This high speed run combined with a 13 hour endurance run at approx 250rpm has caused the plating to wear off the displacer rod and now the engine barely run at all even on the hot plate, the displacer tube is cracked and when I removed it to inspect it i found it was so badly warped that I think it is no longer air tight. These engines where never designed to run this fast and at the temperatures that I have used here, I am surprised it actually lasted as long as it did.
Yes, I have indeed water cooled a Chinese made LTD Stirling engine. Why?.... curiosity mainly, and simply because It was not all that difficult to do.
I was counting the clicks of the piston between each tick of my overly loud clock to give me approximate rpm speeds, it now goes to fast for me to count, I will do a video giving the real numbers once I replace the acrylic displacer tube with glass.
The water tank is a large pear tin, its base knocked together from bits and bobs I had at hand in the shed ie. a pine plate i had turned for practice and some scarp dowel I found on the floor of the shed.
the cooler is made up of scraps of 15mm copper pipe and 90* bends i picked up in the bargain bin of B&Q with 2 reducers to 10mm to fit the PVC tube. It is soldered to a hard drive platter using solder paste(find it on eBay, they say it don't keep well, but's they be lying).
The water pump is a 5-12V DC brushless submersible water pump I picked up for £11.00 on eBay, at 12V it draws 1 amp and shifts 500 ltrs per hour. I run it on 6v as that's more than enough for this job. I should have done the maths before testing the water pump, I had to dry the laptop out when i tested it with no lid on the bucket, it pumps approx 138 ml per second and the 1 second burst on a 12v battery send a column of water about 4 feet in the air and it naturally all hit the laptop.
8mm PVC tube was used to join it all together with some 1/2" tubing used to join the outlet of the water tank to the inlet of the pump.
This test run managed to get a temperature differential of 78*c approx, I didn't push it any further as the displacer tube is seriously distressed now due to way to much heat, I am waiting on a G2 bottle cutter to arrive so i can replace it with glass any then turn the heat right up.
I can also use Ice water in the tank and use thermal grease between all the surfaces to coax the last few RPM out of this thing. I will make a video of the high speed destruction run, a friend has both laser tachograph and thermometer and also a HD camera I think so stay tuned as we will most likely find out at what temperature the displacer fails at or the CA glue holding it to the displacer rod melts, either way it should be interesting.
Thanks for looking.