Stirling engines Adjustable Stirling engine crankshaft

Ive been busy making the tips of my fingers raw.

Wire seems to enjoy hurting people.

But I love the stuff.

My time learning how to make screw in eyelets for my hand made fishing lures was well spent. Every new skill I pick up seems to inform my next project. Working with wire is a really worthwhile thing to learn.

• This post appears to be in bullet point style.

One thing I dont really understand is the relationship between the size of the cams on the crankshaft and the performance of my little tin can Stirling engines. With this lack in mind, I thought Id build a completely adjustable crank shaft.

It looks like this.

With it, it should be easy to try a stack of different configurations to see what they do.

The cams (bits that are offset from the main shaft) should offer different combinations of engine torque, and speed when they are adjusted to different heights.




I think.

Ideally I need an adjustable chamber for the displacer as well. Ill have to feed that idea through the invention engine at some stage because I have no idea on that one.

All the brass fittings come from the brass bits in strip electrical connectors.

Once the screws are undone as far as they can go, all the brass bits fall out with tap and a jiggle.

Lots of taps and jiggles actually, but they all come out in the end.





In my adjustable cam, the brass tubes that accommodate the cams have had an extra hole drilled through. Brass is very easy to drill, and a pleasure to work with. I dont think Ive ever done anything with brass before.

I officially like brass.

• Bullet points

Also, many other people have used these as the adjustable bits on Stirling engines, and my only contribution to the science is to take their use to absurd levels.



120 Things in 20 years - No time to post because Im too busy learning stuff about Stirling engines.












All the brass bits are taken from a strip of electrical connectors.

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Stirling engines My first Stirling engine

Sometimes I struggle a bit with certain aspects of construction, but in this case I wasnt even certain of what I was attempting to construct.

Most of the problems trend around a certain frantic waste of pace and failure to pay attention to detail.

This time was no different.

A Stirling engines basic list of components include a cylinder, a displacer, and a crankshaft.

They also include a hot bit, and a cold bit.

Its the difference between the hot bit and the cold bit that makes a Stirling engine an engine.

Theres also another really important bit, called the power piston. The power piston is connected to the same crank shaft, but on another crank. This crank is offset from the displacers crank by 90 degrees.

Im not really sure how it does what it does, but this is my first attempt at making a Stirling engine.

The power piston is the bit thats missing, because I didnt get that far.


Some of the other missing bits include the rest of the components that make up a Stirling engine.



120 Things in 20 years - On a scale of one to ten, where one is a total fail, and ten is a total success, I wouldnt bother rating my first attempt at making a Stirling engine.

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Stirling engine Slow motion power piston video

Opps.

For some reason the video wasnt displayed on my last post.

Here is the video for those that missed it...

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Stirling Engines My first Stirling engine build

In spite of my video camera running out of battery during filming, I managed to get the first (and only) moments of my first Stirling engine running.

Tis a funny kind of beast running so slowly and deliberately.

I officially like Stirling engines. Mine looked like this...

It ran for a total of about a minute before the displacer fell to bits. It was sealed airtight, and as it got hot it just popped. It turns out there isnt really any need to make it air tight.

I think.

My displacer started life as a soft drink can.

I marked out a straight line to cut it down to size.

I took a guess as to what size it should be.

I scratched a series of arcs with a bent piece of sharp wire, each at different points, to find the centre, then punctured it with a drawing pin. 

I marked out another can, but this time much shorter.

Then squashed the big one over the little one after turning the little one upside down.

This gave me a sealed can again.

I glued it with super glue.

The gluing was what killed my brand new Stirling  engine after only 60 seconds. As the heat increased, so did the pressure inside the sealed displacer, and eventually it popped open.

I poked a straight length of fencing wire through both holes, then bent and super glued one end to stop it slipping through.

My wire originally had a slight loop at the other end, but I had to cut it off to remake the thing after I glued myself to it.

Dont do that.

And if you want to be really scared, use super glue, then adjust the dials and buttons on your new camera with the same fingers.

Anyway, the main thing is stick some wire through the displacer.

Next I took a tin can and smacked a hole in it with my familys trusty meat mallet.

This meat mallet used to be my mothers (it probably still is), and was used as the household hammer for as long as I can remember.

Here we see the entire family history of hammering.

Actually thats half the family history of hammering. The other half is of course, on the other side.







So then, I took the length of wire sticking out of the displacer (soft drink can thing), and threaded it through the bottom of the tin can.











Like this.

Its a bit difficult to see, but thats the soft drink can displacer thinggy under the tin can.









Next, I took another tin can and drilled a big hole in the side.










And sanded down a small plastic bottle so that its contour matched the tin cans.










Then cut a really big hole in the side of the small plastic bottle.

Something like a pill bottle would work.

All this, so I could glue the small plastic bottle on the side of the tin can with a big hole in the side. 

Next, I stretched a balloon over the entire little plastic bottle, and pulled the slack so that it was tight everywhere but the top.

I also glued a length of wire to the centre of the slack bit.

This, believe it or not, is something called a "power piston".

Ill explain what all this stuff does later.


