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Old Apr 17, 2012, 01:06 PM
Mildly Confused
Paul 1968's Avatar
UK
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Quote:
Originally Posted by teamdavey View Post
"Huey types won't lean due to the position of the tail rotor"

Only true if the head is fully teetering. The thrust to counteract the tail rotor thrust has to come from somewhere - if not the helo will drift sideways. Both my old Morley UH-1 and the big Turbine UH-1C I sometimes fly hover left skid low. (Both are left hookers.)
Appreciate the clarification Jim, many thanks.
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Old Apr 17, 2012, 01:21 PM
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lcc014's Avatar
United States, MA, ALLSTON
Joined May 2011
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Quote:
Originally Posted by PHMX View Post
That's actually incorrect, as the torque and turbulence effect you guys are talking about doesn't actually make a helicopter lean at all.

In a worst case scenario it'll influence the general tail authority, just like a tail gyro will have an easier task when going with the torque direction.

But trust me on this one, if a helicopter leans in such a way that it's that noticeable, it's all about it's center of gravity being off.
So the explanation in this link http://www.helifreak.com/showthread.php?t=146504 is incorrect ?

Ching-Ho Cheng
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Old Apr 17, 2012, 01:30 PM
Never trust laughing dolphins
Joined Feb 2011
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Quote:
Originally Posted by lcc014 View Post
So the explanation in this link http://www.helifreak.com/showthread.php?t=146504 is incorrect ?

Ching-Ho Cheng
Yes, that explanation is quite incorrect.

To me that explanation sounds like it assumes that the centrifugal forces at one (!) of the tips of the rotor blades are somehow bigger than any of the other forces involved with flying (general drag, weight/mass, lift), which is in fact quite untrue. There's also no such thing as a 'pendulum stability' when a fixed main shaft is how the body and rotor are linked together.

I honestly do not get why people think that this is a normal thing. None of the scale helicopters I've got, none of the regular helicopters I've got exhibit any of this leaning.

While I do fly a lot of 3D with many of my helicopters, I do know what people talk about when in a basic hover or not just as well lol.
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Old Apr 17, 2012, 01:45 PM
Team Mulikow 3D
Oxfordshire, UK
Joined Jan 2007
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I just knew that you would see it differently

Quote:
Originally Posted by PHMX View Post
When I think about it, did you ever see a pro fly with a non-level flying helicopter??
YES - I was taught by former World Champion Paul Heckles, and he is the one that taught me to watch the skids and rotor and have them off-level to counter the sideways movement, but he's presumably wrong as well
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Old Apr 17, 2012, 01:49 PM
Registered User
Sunnyvale, CA, USA
Joined Apr 2000
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All the "why" is here:

HELICOPTER HOVERING ONE SKID LOW
http://www.askharryhelicopter.com/ne...er/march09.pdf
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Old Apr 17, 2012, 01:54 PM
Never trust laughing dolphins
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Quote:
Originally Posted by MikeHRC View Post
I just knew that you would see it differently



YES - I was taught by former World Champion Paul Heckles, and he is the one that taught me to watch the skids and rotor and have them off-level to counter the sideways movement
That would make him just as wrong as you are, as the only moment a helicopter will lean slightly is during take-off when ground resistance is adding more friction to the entire equation.

Then at full lift-off, it's gone.

To all the skeptics, just answer the following question please.

If this rotor disc effect is so great, then why do none of my helicopter nor most helicopters for that matter exhibit the leaning effect under all conditions?

When it's all about lift, a rotor disc at an angle will make it more susceptible to wind-caused drift, instead of less. At high rpms the torque really can't cause a lean.
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Old Apr 17, 2012, 02:03 PM
Team Mulikow 3D
Oxfordshire, UK
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Quote:
Originally Posted by PHMX View Post
When it's all about lift, a rotor disc at an angle will make it more susceptible to wind-caused drift, instead of less. At high rpms the torque really can't cause a lean.
You are not listening again - the torque does not cause the lean, the lean is to counter-act the sideways force of the tail rotor
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Old Apr 17, 2012, 02:04 PM
Never trust laughing dolphins
Joined Feb 2011
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Quote:
Originally Posted by teamdavey View Post
All the "why" is here:

HELICOPTER HOVERING ONE SKID LOW
http://www.askharryhelicopter.com/ne...er/march09.pdf
No math? No physics equations proving any of this?

