Back to the Future
Back to the Future
Leviterande's initial post asked the question; "What I am wondering is, is there a helicopter made just like a gyrocopter with a direct tilt teetering hinge? (such a helicopter incorporates also an independent collective of course.)"
Chuck responded on post #2 "None if you mean cyclic control via rotorhead tilt. A component of drive torque will be present in the cyclic control system that will make manual control impossible."
On post #8 Chuck elaborates on the effect of torque due to the Universal joint (also referred to as a Hooke's joint and a Cardan joint)
I agree. If a Universal Joint is located between the axis of the mast and the axis of the rotor disk, there will be a 2-per-rev pulsation when there is an attempt to tip (misalign the two axe). However, this pulsation will be eliminated if a Constant Velocity Joint is inserted between the rotating mast and the rotorhead.
Perhaps "a helicopter has never been made just like a gyrocopter with a direct tilt teetering hinge". However, that does not necessarily mean "that a helicopter" cannot be "made just like a gyrocopter with a direct tilt teetering hinge".
The following should be relatively easy to make. If someone can give a valid or perceived reason why it cannot work ~ please say so;
1/ Locate a
Constant Velocity Joint between the rotating mast and the rotorhead. Now, it should not make any significant difference whether the rotor being driven aerodynamically (gyrocopter) or mechanically (helicopter). Of course a tail-rotor will be required.
2/ Then rigidly mount a pair of propeller blades to this rotor hub at 0-deg and 180-deg azimuths, just like
Schoeffman's rotor.
3/ Then mount a teetering rotorhead, which has a large opening in the middle ~ i.e two-part teetering hinges, with these blades located at 90-deg and 270-deg azimuths.
4/ Then give the teetering rotor
Hub springs or
Bi-teetering Offset.
This weight-shift craft should now have faster controllability and auto-rotative ability.
Here is detailed information on a 3-blade Constant Velocity Hub, which can be modified for 2 blades.
Here is information on a widened teetering hub. It also incorporates a torque-pitch collective, if desired.
Or, let other countries innovate.
Chinese eye Marine One Contract
Dave