helicopter hammerhead-like maneuver
A response to a previous question indicated, “In a helicopter, aft cyclic (“pitching up” in a plane) will only serve to make the helicopter climb and slow down until it reaches equilibrium in the new ...
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Can a helicopter autorotate from a hover?
If a hovering helicopter's engine fails, can the helicopter autorotate as it could if it were moving?
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what is Limit load factor structural and aerodynamic envelope at structural design gross weight and maximum gross weight?
As an aerospace engineer, as soon as I saw the words "structural and aerodynamic envelope" the first thing that popped into my mind that is it V-n diagram? But when I searched about it in ...
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What was the actual cockpit layout and crew of the Mi-24A?
I have spent all morning trawling around the Internet trying to get a definitive answer on this. In the early Mi-2A variant with the large glass cockpit enclosure, what was the actual crew and layout? ...
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Can an individual land a personal helicopter used for personal use in their son's yard within a subdivision for pleasure? [duplicate]
Can a pilot legally land a private helicopter in a private subdivision?
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How is the planform geometry of a helicoptor rotor designed?
Rotor planform specially the tip is designed differently for different helicopter rotor. How the shapes are determined? For example I added 2 photos. How the dimensions of the tip or root of these ...
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Autorotation Index: The more gravity, the better?
I have been working on helicopter design and autorotation for a while. An Index used for this is the so-called "Autorotation Index" Evan A. Fradenborugh derives it in this work https://doi....
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How to plot figure of merit vs blade loading coefficient for helicopter rotor?
I know the formula of figure of merit and blade loading coefficient individually but how the plot can be obtained I am not getting that. What would be the formula for figure of merit in terms of blade ...
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Why was the Ka-50 designed with only one seat?
The Soviet/Russian attack helicopter Kamov Ka-50 Black Shark is unique in many ways, one of which being the only attack helicopter to my knowledge that only seats one crewmember. Generally, attack ...
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Moment required for disk tilt Cierva Autogyro?
The first prototypes of the Cierva autogyro used a disk tilt mechanism rahter than cyclic pitch by means of a swashplate to achieve roll and pitch (DOI: 10.13140/RG.2.2.19168.94729).
Let's first ...
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What is name of this part on a helicopter?
What is name of this highlighted part of helicopter and what is its use?
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Helicopter total power required: zero wind speed while climbing --vs-- down wind speed while hovering
I've been stumped on this for a while. Let's say you have a helicopter in climb mode (i.e., 100 ft/min) with zero wind speed present. Would the total power requirement be the same as if the helicopter ...
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Can a helicopter's main rotor mince a human?
Prompted by one of the answers to a prior question of mine regarding a scenario involving a helicopter mincing someone with its main rotor in flight:
...I suspect having a human body come in to ...
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Why should the dust protection on the Mi-17 helicopter not be used above 3000m?
The Russian Mil Mi-17 helicopters have a dust protection device fitted at engine intake (see the rounded part in front of the intake):
Its checklist gives an altitude limitation from sea level to ...
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Is a broadhead arrow fired from a bow or crossbow a significant threat to the safety of a civilian helicopter?
Let us suppose that we have a civilian helicopter, such as an MD900, Bell 407, Robinson R44, Bell 47 or another common civilian design, hovering or flying slowly just above treetop level (50-70m).
If ...
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Payload capacity of a quadcopter/helicopter with increasing altitude
I am trying to create a simplified model of a heavy-lift drone payload at different altitude during hover mode. I tried to derive it simply by considering that the thrust, $T$ is equal to the weight ...
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Would an S-92 / CH-148 (or any helicopter) be able to land successfully after rolling over and eating someone with its main rotor in flight?
In the SCP Foundation story "Over/",1 the protagonist and his fiancée get kidnapped by some terrorists looking for information, who eventually throw the two of them out of a CH-148 (with ...
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Between hover and moving straight forward, which one is this Sikorsky uses more power?
Source:
Consider this Sikorsky–Boeing SB-1 Defiant is being flying forward level and straight and being hover, which state is consumes more power? For both states, we assume that air is very still and ...
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limits of the cg envelope graph for a helicopter
I am looking for information or any explanation, I want to know how this envelope is graphed, the limits (underlined in the image) from where they are obtained and what do they tell me? I want to know ...
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Does a helicopter actually have a lower rate of fuel consumption in cruise than in hover? [duplicate]
Recently the thought of autogyro flight as "powered autorotation" came to mind. The rotor acts like a fixed wing, providing lift, while a separate source of thrust provides forward motion.
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