In the topic ‘Lever-arm Launch”, I suggested an alternate method using a number of LTA tubes to lift the kite to an adequate launching height. It occurred to me that the device can be simplified by having a rigid network of inflatable tubes which can be secured at the corners. (See drawing). BALLOON FRAME.pdf (69.9 KB) This frame of tubes is filled with hydrogen, helium or even hot air. With this scheme, the kite is lifted to an acceptable launching height, and at this point the frame of tubes is restrained from lifting further by four tethers at the corners. After the kite separates, the frame is lowered and the lifting gas can be pumped out of the tubes and the frame will be stretched out on the ground ready for the next refill and launch. The weight of a single skin kite with bridling is minimal, and therefore the size of the tubes and volume of LTA gas required is not excessive. The balloon frame can be used in conjunction with my concept of a fully restrained kite which is launched and landed from the same spot. On the ground, the kite is spread out over the balloon frame and when it is landed, it returns to the same location. I feel that with this system the kite can be reliably launched and landed without human assistance. The determination of when to land can be controlled by continuously monitoring tether tension and setting maximum and minimum limits. Similarly the decision to launch is determined by the strength and direction of wind speed. Of course we can override the automatic launch and land system for the purpose of maintenance or if there are reports of turbulent weather.
With a fully restrained kite and balloon lifting system we might be able to operate a fully automatic and “unassisted” launch and land system.
As an example let us consider an approximately 1 MW system. This will require an approximately 1600 M² single skin lifter kite to support the turbine system. The lifting frame will consist of 54 tubes 40 meters long. Tubes are 0.3 M diameter and are laid out in a grid 1.5 M on centers. My estimates of weights, volumes and costs are as follows:
BALLOON FRAME DATA.docx (13.3 KB)
This method can be tested out on a small scale. Instead of winders at various locations, we can transfer all the cables by means of idler pulleys to a single winder. This method might be employed on a full scale system