I think you could also achieve this variable stroke length by making something similar to a steam "beam engine". You can adjust the beam so that the piston has a shorter lever arm. That way you can get a regular 3 block stroke on the crankshaft with a 1 block stroke on the piston.
Regarding the piston being stretched, that's not actually a problem, passive piston stretching is actually beneficial in most cases due to scrap mechanic being scrap mechanic and just how the pistons are coded. Also, even though you mentioned it, its still extremely important to balance your engines, especially with short stroke. If you dont then you can potentially lose performance. Other than that you did a pretty good job considering its your first short stroke engine, all you needed was a bit more timing, looking forward to when you do it with the Kein engine. Also with your radial, the only thing you need to change is the 45 degrees in the controller, that's why it was surprisingly the first piston engine to have an adjustable stroke.
6:31 You probably want all of the pistons on a shared distance-reduction piece, or else each piston will bend its own bearing as it tries to expand and contract. Then again, the wobbly shaft is probably a bigger problem. Also, with how much of a wet noodle your crank shaft is, your balancing efforts should probably include making it a boxer or even star configuration.
I think I remember making a variable stroke length engine in survival once. It was a kind of a trike with one of those large generator pipe pieces for the back wheel. It was like having a transmission, long stroke for torque, short for speed, and it could go pretty fast. It also worked as a reverse by turning the crank over 180 degrees.
The major issue your engine has is crank balance. As you can see when it is running it is very wobbly, making it less efficient. Balancing a crank is very important, especially on a variable stroke, as bearings are notoriously bad at creating centripetal force. Thus if the axis of rotation of a body is not in line with its center of mass it tends to pull outward. In the case of a variable stroke this means the stroke length expands as the engine speeds up. This is very much undesirable, in fact you'd rather have the opposite happen as small stroke means less torque but even more speed. Given the method by which variable stroke is attained, they will never have their center of mass in line with the crank, but we can get very close. I won't explain how to do so in this post, because it requires some very specific block placement. As kAN stated, he's already received the images. Regarding the length of pistons, the best way is to run a piston in a streched state. As you demonstrated at the start of the video, pistons have a fade-in and fade-out. This fadeing period is proportional to the length of the piston, but the maximum speed stays the same. Due to this a piston that extends 15 blocks is slower because the fading periods are longer. This is probably also why a piston with a length of 1 and highest speed jitters so much, the fade-out period is too short to stop the piston in time. Preferably we want the piston to be at the maximum speed at all times, so the optimal length for a piston would be 15, but only if you stretch them out such that they extend from 7-9 blocks (on a regular inline engine). This method tends to give you a similar speedup compared to what you got in this variable stroke engine as well as some extra torque. We call this "piston stretch". P.S. this engine would be a 1-block stroke, not 2 blocks. You need to measure the radius from the center of the shaft to the center of the crank pin bearing. In the case of a standard inline engine this distance is 1, so the diameter (and thus stroke length) is 2 blocks. On this engine the stroke is therfor < 2, not 2 (I heard you mention 2 a lot but never 1).
A big thing for your i4 engines, is to have the axle rotation at 270 -90 180 instead of 90 90 90 - or however it gets to piston extension of 1 3 2 4 or 1 4 2 3, as that timing helps reduce the axle deflection
Using the puston speed concept you can put your pistons to max distance. They will move faster, the timing wheel will shut them off at the appropriate length. This helped my boxer build really get those rpms up
While you're still experimenting with what works on a variable stroke engine it might not be a bad idea to adopt an I4 crank you'd see in real life. Cylinders 1 and 4 are on one side and cylinders 2 and 3 on the other. This should help eliminate balance as a variable while still keeping things simple.... mind you the secondary balance problems of this design could be an issue, but with scape mechanic it might not. The higher rpms that are possible with shortening the Stoke could mitigate the choppiness of running it like a 2 cylinder, that and a flywheel.
I wonder what happens when you combine 2 different engines... So take an I4 for more torque and that fancy engine from your last video for high rpm for more speed when momentum has built up. They should cancel out their weaknesses, right?
Just connecting them at the crankshafts would be a terrible idea. You are RPM limited by the slower engine, and will lose some torque to it powering through the other engine.
If you look closely the piston actually travels 2 blocks and not 3. Just set it to 2 and it will run smoother. I always set them to 2 and they easily reach 300 rpm at 34 hp.
To make it faster (the small one), let the sensors activate controllers that moves the pistons, they move faster when connected to controlers for some reason
shorter stroke means higher rpm and less torque, which is with you saw. longer stroke means lower rpm but way more torque (more mechanical advantage against the crankshaft)
PLS Kan, edit your old engines to remove the stupid wedges on your timing wheels. We know those are problematic so keeping them there to judge against your newer creations will end up corrupting the results and thus not making them accurate.
