Stirling Engine Generator Mk4 (Rocket Stove!) Part 5

Building of an easy, cheap and reliable, DIY stirling engine full size model! It will be fired by wood and could be a great stirlingkit if it works!

This is a fun engineering project that I will use to power a generator to provide energy. It will use an efficient rocket stove that burns really hot using wood that will hopefully drive it at great speed! This technology can use any fuel type with the correct burner so is dual fuel as well. I would like to provide plans / stirling engine kit for DIY builds and possibly build machines too.
This is all pivots on being able to produce an easy, cheap and reliable stirling engine! Watch this space…..

This video

So, I’ve just completed a few of the last jobs and am now ready to test it

Well it worked (just about!) and a few changes became immediately apparent.

-The first one is the flywheel isn’t quite big enough and this can be seen by the unsteady motion. I’ve already got a bigger flywheel available so this should be a simple solution
– The compression ratio is about 1.4 : 1 which is probably in the ball park. I can probably raise this a bit by reducing the piston assemblies dead space

One thing that I didn’t consider important at the time is the water vapour within the engine. This was coming from the concrete that I used to form the cylinder assemblies. I’m now wondering if this free water vapour in the engine would have had a detrimental effect on performance. I’ll properly dry out the engine and give it another go.

Till next time……

Thanks for watching

shanepomeroy@hotmail.co.uk

Big Horns Intro by Audionautix is licensed under a Creative Commons Attribution 4.0 license. https://creativecommons.org/licenses/…

Artist: http://audionautix.com/

Right hello once again um so I think this is the fifth video now um I think it’s the fifth or was the sixth I can’t remember it’s been quite a few uh few videos and it’s been very busy last month really trying to get this engine

Together so I got a few more things to finish off the engine which I’ll show you now um and then we shall get on with actually testing the engine out so I’m just a trial fitting the the Piston assembly um I’ve got this uh oven mat

That my um my father purchased for me on the internet it says it’s um it’s F glass cloth with PTF on top I suppose that’s the black bit I I don’t really know if I’m honest um if anybody can answer that question and I’m alls so this is my idea for the moment

I’ve got the oven mat on the outside and then on the inside I’m going to put this silicon um this 0.8 mm met thick silicon baking trait the idea is that this will create create the seal and this uh black oven mat which is a bit more rigid will

Actually support the the thin seal a bit like a inner tube in a tip so that’s what we got so we got the front of the Piston there oven tray and then silicon rubber on the inside so there you go I’ve just Tri fitted the seal assembly now I hav’t I

Haven’t moved it yet so this is uh interesting to see what it’s like it’s a bit crinkly but it does seem to function of course it’d be interesting to see what happens when it’s actually under pressure as well because it will actually force all this out upwards yeah

We shall see one of the other concerns was the actual stability of the Piston but so far that looks to be all right as I said when it’s under pressure things will change somewhat so here’s my attempt at forming the um or removing the dead space from

The the Piston cylinder assembly um the first method I tried wasn’t particularly successful CU When I extracted I tried pouring the cement um when I tried extracting the the piston out I actually pulled all the pieces so what I actually did this time was I just filled it in my

Hands and pushed the Piston down and connected this and put a load of weight on it and uh it’s actually ended up better I’m happy because this bit at the bottom is pretty much formed as it’s meant to be shape wise so now I can dig

Out the circle there um then I’ll get a a carving knife or something and just uh just sort um sort all this out make sure it’s all flat up against the edge there you go starting to take shape it’s not as quite as bad as I thought it might

Have been still got a few bits to fill in but that shouldn’t be too much of a problem so I’ve had second force with the material that I’m going to use for the diaphragm seals um because I’ve installed and um taken seals off again I’ve actually ended up with a bit damage

On some of them so I’m not actually sure they’re actually going to last in operation this is one of the seals uh so this is a silicon bit um well I’ve got the holes here they they do seem to rip out quite easily um so I don’t think that’s going

To last so what I’ve done is I’ve actually I’m upgrading the seals so I’ve done a few practical experiments um I’ve actually found that cotton canvas is surprisingly resistant to burning um I had a hot air gun at about 300° um on the temperature um on setting

