All i need now is the balls to try it

[Graviman]

Some constructive thoughts...

Bug,

Just make sure that when the tethers are taught they line up with the C of G.

The reason the rotorway went over is that skids do not allow any compliance (in comparison with oleos). So the skid touches and applies a force that does not pass through the C of G - this is called a torque and clearly overpowers any cyclic input. If you are lucky and dump the collective then the aircraft has not accumulated enough inertia about the longitudinal axis to roll over. Interesting to note that ship based helicopters allow negative pitch to apply a downwards force, which would help recover.

Allow as much compliance as you can in the tethers - bungee chord maybe. The more gently you deccelerate the airframe the lower the forces will be.

Ideally, tether the fuselage and not the skids to minimise effect of angular movement (ie CG moving off thether axis). Hard to achieve and be sure that tether does not foul the skids too (which could be a disaster). This may be why a lot of the pioneers used widely spaced oleos to allow tethers freedom of movement.

I still think you might be better off replacing skids with ball end links and do initial ground runs on a wide base trolley overweighted to overcome any lift the rotor could develope - including transition. Have links forming corners of a pyramid with apex just above CG. Diagonal crosses with bungee chord will overcome any tendancy to fallover. If not a scissor link under the fuselage then use a Watt Z-linkage on tail boom to stop any yaw without affecting pitch and roll. This will let you "fly" the machine to get a feel for its dynamics, albeit slowed down a little, as well as gain confidence in the design.

I'm pretty busy, but would be happy to talk off-line.
Still in Cambridgeshire but don't mind a day trip.

Mart