Thumbtacks 2 Metal rod 1 about 20' For the crankshaft. I used a. Other diameters may work as well, depending on ductility and strength. Metal rods come in different tempers, some more springy and more difficult to bend. Select one that bends easily, yet is strong enough to support the flywheels without excessive bowing.
Rubber stopper 1 3 size, to fit middle opening of the copper tee. Soda cans 2 Aluminum. Look in hard- ware stores, in the small parts bins that contain specialized fasteners. Metal diecast sheaves 2 5'-diameter metal diecast sheaves or pulleys. Steel cans 2 At least 4' in diameter. Large juice cans or 1lb. Tools Allen wrench to fit sheave setscrew. Drill and bits. Hacksaw Propane torch Ruler and tape measure.
Sandpaper Screwdriver Utility knife Vise vise-grips, needlenose pliers for rod bending. Project Steps View All 1. You could put a small fan in place of the flywheel and use it on top of a wood stove to move heat into the room I have tried multiple times to build one of these stirling engines using various designs and instructions. All have failed lol! Yours looks pretty good, maybe I'll try another! Same here. I have tried a bunch of designs I have been to the point where I just want to hurl the thing against the wall.
I wanted it to work for a school project, but that wasn't going to happen. I love this kind of engine, but it is sometimes a pain to make even when it is simplified.
So, if this one or different one works pretty consistently person to person, please let me know. Senft who is also a great machinist was a real inspiration to me as a teenager, through his books and articles in Live Steam Magazine. He and Dr. Ivo Kolin at the University of Zagreb back in the 80's had a friendly competition to see who could build a Stirling engine that ran on the smallest difference in temperature. This ended with an engine that Dr.
Senft built that could run on as little as 1 degree C. Too bad it seems to be out of print. This configuration of engine was looked at, among other uses, as a CPU cooler for computers. It would be great if people would refer to this type of Stirling as the "Senft engine" to give credit where credit is due. Nice instructable. In the internal combustion engine, the explosion does all the work.
The basic problem is because gases are insulators. The heat transfer occurs between a solid surface and the gas. To maximize heat transfer, it is better to minimize the distance between the solid and the gas. In other words, the volume of air should be confined to a thin layer near the solid. The net result is that it is easier to make a small Stirling Engine than a big one.
Big ones have been made though. Practical Stirling Engines employ several tricks. First, they use gas at high pressure. Second, they use hydrogen or helium, because they conduct heat better. Third, they maximize the heat exchange surface.
By lushi Follow. More by the author:. There are 4 steps in this process: 1. The displacer is lifted and the air is pushed to the heated side, causing the air to heat up 2.
The heated air expands and pushes the piston out, turning the wheel 3. The displacer is lowered and moves the air to the cooler side 4. Using steel wool or sand paper, take off all the paint and clear coat on the aluminum sheet.
Cut out 2, 1x1 inch squares from the balsa wood 6. Measure a 2 inch section of pipe and cut it with a hack saw, rotary tool or pipe cutter. Using steel wool, sand paper or a rotary tool, polish the pipe, especially on the inside. This is the power piston Now that we have all our pieces, we can put it together. Let this cure before moving on. This is easy to buy in crystal form from the supermarket and does a good job of cleaning up copper, brass, and steel. Soft soldering Both the drive and displacer brackets have further parts soft-soldered to them.
These were a simple turning job in the lathe. My secret to professional soft-soldering is electronic solder paste. You can buy this in a syringe commonly used for rework and repair of circuit boards. I put a tiny amount on the parts that need to be soldered together and remove any excess. You can control the temperature very well and not discolour the workpiece. I go for two or three top coats with a light sand between each coat. For the hole for the meths burner in the aluminium plate and the timber base, I used a 38 mm hole saw for drilling, then a chisel and a hand router to bottom the hole to the correct depth.
I completed this sub-assembly by drilling screw holes and polishing the aluminium plate, screwing the completed brackets to the plate, and the plate to the base. The counterweight was easily done by milling away each side while the crank disc was held in a machine vice. First I machine one side usually the most complex of the two sides and centre-bore it. I faced and drilled then bored out the acrylic plastic using a boring bar to the correct size. While the cylinder was still in the chuck, I drilled the four bolt holes using a mill drill and a dividing head.
The cylinder needs to be held from the internal hole and the outside turned to the required dimensions. I use a home-made tapered screw to clamp the workpiece securely. Acrylic or Perspex will polish up really quickly and easily with a bit of Brasso on a rag. The internal bore was polished using a Dremel with a 12 mm felt polishing wheel and the bolt holes were done with a pipe cleaner soaked in Brasso. It looked like it had been glued together from three sheets which made it have two internal rings.
