@cellman64 They're 1/2" thick, 1.5" wide, and long enough to reduce side stresses on the displacer rod. Good luck! Post a video when you finish it, I'd like to see it.
@teacupoftea Keep the friction as low as possible, use bearings wherever you can, take pains to make the crankshaft as true as possible, don't pack the steel wool too tight, make sure there are no leaks, keep the heat away from the cooling section, have good water flow through the cooler, pre-stretch the diaphragm by forming into the shape you want, apply some heat from a heat gun or similar, then leave it overnight. When you remove it next day the rubber will retain it's shape.
I'm attempting to make a dual motor version based on your design ( and specallez's). What is the idea behind the steel wool displacer? What is the difference between fine and coarse steel wool for this purpose?
@jason158x the steel wool displacer has an enormous surface area for heat exchange to take place. Even though the compression ratio becomes lower using it I've found it more than compensates by pressure changes created using it. Fine is better since it has more surface area per volume and exchanges heat faster.
@approtechie - I ask only because various other sites I notice the questions on how much power will it produce. Since the engine does not produce power the I think the more correct question should be, how much power does it convert from heat to mechanical energy? What is the heat input from the burner? Have you been able to calculate the efficiency of the engine?
@1foxtrot70 I have not been able to calculate the efficiency of the engine yet. For me it's a secondary issue since I'm aiming for usable power, low cost, and ability to run on cheap or free fuels. I'm sure much fine tuning could be done but the cost needs to be kept low to keep it accessible to a broad population.
10 watts is a good amount of energy for a stiling like this one. God job sr. Your flywheells always seem so well connected to the cranks... How do you connect those two pieces togheter so they can work so weel as I see in the videos? I've seen some stirling videos and the flyweels always spin and seem to have a bad connection to the crank, but not yours... How you do it? (can u stop this engine by your hand at those RPMs?)
@SteamStirlingCP Thank you! I've tried various ways of attaching the flywheels, but I currently use a 3/16" shaft for the crank and I thread it on both ends so I can put nuts and washers on it to hold the flywheel. I also thread the flywheels at times and install a lock nut on the shaft. At times I've just super-glued the flywheel to the shaft. Euro connectors can also work for a lightweight flywheel.
@SteamStirlingCP I can stop the engine by hand on the flywheel, but if I try to hold just the shaft then no matter how hard I squeeze I can't stop it. I've noticed that the more I load down the engine the more torque it develops, up to a point of course.
@superbungabunga I think I pretty well maxed it out on propane, the heater head was red hot, so I doubt I'll get any more power out of it by changing fuels.
Oh, and just other question i forgot. It's possible to run a stirling engine without any flywheel. Tath's a correct point right? But is there any condition so that it runs without that element (because the flywheel main function is to give stability and a small vibration)? Do u have any experience on this? I like to know because almost engines can work without flywheel (steem for exemple), of couse loosing power... but about stirlings i dont find many information.
@olemac20 None of my engines will run without a flywheel, I've tried. Also, to get the most speed the flywheel has to be balanced so vibration is minimized. The higher the rpm the more important that is.
Hello once again. I wonder what your opinion on the weight of the flywheel. I noticed that this video shows the engine with higher RPM, but also seems to me that the flywheel has more weight. Not taking into account the initial charge, and taking into account the inertia at the time of starting the engine, and continued rotation of the same, would you recommend use a lighter or heavier in order to achieve a tensile force to a good average speed of 1200-1500 rpm, for exeample?
@olemac20 The flywheel just needs to be heavy enough to carry the crank through the compression stroke. Too light and there will be excessive vibration and jerking at low rpms, too heavy and the engine will be less responsive and the bearings will have to carry too much weight. In this video the aluminum wheel is actually quite light.
Developing and making these engines just to produce a few VA may be the reason you started building them, but I bet the enjoyment you're get from running what you build is measured in KVA . Nice work.
@sirklCZ I think the displacer is about 3" long and fills the water bottle. Not sure about weight. I'll have to weigh it when I have it apart some time.
@boharihamen It's actually quieter than in the video - my camera mic seems to amplify all the sounds. But, yes, it's still a bit noisy, the diaphragm especially still makes a slapping sound. Really well-made machined Stirling engines can be very quiet and virtually vibration-free. They also usually cost a lot of money to make.
