And therefore, the power involved in the 500,000 volts was extremely-extremely low. Otherwise you would be dead. That 500,000 volt source wouldn't even power a 2 hole toaster.
Industrial generators about the size of a small house. I would imagine they were designed to accommodate the 500KV transmission lines. I don't know where else they might be used. But I guess there could be some very high power industrial processes that require Very high voltage.
I was poking around and found these https://new.siemens.com/global/en/products/energy/power-generation/generators.html 2235 MVA but I couldn't find the terminal voltage for the 4000 series. The 3000 series tops out at 27 KV
Again, any links? Show me. The insulation requirements of an electromagnetic generator operating at 500,000 volts would be enormous and is the limiting factor. As Herby said above, there are practical limits to the voltage produced by an electromagnetic generator. 30KV is about the limit. Why do you think the conductors on high voltage transmission towers are so far apart? In a generator, the conductors by necessity must be in close proximity, and insulating them from each other and from the metal housing is problematic. If I am wrong on this, provide me a link. I would certainly like to see a 500,000 volt electromagnetic generator. I would especially be interested in how they solved the insulation issue. "Very high voltage" used in industrial processes are low power and do not use electromagnetic generators to produce the high voltage. Again, if I am wrong, please show me links.
I doubt it. Highly specialized devices and custom builds often don't have your typical website presence. But you beating this to death is stupid. I have seen them. Believe it or don't believe. I really don't care. And beyond that, a transformer could be used to boost the voltage anyway, I have engineered large industrial system for 30 years - nothing of this size but as anyone who has watched The Flight of the Phoenix would know, size doesn't matter.
Do you remember saying the following? I already stated that 500,000 volt generators can be purchased off the shelf. And I know we can go to 1 million volts. So "off the shelf" is now a highly specialized custom build? Actually, my concern is 100 percent pertinent. And if you were a physicist who had any business making the claims that you are making in this thread, you would have realized that my concerns are pertinent, not stupid. Of course, you are the physics authority here, so I may very well be wallowing in ignorance. You already claimed that 500,000 volt electromagnetic generators exist "off the shelf". I doubt highly that they do. And I doubt highly that a custom build is feasible - because I understand that 500,000 volts requires tremendous levels of insulation which makes an electromagnetic generator of this potential physically impossible with current "off the shelf" insulation technology. As a physicist, I would think you would understand this too. But again, perhaps I am just being stupid, and perhaps I have zero knowledge of things electrical. That is correct, and that is how it is done in the real world. But concerning flying apparatus, that would add tremendous weight to the thing. Do you realize how big and cumbersome a 5 billion watt 30KV to 5,000KV xfmr would be? Add that to the generators, and the wings/blades, and supporting structure, and control systems/surfaces, and cables dangling, and this thing would be monstrous. To this uneducated mind, most of the energy of the jet stream captured by this device would be used in keeping the darn thing in the air. Still, I could be completely wrong about this since I am being stupid and beating this to death. I would appreciate it if you would enlightening me. How much will this thing weigh? How much of the jet stream energy would be used in keeping the device aloft and how much would be left for generating power? How much horsepower would it take to turn the generator(s) to produce the power you claim? How big would the generator shafts have to be? Bearings? Stators? Control surfaces? Would a cooling system be needed? What kind of torque would the generator supporting structure be subjected too? How robust would it have to be to withstand that torque?
I was wondering about that too. Here is a very rough estimate. For an ambitious 2 GW aerial generator, the drag force required to generate the power is F = P/v = 2GW / 50m/s = 40MN (higher, if inefficiencies are taken into account). That corresponds to a weight of 4'000t (metric tons). Commercial airliners have a lift to drag (L/D) ratio in the 12 to 20 range. Assuming a L/D ratio of 10 for this contraption, you could lift about 40'000t, if your goal is to use half the power from the jet stream for lift and the other half for energy generation. That would be a rather wasteful design, but it shows that reducing weight is not as critical as I initially thought. After checking some of HereWeGoAgain's claims and some back of the envelope calculations like this, I still like this idea. As freaky as it may look, I think that it's doable, but obviously different enough to give rise to all sorts of concerns. Whether it's commercially viable, when compared to other sources of electrical energy, I have no idea.