I feel like you're confused a little. As long as it's an inline engine, it'll never break the 300 barrier. So right now you have an inline 4, the pistons fire in series. The reason the kine engine breaks that barrier is because it's an inline 2 with 2 parallels. Think of the 2 pistons facing opposite directions as two parallel circuits working together to move along a singular axis. They achieve that by alternating power states. So when one piston retracts, the other is helping by pushing; because 2 pistons are working simultaneously in the same direction, you get a movement that's twice as fast. Your engine in its current design still won't break that 300 barrier because all the pistons are working solo.
Wow. I played this game years ago just for the survival, so I had no idea that you could take it this far! There's no way, but I wonder if balance shafts and more main bearings would affect the operation of the engine 😉
Wouldn't the extra bearing make the crank a bit more floppy though? Even with a controller locking it in place. I'd stick the length controller on a pair of buttons and attach them to the seat, so you can make adjustments on the fly. IRL short stroke is the way you get high RPM out, coupled with a small piston, you can get crazy speeds. But that's got to do with rotating mass, which SM doesn't really calculate like IRL. I would also try a multi piece adjustable duration timing wheel, for more precise timing control.
@mystifoxtech you do still need the pistons on 3 length, having them on 2 slightly increases rpm but drastically decreases torque to the point where you get less hp
The short piston moving faster does make sense if you use the example of low and high gear in low gear you don’t have to give a vehicle much throttle for it to move a certain distance to whereas high gear you have to give it more throttle or pressure to move it the same distance with the same acceleration. I am not entirely sure that this is correct? I am only in high school
I'm not sure what your goal was with this? You were judging it based on rpm but 300rpm is the known limit of a single piston per "cylinder" design, I don't get what you're trying to accomplish with this. Are you trying to disprove the 300rpm limit? No hate or anything just trying to figure out the goal of these builds.
Hey kAN, just to let you know you kept calling the crank shift the drive shaft, idk if you've been calling that prob not cuz your smart guy. But you might want, to fix that👍 love your content btw
Yeah so that bearing asembly was my idea, however, I forgot how flimsy controler bearing combo is. Soooooooo... my suggestion is to get rid of bearings over pistons and if possible get rid of the curved pipe meaning bearing driven by the piston could go coaxially with the shaft. Also, really curious about combining it with that Kein engine of yours.
why don't you just take your i4 and add 2 pistons on either side of your top. you can set them to be always on and move your entire top line up and down. it won't allow you to get a one block stroke, but you could test the difference between a 3 and 4, or an 8 and 4. when testing it is important not to change the timing, one variable at a time (and in theory it should be the same anyways). you could also play with the order the pistons fire; instead of 1234, maybe 4321 or 3142 gets more power. the engine layout could also change things. a V4 typically puts out more horse than an I4 (Donut has a great video going over engine layouts). if V is better, how much of a V is better? it might be worth your time to develop a completely adjustable engine just to see what works. make each cylinder completely separate with passthroughs inbetween so you can play with anything independently from the rest.
All your standard piston engines actually do have a stroke length of 2, because the natural position is 0. If you set them all correctly it won't increase rpm but should help wobble and consistency. The variable length should be able to do 1 stroke length
6:14 No, you do not want to push the pistons down. Quite the opposite; Piston stretch is when you push the pistons up, so all the pistons are stretched about a block away from regular when at the top dead center. This will allow the pistons to have a better angle with the cranks for more of the powerstroke, and it can increase power by a lot. Like 50-100% more power.
wonder if it would perform better or worse putting the offset shafts in opposing directions as opposed to having them be on the same side... and which config would be best.
This piston engine concept is cool but might need improvements later...
Some Nissan’s use this same or a similar mechanism for adjustable stroke length.
kAn the pistons on a normal engine only need to extend by 2. They weren't supposed to be on 3 in the first place.
You should have just done it on the piston side not the crank, because you could have moved the piston one block closer to a normal crank
same problem as always. need a heavy flywheel to run smoother.
What if you use your glitched passthroughs to put a carrier bearing between each cylinder? Think that might stiffen the crank?
I think you could also achieve this variable stroke length by making something similar to a steam "beam engine". You can adjust the beam so that the piston has a shorter lever arm. That way you can get a regular 3 block stroke on the crankshaft with a 1 block stroke on the piston.
the base stroke is actually two blocks
Regarding the piston being stretched, that's not actually a problem, passive piston stretching is actually beneficial in most cases due to scrap mechanic being scrap mechanic and just how the pistons are coded. Also, even though you mentioned it, its still extremely important to balance your engines, especially with short stroke. If you dont then you can potentially lose performance.
