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Hanging one side low

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Hanging one side low

Old 25th Mar 2020, 11:31
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Originally Posted by [email protected] View Post
ISTR the people that investigated the 2 Sea King dynamic rollovers (one at St Magwan and the other brilliantly reproduced at Boscombe Down) on level ground were very interested in rolling moments from MR and TR and especially their position relative to the vertical C of G
I wondered whether to mention dynamic rollover. In this case there is a pivot and it is critical to what happens. Is this thread-drift too far now?
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Old 28th Mar 2020, 15:25
  #102 (permalink)  
 
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Can't believe I missed this thread!
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Old 5th Apr 2020, 02:12
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Regardless of direction of rotation...
Regardless how high or low the TR output shaft is...
Regardless of how passengers are arranged...

ALL SINGLE ROTOR HELICOPTERS have a vertical propeller creating horizontal thrust that blows the aircraft sideways. The correct term is "translating tendency."
THE ONLY WAY TO STOP the sideways movement of the helicopter is to tilt the rotor tip-path-plane a little bit to the opposite side and create an equal amount of sideways thrust the other way.
All helicopters' fuselages will tilt along with and in the same direction as the rotor's tip-path-plane, some head designs more than others.
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Old 5th Apr 2020, 10:08
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Nobody calls the rotor a 'vertical propeller' and translating tendency is a term of US origin, it is better understood when called tail rotor drift, with tail rotor roll the description of the fuselage attitude after the rotor had been tilted to counter the drift.
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Old 5th Apr 2020, 13:24
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Originally Posted by [email protected] View Post
Nobody calls the rotor a 'vertical propeller' and translating tendency is a term of US origin, it is better understood when called tail rotor drift, with tail rotor roll the description of the fuselage attitude after the rotor had been tilted to counter the drift.
A Tail Rotor is in fact a vertical propeller that produces horizontal thrust. A Main Rotor is in fact a horizontal propeller that produces vertical trust. If you are wound too tightly to accept that description,
then you are part of the reason beginners find it difficult to understand the rotors, how they work, the job they do, and the side-effects they cause.

Bryan
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Old 5th Apr 2020, 13:45
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Originally Posted by [email protected] View Post
Nobody calls the rotor a 'vertical propeller' and translating tendency is a term of US origin, it is better understood when called tail rotor drift, with tail rotor roll the description of the fuselage attitude after the rotor had been tilted to counter the drift.
If your springy-thingy is wound too tightly to accept my characterization, then you are part of the reason beginners have a tough time understanding helicopter rotors, their design features, how they work, the job they do, and the side-affects of it. A Tail Rotor IS in fact a vertical propeller that produces horizontal thrust, and a Main Rotor IS in fact a horizontal propeller that produces vertical thrust.

If a beginning student's first exposure to rotor systems is through this viewpoint, and as their depth of understanding grows, they continue to process ideas through this idea, they will fully grasp all the other complex principles like flap/hunt/feather, transverse flow, driven/driving/stalled regions, dissymmetry of lift, retreating blade stall, and all the other tough to grasp subjects.

Bryan
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Old 5th Apr 2020, 14:10
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Oh dear me....next thing we know there will be colored pencil drawings required and the mandate that only CFS terminology be allowed.



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Old 5th Apr 2020, 14:56
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It just shows where people don't actually understand a thing - they can only parrot what was on a training slide.

PDR
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Old 5th Apr 2020, 20:14
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only CFS terminology be allowed.
Too true,Sassy, and you must use the Vu-Graph for the slides, turning it off before removing one slide and putting the next one on.
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Old 6th Apr 2020, 07:01
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I'm watching Ascend Charlie.
E86
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Old 6th Apr 2020, 07:07
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Bryan - perhaps it is you who is wound too tight I didn't say the MR and TR were not propellers in the strict definition of one - just that nobody in the rotary world calls them that.

Talking about propellers when you mean rotors is surely a quick way to confuse newbies.

I've only been teaching helicopter stuff for 31 years so I probably don't have a clue.......................................

CFSH has quite a good reputation worldwide but its easy to knock if you haven't experienced it.
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Old 6th Apr 2020, 08:11
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I've only been teaching helicopter stuff for 31 years so I probably don't have a clue................
It is more likely that you have been teaching CFSH stuff for 31 years.
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Old 6th Apr 2020, 10:54
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Originally Posted by [email protected] View Post
Bryan - perhaps it is you who is wound too tight I didn't say the MR and TR were not propellers in the strict definition of one - just that nobody in the rotary world calls them that.

Talking about propellers when you mean rotors is surely a quick way to confuse newbies.

I've only been teaching helicopter stuff for 31 years so I probably don't have a clue.......................................

CFSH has quite a good reputation worldwide but its easy to knock if you haven't experienced it.
Well THIS 34 year helicopter guy (87-17 Royal Blue Ft. Rucker) will continue to refer to the rotors as propellers
sometimes, as well as air-pumps, egg-beaters, paddles that thump the air, a "a big fan that keeps the pilot cool."
LOL Because if it stops...watch the pilot start sweating.

In your defense, I work as an engineer in advanced composites for Meggitt, a pretty large aerospace manufacturing
company. A few of my peers at work are wound a little too tight also and they used to give me grief for my red-neck
analogies. After several years there (in my 6th) they have learned that I can often "get-through" to someone when
they can't.

Bryan
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Old 6th Apr 2020, 11:19
  #114 (permalink)  
 
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I'm watching Ascend Charlie.
E86
Oh jeez, I was talking when the teacher was standing behind me. I'm in trouble now.

The CFS books, I think it was the AP3456A, had some glaring faults, as do the FAA helicopter instructional documents. But if you show it on a Vu-Graph, it seems to make sense, even if it's horsefeathers.
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Old 6th Apr 2020, 15:13
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I looked up the acronym for CFSH online. I'm sure it stands for "Chicken Follicle-Stimulating Hormone".
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Old 6th Apr 2020, 22:00
  #116 (permalink)  
 
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It is more likely that you have been teaching CFSH stuff for 31 years
and Prouty, Wagtendonk, Coyle and others. The CFS H teaching is a method of teaching not the syllabus and uses the best of the best techniques gleaned from all areas of education.

You do the course and then start learning your trade - the quality of instruction comes down to the character and personality of the instructor not the need to use the right colours.

AC are you referring to the OverHead Projector when you say vu-graph?I'm too young to know what one is otherwise

Jim Eli - it's all about Pelicans not chickens
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