I appreciate your commentary and demeanor. Thank you. I recall that the original poster claimed that a FEG could replace 2000 land-based turbines. An internet search revealed that typical LBTs ranged between 2 and 3 MW. Split the difference, lets use 2.5 MW. Multiply by 2000 and the result is 5 GW. In another post, the OP suggested 6.4 GW for one FEG. Your suggestion of a 2 GW FEG isn't all that ambitious. Now, this point isn't all that important. Even the lowly figure of 2 GW would be pretty amazing. From post #22: A delta shaped wing having the same span as a 787 [200 feet], with a turbine located on each end, is large enough to accept turbines [props] having about a 100 foot radius. My skepticism arises from the forces on the delta shaped wing, on the props, and on all the connecting devices. I assume that the turbines would have to rotate in opposite directions, otherwise the entire assembly would spin - the generators wouldn't even turn. And if the turbines turn in opposite directions, that is placing tremendous stress on the wing. I feel that this wing certainly could not be a conventional hollow aluminum wing. Seems it would have to be a massive structure that could resist the "crumpling" forces imparted from the turbines. What would it be made of and how much would it weigh? Another issue is the props. Are there any materials/design that could extend 100 feet and withstand the massive torque involved? What about the connections of the blades to the shafts? Certainly these props would have to be variable pitch for control purposes. Is a variable pitch device capable of withstanding the required magnitude of HP and torque? We could do the calculations to determine the HP and torque that would be involved. I will defer to the physicist, or to you, to do the calculations. If the offer is declined, I will do the calculations. (A rough calculation would be to convert watts to horsepower and horsepower to foot-pounds/sec. If this is incorrect, let me know.)
The ground-based turbines have variable pitch control. The turbines/generators don't have to be on the wings. How about two counter-rotating turbines mounted longitudinally?
Yes they do. But the ground based units at 2 to 3 MW are experiencing 1000 times less force than each of the two prop systems proposed by the OP. Would a variable pitch controller that could withstand these forces be practical? How much would it weigh? I think the OP intended for the wing to provide some added lift instead of just relying on the props. Your idea is interesting. Where would the tether be attached to avoid the props? The longitudinal structure would be subjected to a massive internal twisting force though. We could do the calculations and then decide how robust the structure would have to be. And how much would it weigh? We probably need a mechanical engineer to help with the material strength. And would it be stable in the atmosphere, or would it try to rotate? Massive generators, massive step-up transformers, massive connecting structure, massive pitch controllers, massive gear boxes, massive props, and massive forces trying to rip the entire thing apart. Huge rotating masses, possible adverse gyroscopic action, and possibilities of resonant vibratory frequencies that could render the thing uncontrollable. Not sure this is physically possible on such a large scale.
I'm guessing... maybe two counter-rotating generators in the same housing, or fastened together in some way, would remove most of the forces from the fuselage
That would just focus the twisting force onto the housing. The housing would have to be robust enough to maintain its integrity under the massive twisting it would experience. Still hoping that Herby or the OP will chime in with some horsepower and foot-pound calculations.
As far a lightweight materials are concerned that are strong enough to handle these forces there is carbon fibre which can deal with these stresses. An F1 car exceeds 200 mph and 5G forces through the corners and this is what a rear wing looks like. Building the delta wing would not be the problem since we have a great deal of experience and knowledge of the relative strengths of materials and the forces involved. Combined with a gyroscopic pilot system to maintain level flight at all times the stresses should all be within tolerances IMO.
The simplest means of dealing with any rotation is to use vertical fins. They will counteract any such forces and can be at the end of trailing booms if necessary. After all this is supposed to be flying into the jet stream so fins would provide the necessary force to stop rotation. Pitch and roll are managed via flaps and ailerons which are well understood and operated by autopilots on large planes like 747's. The large rotating blades are part of the overall design and will probably be hinged in the same manner that they are on the Osprey.
One might choose coaxial contra-rotating blades to avoid issues with torque. That has worked on aircraft. Perhaps weight and balance would become an issue.