Other than that you did a pretty good job considering its your first short stroke engine, all you needed was a bit more timing, looking forward to when you do it with the Kein engine.
Also with your radial, the only thing you need to change is the 45 degrees in the controller, that's why it was surprisingly the first piston engine to have an adjustable stroke.
6:31 You probably want all of the pistons on a shared distance-reduction piece, or else each piston will bend its own bearing as it tries to expand and contract. Then again, the wobbly shaft is probably a bigger problem.
Also, with how much of a wet noodle your crank shaft is, your balancing efforts should probably include making it a boxer or even star configuration.
You should combine the passthrough with the rotation using the edited pistons, for higher torque
I think I remember making a variable stroke length engine in survival once. It was a kind of a trike with one of those large generator pipe pieces for the back wheel. It was like having a transmission, long stroke for torque, short for speed, and it could go pretty fast. It also worked as a reverse by turning the crank over 180 degrees.
The major issue your engine has is crank balance. As you can see when it is running it is very wobbly, making it less efficient. Balancing a crank is very important, especially on a variable stroke, as bearings are notoriously bad at creating centripetal force. Thus if the axis of rotation of a body is not in line with its center of mass it tends to pull outward. In the case of a variable stroke this means the stroke length expands as the engine speeds up. This is very much undesirable, in fact you'd rather have the opposite happen as small stroke means less torque but even more speed. Given the method by which variable stroke is attained, they will never have their center of mass in line with the crank, but we can get very close. I won't explain how to do so in this post, because it requires some very specific block placement. As kAN stated, he's already received the images.
Regarding the length of pistons, the best way is to run a piston in a streched state. As you demonstrated at the start of the video, pistons have a fade-in and fade-out. This fadeing period is proportional to the length of the piston, but the maximum speed stays the same. Due to this a piston that extends 15 blocks is slower because the fading periods are longer. This is probably also why a piston with a length of 1 and highest speed jitters so much, the fade-out period is too short to stop the piston in time. Preferably we want the piston to be at the maximum speed at all times, so the optimal length for a piston would be 15, but only if you stretch them out such that they extend from 7-9 blocks (on a regular inline engine). This method tends to give you a similar speedup compared to what you got in this variable stroke engine as well as some extra torque. We call this "piston stretch".
P.S. this engine would be a 1-block stroke, not 2 blocks. You need to measure the radius from the center of the shaft to the center of the crank pin bearing. In the case of a standard inline engine this distance is 1, so the diameter (and thus stroke length) is 2 blocks. On this engine the stroke is therfor < 2, not 2 (I heard you mention 2 a lot but never 1).
The stroke is actually the total piston travel per powerstroke, which is more in line with the diameter
A big thing for your i4 engines, is to have the axle rotation at 270 -90 180 instead of 90 90 90 - or however it gets to piston extension of 1 3 2 4 or 1 4 2 3, as that timing helps reduce the axle deflection
if you put the adjustment on a looped controller you can have an engine with a built in cvt, high stroke low rpm - low stroke high rpm
Will you do anything with SM, moonbo in a piston race? You guys all make piston cars and race them against each other
Hey kan I love the piston powered vids keep learning I find these super interesting
Using the puston speed concept you can put your pistons to max distance. They will move faster, the timing wheel will shut them off at the appropriate length. This helped my boxer build really get those rpms up
Your Scrap Mechanic videos make me wish there was a crafting gamer where the only mechanical component you get is pistons.
You should try to somehow build a pistonengine with a strokelength of two or one if it's possible.
While you're still experimenting with what works on a variable stroke engine it might not be a bad idea to adopt an I4 crank you'd see in real life. Cylinders 1 and 4 are on one side and cylinders 2 and 3 on the other. This should help eliminate balance as a variable while still keeping things simple.... mind you the secondary balance problems of this design could be an issue, but with scape mechanic it might not. The higher rpms that are possible with shortening the Stoke could mitigate the choppiness of running it like a 2 cylinder, that and a flywheel.
I wonder what happens when you combine 2 different engines...
So take an I4 for more torque and that fancy engine from your last video for high rpm for more speed when momentum has built up.
They should cancel out their weaknesses, right?
Just connecting them at the crankshafts would be a terrible idea. You are RPM limited by the slower engine, and will lose some torque to it powering through the other engine.
Someone needs to make a mod for Scrap Mechanic that changes the bearings to black, just for kAN
If you look closely the piston actually travels 2 blocks and not 3. Just set it to 2 and it will run smoother. I always set them to 2 and they easily reach 300 rpm at 34 hp.
To make it faster (the small one), let the sensors activate controllers that moves the pistons, they move faster when connected to controlers for some reason
shorter stroke means higher rpm and less torque, which is with you saw. longer stroke means lower rpm but way more torque (more mechanical advantage against the crankshaft)
PLS Kan, edit your old engines to remove the stupid wedges on your timing wheels.
