Big wind

F-35 shown obsolete on previous posts.

   Doing wind measurements above ground level in the 1950s as part of the work for rocket launches, it was determined that over the U.S. there were constant winds at 100 ft ( 360 m) above ground level.  The winds shifted in direction and strength byt were always present.  In fact, the 1200 ft level represented the maximum velocity of winds near ground.  In order to build wind power, that 1200 f levell would be the optimum point for the rotor hub with the blades extending above and below.

  Building a tower of that height would best be accomplished by using the tower itself as part of the lifting crane.  Wheeled ring elements would be lifted against the tower after it has had its lower section assembled by cranes, B, and then the assembled sections would ride up and down along the outside of he tower.

   The individual sections would have, D, spring elements, most likely similar to leaf springs, s, to allow for some movement between them and keyway blocks, k, to prevent them from sliding relative to one another. The keyways would be solid metal rod that would slide into openings in the other element.  The springs could be fiber reinforced plastic or metal.
   To hold the unit together, wires, w, would be wrapped around the sections and placed under load before being clamped in position, to serve as structural connection and to provide downforce on the wheels while running up the tower for traction.
   After the elements are connected, crane booms would be erected on top of them and then the booms would be connected by a top frame which would have lifting cables, C.
   Inside the tower a spider would climb and then help to position each element.  The spider would have an upper and a lower body which could rotate relative to each other.  The upper body would have arms that could grasp and position the next element to be added.  The lower body would have 6 to 8 legs to hold and position itself against the sides of the tower.  To climb,  all the legs would extend raising the spider upwards.   2 opposite legs would detach from the tower sides and would rise to a new holding position, then this would be repeated until all the legs have been repositioned.

   In order to join the sections explosive welding would have to be used, E.  In explosive welding continuous  explosive charges are placed outside one of the pieces to be joined.  Upon detonation , the shock waqve dislodges metal ions across the joining surface, yet these ions still have bonding with the parent material forming a solid bond,.  Even dissimilar metals such as aluminum and steel can be joined.
Conventional  welding involves melting and then resolidifying the metals.  By the time steel melts the aluminum would be a puddle on the floor, defeating the purpose of the weld.  With thick metal sections , it is very hard to keep the metal at the proper temperature during welding since metals conduct heat well and dissipate it rapidly.  In this case it would because of the thick sections that explosives would be used.  After the explosives are fired ultra-sound inspection would be used to insure that the weld was effective.  Attemptong to use bolts would cause enormous stress concentrations around the bolts.
   When the tower is completed, the spider would be lowered by the crane and then a top plate positioned before emplacing the generator and the rotor blades.  The crane would the swing over the back of the generator  before being lowered to the ground for disassembly.
   For access to the crane and spider basket cars lifted by cable would be used as elevators.  The cars would be stabilized by ground wires while lifting and to prevent the basket from being forced into the tower by wind gusts.  The car would hav a docking port on the crane assembly.  It would be advisable to have more than one wire rope for lifting in case one breaks.
   The spider and crane would be powered by electricity from cables that would trail to the ground,
The spider's cable would become the power cable for the generator.
    To examine stresses, I will assume that the blades turn to prevent wind loading above wind speeds of
40 mph (65 kph), 60 feet per second, fps.  the magic number for conversion to force is to square wind speed in fps and divided by 800 to obtain pound per square foot, psf.   60 X 60 / 800 = 4.5 psf.  Assuming that the rotor blades are 1/2 the tower height, they would be 600 ft (180 m) long, their area would be 600 X 600 X pi = 1 100 000 square feet, f2.   1 100 000 f2 X 4.5 psf X 1200 ft (tower height) = 6 000 000 000 lb-ft.  Steel yield point can be over 50 kips (kilopounds, thousands of pounds, per square inch), assume the loading is allowable to 20 kips, allowing for fatigue and some allowance for thin walled buckling of the tube.  Assume the tube is 60 ft (18 m)  diameter, so ft radius; there is a formula, pi X radius squared X wall thickness, t, X allowable load = moment,  pi X 30 X 30 X t X 20 (000)kips X 144 inch2/ft2 = 6 000 000 000;
t = 0.75 ft.   60 ft, diameter, X pi X 0.75 X 580 pounds per cubic foot, weight of steel, = 70 000 lbs /linear foot at base maybe 30 000 lbs/ft at top.  Thin walled bucking would have to be checked and it might be necessary after erecting steel to line the tower with concrete to increase the wall thickness.
  Assuming the crane can lift 1 000 000 lbs, the average weight would be 50 000 lbs/ft and the average section lifted would be 20 ft long or 60 lifts minus the original placement to complete.
   Whether rotor blades could be designed and built of this size would be another question.
    The only way to move sections this size would be by airship.  If the airship could carry 500 000 lbs, 2 sections would be joined on the ground before lifting.  The difficulty with airships is that  in transferring the load they must remain stationary even with some wind gusts, companies, such as Lockheed, have designs to allow for this.  The airships could be filled with hydrogen to save money.  The danger of a hydrogen fire particularly in a cargo carrier is of minimum risk, although it might be advisable to avoid flying over densely populated areas.