My 18cc Alpha Stirling Engine

[PlaniTechic]

Hi

tew, the Displacer has in fact a dome on top of it. So it is only the length of the stroke shorter than the cylinder (plus some reserve to prevent it from hitting the top, but that's les than 1mm). The dome, also called Heylandt Crown, is made from thin walled stainless steel tube in order to keep it lightweight and to prevent losses from heat conduction.

Thank you, Ian S C. I was already thinking of that experiment with driving the engine too. I will do that as soon as I get everything fixed an running again. Concerning the cooling I thought once I get everything running steady on the Prony Brake, I'm going to drop some ice cubes into the bucket of cooling water and look what happens to the power output. That will be interesting.

Plani

[Ian S C]

Plani, I find that a big part of the fun of running these motors is the experimental work you can do. Running the motor as a cryocooler was done using my large(1 3/4" bore x 3/4" stroke) GAMMA motor to drive it, the two motors have very similar power, if I had used a more powerful motor to drive it, no doubt the temperature could be lowered further.
Ian S C

[PlaniTechic]

Hi

Sometimes it's a small ting that makes a big difference.
After the mishap with the snifter Valve a new one was made up. Therefore an new valve cup was inserted in the wrist pin block and I also drilled a hole from the back side to allow for a good airflow through the valve. This time the valve is secured with a tiny little C-clamp on its stem instead of a retaining nut. So far that worked out ok, nothing got lost anymore.
But the engine did still not perform as expected. It was difficult to get it started and once running power was poor. There was a leakage somewhere. At first I suspected the new snifter valve to be the problem. It took quite some time until I discovered, that the valve was holding tight but the air was leaking between the piston and the wrist pin block. A little gasket cut from ordinary paper took immediately care of this problem.
What a difference this made! The engine is running fine again and with the snifter valve properly working the power output almost doubled . It peaked at over 15W!

WP_001584_15W_640.jpg (101.09 KiB) Viewed 9630 times

Over 15W
This got the dyno already close to its capacity. I think, I'll have to get a bigger magnet to get more braking Action.

Plani

[Kenedy]

You really did your best and I appreciate your efforts.

[PlaniTechic]

Thank you Kenedy, every encouragement is very much appreciated!

In the mean time I have made a seal for the Shaft:

Seal.jpg (79.38 KiB) Viewed 9549 times

And a manifold to carry a manometer was made too:

Manifold.jpg (141.2 KiB) Viewed 9549 times

The Seal is a bit stiff at the moment, I hope that this one loosens up a bit when I run the engine.
On the backside of the manifold is a schrader type air valve throug which I plan to pressurize the engine. But there are some mor efforts needed because the crankcase is leaking air all over the place.

Plani

[Ian S C]

Plani, you may need either proper gaskets, or liquid gaskets, if the latter make sure that you seal right round all the bolt holes. Every thing is looking good so far.
Ian S C

[tentstovenerd]

There are too many hobbists doing it.
But MOST are nothing but a toy.
Why NOT do it bore of 160mm or even 320mm instead of 32mm.
It can be placed on top of a rocket stove.
As long as the output can reach to 10 to 20 Watt, it is a great help to remote poor area. It is good for LED light
100 to 200 watt would be good for a TV set.
500 watt shall be good for water pump

[Ian S C]

There are not enough hobbyists building Stirling Engines, the more people that build them the greater will be the chance of some one developing a good design. In this country they have been studied, and developed to a commercial level at the local university, and sold in Europe as the Whisper Gen, domestic power supply, it is a 1 Kw unit plus 5 Kw of heating for water and central heating.
Ian S C

[tentstovenerd]

heating and generating together is a great idea for long period.
But to store the 1Kw electricity, the cost of battery must be well over the value of electricity itsself.
To sell electricity to the grid and get subsidery is another big joke make by politician.
It must be developed when oil price was 100 to 200$.
As long as oil is under $50, this unit is useless.
If this world is controlled by GOOD people than greedy and war lord, the oil price will be under US$50 for another 50 years.
I am sure in less than 50 years there must be big breakthough on energy.
Again in my opinion Stirling is only good for emergency, off grid, poor by burning wood

[PlaniTechic]

Why NOT do it bore of 160mm or even 320mm instead of 32mm.

Because I have chosen to do so. This Engine was was designed to operate with high temperatures from the beginning.

As long as the output can reach to 10 to 20 Watt, it is a great help to remote poor area.

I agree. So please go ahead and develop the engine you envision and then let us know what you came up with. There are fare too many factors influencing such a design and therefore it's virtually impossible to come up with a cook book recepie.

Back to topic:
I had to use liquid Gasket to seal up the crankcase. That actually worked out ok. But I have still a problem with the shaft seal. This one is still leakin pretty badly, so I think I'll have to come up with a different solution. Any Inputs are very welcome.

Plani

[tentstovenerd]

So please go ahead and develop the engine you envision and then let us know what you came up with.

I am not an expert on this aspect.
I find a few graduate papers in chinese written in 2010-2014.
There are schoolars on this aspect.
But I do not find any commercial model ready in China.
The experts avoid making real engine but focus on pure theory study on this or that point.
There must be reason behind.
If experts avoid it, how can hobbists do it,

I am willing to pay US$1000 for drawing of a real workable stirling engine, weight under 4 lbs, output 10 Watt, heat source of wood stove.
My aim is to make it commercial.
I can sell it to charity fund, and distributed to poor area.

[Ian S C]

To develop an engine, no matter which country, it costs many thousands of Dollars, Ford motor, and General Motors, NASA in the USA, have spent millions of dollars on the development of engines, as has MAN-MWM in Germany, United Stirling of Malmo Sweden.
Ian S C

[tentstovenerd]

so, millions , or tens of millons of US$ was spent,
still there is not a real commercial model on market.
All hobbists are nothing but reinventing perpetual motion machine.
sad.

[Ian S C]

There are commercial hot air engines, look at the Swedish submarines, I think the US navy is, if not all ready using hot air subs, is thinking of them. I think Japan has hot air powered patrol boats. Nuclear powered hot air motors are in use in space. Also these motors have been in use for many years in reverse as cryo coolers for producing liquid gasses, and cooling computers, and instruments on space vehicles.
Ian S C