Sunnytech Low Temperature Stirling Engine Motor Steam Heat Education Model Toy Kit For mechanical skills (LT001)

It works very well. Entertaining while waiting for a hot beverage to cool. It appears to be well made. I have fat fingers so it took a bit longer to assemble than I expected, but I was successful in a reasonable period of time. There is something relaxing to watch it spin. A nice model.

This is a great gadget and a lot of fun. It comes fast, works well, and is easy to assemble, though you may want to have a tiny screwdriver or dull knife point to click the two little drive shafts in place. It's super easy and the instructions are good. It took me fewer than five minutes to set up. The great thing about this, which is better than other similar products, is that you don't have to light a fire or use a candle or anything like that. You simply place it on the top of your coffee cup. You can put it on a hot beverage cup you want to keep hot, and watch the little motor do its cool thing, or you can microwave some water in a cup for two minutes and set this gadget on top of the cup for lots of fun. Kids are blown away by this and it is a real conversation piece for adults. Any kid would love to get this as a gift--birthday or Christmas or whatever, because everyone drinks hot tea, hot coffee or hot chocolate at some point, and if not, just hot water--no open flame. Also it is great for teaching kids about external combustion engines and the principles of physics. I haven't had it long, but already its my favorite gadget to play with in the kitchen while I am waiting for the rest of my meal, and I can't wait to show my friends when they come over for dinner. Just a lot of fun without an open flame or any dangerous substances to ignite.

This an elegant engine, both in appearance and in its functioning. You can see all the parts moving. Of my five Stirling engines, it is the best performer at low temperatures. The Stirling engine is a heat engine, just as are steam engines, gasoline engines, hurricanes and the "drinking bird" toy busily bobbing.The large cylinder at the bottom contains the displacement piston. I will call it the displacer. It is driven by a crank on the flywheel. In the small cylinder, the power piston cranks the flywheel twice each revolution, making everything move. The displacer moves the air in the displacement cylinder, alternately to the bottom plate to be heated and then to the top plate to be cooled. This air is confined to the interior of the engine, so that when heated (or cooled), it cannot expand (or contract) but instead must increase (or decrease) its pressure compared to the air outside in the room. The pressure differences cause two power strokes per revolution, one in which the pressure in the engine is below room pressure so the power piston is pushed down, and the other in which the greater pressure inside the engine pushes upward on the power piston. Crucial to a Stirling engine is that the cranks control the pistons so that the power piston is always a quarter of a turn behind in its motion compared to the displacement piston.Here is how this offset between piston motions causes the needed pressure changes. The downward power stroke begins when the power piston is at the top of its cylinder and the displacer is at the middle of its downward stroke. At this point in time, the air is divided evenly between the cool upper region and the warmer lower one. The turning flywheel pushes the power piston to start the power stroke. As the power stroke continues, the displacer pushes more air into the cool upper region, and the overall pressure in the interior drops below room pressure.When the power piston reaches half way down in its power stroke, the displacer is all the way down, so all the air is in the cooler part of the interior space. The pressure in the interior of the engine is at its lowest point so the room air is pushing hardest downward on the power piston. This is the most powerful part of the power stroke, the more so because here the power crank is oriented to furnish its highest torque. The power piston continues downward, reaching the end of this power stroke. The upward power stroke now begins, and the explanation as to how it functions mirrors that of the downward stroke.You can see the two power strokes, one down and the other up! Start the engine on a hot cup. After it is moving at about 1 rps (60 rpm) take it off and set it on the table. Watch as it slows to a stop. In the last 2 or 3 revolutions the flywheel moves with an easily seen jerk at every power stroke. I find it easiest to see this by watching the power crank. The up stroke is harder to see because the engine is not rotationally balanced. The flywheel probably is balanced, but the combined weight of the pistons pulling down unbalances the system.This explanation raises some questions. The main one is that we know that the heat flow between the air and its nearby plate is not instantaneous. But there is a hint that it does happen very quickly. As the engine runs, the rim of the top plate becomes much hotter than the center of the plate. (I measured the plate temperature with one of those thermometer "guns" whose laser pointer shows a red dot showing just which spot is being tested.)The rim is the place that the hot air from below the displacer enters the top space. So for that place to be much hotter than the rest of the plate indicates that much of the heat from below gets dumped here quickly, before the air moves further into the cold region.Another point: the engine leaks air from the space between the power piston and its cylinder wall. This leak is slow enough that it does not affect the efficiency of the engine. But the leak is crucial! If the engine did not leak, it would soon not run at all! The air inside the engine becomes much hotter than outside, and its pressure therefore would be enough to push the power piston all the way up and lock it there! But this is avoided because some interior air leaks out, restoring the interior pressure (averaged over a cycle) to match the outside pressure.You can observe this leak yourself. Hold your cold engine with its power cylinder horizontal. Turn the flywheel so that the power piston is at one end of its motion, and hold it there for about 20 seconds. Then turn the flywheel so the piston is at the other end of its allowed motion, and release it. You should see the piston move back close to where you had held it! Repeat, starting this time with the piston at the other end.

This is a quite cool example of a Stirling engine -- a motor that runs on thermal energy. Although these are sometimes referred to as "external combustion" engines, this particular model is a LOW TEMPERATURE Stirling engine, so no open flame is required. You simply set it on top of a cup of hot coffee or tea, and away it goes. I put it on top of one of those electric "cup warmers" used to keep hot drinks warm, and it ran for hours.It is sensitive enough to run off the heat of your hand, if you either place an ice cube on the top plate, or hold it on your palm outdoors on a cool day.Assembly it pretty simple, but do be careful of the brackets which support the large flywheel. They bend relatively easily, and if the wheel is off-center it may rub against the cylinder wall -- and you don't want that.This would be five stars, but I found the flywheel to be a little unbalanced. This means that at lower heat levels you might have to give it a little "push" to get things moving. If the wheel were better balanced, I believe the engine would start on it's own.Fascinating gift for a science-minded kid, or the techno-oriented adult who has everything.

It is well designed and the quality of manufacture is outstanding. This is a functional engine and it can also be displayed on a shelf or desk. It is so cool to watch the thing run for a surprisingly long cycle the first time out. I am a retired Mechanic and I highly recommend this product.My video went offline and could only display a photo.