I think that many are underestimating the magnitude of forces that are involved. Building a delta wing to withstand the forces would not be trivial. Please note that large scale generators in nuclear or coal power plants are connected to the earth with massive concrete and steel foundations. If they were not, when the turbine started turning, the generator stator/rotor would simply turn as a unit with the turbine and no electricity would be produced. Holding the stator of a generator stationary while the rotor is turning and producing billions of watts of power is a very serious engineering concern. Placing those generators up in the air with no substantial supporting structure such as concrete footings embedded deeply into the earth is a major issue with what is being proposed. The OP suggested that a single FEG could produce as much wattage as 2000 land based wind turbines. Typical land based wind turbines produce between 2 and 3 MegaWatts. Choosing an in-between number of 2.5 MW and multiplying this by 2,000, a single FEG would have to produce 5,000,000,000 watts to meet the OP's goal. That is 5 billion watts. It requires 1 horsepower to produce 746 watts, assuming 100 percent efficiency (of course, it would not be 100% efficient, so the numbers are even higher than what I am presenting). Dividing 5 billion by 746, we need 6,700,000 HP to turn the generator(s) (we can further convert to foot-pounds/sec of torque, but probably not necessary at the moment. Understand that if 6,700,000 HP is being used to turn a rotor in a generator, there has to be an opposite force of 6,700,000 HP holding the generator stator in place so it doesn't turn. Now, to put this in perspective, a Nimitz class air craft carrier propulsion system produces 280,000 HP. The FEG device would be subjected to 24 times that force. This is no trivial matter. Granted, using 2 generators cuts the forces in half for each one. Four generators cuts it to 1/4 for each. Still, these are massive quantities of force and have to be accounted for in the connecting structures. The total stresses would be even higher, because the FEG would have to provide lift to keep itself in the air. I am making a wild guess that the contraption would weigh 1,500 tons. (generators, xfmrs, blades, gear boxes, supporting structure, control systems, lubrication systems, etc.) The heaviest fixed winged aircraft today has a max take-off load of 640 tons. The largest helicopter has a take-off max of 40 tons. This brings up additional concerns of getting the FEG into the jet stream. If the 5 billion watt device used 2 generators as is being suggested, each one would require 3,350,000 HP. If these 2 generators are "coaxial contra-rotating," there would be 6,700,000 HP force trying to twist the 2 generators apart. A thought I just had, and perhaps this is what WillReadMore meant, is to have a single generator with the stator connected to a set of blades at the rear, and the rotor connected to a set of blades at the front. The blades rotate in opposite directions, with one spinning the stator and the other spinning the rotor. Interesting. Still, the shaft/blade connections within that system are going to be subjected to 6,700,000 HP. Another issue would be stabilization. Minor variances in wind velocity and density could cause the apparatus to spin out of control. If the 2 generators were mounted at the ends of a wing as the OP suggested, the physical connections from the generators to the wings would have to withstand the torque from 3,350,000 HP. The stator/wing connection would be taking the place of hundreds of tons of concrete, steel, and earth. I am not a mechanical engineer so I can't suggest what it would take to keep the wing/generator connection from failing. Intuition says it would be a tremendous amount of carbon fiber indeed. If the generators are on the ends of the wings, they would need to spin in opposite directions. If they spun the same direction, it would be impossible to stabilize the system. The entire device would rotate as a unit and the rotors wouldn't even turn within the stators. Concerning the opposite spinning generators on the ends of the wing: The wing would be subjected to a "crumpling" force from 3,350,000 HP spinning one way and 3,350,000 HP spinning the other way. And at the proposed wingspan of 200 feet, this would be very high torque indeed. As I said, I am not a mechanical engineer, but I can attempt the calcs later to see what these forces would be. This post is too long already.
Yes, I don't know the numbers, but the required weight seemed likely to be huge. I suspect that separating the counter rotating blade assemblies of the opposite sides of the wing and then connecting one to the stator, etc., still results in torque between them. I think you would have to have the two blade assemblies adjacent to each other and then have them attached to a compound shaft - one inside the other. Then, they could be separately attached to the rotor and stator. I think that would result in less twisting forces, but it still sounds like monumentally heavy equipment that would require serious mounting.