This time it had perfect clarity. Polishing the acrylic cylinder. Tube turned for acrylic cylinder outlet. Displacer piston with threaded shaft. Connecting rod As with all reciprocating engines, the connecting rod is straightforward to make.
You just have to bore both holes at the same time so they end up parallel to each other. The piston has the gudgeon pin held internally via a yoke that is screwed into the top of the piston and allows the piston height at top dead centre TDC to be adjusted.
The only tricky part here is to get the piston outside diameter OD to match the cylinder bore. The Stirling engine must have low friction and be gas-tight at the same time so the match of these two components is critical to the success of the engine.
Piston I turned the piston down to almost the correct size, measuring with a micrometer as I went. With a bit of sewing machine oil in the bore, the piston traveled up and down very smoothly.
I breathed a sigh of relief with all the hard parts successfully out of the way. Displacer positioning jig used to drill accurate holes. Cylinder head, air port The drive cylinder head and air port were straightforward parts to machine and were soft-soldered together using my heat-gun method.
With this installed, the drive cylinder was completed. For a bit of light relief at this point, I made the burner and the two guide rods plus their support angle bracket before tackling the displacer cylinder. Displacer piston The displacer piston was made out of a felt-tip pen housing of thin-walled aluminium. I unscrewed the pen tip, removed the felt, rinsed out the ink with meths. Each cylinder is formed from the copper tubing, the power cylinder is soldered to a Paxolin board that is bolted to the two heat-sinks.
The diffuser cylinder will be bolted to a second Paxolin board and bolted to the chassis via a gasket. This should enable me to seal the two cylinders and then simply link them with some tubing. I hope. I cleaned up the two heat-sinks with the Dremel to ensure good mechanical contact between them. I cut and marked out the two Paxolin boards, then drilled the power cylinder board to bolt to the heat-sink. The diffuser cylinder board was marked up and drilled for the bearing and the feeder tube, then tacked on with super-glue.
The four mounting bolt holes were drilled through and then the two feeder tubes were soldered into place. The power cylinder was soldered on and the nylon bearing for the diffuser piston glued in. Finally the feeder tube was connected up. That completes the main chassis assembly. I wanted to make the engine look nice, so I decided to try and make an elegant flywheel. I had found an old brass centre from a defunct CD or DVD player, then I downloaded a protractor template from the net and marked lines at 0, and degrees to give three equal spokes.
I still had the top ring of a food container I had cut down for my first Stirling, so I used that as the flywheel outer ring.
You could cut a ring from 3" plastic drainpipe instead. I placed the brass boss onto the protractor with double sided tape and then measured and cut 3 lengths of 1. These were then supported on some levelling materials and soldered to the centre boss. The outer ring was laid onto the protractor and marked then drilled 1. Because the ring is slightly flexible it was easy to deform it enough to force the spokes through.
Once it was all back in shape and trued up on the protractor, the spokes were super-glued into the ring. A piece of 10mm aluminium was cut to size and drilled ready to accept the crankshaft. It was then super-glued onto the brass boss. That completes the flywheel. Recognition for the idea for the support pillar and bearings must go to eVolti which was an inspired bit of 'ible. I decided to use a very similar system, just a bit simpler in execution.
The head had originally had four read arms, three of these were ground off with the Dremel and all the ancillary coils, wire and the actual heads were removed. The arm was carefully ground to fit a piece of aluminium channel, then the channel was drilled and the arm bolted to it.
A little epoxy glue was added for a really good strong joint. The channel was cut 60mm long, but you can set the size to whatever you require. The bottom of the channel was bolted to the third heat-sink I found in the old TV which had a good 90 degree bend in it. The bend will be bolted to the main chassis plate. The crankshaft consists of a short length of 2. This is passed through the bearing head and carries a flywheel on one side and the cranks on the other.
The cranks are formed from 15mm disks of brass. You could cut these off a piece of brass bar, as I intended to do, but whilst I was in the plumbing section of the hardware store buying the compression end cap for the diffuser cylinder I came across a pack of four 15mm 'blanking caps' for 79p.
These will do the job very well. I drilled the centres of three of the caps 2. This will give a stroke of 10mm. The first disk was slid onto one end of the shaft and soldered in place. The distance between the cylinders 26mm was marked onto the shaft and the pair of disks for the second crank were slid on and soldered in place.
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