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Posted: 9/25/2014 9:45:51 PM EDT
[#1]
We like to hover.
However, rotor efficiency increases much more due to ETL. Just google ETL. As for forward flight, staying out of the Avoid or Caution sections of our Height/Velocity diagram is just smart piloting. However, sometimes, we have to work in it. EDIT: Hovering is fun, and in some aircraft its more work that others. My helicopter will hover itself if I want it to. Here is some light reading: H-V diagram ETL some videos 
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Posted: 9/25/2014 9:46:11 PM EDT
[#2]
I always enjoy watching movies where helicopters makes strafing runs when there is no threat of being fired up on.
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Posted: 9/25/2014 9:50:39 PM EDT
[#3]
Cause once you learn to hover you're so darn proud of yourself you just want to do it over and over.
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Posted: 9/25/2014 9:53:09 PM EDT
[#4]
Seeing as how the technical answer has already been provided... Generally we rush to get forward airspeed because we are trying to go somewhere, and I prefer to fly forward. 
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Posted: 9/25/2014 10:05:48 PM EDT
[#5]
Google "Dead Man's Curve".
http://en.wikipedia.org/wiki/Helicopter_height%E2%80%93velocity_diagram Basically, there is a envelope where if you are too low, and no forward airspeed, and your engine fails, you can't autorotate - you just auger in, make a crater and get splattered around the cockpit. |
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Posted: 9/25/2014 10:10:10 PM EDT
[#6]
so if a helicopter takes off from a treadmill...
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Posted: 9/25/2014 10:43:15 PM EDT
[#7]
Any aircraft has a curve for induced, parasite, and profile drag.
Induced drag decreases as speed increases and Parasite and Profile drag increases as speed increases In a helicopter, these curves intersect around 55 knots. Anything faster or slower and it takes more power to overcome the drag. Combine the fact that from a hover it takes LESS power to fly faster, it's safer to get speed as you climb because of the dead man's curve, and the fact that you're going somewhere are all reasons why we accelerate to takeoff. 
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Posted: 9/25/2014 11:33:30 PM EDT
[#8]
Quote HistoryQuoted:
I always enjoy watching movies where helicopters makes strafing runs when there is no threat of being fired up on. Fixed forward weapons are aimed by pointing the aircraft at the target. When you point the aircraft at the ground it moves forward.... aircraft are also much more stable in forward flight which gives better accuracy. |
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Posted: 9/26/2014 1:08:40 AM EDT
[#9]
A big part is staying out of the "avoid" area of the height-velocity diagram. Being able to autorotate successfully is a BIG desire! Also, going faster than effective translational lift dramatically reduces power requirements. For example, in some cases hovering at 5ft requires double the power of flying at 60Kts.
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Posted: 9/26/2014 1:50:27 AM EDT
[#10]
Unless I'm waiting for a clearance or doing a maintenance check, I don't spend much time hovering. Besides the high power demand already mentioned, It's a waste of time, and it also creates a lot of noise and rotorwash which is not always welcome. Pick up, make sure everything is in the green, and get on with it.
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Posted: 9/26/2014 5:27:06 AM EDT
[#11]
Quoted:
Strange question, strange wording rather... So it seems that almost always when helicopters take off, the pilot attains some forward speed as quickly as possible. I always thought this was because flight with forward (or any direction, for that matter) speed requires less energy than a hover. less energy requirement = less fuel burn and less wear and tear. But why does moving require so much less energy? Sure, you get to add the forward component to the advancing blade, and that helps, but doesn't any gain just come off of the retreating blade? Or, am I all wrong here, and the real answer is that hovering is a lot of work on the pilot, and if you don't have to, why expend your energy on it? The technical aspects have been, pretty much, addressed so... There's nothing "don't like to" about it. If what I need to do to accomplish my mission requires me to hover, I hover. (Thankfully I don't have to sit in an OP and do it OGE for 6-8 hours at a shot anymore. I admit, that got old.) Most of my mission do not require me to hover much so I'm not doing it more than 10 or 15 minutes a day. I've got shit to do. If I'm driving to the store, I don't pull my car over and sit idling because it's fun either.
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Posted: 9/26/2014 4:21:38 PM EDT
[#12]
Quote HistoryQuoted:
Any aircraft has a curve for induced, parasite, and profile drag. Induced drag decreases as speed increases and Parasite and Profile drag increases as speed increases In a helicopter, these curves intersect around 55 knots. Anything faster or slower and it takes more power to overcome the drag. Combine the fact that from a hover it takes LESS power to fly faster, it's safer to get speed as you climb because of the dead man's curve, and the fact that you're going somewhere are all reasons why we accelerate to takeoff. http://www.dynamicflight.com/aerodynamics/drag/avd.gif Another way that you can correlate this is by looking at a cruise data chart and determining your max rate of climb / max endurance airspeed. This will be the point that a particular air-frame will be its most maneuverable with the largest power margin. Particularly during an engine failure. It's all about keeping yourself in a good flight profile for when an emergency occurs, particularly engine failures. As stated previously going out of this window is going to always require a tradeoff between power or airspeed. At the end of the day its all about efficiency and power management. Sometimes you will be required to hover IGE or OGE which is going to introduce a whole other set of considerations if an emergency occurs. |
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Posted: 9/26/2014 5:00:13 PM EDT
[#13]
Depends on the mission I guess.
