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.
665
questions
4
votes
1
answer
1k
views
Why do I often see bunches of medical helicopters hovering in clusters in various locations
As you can see in the screenshot there are hovering clusters of medical helicopters in multiple areas. I feel like I see hovering helicopter clusters every time I open the flightradar24 app. I couldn'...
- 51
0
votes
0
answers
33
views
How does flare rate and attitude change with altitude during autorotation in Helicopters?
I am presently undergoing Flying Instructor Course on a Single Engine Helicopter.
I have been wondering about following queries :
How does, if it does, the flare rate and attitude change with ...
- 1
16
votes
1
answer
5k
views
In 1982 Admiral Grace Hopper said "I still haven't found out why helicopter rotors go the way they do". If she were here today, how might one answer?
After about 24:50 in the video NSA Releases Internal 1982 Lecture by Computing Pioneer Rear Admiral Grace Hopper Admiral Hopper says:
...Now when it comes to carousels at airports I can see a good ...
- 6,168
13
votes
1
answer
3k
views
What happens when a helicopter loses the engine and autorotation is not initiated?
I am thinking of a very basic main and tail rotor configuration helicopter, without any aerodynamic surfaces like vertical or horizontal stabilizer, in a steady state horizontal forward flight at ...
- 131
1
vote
1
answer
84
views
Trouble with flight school and the change in flight instructors
How do I easily adjust to the instrucuting processess of a new flight instructor, So I can fininsh flight school early enough, I have had 3 flight instructors in the past 2 months and it has stalled ...
- 9
9
votes
4
answers
2k
views
What is the airspeed record for a helicopter flying backwards?
How fast can a rotocraft go, relative to the air, if it is flying towards its tail?
Tiltrotor and powered lift aircraft do not count. Helicopters and gyroplanes do. The aircraft must have a readily ...
- 3,461
0
votes
0
answers
29
views
what is the lower pressure plate in the swashplate assembly? is it the same as the lower stationary swash plate? or is it the drive scissors?
Im looking at the rotor assembly of a BlackHawk. The natops manual states the following, "...The lower pressure plate, in conjunction with the main shaft nut, secures the shaft extension to the ...
- 429
20
votes
4
answers
3k
views
Could Swashplate be replaced with small electric motors?
In helicopters, the swashplate is used to control the pitch of the blades. Could a set of electric motors, each placed at the root of each blade, be used to control the pitch instead? Has this method ...
- 303
-1
votes
2
answers
140
views
Formula relating propeller torque to lift
I'm trying to find a formulas that relates lift to torque on the rotor shaft. Torque, angular velocity and power are related by the following relationship: $P=\tau \omega$.
I am especially interested ...
- 99
1
vote
1
answer
49
views
Does information about private heliports need to be published in the AIP?
I am seeking information on what international regulations specify regarding the publication of aeronautical data for a private heliports.
0
votes
1
answer
103
views
How to balance the main rotor of helicopter?
In mi17 class helicopters, the OEM had not given an option of adding weights at main rotor hub or blade tips at unit level. The blade sets are usually static balanced when received by units. Is there ...
0
votes
2
answers
87
views
Can you do a IFR flight in a uncontrolled space in a helicopter?
Can you do a IFR flight from point A to point B (both within an uncontrolled airspace) in IMC in a helicopter?
Would there be a minimum altitude?
- 4,945
14
votes
1
answer
3k
views
What does a letter "R" means in a helipad?
What does it means when a helipads has a letter "R" and a arrow?
Here are some examples and the link to google maps:
https://www.google.com/maps/search/heliport/@35.4638657,139.6262343,40m/...
- 4,945
3
votes
0
answers
215
views
What's the purpose of the holes on the Cabri G2 fenestron blades?
What is the purpose of the holes on the blades of the Cabri G2 fenestron? In my opinion drilling the blades like that weakens their cross section under the action of the centrifugal force. Is it ...
- 31
6
votes
1
answer
6k
views
Am I seeing double? What kind of helicopter is this, and how many blades does it actually have?
This June 9, 2024 CNN news video begins with an inset of video of what looks like an Israeli IDF "event". Looking down from a relatively static point in the air, another helicopter is seen ...
- 6,168
0
votes
2
answers
125
views
How do you communicate with atc and how can they communicate with you when you change frequency?
How do you let atc know that you are going to a different frequency and how will you be able to talk to them if they need to talk to you will they go to that frequency that you went to?
- 15
1
vote
1
answer
160
views
What frequencies can you freely speak on? [duplicate]
Are there any frequencies that you can use to communicate with your family at home when you are flying and for a wokie talkie I am wondering if there are just any frequencies that you can speak freely ...
- 15
0
votes
0
answers
1k
views
Is it plausible that helicopters are safer than cars?
For some reason there is a lot of talk on helicopter safety online at the moment, and one fact that keeps coming up is "helicopters are safer than cars", supported by this article "Are ...
- 309
4
votes
3
answers
274
views
Can a wind gust below the rotor affect the lift force in a helicopter?
If a helicopter is hovering and a very strong, narrow and focused wind gust comes from the front and passes few feet below the rotor blade without touching the fuselage or any part of the aircraft for ...
- 4,945
6
votes
1
answer
485
views
Why do American Helicopters not have ejection seats or some form of ejection system?
In Russia there is the Kamov Ka-50 which is a helicopter with a ejection seat that blows off its rotors before the pilot ejects. I was wondering why here in America we Don't have some form of similar ...