What the heck? Flying electric generator? I just googled it. It seems dumb to me and not practical. I tend to think other methods of electric generation are more better...I once read of a solar display in space generating electricity and converting it to microwaves and sending it to earth....that was a while ago.
Yes, there are large forces at work but you seem to be ignoring the fact that we already have aircraft flying with massive amounts of horsepower. https://www.quora.com/How-many-horsepower-is-a-Boeing-747-Jet Depending on how you do the math and the configuration of the 747 the horsepower involved ranges from 80,000 to 266,000. IOW we already know how to lift heavy masses off the ground and push them through the jet stream at 500 mph. Given that the FEG only needs to do 170 mph that reduces both the loadings and the forces by several factors. The wing would be designed to provide maximum lift at that low speed which would be the counteracting force supporting the structure while it is airborne. Using counter rotating blades eliminates the torque factor which only leaves us with the issue of the weight of the generator itself. There is no reason there needs to be ONLY ONE massive generator. Several smaller generators can produce the same amount of power which means that the load can be spread more evenly across the entire structure and it would also make the FEG more robust given that there would no longer be a single point of failure. What we need are some small scale test models to determine feasibility. If the best power to weight ratio works out at even a third or a quarter of the original concept it won't matter because there is plenty of space up in the jet stream to have a lot of smaller FEG's instead of fewer massive ones.
I agree with many of your points. There is no doubt that FEGs are possible because they actually already exist. The question I have been posting about is "how much electrical energy can be derived from a single FEG?" It is all a question of scale. The OP claimed that a single FEG could replace 2000 land based wind turbines. I do not think that is feasible because of the forces involved. That is what I have been discussing. Could energy be derived by using 1000s of smaller FEGs instead of 1 gigantic one? Of course. Would it be practical? I don't know. If the engineering difficulties were trivial, and if the concept was profitable, I would think we would already have thousands of these things up in the air right now. I didn't ignore it, I actually posted that the largest fixed wing aircraft has a max take-off weight of 640 tons. The largest helicopter has a max take-off weight of 40 tons. I used that as a comparison to a single 5 billion watt FEG. I believe that the stresses on the FEG would exceed the limits of any practically-sized materials we could use. Which means that a large number of small FEGs would be more practical than a small number of large FEGs. Depends on how they would be arranged. If the opposite rotating generators are placed on opposite ends of the wings, there will be torque placed on the wing. To eliminate the torque, the opposite rotating blades would have to be on the same rotating axis. There would still be torque on the blades and the connections to the shafts. Depending on the size of the generators, the stress may be so great to make those mechanical connections infeasible. The question goes back to scale. Obviously, there is a practical limit to how large a Flying Generator can be. There may be other issues with coaxial rotating blades. The blade in front would disrupt the air flow to the blade in the back. The rear blade may need to be bigger or designed differently. Also, there may be significant gyroscopic forces that would cause the FEG to spin. Not sure on this. Agreed. I feel that a good solution is a delta wing with 4 generators, 2 on the left, 2 on the right. Each pair would be aligned axially, one at the front, one at the rear, and counter-rotating. Still, it isn't going to replace 2000 LBTs. Maybe 10? Or 1/10, or 1/100, or 1/1000, or 1/10,000.... Question: Do you envision the wing providing 100% of the lift, with the blades providing 100% of their captured wind energy into the generators, or would the blades also be providing some of the lift?
And let's not forget this from the article cited in the OP: Papers about the FEG were first published in 1979, and in 2002 a company was founded to commercialise the FEG. So far, this has not happened, and many details of how the technology would operate remain uncertain, despite three decades of research literature. Only small test craft (rotors of up to 24 feet in diameter) have flown at low altitudes (up to 100 feet). Many of the claims in the literature, which are optimistic about the FEGs performance at high altitude, are experimentally untested. FEGs have never operated at the altitudes described in the corresponding literature... People way smarter than us have been looking at this for 40 years and not much progress has been made. Seems to me that small FEGs would work.
