Experimental - Lifting rotor Using a lift line for Mechanically actuated cyclic banking

A description of something I’ve been working toward.

A while ago Windswept came to a point where we realised we needed a rotary lift system.
Our lift line tension was too low for scaling, we needed much more active kites, moving fast in order to build line tension to support lower rotors that drive torque.

I’m lazy, I wanted something simple and mechanical. I didn’t want to fly a bunch of electronics in the air.
Another terrible trait I have is wanting to do several experiments at once. So I’d like to try a rotor that can pack away and fold into a really small volume.

Two line delta kites fit the bill. They’re semi-rigid, they pack away very small, they’re very fast and they can perform tight looping maneuvers. I’ve nearly finished building a little rig, to test how they work on a rotor, and to see if I can bank them cyclically in a simple mechanical way.

The premise this time is really simple (Probably too simple)
Rotors are heavy, so they will sit lower in elevation than the line of a lift kite. Yes, I’m still using a lift kite.
The low elevation means that
There is a misalignment between the plane of the rotor and the lifting line.
This misalignment allows us to add a new kind of bridle, a topside bridle, Which I suspect can be used to power the actuation of cyclic banking

Quite the extent of efficacy or the wind range applicable or the balance of forces…
Well
I’m just going to stick the £^*%£ thing in the air eventually to find out what I can
There’s a video of the model to help your understanding
here

and some pics of the parts



This second picture shows the top bridle, the two lines in yellow.
The idea is … the rotor is heavy, So the blade on the bottom side of the rotor will be pulled more by the outside - making the bridle tighter. This hopefully makes the kite bank to be more flat when it’s on the bottom side. Thus promoting a more lift shape than a vertical oriented blade. Similarly on the top (Though probably to a lesser extent) the force shifts to the inside of the rotor.
Typically my rotor blades are already banked in (Outer tip down) a bit to help with expansion. As such the topmost blades are usually already more horizontal than the rotor.

Potentially an obvious problem with this is the lift line tension is going to be lower than the tension developed on the rotor blades. Therefore the effect will not be very strong.
It’s something I’m willing to test.
I’ll explain more in a write-up and video.

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Good to see some activity again, not just on paper

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I’ve had the same idea. I couldn’t reason out if it could work or not, so thanks for trying it out. Reconsidering it now, with your low line tension comment, you could make the top bridle be wider than the bottom bridle. Taking that to the extreme would be the top bridle going to the wingtips, and having no bottom bridle. That way the top bridle would have a bigger moment arm than the bottom bridle and so would have a bigger influence. You could do moment arm * line tension comparisons to see what could maybe work. You can do the same for all the kites down the train.

Within your design constraints, I like my cam-actuated cyclic banking idea better.

I like having a lifter kite, if for no other reason than to prevent the kites from falling to the ground if you stop rotation.

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Yep
valid points on the top bridle geometry relation to force, drag, actuation, stability…

I also like the idea of a cam on the lower sider (Upwind, high tension, normal bridle side) being used to actuate the cyclic bridling changes required for cyclic banking (roll) control.
I worry though that the cam would have to be quite a large component and require vanes and mass to hold it’s position against the tensions of the active bridle set.

That’s why I chickened out and decided to try topside