No, certainly not. Assumption is a fundamental to convert ideas into applications. Well, my assumption doesn't make an ass out of any one. Because I have been very conservative in my assumption. I assumed all recovered spare power used on friction and wind when possibly you may not need more than a quarter of that as the friction is negligible and the wind is not always against you. Let us to do some formulas to support the concept. In the figures it is assumed the slope to be 1/100 and the gross weight of a glider to be 20,100.00kgs. We assume 100.00kgs as a driving weight. So we need to recover only 20,000.00kgs/glider of water to a height of 100.00metres as counter weight and spare power. A counter weight of a glider of gross weight 20,000.00kg on a slope of 1/100 is 20,000 x (1/100) = 200.00kg. In other words a glider of 20,100kgs has to pump up 200kg of water to a height of 100metres for each 100metre glide. So what sort of cross sectional area pipe we need? 200.00kg of water = 200,000.00grams=200,000.00 cubic centimetre volume Convert this volume to a pipe of 100m long, high. To do that use the following simple formula: volume = height x cross sectional area 200,000.00 = 10000 x cross sectional area 20.00CM Sq = Cross sectional area.