On it and um and it doesn’t it doesn’t really have a great deal of effect on Cotton canvas of course they use um they use 100% cotton for um oven gloves and things like that so what I’ve done is I’ve cut out a circle of cotton canvas

And I’ve got some silicon sealant and I’ve actually um painted like an Emulsion of silicon sealant onto the clo onto the canvas um I’ve brushed it around quite a lot so it soaks in so I’m hoping this will actually um um add to the protection for it and also create um

Some kind of seal so I’ve got that as my first uh the inside um diaphragm and for the outside diaphragm I’ve got some of this natural rubber now I’m hoping that this will act as a secondary seal but also because it’s quite springy being natural rubber it will actually keep the Piston

Assembly Central as well um this doesn’t have a particularly High um temperature resistance um but it does have very good uh mechanical uh it’s very stretchy and fairly strong um but time will tell whether the heat gets to it or not so there you go okay that’s all the Pistons s’s put

Together so when I turn the flywheel scope of course you can hear the uh leaking out of the uh the holes there for the gauge for the gauge and uh non return valve and the stop valve so next job is to stick those on right so this is what I got for stop

Valve some old gate valve I’ve got kicking around left over from another project I have take the handle off because I can’t spin it around this is a fairly low pressure pressure gauge it only goes up to two bar which is about perfect for a atmospheric Sterling

Engine so that’s all the valves in place now now the last thing to test is the compression ratio so this a gauge here about here is um half a bar and that’s what we’re aiming for so so valve valves closed off so I’ll spin the flow wheel you’ll hear the non-

Return valve sucking air into the engine turn oh not quite half a bar about3 of a bar but it it might be enough to get it to run not too bad but I I think it I think it might run like that so um so yeah I

Think we’re pretty much ready to give it a go so here we go so you got the engine outside all in one piece and ready to go so I’ll just go and get some wood a minute there’s my father there he always comes over for all the test runs there’s young Isaac hello All right so this is a a rocket stove of types um this is wood going to be burning so it’s basically kindling um you could also run it on sticks and that kind of stuff um it doesn’t like the bigger wood so much so um so I’m only

Ever going to run on sticks and small small bits of wood right so here we go okay so we’re about a few minutes in now you can start you can start to hear the howl how the fire yeah right so um give it a go now it’s been about five minutes since we

Lit the fire um the stack is pretty smoke free now as all good rock so should be um I’m going to close the valve here and I should spin it and it should go was just about go very just well at least it there a good starting point it goes at

All right it’s um starting to heat up now things are starting to get going quite nicely what’s going to be of interest with this engine is um because all the uh all the well I call it regenerat section it’s a cooler section really but it’s kind of

Acting as regenerating some in some way we can actually monitor the temperatures as are going along so that would be quite fun I’ve got no um got no way actually monitoring these temperatures at the moment I’ll have to S some that uh one you recommended to get a FBO

Camera it sounds like a good idea to be fair so I’ll have a look see how much they are right so the fire is about to run out so it’s about to stop one point I like to make is there’s a loud clonking noise coming from um from this side I’m

Coming to find out I left the bolt loose so that’s what that noise was so there you go yeah it’s uh it’s only running very slowly uh it’s been going for three quarters of an hour now so that’s something um I’ve already got a few ideas in my head about um some

Improvements um one thing I’ve noticed here is the flywheels um not quite big enough if you can see look at the flywheel see it’s pulsing it’s speeding up and slowing down uh that’s problematic in Sterling engines because um uh the at one point in the cycle the

Energy is imparted into the flywheel if the flywheel just just gives away and moves out the way then then the energy isn’t collected at the right Point um so that’s one point um another point is on these seals there you can see they’re puffing out I’m actually losing compression ratio on those because

They’re puffing out I’ll just stop a minute see it’s puffing out like that um I might have to change the design of this so it supports the seal as as it pushes in um yeah so uh yeah it’s about it really um one really good thing is it’s

Uh it’s only ran on a few sticks to achieve this you look at our fire here it’s just um I mean it’s uh it’s used a handful of kindling and and a few few logs and that’s SP it really you look at the chimle uh no smoke at all um

So uh I would say the concept is um basically proven so thank you for looking at that um I’ll be interested what you think about all this and um I’ll see you next time T