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HomeAircraftHelicopterHelicopter Main Discussion › Why real heli do not have flybar
04-11-2014 03:28 PM  4 years agoPost 21
AirWolfRC

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AirWolfRC, you used the terms teetered rotor head and semi-rigid rotor head in reference to right side up and upside down horizontal stabs on the tail like they were two different types of rotor systems when they are the same. Did you mean to say semi-rigid/teetered and articulated?
Every industry likes to invent new words or definitions for what it does. Makes it sound more mysterious.

I'm talking about the rotor head difference between a Bell47/UH1/AH1 and UH60/CH46/CH47/CH53

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04-11-2014 10:42 PM  4 years agoPost 22
Vaderluck

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Melbourne - Australia

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Has anyone experiment with replacing a flybarless gyro with a flybar gyro (ie. normal tail gyro) on a DFC heli ?
It will probably fly ok on large heli like 600 or 700 ???

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04-11-2014 10:48 PM  4 years agoPost 23
JKos

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Redondo Beach, CA

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Has anyone experiment with replacing a flybarless gyro with a flybar gyro (ie. normal tail gyro) on a DFC heli ?
That's where RC augmented FBL began! Rewind history (do some searching) and you'll find it back there somewhere.

- John

RR rules!

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04-11-2014 10:59 PM  4 years agoPost 24
philip 01

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ft worth

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The SCAS system and many like it have been around for a long, long time.

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04-11-2014 11:42 PM  4 years agoPost 25
Trexwilly

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FL USA

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I took a couple of lessons in a Bell 47, it had a flybar, the instructor had me bang on it, during preflight, I don't remember why?

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04-12-2014 12:42 AM  4 years agoPost 26
Gearhead

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Vt

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here is another Huey Head, it is slightly different than the other Huey Head I posted, I believe this is an older head, notice the Hirobo Grips

Jim
Buzz Buzz Buzz

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04-12-2014 12:48 AM  4 years agoPost 27
Chuck Bole

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Tulsa Ok. U.S.A.

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Anybody remember this?
http://www.rcgroups.com/forums/showthread.php?t=500904

chuck

Team Synergy Field Representative / Thunder Power

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04-12-2014 01:05 AM  4 years agoPost 28
HeimD

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the great southwest

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Many full-scale helicopters do have flybars (Stabilizer bar).
List some modern helos. The UH-1 Huey isn't modern.

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04-12-2014 01:08 AM  4 years agoPost 29
HeimD

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the great southwest

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Why is there a up-side-down airfoil on the tail boom producing down force on helis with a tetering head ?
To provide down force on the tail boom aft of the CG to provide a more comfortable nose level attitude at cruise.
And a right-side-up airfoil producing up force on a semi-rigid rotor head ?
Which helo? The Bell 206 head is both teetering (underslung) and semi-rigid. It has the upside down airfoil of which you speak.

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04-12-2014 01:14 AM  4 years agoPost 30
HeimD

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the great southwest

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It also has a lot to do with the head most full scale are running multi bladed heads. If you had a 4 bladed head on yours you would have a pretty stable bird without the need for a flybarless system. Would just be that much more drag and strain on the system. Which is why most 3d helis only have 2 blades.
Then explain why two of the most popular two bladed helis in history (Bell 206 Jet Ranger and Robinson R22/44) don't have flybars.

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04-12-2014 02:58 AM  4 years agoPost 31
AirWolfRC

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42½ N, 83½ W

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The difference is the up-side-down foil at the tail counters the air drag on the fuselage to help keep the fuselage perpendicular to the rotor disk because the mast is basically on a "free" pivot hanging under the rotor head.

The other way is also sometimes represented by a down angled tail rotor providing up force to help counter the tendancy of the rotor disk to pitch up in forward flight. This helps with the overall aerodynamic efficiency.
See the CH-53E

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04-12-2014 04:50 AM  4 years agoPost 32
UH-60PILOT

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Seoul, South Korea

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OK AirWolfRC, just to set the record straight none of those are new or mysterious terms related to rotor systems. Teetered and Semi-Rigid are the same thing. The Bell 47/UH-1/AH-1 all have the teetered/semi-rigid design and the UH-60/CH-46/CH-47/CH53 all have fully articulated heads.

Kenny Thompson

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04-12-2014 06:24 AM  4 years agoPost 33
HeimD

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the great southwest

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The difference is the up-side-down foil at the tail counters the air drag on the fuselage to help keep the fuselage perpendicular to the rotor disk because the mast is basically on a "free" pivot hanging under the rotor head.
I believe the word you are looking for is "parallel". And, even that's still not entirely true. A forward tilted rotor disk in forward flight with an accompanying nose down attitude of the fuselage is undesirable, hence the "upside down airfoil" back on the tail boom which helps keep the nose up and more "parallel" with the earth's surface.

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04-12-2014 07:08 AM  4 years agoPost 34
Gearhead

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Vt

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sO what about UFOs ????

Jim
Buzz Buzz Buzz

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04-12-2014 06:55 PM  4 years agoPost 35
AirWolfRC

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42½ N, 83½ W

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I believe the word you are looking for is "parallel". And, even that's still not entirely true. A forward tilted rotor disk in forward flight with an accompanying nose down attitude of the fuselage is undesirable, hence the "upside down airfoil" back on the tail boom which helps keep the nose up and more "parallel" with the earth's surface.
The idea is to keep the mast (fixed to the airframe) perpendicular to the rotor disk.

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04-12-2014 08:49 PM  4 years agoPost 36
HeimD

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the great southwest

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The idea is to keep the mast (fixed to the airframe) perpendicular to the rotor disk.
Okay, but that's not what you said. The fuselage being perpendicular to the rotor disk would be a very, very bad thing. Mast bumping anyone?

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04-12-2014 09:00 PM  4 years agoPost 37
AirWolfRC

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42½ N, 83½ W

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OK AirWolfRC, just to set the record straight none of those are new or mysterious terms related to rotor systems. Teetered and Semi-Rigid are the same thing. The Bell 47/UH-1/AH-1 all have the teetered/semi-rigid design and the UH-60/CH-46/CH-47/CH53 all have fully articulated heads.
"semi-rigid" and "fully articulated" doesn't really clarify much unless you're already long in the business.

. . . and that's my point.

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04-12-2014 09:47 PM  4 years agoPost 38
HeimD

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the great southwest

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"semi-rigid" and "fully articulated" doesn't really clarify much unless you're already long in the business.
Brand new Navy helo flight students in HT-8 or HT-18 learn this difference in ground school on a daily basis.

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04-12-2014 10:08 PM  4 years agoPost 39
AirWolfRC

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42½ N, 83½ W

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When the people on this list start attending Navy helo flight school,
. . . I'll give you that argument.

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04-12-2014 10:34 PM  4 years agoPost 40
torque

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bolivia , north carolina

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I have a bunch of hours in a hiller 12c, (killer hiller) nice
machine, cyclic response is slow as opposed to hydraulic assisted.

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