We know those are problematic so keeping them there to judge against your newer creations will end up corrupting the results and thus not making them accurate.
Kan, have you tried painting the piston engine red? Red makes things go FASTA!
I feel like you're confused a little. As long as it's an inline engine, it'll never break the 300 barrier. So right now you have an inline 4, the pistons fire in series. The reason the kine engine breaks that barrier is because it's an inline 2 with 2 parallels. Think of the 2 pistons facing opposite directions as two parallel circuits working together to move along a singular axis. They achieve that by alternating power states. So when one piston retracts, the other is helping by pushing; because 2 pistons are working simultaneously in the same direction, you get a movement that's twice as fast. Your engine in its current design still won't break that 300 barrier because all the pistons are working solo.
Wow. I played this game years ago just for the survival, so I had no idea that you could take it this far!
There's no way, but I wonder if balance shafts and more main bearings would affect the operation of the engine 😉
Wouldn't the extra bearing make the crank a bit more floppy though? Even with a controller locking it in place. I'd stick the length controller on a pair of buttons and attach them to the seat, so you can make adjustments on the fly. IRL short stroke is the way you get high RPM out, coupled with a small piston, you can get crazy speeds. But that's got to do with rotating mass, which SM doesn't really calculate like IRL. I would also try a multi piece adjustable duration timing wheel, for more precise timing control.
the stroke of the basic piston engine is actually only 2 because of the bearings connecting in the middle of the block
you don't need the pistons on 3 block range
@mystifoxtech you do still need the pistons on 3 length, having them on 2 slightly increases rpm but drastically decreases torque to the point where you get less hp
I've been using a low friction adjustable stroke for years.
As much as i like pistons engines for aesthetics i use bearing drive engine in survival for their simplicity.
Love the vids!
Bro that music! U make me wanna play Hay Day again!
The short piston moving faster does make sense if you use the example of low and high gear in low gear you don’t have to give a vehicle much throttle for it to move a certain distance to whereas high gear you have to give it more throttle or pressure to move it the same distance with the same acceleration. I am not entirely sure that this is correct? I am only in high school
Your videos are really intressting and i think you should find more enginering games❤❤😁
I'm not sure what your goal was with this? You were judging it based on rpm but 300rpm is the known limit of a single piston per "cylinder" design, I don't get what you're trying to accomplish with this. Are you trying to disprove the 300rpm limit? No hate or anything just trying to figure out the goal of these builds.
Hey kAN, just to let you know you kept calling the crank shift the drive shaft, idk if you've been calling that prob not cuz your smart guy. But you might want, to fix that👍 love your content btw
Noice lets see wath we got in this video
Build a piston engine with the challenge mode pistons
Lovely.
Yeah so that bearing asembly was my idea, however, I forgot how flimsy controler bearing combo is. Soooooooo... my suggestion is to get rid of bearings over pistons and if possible get rid of the curved pipe meaning bearing driven by the piston could go coaxially with the shaft.
Also, really curious about combining it with that Kein engine of yours.
9:32 Your execution failed succesfuly XD
why don't you just take your i4 and add 2 pistons on either side of your top. you can set them to be always on and move your entire top line up and down. it won't allow you to get a one block stroke, but you could test the difference between a 3 and 4, or an 8 and 4.
when testing it is important not to change the timing, one variable at a time (and in theory it should be the same anyways).
you could also play with the order the pistons fire; instead of 1234, maybe 4321 or 3142 gets more power.
the engine layout could also change things. a V4 typically puts out more horse than an I4 (Donut has a great video going over engine layouts). if V is better, how much of a V is better?
it might be worth your time to develop a completely adjustable engine just to see what works. make each cylinder completely separate with passthroughs inbetween so you can play with anything independently from the rest.
these type of engines should be able to spin at 724 rpm
I love you
I wish I had an adjustable stroke 😢
Can you do a 1 block stroke?
nice
Kan you should do a thruster engine
He’s done that awhile ago
why not have the pistons move only 1 block? 1:53
When will You do another survival video?
what happened to zeepkeist?
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All your standard piston engines actually do have a stroke length of 2, because the natural position is 0. If you set them all correctly it won't increase rpm but should help wobble and consistency. The variable length should be able to do 1 stroke length
6:14 No, you do not want to push the pistons down. Quite the opposite; Piston stretch is when you push the pistons up, so all the pistons are stretched about a block away from regular when at the top dead center. This will allow the pistons to have a better angle with the cranks for more of the powerstroke, and it can increase power by a lot. Like 50-100% more power.
wonder if it would perform better or worse putting the offset shafts in opposing directions as opposed to having them be on the same side... and which config would be best.