Moggy’s Tunaboat Helicopter Manual Ch.3-H-1 “Drawings “
Posted on October 8, 2009
Here are two drawings that attempt to illustrate two different possible roll-over scenarios.
They illustrate parts of the story described in
“Blip on the Radar(8) ” “Eyes of Dead Man “.
(note: for an interesting discussion on Dynamic Roll-over, see Vertical Reference.com Here is the link) 
You can imagine wobbling about, big rollers coming through, buffeted by the wind, with NO references to orientate yourself relative to the invisible (heavy) vertical log. To which you are firmly and immovably anchored.
In practice, you will “feel ” when you are at either limit, when the rope goes tight, there are a series of increasingly powerful “tugs ” felt, and your controls no longer respond normally. It’s a case of making “small movements ” and analyzing what the aircraft response is telling you. In the second example, an abrupt “panic reaction “, the instinctive application of up collective and left cyclic, will be utterly disastrous in a fraction of a second.
Yep! I screwed up. I hope you never make the same mistake…
Last edited by Francis Meyrick on April 22, 2014, 10:07 am
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So ya big Irish mug, what is tarnation is a dynamic roll over for those of us who don’t understand? Where ya gonna go upside down, sideways or what? Good grief, Moggy, not everyone skittles around in those helicopters, ya know?
So, now like Ricky Ricardo used to tell Lucy, ‘splain yerself!
Oh, it’s easy to understand.
It’s just like sex.
When a man’s in bed with his wife, he rolls over on top. That’s just a normal roll-over.
When he manages to sneak in a steamy session in a cheap motel room, with some drop dead, gorgeous, big breasted mama with succulent nipples, then he sticks his elbow out for extra leverage as he rolls over in a hurry. Now it’s a DYNAMIC roll-over.
In helicopters, a roll-over is just that, the stationary helicopter, engine off, blades not turning, parked on a slope perhaps, rolls around one of the skids, and falls on it’s side.
But when everything is turning and burning, and the helicopter starts to roll over, perhaps due to pilot error, or a tie-down attached, etc, then an additional force comes into play (like the randy dude’s elbow) which tends to greatly accelerate the tendency for the helicopter to want to continue the rolling motion…
(ducks flying objects)
(Yo Baby! With that simple metaphor, I just re-wrote all the basic helicopter training text books!)
MotherofJeffersonDavis – both of those descriptions, the first one you put and this revised one are something else! Do ya think that will embarass me and keep me from asking questions, Moggy? You should know me bettern’ that. At least I know now what a dynamic rollover is , but what is collective and cyclic, eh?
Told ya the risque puns don’t work! Maybe ya should try burning prayers to that little andy statue.
Embarrass you? Oh, no, no! Not at all. Keep asking questions.
I’m delighted with your interest in the finer points.
I’ll be delighted to show you one day.
Cyclic and collective? Oh, easy.
A helicopter pilot is fortunate in that the Designer has given him two sticks to play with. One between his legs, and another beside his left hip. The cyclic stick between the pilot’s legs is very intuitive for him, and it always sticks up straight. The pilot grabs it firmly. Let’s say he is in the hover, where vertical thrust is matched by the weight. They get pretty heavy. All our hero has to do is waggle the stick in whatever direction he fancies going. Forward a bit? He moves his stick forward. Back up a bit? He moves the stick back. And the same for left and right. The immediate response is very pleasing indeed.
Some pilots have autopilot, and you could then do it ‘hands off’. But most of us feel we have more control with a ‘hands on’ approach.
The collective stick, as I said, is mounted beside his left hip.
It does not also stick up vertically. It’s rather like an old fashioned car hand brake that is hinged on the floor behind or beside you. It comes up at an angle, but this one’s closer to the horizontal than the vertical. A helicopter pilot will pull it up to increase thrust, and push it down to reduce thrust. Helicopter pilots do that constantly, all day long. Pull up, push down, pull up, push down. In this way they are adjusting the thrust to where they want it. It might sound boring, but, believe me, it never is. Some guys are really rough on their collective stick, but others are more gentle.
I suppose the Designer could have also mounted the collective stick vertically, the same as the cyclic stick. I imagine he decided that helicopter pilots already have enough to play with, with just one vertical stick between their legs. So they made the collective do it differently. Even so, it is amazing how helicopter pilots do so well, handling two sticks all day long.
To make the whole thing more pleasurable for the helicopter pilot, the Designer also arranged it so that the pilot can adjust the friction.
He does this by fiddling with his knobs, located at the bottom of the stick. It’s important to get ‘good feedback’ through your controls, and too little sensitivity annoys the pilot.
Pilots measure all that thrust from their engine in terms of raw horsepower. The more horses, the better. You just have to stay in the saddle and ride ’em good.
The sticky part of being on the job, is at the end of it all, when you’re getting tired, but you don’t want it to show.
Sometimes you have a lot of people watching, and you want to put on a good show. As you hover in to land, for your final act of the day (or night), it is imperative that you nail the sweet spot, right in the middle of where you want to be.
It’s the only job I know of where they will pay you for this line of work. The thrust of what I’m saying is that the sticky part of the job isn’t too bad if you keep your frictions just right, and never rush a good thing. Just take your time, find the sweet spot, relax and enjoy it. After that, it’s all brute horsepower.
I hope this has answered your query, and feel free to ask me anything, anytime.
So, are ya always moving yer hands and legs all the time doing stuff? Is there ever a time you just fly along without doing any of that?
Thinking about this – you all are just really cowboys – it is just like riding bucking broncs, eh?