I'm genuinely surprised that it lasted as long as it did in all fairness. I thought it'd fail far before it got any temperature in it. Very interesting!
it is interesting to notice that the rod handled pretty well the static and dynamic loads generated by the piston movement, despite the fact that it failed because of the friction at the bearing points
it's be interesting to see how long it would last with a metal bushing in the ends, something like phosphor bronze, instead of the petg because it looks like it failed because of friction at that point
Miniature modeling engines are a great hobby, almost like Formula One technology. The motors are subjected to heavy loads and the test selection of appropriate technology elements, etc. There should also be openings or slits to replace the oil, as in the case of the original crankshaft, and for longer work it would probably form the connecting rod element under the influence of a higher temperature. In miniature high-speed motors, however, connections with a colored matte are more durable in the long run.
He should have used the bronze bearings. Even the aluminum rods have them because they can't handle the friction. I doubt that the heat radiated of the piston will be enough to melt the con rod right away. You have to consider that the fuel-oil-air mixture is also cooling the moving parts (because of evaporation).
Stuart Smith In this case, friction was the reason why the con rod failed. I don't think it would have reached the 80 degree celcius that fast. You can see in the video that the heat damage accures on the bearing surfaces.
@@Fuaarrkk there are multiple types of plastic that are multiple times stronger than steel. It's very doable theoretically, not using a 3d printer but certainly maunfacturable
What was wrong, with the 3.3's connecting rod? I played with 3.3 Revos, for over three years and no failures. Proper breakin and they were as good, as anything else. I had 4 3.3's in various cars (Tmax, Revo and 2 Jato's). Not a single one failed and i wasn't easy on them, From local racing to speed bashing they worked fine. I play with brushless now, much less cleanup, but have 0 bad memories of 3.3 connecting rods. The 2.5 was s different story, though is was tuning, not failures in that case
@crazyjr they have a channel in the middle of the connecting rod that creates a weak spot and it will split in half from bushing to bushing. i've never done it, but i always get them in for repair like that.
cool video. expected a little more destruction but the plastic held together well. That engine is awesome and i like how just about every part is replaceable.
As a concept if worked, but you always knew it would fail fast. However, you proved it can be done. Tech moves on, next time this could work. In other applications it may be necessary for a fail to happen at a timing or load. Nice job.
You'd actually be surprised how many cheap weed whacker engines are using plastic conrods now! I used to do an engine lab for students were we broke down such an engine to show the parts, and, sure enough, it had a black plastic conrod!
I think you should add a metal bushing onto it, like have it impregnated into the plastic so it doesnt move. Looks to me like the friction melted the bearing surface which caused the rod to twist and deform further up. Idk could have just been the camera angle when the part was shown at the end
i have a feeling the weirdly 'modified' or mangled crank pin (the pin where the connecting rod attaches to) has a lot to do with how the rod failed (after the fail: the bend in the rod, the shape of the hole, the crack or scorch or whatever on the side of the rod) the top hole(piston side) is probably totally fine. but we never got to see that part lol
Next time you should make a brass bushing, for the ends of the Rod. I believe it was excessive friction, that caused the failure. You can see the way it moved (the plastic), inside the lower hole. I'm not saying it wouldn't fail anyways, but might last longer with the bushings
Exactly what I expected. But there was no hole for lubrication in that plastic connecting rod, so of course it´s melting. But I think it would melt also with a lubrication hole, but maybe one or two minutes later.
Not sure if anyone's mentioned it yet or not, but the big end of the conrods all have small oil holes in them. If I missed the part where you drilled one, my apologies, but if you try it again with a small 1/32" hole, you might get better results.
Put some copper or bronze bushings in there, even the stock metal connecting rod has bushings pressed in. Nothing is going to survive metal on metal like that without a bushing.
You should have done that garage 55 way instead of making a plastic connecting rod make the Piston itself plastic it probably wouldn't work for a long but it would be super cool!
I really do like what you do. You are a talented machinist. Also I saw that you are obviously into rc stuff. You should make a video about your planes. I would really like to see them.
I highly doubt it, but it would be cool. If they can make the parts as strong as the aluminium ones and the manufacturing process is faster, then there are some chances.
could I suggest you consider using the 3d printed conrod and do a last wax type of casting in aluminium by building a gas forge would also open up a new world of projects for you
Hey Johnny! Long time fan! If you are interested, I could print this connecting rod out of nylon for you to test, if that is something you are unable to print. I'd be willing to ship it to you at my cost as well, just to see it tested!
nice vid Johnny! Since you are the best with the lathe, I would like you to introduce brushless motors to your channel (high KV motors to be exactly), Could you make a big gear with 5 brushless motor around connected in parallel to convert 50k rpm to 5k rpm? those motors are really powerful but not really efficient at 50k rpm and would be a great idea to move a large prop or to use it on a go-kart or e bike, there are plenty of 3750 KV motors on internet and they are powerful and cheap! but a big brushless motor is really expensive !
That leaves the question was it thermal expansion because the friction or just the surface of metal to plastic without enough Lube that caused the failure? 1+ trying brass bushings.
