1177

Item 1177

DESIGN: Dragonfly ~ Control - Flight - Assembly - Layout (w/ Swashplate)

Drawing:

Look into the possibility of decreasing the V-angle and/or the Stagger even more.

But what about yaw??
Notes:

A spider might be a usable option to the swashplate.

The horizontal control rod passes straight through the yoke. There is a universal joint in the center of the yoke. The vertical rod in mast move horizontally slightly.

Phase Lag:

The controls, as currently shown on the drawing, are located for a phase lag of 90º. The teetering hinge offset will result in this angle being less.

Pitch Angle Considerations:

DESIGN: Dragonfly ~ Control - Flight ~ Pitch Angles & Pitch Angle Considerations

The following is related to the Dragonfly w/ swashplate:

The pitch horn (in the mast) is approximately 1.75" long.
The total collective pitch change of 20º at the 1.75" radius on the pitch horn is xx" of vertical movement. The radius at the hub end of the horizontal control is xx". This means that the swashplate must have xx" of vertical movement.
The longitudinal cyclic movement (which is the greater of the lateral and the longitudinal) of 22º at the 1.75" radius on the pitch horn is xx" of vertical movement. The radius at the hub end of the horizontal control is xx". This means that the swashplate must have xxº of angular movement.

Interaction in Hub - between Control Rods and Tie-Rods:

The movement at the top of the pitch link, for 10 of flap is 0.22".

The movement of the tie-bar, for 10 of flap is 0.50".

It must be noted that

These two components basically move in sync with each other.
In addition to flap, lead/lag will also effect the position of the tie-bar.

Therefore clearance is ........?? Will the base of the rod end clear the tie-rod?

At the present time, see drawing 1181 for dimensions and development.

Blade Pitch Control Bearing:

The inboard end of the flight control torque tubes is mounted on a bearing in the center of the rotor hub. The torque tubes must rotate approximately 30º and move axially approximately 0.5". This axial motion will cause a vertical angular motion of approximately 0.01º. A couple of ideas for mounting these three bearings is;

Use a self-aligning control bearing and mount in a fixed structural part of the hub. The torque tube will have to slide axially in this bearing, or in a bushing located in this bearing.
Locate a normal control bearing at the bottom of a vertical tongue. Hinge the top of this tongue to the mast's top cap. As the torque tube moves axially, this bearing will move with it and skew. Because of the hinge at the top of the tongue, this bearing will rise, visa-vie the pitch link, when the blade flaps up and down. This rise and fall visa-vie the pitch link can be used to pull pitch, non-linearly, during flapping; and this should be operationally similar to delta-3. Note that the universal joint will probably be able to add or remove some delta-3, depending on the azimuths of the X-yokes arms at instalation. It appears that the self-alignment in the bearing must be +/- 9º and the Torrington KSP-A control bearing has only 8º, while the larger KSP control bearing has 10º.

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Last Revised: August 13, 2003