If you watch my 20" box fan video you'll see that it's a lot quieter under load and running more slowly.
1.06lb.inch equals 0.12 Nm and @540rpm it means app. 7W shaft output. Congratulation! Very good result for such as simple to build design! But to reach 10W won´t be easy keeping the design simple... GL
@sirklCZ The point of maximum power is not the same as the point of maximum torque in this case. At the point of maximum power the torque reading was .88 lb.in. at 1000 rpm. Calculating that out gives a power output of 10.39 watts unless I'm mistaken. I was really pushing the engine to get this max. output and I would expect a more sustainable output would be about 8-9 watts. And thanks for the kind words! My goal is to build simple, inexpensive, and durable engines that put out usable power.
@approtechie You are right. I calculated power output at max. torque point. Its really 10W! So, one more congratulation! Your construction is YT No.1 in power/costs ratio. Very inspiring.
@sirklCZ I'm not really sure if it's the best power-to-cost ratio, there are a lot of Stirling engines on YouTube. But thanks anyway! I think I'm getting close to meeting some of my goals, at least at this low power level.
@muddymuddymuddmann I use a piece of inner-tube like rubber that my son scrounged from somewhere. It's flat. I pre-formed it so it wouldn't have to stretch at all when it's running.
@macrumpton It's a diaphragm made from thin rubber, like a car inner tube. It's squashed between the two plates and actually glued to the top one so it doesn't lose its form when I take it apart.
This is just amazing :D
Toerme 2 weeks ago in playlist Uploaded videos
lloll muito lokoooooo
dwarfxxt 2 weeks ago
Would love to do it myself! Could you please provide me with details?(parts,dimensions,drawings etc.,)
106theboss 3 weeks ago
@106theboss Sorry, but I don't have that available yet. If you're handy, though, you can probably figure it out from the videos and comments.
approtechie 3 weeks ago
Sounds great!
TheKarlsruheprotest 3 weeks ago
may you give measure of woods; two of them that holding crankshaft!? I guess I will make like this :)
cellman64 3 weeks ago
@cellman64 They're 1/2" thick, 1.5" wide, and long enough to reduce side stresses on the displacer rod. Good luck! Post a video when you finish it, I'd like to see it.
approtechie 3 weeks ago
@approtechie thank you so much. I hope I can make it and share with you master
cellman64 3 weeks ago
I am about to make one myself. Any tips/tricks for the newbie ?!
teacupoftea 3 weeks ago
@teacupoftea Keep the friction as low as possible, use bearings wherever you can, take pains to make the crankshaft as true as possible, don't pack the steel wool too tight, make sure there are no leaks, keep the heat away from the cooling section, have good water flow through the cooler, pre-stretch the diaphragm by forming into the shape you want, apply some heat from a heat gun or similar, then leave it overnight. When you remove it next day the rubber will retain it's shape.
approtechie 3 weeks ago
I'm attempting to make a dual motor version based on your design ( and specallez's). What is the idea behind the steel wool displacer? What is the difference between fine and coarse steel wool for this purpose?
jason158x 1 month ago
@jason158x the steel wool displacer has an enormous surface area for heat exchange to take place. Even though the compression ratio becomes lower using it I've found it more than compensates by pressure changes created using it. Fine is better since it has more surface area per volume and exchanges heat faster.
approtechie 3 weeks ago
I would love to see the results if you connected several of these on the same crank! Very nice engine!
jason158x 1 month ago
@jason158x My thought exactly. Just the time to do it....
approtechie 1 month ago
were you able to measure the power with a Prony Brake?
1foxtrot70 1 month ago
@1foxtrot70 Yes, that's how I measured it. I had a digital scale at a measured radius from the shaft and made measurements at many rpms.
approtechie 1 month ago
@approtechie - I ask only because various other sites I notice the questions on how much power will it produce. Since the engine does not produce power the I think the more correct question should be, how much power does it convert from heat to mechanical energy? What is the heat input from the burner? Have you been able to calculate the efficiency of the engine?
