Aug 06, 2003, 03:06 AM Rhodesst Rhodesst Guest n/a Posts Re: Large Scale turbine Jet Ranger at 3D masters > >Without the paddles, the bar would not have any incentive to "maintain it's >position 90 degrees >from the rotor mast". Hi Steve S, I disagree. The flybar will try to maintain a position, 90 degrees to the rotor mast. The reason for this is simple centrifugal force. There will be a time lag between the time that the system is disturbed and the time the flybar reorients itself, but it "will" attempt to reorient itself. Fly Safe, Steve R.
 Aug 06, 2003, 03:06 AM Steve Simpson Steve Simpson Guest n/a Posts Re: Large Scale turbine Jet Ranger at 3D masters > I disagree. The flybar will try to maintain a position, 90 degrees to the > rotor mast. The reason for this is simple centrifugal force. There will be a > time lag between the time that the system is disturbed and the time the flybar > reorients itself, but it "will" attempt to reorient itself. > While that does seem logocal, it is incorrect. Gyroscopic force would hold the spinning bar in a single plane unless acted upon by an outside force. Absent paddles, there is no outside force . . until the mast bumps the bar. Consider that centrifugal force exerts a force 90 degrees to it's OWN rotation. In this case the relevant revolution is about the middle of the flybar, not the center of the mast. The mast tilt has negligible effect because it is hinged at the bar and therefore cannot exert influence.
 Aug 07, 2003, 03:02 AM Rhodesst Rhodesst Guest n/a Posts Re: Large Scale turbine Jet Ranger at 3D masters > >Consider that centrifugal force exerts a force 90 degrees to it's OWN >rotation. In this case the >relevant revolution is about the middle of the flybar, not the center of the >mast. Well, exactly "where" is the middle of the flybar, if it's not in the middle of the rotor mast?? The rotor mast "is", in this case, the center of rotation for the flybar and it will try to orient 90 degrees to that point. The mast tilt >has negligible effect because it is hinged at the bar and therefore cannot >exert influence. I would agree with this IF the flybar hinge point was movable in "all" directions, like the center of the swashplate. Only thing is, it's "not!" The flybar can teeter in one plane only, relative to the rotor mast. Now, if the rotor mast is changing it's axis at the exact instant that it's in line with the teeter axis of the flybar, then for that brief instant, the flybar will maintain it's plane of rotation and everything will be happy. Only problem is, 90 degrees later, the flybar is being forced off of it's plane of rotation because it can't teeter in all directions, relative to the rotor mast. It won't like that and "will" try to reorient back to a position 90 degrees to the rotor mast. FWIW, I'm getting this from a video I own, bought it years ago along with several others when I first got into RC helicopters. I was trying to learn as much as I could about how they fly. Anyway, it's part of the "Aviation A.V. Library" and I got it from a company called: Aircraft Components, Inc. Benton Harbor, Michigan 49022 616-925-8863. The publisher is: Ferde Grofe Films 3100 Airport Ave. Santa Monica, CA. 90406 213-397-7524 The specific tape is called "Attack Copter" and includes six parts titled: 1. Evolutions of Attack Helicopters - Concepts of Deployment. It has footage of the Huey, Cobra, and Cheyenne. 2. Tactical Formation Flying and the parts I was most interested in at the time! 3. Helicopter Aerodynamics - Rotor blade actions 4. Helicopter Aerodynamics - The Stabilizer Bar (which is the basis for most of what I'm trying to talk about here) 5. Helicopter Aerodynamics - Dissymmetry of Lift 6. Helicopter Aerodynamics - Rotor Blade Angles. These are basically old army training tapes and they are pretty dry watching a lot of the time. They do have good info on some basics which didn't hurt me to learn about. I have no idea if these tapes are still available. The copies I have are over 20 years old now. Fly Safe, Steve R.
 Aug 07, 2003, 03:02 AM Steve Simpson Steve Simpson Guest n/a Posts Re: Large Scale turbine Jet Ranger at 3D masters > > Head speed has a significant effect on handling characteristics. If a heli > has a tendency to > > pitch up, then varying head speed may accentuate or reduce that tendency > making the handling > > inconsistent if the head speed is changing during flight. > > Shouldn't it then have an equal tendency to pitch down? I'm not sure I > understand why the head speed is the determining factor when a heli is > pitching up. Methinks you are finding information that no one is actually providing. I don't see where anyone said that head speed was a 'determining factor' in a heli pitching up. > > They do . . . I think you may have misinterpreted the comment. > > Then why are flybar-less heads more prone to irregular rotor speeds than > heads with a flybar? Once again, I don't see where anyone has made such a claim. Debate works better if you read carefully and don't fill in the blanks with your own assumptions.