Here is the link to some pictures of the small cilynder inline engine, showing the scotch yoke switch mechanism. I will run the engine tomorrow a bit more and see what i can get out of it, before abandoning it. Small cilynder engines have not enough power. :(
Forum user Anko has made a very nice steam powered engine. Since i just love reciprocating steam engines i convinced him to allow me to post his video. Here it is:
Apparently he uses a steam cooler in order to prevent the steam from melting anything in the engine.
As an experiment and to get some rest from the v8 i decided to play a bit with an inline configuration with the small lego cilynders. Here's the first run of the inline 2 cilynder. Speed updates will follow. The speed computer is geared 3:1 for better accuracy.
This time not more rpms, just a more refined machine, poducing its power more smoothly. The crank is stabbilised with 2 paralel shafts, which prevent it from twisting = more power. Switches use scotch yoke principle of operation.
I goofed around a bit and produced these 2 videos of a dragster featuring the 1660 rpm V8 engine. The first one is an acceleration run, and the second one is a burnout video. The axle did fall of in the end, because the whole "vehicle" was not built for anything more than a small tryout and some fun.
Running approximately 1600rpms, but with a peak when the air pressure was max of 1660 rpms:
I got the engine running a max of 1780 rpms - peak, with a nice steady run of 1720 rpms.
I decided to put the double cam into retirement and will pursue the pushrod road. The first design is instantly better than the double cam setup. (which i was trying to perfect for the past 2 weeks, without any significant improovement). I have to experiment with the opening times, but it's definetly going to be a winner.
I ran the engine again, and it made 1660 rpms effortlessly. The key? I provided timing gears on the back too, thus preventing torsion in the crank and cam to affect performance. It proved to be a huge success. Now i only have to make the switches to align properly...
I upgraded the engine to a double cam setup and voila, promptly got 440rpms more. For now i'm running the engine completly unlubed. If i optimize it a bit further i think i can make it to 1600 rpms. I wonder how an inline 4 would go..... (insert manical evil scientist laughter here...) :)
Not much to say really. Details will follow when the engine is fully understood. Here are some pics. Enjoy the video untill then.
Gizmodo has another nice article about LEGO, accompanied by a nice promotional video. Go and see it. It also contains a list of 229 (weird number, huh) best sets lego ever made. I do not agree with some of the technic choices, but i guess this is a matter of personal opinion.