1foxtrot70 1 month ago
@1foxtrot70 I have not been able to calculate the efficiency of the engine yet. For me it's a secondary issue since I'm aiming for usable power, low cost, and ability to run on cheap or free fuels. I'm sure much fine tuning could be done but the cost needs to be kept low to keep it accessible to a broad population.
approtechie 1 month ago
Very good work!
hjesu 1 month ago
@hjesu Thanks!
approtechie 1 month ago
with what materials did you use to make the piston.
TheYoungTurds1 1 month ago
@TheYoungTurds1 the diaphragm is inner tube rubber, the displacer is fine stainless steel wool.
approtechie 1 month ago
Why dont you put magnets and make a pulse motor on the end? you could also use a thermo couple for looping
ashtweth 1 month ago
is this a rhombic drive???
NOBOX7 1 month ago
@NOBOX7 No, this is just a regular crank drive.
approtechie 1 month ago
10 watts is a good amount of energy for a stiling like this one. God job sr. Your flywheells always seem so well connected to the cranks... How do you connect those two pieces togheter so they can work so weel as I see in the videos? I've seen some stirling videos and the flyweels always spin and seem to have a bad connection to the crank, but not yours... How you do it? (can u stop this engine by your hand at those RPMs?)
SteamStirlingCP 2 months ago
@SteamStirlingCP Thank you! I've tried various ways of attaching the flywheels, but I currently use a 3/16" shaft for the crank and I thread it on both ends so I can put nuts and washers on it to hold the flywheel. I also thread the flywheels at times and install a lock nut on the shaft. At times I've just super-glued the flywheel to the shaft. Euro connectors can also work for a lightweight flywheel.
approtechie 1 month ago
@SteamStirlingCP I can stop the engine by hand on the flywheel, but if I try to hold just the shaft then no matter how hard I squeeze I can't stop it. I've noticed that the more I load down the engine the more torque it develops, up to a point of course.
approtechie 3 weeks ago
Beautiful work! Very smooth running and it seemed to go on forever with the heat source removed, you've a right to be happy with it.
whotoinfinity 2 months ago
thats pretty kool that it makes 10 watts you should try to run it on charcoal and see how much power it does
superbungabunga 3 months ago
@superbungabunga I think I pretty well maxed it out on propane, the heater head was red hot, so I doubt I'll get any more power out of it by changing fuels.
approtechie 3 months ago
@approtechie well if you use it for an alternative source of power than it wouldnt hurt to try charcoal
superbungabunga 2 months ago
that thing makes alot of noise
superbungabunga 3 months ago
@superbungabunga It does make some noise but partly it was because my camera mic volume was set too high.
approtechie 3 months ago
How many degrees off are the displacer and piston? It looks like 180°?
ArduinoAlan 3 months ago
@ArduinoAlan The displacer leads the piston by 90 degrees. It's just the shape of the crankshaft that makes it confusing.
approtechie 3 months ago
Oh, and just other question i forgot. It's possible to run a stirling engine without any flywheel. Tath's a correct point right? But is there any condition so that it runs without that element (because the flywheel main function is to give stability and a small vibration)? Do u have any experience on this? I like to know because almost engines can work without flywheel (steem for exemple), of couse loosing power... but about stirlings i dont find many information.
olemac20 4 months ago
@olemac20 None of my engines will run without a flywheel, I've tried. Also, to get the most speed the flywheel has to be balanced so vibration is minimized. The higher the rpm the more important that is.
approtechie 4 months ago
Hello once again. I wonder what your opinion on the weight of the flywheel. I noticed that this video shows the engine with higher RPM, but also seems to me that the flywheel has more weight. Not taking into account the initial charge, and taking into account the inertia at the time of starting the engine, and continued rotation of the same, would you recommend use a lighter or heavier in order to achieve a tensile force to a good average speed of 1200-1500 rpm, for exeample?
thanks :)
olemac20 4 months ago
@olemac20 The flywheel just needs to be heavy enough to carry the crank through the compression stroke. Too light and there will be excessive vibration and jerking at low rpms, too heavy and the engine will be less responsive and the bearings will have to carry too much weight. In this video the aluminum wheel is actually quite light.
approtechie 4 months ago
Developing and making these engines just to produce a few VA may be the reason you started building them, but I bet the enjoyment you're get from running what you build is measured in KVA . Nice work.
