Stirlingengineforum.com

Hi Thanh - Is that one still being built - Looking good
Trevor

Well! nearly at the finish line now. The engine is now complete and working - Have added the lights with a small 3 phase alternator and as yet to make the radiator and/or cooling tower. To my surprise, this engine has quite a lot of power and I had to use a small flame from a spirit burner to slow it down. When on gas the engine just went overdrive and literarily shook the hell out of itself and nearly blew my lights - Heavens to bid!
Anyway, it is begging to look good. - Pics attached
Trev

Trevor : very nice !! very profession !! I like it...
Can you explain pump principle for me !!?
[img][/img]
Thank trevor !!!

Hi Thanh - Trick little system of using a rubber diaphragm that is driven by the expanding and contraction of air within the displacer chamber. The first lot of photos show you the layout of the diaphragm. This is 25mm in diameter and works very well. Normally I would place the pump elsewhere but this time it suited me to place on top of the displacer chamber. - Photo attached
Trevor

The layout is attached. - Trevor

This could be a good idea Thanh - Instead of using a forced fan feed for radiator I could just go and buy one of these for $40.00 landed at your door.
I reckon the air would flow through and cool the water easy enough if the radiator is placed horizontal - It would fit under my stand at least

Trev

I reckon the air would flow through and cool the water easy enough if the radiator is placed horizontal

That has to depend on the water temperature and the amount of heat you plan to reject. For maximum efficiency, I reckon that the water temperature would be kept at close to 100*C. Having said that, if you work the thermal math upward, you will find the cold side air temperature of the engine is 150*C to 200*C at best (depending on other factors). Ever wonder why stirling engines are always lack of power? With common material out there, how many degrees can we raise the temperature?

hi Trevor !! it finish

Love the paint work Thanh - The model looks absolutely stunning.
Hi Aviator - Re the temperature of the sterling engine. The earlier model I made with a fan attached (diaphragm type) used a radiator. First off, the heat source was a small pressurized all fuel type vaporizing burner that was adapted to using methylated spirits. When full on the water temperature going to the radiator through the coils was 70 Deg C. The temp from the air cooled radiator was 33 Deg C, It made quite a difference and the model ran for 5 hours at a market a few weeks back with no changes to temp, I have actually order one of those radiators to give it a try. I will let you know how it all works on this model on this thread.
Trevor

A few point on temperature. If you can get the water input/output temperature to the radiator and flow rate, you can find out heat rejection. If your engine is producing little power, this might just work.

Thanks Aviator - Another problem come up after running this engine for a couple of hours. The displacer started to full apart (made of steel wool) and jammed the intake to the piston. I think Ian told me this could happen using steel wool. Anyway, I made a stainless one (0.3mm wall thickness) that gave me a clearance of 1.5mmm wall to wall within the displacer chamber, however, after running with this I found the engine was lacking power compared to the steel wool one. I had to use a little more heat for the same amount of power. That said, I had then go to gas with better results. I really did want to use meths but could not produce enough heat to get the revs I wanted. With the gas and extra lights added I now get 2 watts at 4.5 volt - Pretty happy about that. Trev

I made a stainless one (0.3mm wall thickness) that gave me a clearance of 1.5mmm wall to wall within the displacer chamber, however, after running with this I found the engine was lacking power compared to the steel wool one. I had to use a little more heat for the same amount of power.

A case a thermal short. It is the most difficult challenge in a stirling engine. In this case, the heat from the displacer's hot side walks to it's cold side, heating up the working fluid that is supposed to cool. A good beta engine is more difficult to build than an alpha.

Trev, there are a few things you could try with the steel wool displacer, (1)make a cylinder of s steel gauze that fits with clearance, make the end caps with holes (you can get perforated metal), fill the cylinder with with steel wool. (2) Sew through the stainless(as it is in your photo) with stainless wire length wise, and wind some of the wire around the S wool.
I have not had that much success with steel wool, perhaps I should have another go.
Ian S C

Thanks Ian - I will eventually go back with the stainless wool as it seems to hold better. Steel wool is too fine and breaks up easily, even when I have tried A heavier grade, What I can tell you that in small models as I am building, that a regenerator makes a big difference (using wool that is). I really appreciate all the help people have given me. The radiator should arrive tomorrow and soon will have that hooked up and away we will go.....
Merry Christmas Ian and to all the others - Thank you, Trevor