My thoughts too when I looked at one they built. Also I think they used pretty thin lines on what looked to be fairly large tanks, not good for rapid flow of large volume I think.
With all other things considered, it is still ONLY the differnce in weight between the bottom and top that works the wheel! Nothing else matters except that the top and right hand side is heavier than the bottom and left hand side. That is if you want clockwise rotation. The other thing important is where that wieght is located. On the bottom you have the liquid in the bottom of the tank at the outer rim of the wheel. At the top the liquid will still be in the bottom of the tank, but the tank is upside down now so the bottom is not on the outer rim of the wheel, it is inside the rim however long your tank is! 12" tank gives the bottom 12" more leverage to fight the top tank, sort of like running the wheel mounted 12" off center hanging low I think.
Mother earth used what I thought was goofey sideways tanks as I recall, so the liquid is at the outer rim at the top, but it is not at the top at all because the top tank is still off to the side trying to raise to the top. Well I would think that kills that right there. Pretty sure that was the Mother Earths design I am thinking of, I have seen others also.
Now something I am thinking to solve both such problems maybe? Use some type of weighted pistons basically. Use the pressure of the tanks to raise and lower a metal wieght. Top tank is cooler and less pressure, bottom tanks is hotter and more pressure, so the wieght is moved to the top outer rim more and away from the bottoms outer rim and more to the center. This will make the top and right hand side heavier without the movent of the liquid which slops to the side or sits below the top outer rim.
It does not take much weight to create movement. Watch an out of balance blade turn in reverse some time, not that much out of ballance. So by moving a weight up from the bottom a little bit we now have a heavier top, as that wheel rotates then we have a heavier side.
If we balance a 6' wheel, place 12 evenly spaced tanks of propane (maybe those throw away small ones) how much pressure do we need create to move a 1lb weight 1' high at the bottom. If the top is cooling at the same time and setup to create a vacume type effect to pull the weight upwards also that should help. Using a pressure to move the weight back and forth a short distance instead of transfering a liquid a long distance I think would work far better. This of course is not a Minto wheel by design then either, It is a "Nothing To Lose" wheel and I reserve all itellectaul property rights to it :-
You can build all you want free of charge for non comercail private use by non-money grubing greedy corporations! Oil/power companies beware I will SUE!!
So if we take a propane tank, run a hose to a empty cylinder on the outer rim, sealed piston to push upwards, when we heat the propane and presure is created in the tank and below the piston the piston shall rise. The more the piston rises the lighter the bottom becomes. You could have a rod connected to the piston at the other end to also push it to the outer rim at the top. Or it can be made to sit at the outer area by default, vacume of cooling gas sucks it back out, light spring pushes it back out etc.. combination of both? As long as the weight at the top is at the outer rim and the weight at the botton is not, this make the wheel top heavy, and untill things equal out as it turns and temps equal out it will be side heavy also. It could be rotated either direction.
The trick here again though is to not have so much liquid as to equal out the wieght as it flows to the lower end/side of the tank always. Using a moving wieght should mean using less liquid, and the pressure is what moves the weight which in turn moves the wheel.
I think the basic idea of a Minto wheel is somewhat correct, but using a liquid in that manner is not.
Another thought is using simple water and springs to move the piston/weights. Filling and sealing the water tanks so the water does not slop around shifting weight, but does expand when heated and moves the piston. Then use a couple well defined solar collecters to quickly heat the lower tanks. Aluminum tanks could be used for faster heating and cooling cycles. I have a nice portable oxygen tank here I got at a scrap yard, the medical type. Something like this made somewhat into a blader tank should work well, but you need quite a few. Water would not have to steam to a high pressure, only expand enough to move a weight. Other pressurized gas could still be used, but water itself should work provided it is heated and cooled quick enough to expand and contract.
Yet another thought on this, you normally have a friction of the tanks flowing through water in a Minto type design which also is slowing the moving wheel as it works. Using solar collectors to focas the sun under and through the wheel will not cause any fricton forces to fight the wheel rotation. You will not have the extra heat around the wheel like wheel using water tanks. The only heat will basically be where the tanks are in the sun being heated, when the tanks are not there then the sun passes through not hitting any mass and no heat is created. This in turn helps in cooling the tanks when they should be in cooling cycle since no heat is rising from standing water heating the surrounding area. But then it only works on sunny days.