I guess you guys forget that contrary to airplanes, the rotor disc provides all lift.
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Old Apr 17, 2012, 02:07 PM
Never trust laughing dolphins
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Originally Posted by MikeHRC View Post
You are not listening again - the torque does not cause the lean, the lean is to counter-act the sideways force of the tail rotor
Not quite true, I've actually acknowledged the effect on tail authority. But it won't cause a lean, in fact the tail rotor blades rotate inwards on a clockwise rotating main rotor to counter basically all of this. And yes, this is both torque and lift or tail pitch related.

As said, it influence tail authority. Turning the tail in one direction will require less force than the other direction.
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Old Apr 17, 2012, 02:09 PM
Mildly Confused
Paul 1968's Avatar
UK
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All of my helicopters exhibit right skid low hovering tendencies. All of my current helicopters are right hookers, I have previously owned several left hookers which exhibited left skid low hovering tendencies. It seems Mr. Davey beat me to it with his link but I have found this http://www.helicopterpage.com/html/forces.html.

I bet you're going to tell us even the full size is set up wrong too as well now.
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Old Apr 17, 2012, 02:10 PM
Team Mulikow 3D
Oxfordshire, UK
Joined Jan 2007
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Quote:
Originally Posted by PHMX View Post
Not quite true, I've actually acknowledged the effect on tail authority. But it won't cause a lean, in fact the tail rotor blades rotate inwards on a clockwise rotating main rotor to counter basically all of this. And yes, this is both torque and lift or tail pitch related.

As said, it influence tail authority. Turning the tail in one direction will require less force than the other direction.
Sorry mate - I don't think you're reading it still ....

I'm NOT saying that the tail rotor is causing the lean, the lean is there to counter the effect of the tail rotor pushing the heli sideways
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Old Apr 17, 2012, 02:13 PM
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USA, KS, Derby
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Quote:
Originally Posted by PHMX View Post
That would make him just as wrong as you are, as the only moment a helicopter will lean slightly is during take-off when ground resistance is adding more friction to the entire equation.

Then at full lift-off, it's gone.

To all the skeptics, just answer the following question please.

If this rotor disc effect is so great, then why do none of my helicopter nor most helicopters for that matter exhibit the leaning effect under all conditions?

When it's all about lift, a rotor disc at an angle will make it more susceptible to wind-caused drift, instead of less. At high rpms the torque really can't cause a lean.
Just to be clear... we talking of single rotor helis here, correct? Not Co-axial?
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Old Apr 17, 2012, 02:43 PM
Never trust laughing dolphins
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Originally Posted by MikeHRC View Post
I'm NOT saying that the tail rotor is causing the lean, the lean is there to counter the effect of the tail rotor pushing the heli sideways
No, I think you're just being biased here, as that's exactly what I am saying is not actually happening.
.
You're also gravely confusing cause and effect here too, but perhaps you're simply not being very clear.
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Old Apr 17, 2012, 02:59 PM
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Sunnyvale, CA, USA
Joined Apr 2000
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All single rotor helicopters must "lean" the disk to oppose the thrust of the tail rotor or they will drift. The Seasprite AS heli spends most of its life in a hover and actually has the mast inclined slightly to allow the body to stay level in the hover and allow for a level deck landing/take off.

Check any text on heli aerodynamics and you will find a clear description of what is going on and why.

Paul - nice link I wish I had found that one!
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Old Apr 17, 2012, 03:15 PM
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Nottinghamshire, UK
Joined Dec 2009
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Hi Guy's,

I've just added the next instalment to the FBL video series that I'm working on. (Conversion of a 450 v2 to FBL)

I'll be totally honest and after shooting this vid I was a little unsure about it as it's come out too long! Especially for a thread like this where there are many expert pilots and experienced hobbyists Please bear in mind that it was always my intention to be beginner friendly and that I'm new to producing this sort of instructional video. The next vid is being filmed at the moment as and when I can grab some spare time and I'm making an effort to condense it without losing the newbie along the way. We shall see

One this that might hold me up though is that my latest ZYX purchase seems to be delayed in the Easter post

Simon

ps. I'm off now to learn camstudio in preparation for vid 4. Oh and I'll add some links to the video post notes...
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