In reply to BronxFigs and Barnbikes about the Gade cooling, I append a cut and paste article from Farm Collector magazine from December 2013:
Cooling problems?
The Gade engine was touted as being air-cooled without a fan. It breathes air, company literature said. This engine is cooled without fans and water. The theory may have sounded good at the time but Dave has doubts as to how well it worked in practice.
Gades are 4-cycle hit-and-miss engines. They operate on the same 4-stroke principle as your car engine or other 4-cycle engines, that is, intake, compression, power and exhaust strokes. The Gade difference is that it does not have a traditional exhaust stroke where, after traveling to bottom dead center on the power stroke, the piston pushes the hot burned gases up out of the top of the cylinder on the exhaust stroke.
Rather, when the piston in a Gade engine travels to bottom dead center on the power stroke, it uncovers a port (a hole) in the cylinder wall near the bottom of the cylinder in the same manner as a 2-cycle engine. The hot exhaust gases immediately rush out of that port, relieving the piston from pushing gases back up out of the top of the cylinder. That reduces the engines total time exposure to the hot exhaust gases and theoretically should result in a cooler running engine.
Additionally, since the Gade is a hit-and-miss engine, the power stroke (especially when the engine is not carrying a load or doing any work) results in a significant rpm increase. The governor then holds open, for several revolutions, what other engines would call an exhaust valve, preventing more gas-air mixture into the cylinder.
Thus no more firing takes place, but the piston continues to move up and down, and since both the upper and lower ports are held open, fresh cool air is pumped back and forth through the cylinders, cooling the cylinder without water or a fan.
So far so good. But under a significant load, the engine slows down and fires more often, without many (or even any) missed strokes. The cool air coming in the ports is limited and cant keep up with the heat created by the engine. The cylinder fins arent enough help, so after a while the engine just seizes up, Dave says. Probably doesnt damage anything, but it gets pretty frustrating for a farmer.
Now you have a 4-cycle engine without water cooling and fan cooling whose only advantage is ridding itself of hot exhaust gases faster than traditional engines, Dave adds. I would think, but dont really know, that this was not enough of an advantage to forgo a cooling fan or a water hopper. I think the Gades likely couldnt keep themselves cool enough to compete with other engine manufacturers of the same horsepower rating which is why I think these engines might not have been used very much and those at shows dont show much wear.
Makes sense to me.
Dave
The Emerald Isle