- 538
2
votes
3
answers
175
views
Helicopter attitude during take-off and landing (wheels, not skids)
Helicopters with wheels can take-off and land in a level or nose-up attitude (nose wheel off with main wheels on the ground). For example, the pilot of a VIP helicopter might want to take-off in a ...
- 141
2
votes
3
answers
477
views
Do helicopters have to pay landing fee?
Is there a landing fee for helicopters?
I ask because since they usually don't use the runway hence doesn't cause maintenance costs for the airport I would imagine they have at least a different fee ...
- 4,945
2
votes
0
answers
70
views
What is the arrangement of flapping, drag, and feathering hinges on a fully-articulated rotor hub?
Every diagram I have seen puts the flapping hinge closest to the rotor hub, but there seems to be variation whether the feathering comes next followed by the drag/lead-lag, or vice versa.
For this CH-...
- 193
5
votes
1
answer
1k
views
What exactly are these two cones on top of this Sikorsky S-61 helicopter?
Haven't notice this thing on the Sikorsky, what is it?
Another picture from another angle:
- 4,945
0
votes
1
answer
81
views
Can a single-bladed rotor with cyclically varying torque emulate a swashplate?
Instead of a swash-plate cyclically varying the pitch of the rotor blade(s), could a similar effect be generated by cyclically varying the thrust of the motor on a fixed-pitch single-blade rotor? The ...
- 103
0
votes
2
answers
312
views
why does the rotor could head (Nr) "overspeed" if the collective is lowered suddenly, what is the Physics behind it
I know that in helicopters the N2 and Nr are coupled. I would appreciate a physical explanation leading to the cause of how the rotor blades could overspeed if collective (power) is lowered suddenly
I ...
- 429
4
votes
1
answer
219
views
Have there been attempts to break Jean Boulet's 1972 helicopter records? (highest altitude and longest unpowered descent)
So this is the incredible photo of a man accidentally setting a world record.
In 1972 a French pilot named Jean Boulet set out to break the world record for the highest altitude ever reached in a ...
- 6,168
0
votes
1
answer
86
views
How to calculate fuel burn rate in Model BK117 helicopter
I am confused which parameters we are use, I have fuel quantity, fuel flow, fuel weight and speed etc is there so how to using and which parameters using the Endurance time calculate in helicopter
2
votes
2
answers
121
views
How to identify a NDB on a garmin 430W or GTN650?
I have a Garmin 430W and a GTN 650 interfaced with a G500H in my aircraft. I can program either to go direct to an NDB. The question comes as to whether or not I can identify the navaid. Reading ...
- 511
0
votes
0
answers
74
views
Gyroscopic Precession in Coaxial Helicopters
I'm trying to understand gyroscopic Precession in the case of coaxial helicopters. Obviously the effect still exists. But if gyroscopic Precession is a result of counter torque. Shouldn't the effect ...
17
votes
2
answers
13k
views
My ceiling fan preference is to have 5 blades because it's quieter. Do helicopters ever have 5 rotor blades. Why?
My home ceiling fans have 5 blades to reduce the wopwop sound in a quiet room. It probably also moves air more efficiently at a lower spin rate. Can a helicopter operate properly with 5 blades?
- 171
10
votes
2
answers
2k
views
What is the downwash speed on a typical helicopter?
On a typical 2 or 4 seat helicopter like a Robinson R22/R44, at full throttle at 20ft ASL, if you put a Wind Speed Meter/Anemometer about 10ft below the blades and halfway along a rotor blade's span, ...
- 4,945
0
votes
0
answers
54
views
H145 helicopter type rating trainings
There are different variants of H145 helicopter (BK117), there are BK117, BK117 C2, BK117 D2 and BK117 D3 helicopter. So if you finish type rating training for example for BK117 D2, and you want to ...
- 161
19
votes
2
answers
4k
views
Can you identify this helicopter seen near Boscombe Down?
Please can you identify this helicopter seen near Boscombe Down (near Amesbury, Wiltshire, England) in January 2024?
user72881
0
votes
0
answers
56
views
Autorotation Trajectory Datasets?
I was looking for works/datasets on autorotation trajectories. Now, I have found works like this: Aponso et al, Dalamagkidis et al, Abbeel et al or Nonami et al (Chapter 6).
However, I have a hard ...
- 173
0
votes
0
answers
83
views
Do coaxial rotor helicopters have a size limit? [duplicate]
Why haven't there been heavy helicopters like the CH53 with coaxial rotor configuration? Is there any physical limitation inherent to the concept?
I recall someone at Sikorsky saying that their new X2 ...
- 63
5
votes
1
answer
1k
views
Why single engine turbine helicopters can operate on higher altitudes than multi engine helicopters?
Probably you knew the example where H125 landed on Mount Everest (8848 m), and H145 highest landing was on Aconcagua (6962 m), almost 2000m difference.
- 161
0
votes
0
answers
45
views
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 ...
- 101
12
votes
4
answers
3k
views
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 ...
- 313
0
votes
0
answers
128
views
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 ...
3
votes
2
answers
396
views
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 ...
- 173
17
votes
4
answers
13k
views
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 ...
- 179
1
vote
0
answers
152
views
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 ...
- 161
0
votes
1
answer
102
views
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.
0
votes
1
answer
424
views
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 ...
0
votes
1
answer
259
views
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 ...
1
vote
2
answers
198
views
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 ...
4
votes
1
answer
2k
views
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.
0
votes
1
answer
99
views
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.
- 603
1
vote
2
answers
180
views
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 ...