Next I bent a crank shaft, and some mounting points for the wires coming from the displacer (through the bottom of the tin can), and the wire glued to the balloon (power piston)

The crankshaft has one offset bit (offset by around 8mm) to attach the displacers wire, and another to attach the power piston wire to.

The two offset, (bent out) bits, are at 90 degrees to each other.

So from the left...

straight, then down, then straight, then back up to the original.

That makes the first cranky bit.

Then continuing straight, then back, then straight, then forward back to the original plane.

That makes the next cranky bit.

If you look at the crankshaft end on, if one crank was at 12 oclock, the other would be at 3 oclock (or 9)

I found this almost impossible to get on camera (or to explain), but it looks like this.

Its probably best seen on the video.

The crankshaft is lightly held in place with two inverted U shaped bits of wire taped to the sides. (just visible near the top, left rim of the device)

I stuck a cardboard disk about the size of a CD onto the end of the shaft to act as a flywheel, and then added nuts and bolts with blu-tac until the thing was balanced.

To get them in the right spot, I put the disk in a random place, and if it rolled back to a different position, Id stick on a weight so it wouldnt.

I should have been able to do this with just one weight of the correct size, but for some reason it was beyond me.

So...

• The displacer is the soft drink can thing inside the bottom can. 
• The bottom can is sealed ([buy - EDIT  - note from the future-  Who makes errors like this?] by the top tin can) except for the small hole in its top that has the displacers wire poking through.
• The displacer travels up and down inside the bottom tin can with a total travel of around 1cm.
• The displacer gets very close to the top and bottom of its tin can container, but never actually touches.
• The displacers wire is connected to the crankshaft (between pink beads)
• The power piston (pink balloon) is floopy, and connects to the crankshaft 90 degrees offset from the displacers crank.
• The top tin can is there to hold up all the other kit, and as the top seal for the chamber holding the displacer (soft drink can thing)
• When the air inside the bottom tin can heats up it expands, forcing the power piston up. This turns the crank and gives the device its power.
• As the device rotates, and the displacer moves down, forcing the air up and away from the heat, so it cools and contracts. 
• When it contracts, the power piston is sucked down.

Thats pretty much it. Repeat as desired, or until something breaks. 

Some light oil can be added to any surfaces that have friction. (where the displacer wire moves up and down into the bottom tin is a high friction area)

==============>>> IMPORTANT!!! Note from the future - It turns out you probably shouldnt add oil to the point where the wire slides through the can. Theres a chance of explosion as the oil is heated to a gas. <<<================

120 things in 20 years - I made a Stirling engine!

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sudo apt get my top 20 cool cakes

YEAH TUX

YEAH awesome mac

companion cube from Portal

Dungeons & Dragons

Samus

twitter failure whale XD

awesome wedding cake

Really cool wedding cake

Suddenly, Guitar Hero doesnt suck

Cool computer insides =]

best wedding cake award methinks

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Stirling engine Success!

I just made an engine!

I even think I got it on video.

It ran for about a minute at around 78 rpm before making a popping sound and seizing up.

Which would have been perfect if it was connected to an old record player...

playing a very short song...

that I only wanted to hear once.

The camera battery went flat during filming, but but the video should be on there. Ill find out tomorrow. If not, Ill just fix it.

Yay me!

More later...



120 Things in 20 years is very pleased with itself       :{)

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Month of Doubt

lets see...still no power at my house. I dont mind being cold...thats totally not the issue. Its the fact when I go home I cant clean or do anything. Nobody talks to me there and I cant even get online to talk to anyone. This is why I think "death row" inmates should be given a cell with a window, no light other than natural, and no power. They cannot have contact except for cell maintenance (toiletry and such) and food. Its a real killer in itself. Seeing as this is America of course they will have to have heating and air...but thats it.

Imagine how much money that would save.

And I severely want to move...or need to. Since it will be me and some other person that is likely Adam, I probably cannot take rats. Its a hard decision but...its probably whats best. I mean I could take em...theyre only costing me like $30 a year to feed and with a job I could afford to get bedding which could be....$20 for 40lbs of bedding that can be kept in a cage for 3 weeks...theoretically I can keep em.

hah nevermind then

Animals arent even the biggest problem. There are quite a few places that wont charge me extra for them.

Biggest are utilities and rent lol.

The cheapest place in the entire city is $450 not including trash which most apartments include. It is a tiny studio downtown.

I wouldnt be so concerned about power if I lived alone. I mean if most of you have spent more than a day with me, youd know I never think of turning on the heater and only turn on the a/c when Im about to pass out. I dont watch tv so....

My dearest Adam loves xbox...a huge expense when it comes to saving cash. This means operating a tv and a system.

Dearest Adam will have to learn to love games a little less...spoils cant be kept up in a tight situation.

On top of me needing to move, my ID is lost. What can someone do with it? Well I dunno. I dont think anyone looks like me and Im under 21. My issue is getting a replacement...yikes! I dont have the money to do that plus will have family yelling about how irresponsible I am and always will be.

Even though my sister lost like...5 drivers license before she hit 18. This is my 2nd ID...my first expired.