ZebedyBoing 4 months ago
@ZebedyBoing You're right - it's immensely satisfying to watch these engines run, especially if they're doing some useful work!
approtechie 4 months ago
Can you post dimensions and weight of the displacer?
sirklCZ 6 months ago
@sirklCZ I think the displacer is about 3" long and fills the water bottle. Not sure about weight. I'll have to weigh it when I have it apart some time.
approtechie 6 months ago
Well done! You have reached to the level of "Personal Power Range" that is considered to be from 10W to 1000W.
358Eki 6 months ago
@358Eki I think I just barely squeaked by the 10W threshold, but at least I got that far! :-) Thanks!
approtechie 6 months ago
Why do they say that Strling engines are quiet and efficient? i do not see the 'quiet' part of Stirling Engines so far....
boharihamen 6 months ago
@boharihamen It's actually quieter than in the video - my camera mic seems to amplify all the sounds. But, yes, it's still a bit noisy, the diaphragm especially still makes a slapping sound. Really well-made machined Stirling engines can be very quiet and virtually vibration-free. They also usually cost a lot of money to make.
If you watch my 20" box fan video you'll see that it's a lot quieter under load and running more slowly.
approtechie 6 months ago
1.06lb.inch equals 0.12 Nm and @540rpm it means app. 7W shaft output. Congratulation! Very good result for such as simple to build design! But to reach 10W won´t be easy keeping the design simple... GL
sirklCZ 7 months ago
@sirklCZ The point of maximum power is not the same as the point of maximum torque in this case. At the point of maximum power the torque reading was .88 lb.in. at 1000 rpm. Calculating that out gives a power output of 10.39 watts unless I'm mistaken. I was really pushing the engine to get this max. output and I would expect a more sustainable output would be about 8-9 watts. And thanks for the kind words! My goal is to build simple, inexpensive, and durable engines that put out usable power.
approtechie 7 months ago
@approtechie You are right. I calculated power output at max. torque point. Its really 10W! So, one more congratulation! Your construction is YT No.1 in power/costs ratio. Very inspiring.
sirklCZ 6 months ago
@sirklCZ I'm not really sure if it's the best power-to-cost ratio, there are a lot of Stirling engines on YouTube. But thanks anyway! I think I'm getting close to meeting some of my goals, at least at this low power level.
approtechie 6 months ago
That must be the best bend crank ever!
SthealthRaider 7 months ago
@SthealthRaider I take a lot of time to bend the crank and true it up. It's probably the hardest part of making this engine.
approtechie 7 months ago
I continue to be amazed at your engines. Thanks
DIYPhonophile 7 months ago
That is really cool. Thanks for the vids
kungfusnoopy1 7 months ago
is it possibly to make and sell some of your amazing engines?
cheetawolf 7 months ago
@cheetawolf I may be getting close to being able to sell plans and engines. Thanks for asking.
approtechie 7 months ago
Very impressive!
specallez 7 months ago
very nice looks like it has plenty of torque
spider9261 7 months ago
@spider9261 I measured the torque and it maxed out at 1.06 lb.-in. @ 540 rpm.
approtechie 7 months ago
Very nice! Never seen a beta configurationa as this. You are an artists of stirling engines. Congratulations!
impazzitoinvolo 7 months ago
SWEET! 1685 RPMs AND STILL WORKING GREAT AFTER THE HEAT IS REMOVED. WHAT DID YOU USE FOR A DIAPHRAGM?
MUDDy
muddymuddymuddmann 7 months ago
@muddymuddymuddmann I use a piece of inner-tube like rubber that my son scrounged from somewhere. It's flat. I pre-formed it so it wouldn't have to stretch at all when it's running.
approtechie 7 months ago
@approtechie THANKS.
MUDDy
muddymuddymuddmann 7 months ago
Very impressive engine! Does it use a traditional piston or is there some kind of diaphragm/rubber seal under the top plate?
macrumpton 7 months ago
@macrumpton It's a diaphragm made from thin rubber, like a car inner tube. It's squashed between the two plates and actually glued to the top one so it doesn't lose its form when I take it apart.
approtechie 7 months ago