This was the first time that I laughed instead of the knot in the stomach upon seeing an engine fail. Intuitively I knew it would slowly break down and stop, just pop a new rod in. If direct injection and a few other methods of known and accepted cooling were used you might be able to make the entire engine out of plastic. Then if you knew how to make a proper geet pipe, well those who know know what I mean.
Would it have worked better with the brass bushings fitted in the con rod holes? Like you had on the metal one? The brass might reduce the friction heating of the plastic moving on metal at such high speeds. Also what plastic filament did you use? Some of the low temperature plastics like PLA would get soft with that level of friction. Nylon might be a good choice.
Did you balance out the crank after printing the con rod? And is the rod any lighter? Carbon Composite might work better. Plastic why would anyone use plastic in a 18,000 rpm engine that runs at around 200 to 260 degrees Fahrenheit?
lolatmyage the idea is to experiment with the longevity of the part made from that material. Those tiny cheapo tire inflation pumps use plastic rods, so why not try an RC motor? Hand crafting that tiny dog bone would be much harder, and probably not much faster than printing one
Carbon fibres dont melt at all (unless you get to over 4000°C while in an oxygen free enviroment), they will only burn at high enough temperaturs in contact with oxygen. If anything melts its the matrix ^^
It lasted longer than I thought. Might of done better with carbon fibre filled nylon or peek. But the cost of them is far to high. Still cool experiment. Great video. Keep up the good work.
It may not have failed , if you had drilled the lubrication ports and put bushings in the rod or even better a bearing ..on both the wrist pin and crackshaft connecting points ..how ever I think the plastic used for a 3d printer are engineered to get soft at a certain temperature.. it's probably possible to manufacture a connecting for out of a piece of a Teflon kitchen cutting board ..as Teflon is rated for higher temperatures .. plus just the general properties would make Teflon less likely to create as much friction , I had a buddy make a piston ,rod and sleeve in his dad's ceramic shop , whitch actually worked out better then he expected , I believe he still uses that engine today in one of his plane models ..
I'm genuinely surprised that it lasted as long as it did in all fairness. I thought it'd fail far before it got any temperature in it. Very interesting!
i figured the nitro would eat the pet-g first. but the heat got it first. rip
You are the Project Farm of nitro engines
Amen brother
It's like an mid 2000s Jeep grad charokee ,all plasic,even some of the engine!
It would also be neat if you put the brass bushings from the original rod into the plastic one
Will Trautman that might solve the melted connecting rod since it melted from friction rather than burning fuel
bryce sturgis it was like a competition like which kills the rod faster... friction or burning fuel... million dollar question 😂
This was my first thought too, bush the rod ends and give it a go
That's what I was thinking right away too: it's gonna melt!
the holes in the end of the rod are for oiling the bearings! the "brass bushings" are the rod bearings.
That 3D printed rod was still stronger than most of teenager relationships
Wise words
Lol
Jep i know it ;)
Impressive it lasted that long in a high revving engine, so many cool things can be made on those printers.
can you make mini rotary engine?
Erlangga Putra Ramadhan 10/10 idea
There’s a company that makes them but they’re not made anymore and are super expensive
Uaxi so you mean a company used to make them and they're very expensive
.... sounds like rotary engines in general
your wish has been fulfilled
it is interesting to notice that the rod handled pretty well the static and dynamic loads generated by the piston movement, despite the fact that it failed because of the friction at the bearing points
it's really great to see the integration of 3d printing with mechanical stuff and machining
Plastic and heat is like humanity and terrorists...they can't be together😂😂..
abhishek gourav best comment I've ever read
I have an OS engine, blue, 6.5cc and it has a plastic backplate.
Fuckin hell with those shitty emojis
The both go out with a bang though....
Unless you want to make something out of the plastic...🤯
This is what Briggs is going to do next. First you thought it was just the camshaft but now it’s going to be the connecting rod
it's be interesting to see how long it would last with a metal bushing in the ends, something like phosphor bronze, instead of the petg because it looks like it failed because of friction at that point
Miniature modeling engines are a great hobby, almost like Formula One technology. The motors are subjected to heavy loads and the test selection of appropriate technology elements, etc.
There should also be openings or slits to replace the oil, as in the case of the original crankshaft, and for longer work it would probably form the connecting rod element under the influence of a higher temperature. In miniature high-speed motors, however, connections with a colored matte are more durable in the long run.
Nice
5:13 you see... The problem is that your conrod melted...
print a rod again and use bronze bearings. It would be interesting to see how long will it last then
He should have used the bronze bearings. Even the aluminum rods have them because they can't handle the friction. I doubt that the heat radiated of the piston will be enough to melt the con rod right away. You have to consider that the fuel-oil-air mixture is also cooling the moving parts (because of evaporation).
Since PETG has a glass transition temperature of about 80 deg C, it was doomed to failure eventually.
Stuart Smith In this case, friction was the reason why the con rod failed. I don't think it would have reached the 80 degree celcius that fast. You can see in the video that the heat damage accures on the bearing surfaces.