Another reason why I need to move out. Im not a toilet and wont continually take all their shit.

By the way its settled. When I get rich I want a toto or some type of power flush toilet.

Totos now have a quiet lit so if it falls or someone tends to slam them down, instead it has a motor or something to lower it.

or a dual flush. We dont need that much water to flush urine.

or a power dual flush XDD

chea.

ANYWAYS.

Library card is also gone. The rest of my cards I dont think anyone cares about. A marrow donor card, a petco card, a petsmart card (both places I rarely shop at anymore), and a blood source card.

XD

Man I think stress is making me sick.

my biggest stress inducer right now...is my dearest golden. I feel like Im a tossed to the side toy right now. I know I shouldnt feel that way but I do.

=[

toto with heated seat and warm water wash if you get what I mean.

It takes your shit XD

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two months

...thats how long I have to find a job or move out. Why? Its either that or live with my mom in Oak Park, Sacramento, CA.

-_-

There are some goods coming out of that. For number one, Id put up a huge fight if I couldnt bring my dogs (what do you mean were moving to a neighborhood where its best part is a s bad as my current neighborhoods worse part and I cant bring my dogs???!?!?!)

Well I will be closer to CRC when I transfer...I guess.

Personally Id rather live in a trailer. They arent as bad as people say.

Its getting pretty lame...trying so hard only to be constantly put down by family and a dying economy. Im tired of trying so hard but ending up only in failure, coming home and crying every night cause things get worse, and everything is out of my control. Shit better be worth it in the future.

Its times like this that Im glad I have the friends and wonderful boyfriend that I do. I couldnt do it without you guys...you know who you are

=]

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How to wear a shirt

Should I return the map??

First Id like to announce that I pray for the day where I found out Im adopted...as my family is too stupid for me to be related to...

And my sister...beyond annoying. I mean damn...act your age, not my shortest friends shoe size (which is 6 I believe)

Anyway...was playing some Earthbound a while ago...great game.

So what brings me to the internet today is a little different. I have actually come here to try to figure out how to wear a shirt.

yep you read that right.

Its mostly because I have an interview with Macys...a clothing store...and dont want to look too stupid there.

So its the perfectionist coming out in me.

well its more like Im looking for what to wear. Do I wear something on the more casual me-ish side or do I completely dress to impress?

I have yet to tell my family cause they are soooo fucking annoying that Id rather be homeless than deal with them squealing like headless pigs about me needing to look perfect.

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Stirling engine ver 2

I made a few changes to My little home made Stirling Engine.

Change is always required when your engine seizes after only 55 seconds.

This one ran until the plastic bits caught fire.

Much better...

The original displacer popped itself to bits when it got hot enough, so this new version has a different design thats open to air travelling through it.

The autopsy also shows why my little engine stopped so suddenly. There is only around a quarter of an inch of air above and below the displacer when its at its extremities, and the bottom popping off made the displacer touch the bottom of the can it was in.



I replaced the can surrounding the displacer because I had to use a can opener to get the displacer out, and reattached the power piston balloon.

In the process of building the new displacer can, I discovered a new way to drill a hole that suits my personality perfectly.

You punch a hole with a nail, then rip a circular hole with pointy nose pliers in much the same way as opening an old style tin can of fish that the eater would open with a key.





If you arent old enough to know what Im talking about it, count yourself lucky and get on with it. You havent missed a thing.

I drilled a few large holes in the top and bottom of the displacer, and packed it full of stainless steel, kitchen scrubber pad.

Apparently this works, and acts as a thing called a regenerator.

A regenerator can often be found on a Stirling engine and acts to store heat between the hot and cold sections as the air moves between the two.



The regenerator material collects heat from the freshly heated air inside the can the displacer is in. As the heat is displaced from the hot section to the cold section, some heat is removed and stored in the material. This is a good thing, because we want the cold side of the equation to be as cooled as possible. When the cooled air returns to the hot end, it picks up the heat it dropped into the regenerator on the way through, making it heat up more rapidly.

Its not by magic that the heat knows when to sit and when to be picked up, just that the air is hotter on the way up from the heated section, and has cooled a bit at the top before coming back through the regenerator.

I put the new displacer in its tin can, and threaded its wire through the bottom of the top can that holds the crank shaft.










In the process of de-constructing the first version, I bent the shaft a little, and it never ran quite as smoothly again. The little Stirling engine took a lot more heat to get it going this time, but Im not sure if it was due to the new design of the displacer, or just due to the fact that every thing was a bit warped.

Friction really kills these things, so making sure the shaft is straight is a must.

It does run, and its going a lot faster than the first version, but I suspect that has to do with all the extra heat from using a gas burner rather than a candle, and not some gain in efficiency.

I think I now know a little more about these interesting engines, and a little more about the universe in general, and I think Ill have another go at building a better one. Id really like to make one efficient enough to run on the waste heat from my wireless router so it could just jig around all day for free.



120 Things in 20 years is finding the universe yet more interesting as a result of building this version 2 of my first, working, home made Stirling engine.

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