News helicopter hovers all the time. Police helicopter never hovers. Probably to they don't take fire should someone decide to shoot at them. Moving target harder to hit. |
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Posted: 9/26/2014 7:02:09 PM EDT
[#14]
I spent an hour last night at a hover IGE and OGE doing external loads. Comes with the job
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Posted: 9/26/2014 7:11:05 PM EDT
[#15]
As was said, you get more lift from translational movement (forward) than just trying to hover your way up.
When you start to lift off in a hover, you are getting assistance from what is called ground effect. Once you get to a certain height, that no longer applies. Depending on various factors, that is about 3-6 feet. Now, if you're lightly loaded, that loss of ground effect doesn't matter, you can still keep lifting, although not as effectively as if you were moving forward, too. But, as your weight load increases, you hit a point where you CAN NOT continue to lift solely via hover once you lose ground effect, and you HAVE to have translational lift if you want to go any higher. |
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Posted: 9/26/2014 9:25:33 PM EDT
[#16]
For the same reason that wives don't have to continue premarital services. Only when it is absolutely required.
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Posted: 9/26/2014 11:12:41 PM EDT
[#17]
First I've heard of it.
I see them do it all the time. Hell my trainee got a Blackhawk to hover so a scared pilot in a lightsport could take advantage of a lull in the winds. It was fun watching the Blackhawk come in behind that little thing. |
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Posted: 9/26/2014 11:23:25 PM EDT
[#18]
I've always thought that the easiest job in the world would be an air traffic controller at an Army Air Field.
"EVERYBODY JUST STOP FOR A DAMN MINUTE!"
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Posted: 9/26/2014 11:43:48 PM EDT
[#19]
Quote HistoryQuoted:
I've always thought that the easiest job in the world would be an air traffic controller at an Army Air Field. "EVERYBODY JUST STOP FOR A DAMN MINUTE!" Depends on where they are stationed. I knew an ex army controller with no fixed wing experience where as a guy I worked with had quite a bit all over the world |
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Posted: 9/27/2014 12:47:06 AM EDT
[#20]
Quote HistoryQuoted:
Depends on where they are stationed. I knew an ex army controller with no fixed wing experience where as a guy I worked with had quite a bit all over the world Quote HistoryQuoted:
Quoted:
I've always thought that the easiest job in the world would be an air traffic controller at an Army Air Field. "EVERYBODY JUST STOP FOR A DAMN MINUTE!" Depends on where they are stationed. I knew an ex army controller with no fixed wing experience where as a guy I worked with had quite a bit all over the world That was kind of a joke. |
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Posted: 9/27/2014 12:54:35 AM EDT
[#21]
Quote HistoryQuoted:
That was kind of a joke. Quote HistoryQuoted:
Quoted:
Quoted:
I've always thought that the easiest job in the world would be an air traffic controller at an Army Air Field. "EVERYBODY JUST STOP FOR A DAMN MINUTE!" Depends on where they are stationed. I knew an ex army controller with no fixed wing experience where as a guy I worked with had quite a bit all over the world That was kind of a joke. But not far off. One of my trainees actually said the same thing. " The Army was sweet, everyone can stop wherever you want. On the runways, in the air or wherever they are calling up from" |
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Posted: 9/27/2014 3:23:33 PM EDT
[#22]
Quote HistoryQuoted:
We like to hover. However, rotor efficiency increases much more due to ETL. Just google ETL. As for forward flight, staying out of the Avoid or Caution sections of our Height/Velocity diagram is just smart piloting. However, sometimes, we have to work in it. EDIT: Hovering is fun, and in some aircraft its more work that others. My helicopter will hover itself if I want it to. Here is some light reading: H-V diagram ETL some videos  http://www.youtube.com/watch?v=HrsGM0PzQFo
http://www.youtube.com/watch?v=0f3YDL273XMGotcha. ETL is the key to understanding it. The bang for the busk out of forward speed is a lot higher than one would think! |
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Posted: 9/27/2014 3:31:47 PM EDT
[#23]
Quote HistoryQuoted:
Gotcha. ETL is the key to understanding it. The bang for the busk out of forward speed is a lot higher than one would think! Sure. That and the need to accomplish something besides turning Jet A into noise. 
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Posted: 9/27/2014 8:13:47 PM EDT
[#24]
Quote HistoryQuoted:
I've always thought that the easiest job in the world would be an air traffic controller at an Army Air Field. "EVERYBODY JUST STOP FOR A DAMN MINUTE!" ...right up until they tell you to hold for spacing half-way down the ILS in IMC. 
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Posted: 9/27/2014 8:20:48 PM EDT
[#25]
Quote HistoryQuoted: I've always thought that the easiest job in the world would be an air traffic controller at an Army Air Field. "EVERYBODY JUST STOP FOR A DAMN MINUTE!" Fixed wing is much more challenging.
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