Sunnytech Hot Air Stirling Engine Motor Model Imagination Development Educational Toy Electricity Generator Colorful LED SC (SC02M)

This is a delightful little engine. I'm amazed by the precision of the craftsmanship and the reliability at this price point. It comes fully assembled, works flawlessly every time, and is very fun to watch and tinker with. If I could improve anything about it, it would be:1. A heavier base, or some sort of counterbalance: The engine does vibrate at high speed and will occasionally try to walk off my desk. The base, and the engine itself are already quite heavy, so I think the right solution would be some sort of counterbalance to eliminate the vibration. But simpler solution might be to add some balast.2. Power connectors for the little generator: I've enjoyed powering small items with the generator. LEDs, a little heating coil, some motors, etc. It would be nice if this came with terminals and a switch for connecting various items. Clearly this is something you can add on your own, but it would be a nice addition.Overall it's been wonderful fun. I think the electrical power output tops out somewhere in the 2 watt range, which is enough to do some nice demonstrations. And it looks beautiful sitting on a desk or shelf when not in use. Overall I'd highly recommend it to someone looking for a fun, easy Sterling engine.

I am fascinated with Stirling engines and bought one of the low-temp coffee cup ones that I enjoyed for a little while before wanting more. I saw a couple of others but figured I'd get this one due to aesthetics and it was very well-rated.Build QualityI did not expect it to be as well-built as it is. It is very hefty and looks and feels expensive. The amount of compression felt as I turned the flywheel told me I was in for a treat in terms of power compared to the coffee cup one. It is fully assembled other than stringing the wick into the fuel chamber and mounting the LED. The wick can be a little fiddly but no issue once done as long as you don't pull on it. The LED (a spare is provided) is super simple to install...just put the ends through the provided terminals of the little generator, bend and you're done.Up and RunningI initially started with 70% isopropyl alcohol but that sucks so I got some 90% and got up and running. It takes about 30 seconds before you can get it to spinning on it's own but once it gets going, it is quite powerful for it's size and fuel source, The LED light is quite bright once it gets going and flashes and changes color to give the unit a bit of extra flare but I ended up removing it for something more useful and interesting to me (see Modifications). I've not let mine run much more than 5 minutes but I can usually run it three times before I need to add more alcohol so I would guess 15 minutes on a tank.ModificationsWhile the LED is okay, I wanted to measure the performance so I removed the LED and bought a small 2-wire voltmeter, cut the wires just short enough that they would support the weight of the voltmeter while remaining adjustable and soldered the ends to the generator terminals to give it rigidity and have a nice presentation. Display does not come on until 2.7-2.8v but it only takes a few seconds for it to get to that once it is running on its own. Typically my motor will generate 4.5-4.8v on a run but every now and then when the conditions are right I get over 5v with my current record being 5.35 volts. Love it.ConcernsIt has run flawlessly so far but I do fear that if it does break down, it may not be easy to repair as there are only a few spare parts included. Only other issue is that on many surfaces (glass and sealed stone seem best) it will start to move once it really gets to going and potentially could walk off the table if you walk away.This was a splurge of a purchase at the price I paid but I am loving it.

Overall impression:I was very impressed with the overall quality and "fit and finish" of this model. There is very little I can find to complain about in this regard. Despite some of the minor negatives I'll discuss in a moment, my overall impression is very positive and I would not hesitate to recommend this model to anyone who has an interest in these things. The asking price is a bit on the high side, but given the niche market this appeals to, along with the high quality and solid construction of the unit makes me think that I got a fair deal for my money.Some details:I found all of the manufacturer's claims in the product description to be accurate. It comes equipped with everything shown in the pictures.Packaging was quite adequate for any form of shipment. The main engine was securely wrapped in bubble-wrap, and the spare parts were separately foam-wrapped. Everything was placed in a small medium-weight cardboard box, which was then in turn shipped in a larger Amazon heavy cardboard box with extra protective packing.One of the features of this product that I appreciated the most was the heavy, solid, brushed-metal base that the engine is mounted on. At least 2/3 of the total ~1Kg weight of this engine is in the base. Unfortunately, even this heavy base is not enough to prevent the engine from "walking" across a smooth flat surface when it's running, even with the (included) rubber "feet" on the base.Unloaded, this engine flywheel runs around 1800 RPM when powered with alcohol fuel. The mfr. recommends 95% ethanol, but I did not have any on hand so I used 91% isopropyl alcohol, which works just fine. I would not recommend using anything with a <90% alcohol content (such as common 70% "rubbing alcohol").The tricolor flashing LED supplied (which you hook up to the attached generator) looks cool when the engine is running, but given its dynamic nature, it places a constantly varying load on the generator, which can result in the engine speeding up or slowing down as the LED runs through its display pattern. The generator outputs a bit over 6V unloaded (6.2V is what I measured). I've not yet had a chance to test/measure the generator output operating under a constant-current load (the included LED is definitely NOT a constant current load).Some (minor) negatives - things that could be improved.Note that I did not regard any these issues serious enough to detract from my overall high rating.The provided fuel bottle and cap/wick arrangement is something of a safety hazard. The cap does not screw on or sit on the bottle mouth securely, which means that if the bottle is tipped or jarred hard enough during operation, fuel (alcohol) could escape from it. The fuel bottle does not fit securely in the indentation for it on the engine base, so it is free to rattle around as the engine operates. Having said this, the fueling arrangement is 'safe enough' if it is supervised during operation. Adding a simple (heat resistant) silicone rubber O-ring around the metal wick cap so it would sit in the bottle mouth with a liquid-tight seal would make this a lot safer. A smaller diameter holder (on the engine base) for the fuel bottle, with more sharply beveled sides, should be used so the fuel bottle has less freedom to move around during operation.The operating instructions that come with the engine are poorly written, badly translated, and do not provide any significant detail on engine construction or maintenance (e.g. how to replace a broken cylinder, or remove it for cleaning). I did not find any instructions or contact info for ordering replacement/repair parts. A more detailed manual, showing a "blow up" diagram of all the engine's parts, along with care and maintenance instructions, which has been properly proofed and translated would have been appreciated, esp. since this is the sort of "toy" that someone who is mechanically-minded (and thus have an appreciation for design details) is going to have an interest in. I would have also appreciated some electrical specs on the attached generator - not the whole datasheet, just some basic details such as rated output voltage and current when used with this powerplant.I found one _very_ minor "fit and finish" flaw after a close examination of the entire engine - the pilot hole in the flywheel, where the setscrew that secures the flywheel to the drive shaft is inserted, was drilled a bit unevenly - it is not perfectly circular on my model. However, this very minor flaw does not adversely affect the operation of the engine or appear to have any notable effect on the flywheel balance.

The media could not be loaded. I bought this as a gift for my brother in law who is an engineer. He was very happy. It came almost fully assembled, we only had to attach the LED to the generator. We both were fascinated of how beautiful the machine is designed and built and how fast it runs (see my video). The manual is translated from chinese into english by a non-native english speaker and reads very funny. But the machine is awesome, very educational and well worth the money.