Even if it did survive the heat, due to the surface finish of 3d printed parts, it would very quickly crack and have a catastrophic fatigue failure.
I 3d printed the conrod for a pneumatic hammer drill. Worked a treat. Makita are painful to get parts from for quick turnaround. It was nylon anyway
It's cool how people get to see how a nitro motor gets lubricated
Do a whole 3D-printed nitro engine and run it!
TheNoisePolluter no
TheNoisePolluter are you fucking dumb?
@@Fuaarrkk there are multiple types of plastic that are multiple times stronger than steel. It's very doable theoretically, not using a 3d printer but certainly maunfacturable
"Because I could" -- Nice work!
This is how they will make the connecting rod in china in the future :)
dont give them ideas
looks stronger than the TRX 3.3 rod lol
steve polychronopolis lmao too true
What was wrong, with the 3.3's connecting rod? I played with 3.3 Revos, for over three years and no failures. Proper breakin and they were as good, as anything else. I had 4 3.3's in various cars (Tmax, Revo and 2 Jato's). Not a single one failed and i wasn't easy on them, From local racing to speed bashing they worked fine. I play with brushless now, much less cleanup, but have 0 bad memories of 3.3 connecting rods. The 2.5 was s different story, though is was tuning, not failures in that case
True that!
Ahahaha, holy shit my 3.3 rod broke back in 2009. Good memories.
@crazyjr they have a channel in the middle of the connecting rod that creates a weak spot and it will split in half from bushing to bushing. i've never done it, but i always get them in for repair like that.
You should have inserted bronze/copper bearing it would have lasted for some time!
cool video. expected a little more destruction but the plastic held together well. That engine is awesome and i like how just about every part is replaceable.
As a concept if worked, but you always knew it would fail fast. However, you proved it can be done. Tech moves on, next time this could work. In other applications it may be necessary for a fail to happen at a timing or load. Nice job.
4:54 *when v-tec kicks in*
a complete 3d printed nitro engine would be amazing
You'd actually be surprised how many cheap weed whacker engines are using plastic conrods now! I used to do an engine lab for students were we broke down such an engine to show the parts, and, sure enough, it had a black plastic conrod!
The perspex side worked great
Lasted much longer than I expected
I think you should add a metal bushing onto it, like have it impregnated into the plastic so it doesnt move. Looks to me like the friction melted the bearing surface which caused the rod to twist and deform further up. Idk could have just been the camera angle when the part was shown at the end
i have a feeling the weirdly 'modified' or mangled crank pin (the pin where the connecting rod attaches to) has a lot to do with how the rod failed (after the fail: the bend in the rod, the shape of the hole, the crack or scorch or whatever on the side of the rod) the top hole(piston side) is probably totally fine. but we never got to see that part lol
Next time you should make a brass bushing, for the ends of the Rod. I believe it was excessive friction, that caused the failure. You can see the way it moved (the plastic), inside the lower hole. I'm not saying it wouldn't fail anyways, but might last longer with the bushings
In all honesty, that failure was a lot better than what I originally predicted would happen.
I was expecting catastrophic failure.
Nice! ... try add a metal sleave bearing, like a peice of copper or brass in the ring, may help the plastic sustain the heat produced by friction...
FDM 3d printed plastics are, by their nature, thermoplastics, and soften with heat. I wouldn't have expected any other result. :)
Exactly what I expected. But there was no hole for lubrication in that plastic connecting rod, so of course it´s melting. But I think it would melt also with a lubrication hole, but maybe one or two minutes later.
Surprised it lasted that long
It did alright, ran longer than I thought it would!
I finally have the answer to why manufacturers don't make connecting rods out of plastic. I am at peace now.
Not sure if anyone's mentioned it yet or not, but the big end of the conrods all have small oil holes in them. If I missed the part where you drilled one, my apologies, but if you try it again with a small 1/32" hole, you might get better results.
U forgot to put oil hole in bottom of rod !🤔
Put some copper or bronze bushings in there, even the stock metal connecting rod has bushings pressed in. Nothing is going to survive metal on metal like that without a bushing.
Try again with a bushing and have the engine running on very cold air, and also run air over the cylinder. See how long it can go!
Try it with load, and see if it can handle high stress running, just make sure to use metal bushings or ball bearings. Nice vid by the way.
Should try it again with the metal bushings inside the plastic rod!
Metal bottom end race!
In fairness, it lasted longer than I first thought.
If only sleeving an engine was this easy!
You should have done that garage 55 way instead of making a plastic connecting rod make the Piston itself plastic it probably wouldn't work for a long but it would be super cool!
I wanna see this on a full size engine, even if it just blew up it'd be interesting to see
Be interesting to try it bronze bushed and see if it survived longer, maybe an oiling hole too
Really surprised that it lasted that long..
it melted under the heat, it's plastic after all, but I think there are plastics that could withstand that, either way a really interesting test
I really do like what you do. You are a talented machinist. Also I saw that you are obviously into rc stuff. You should make a video about your planes. I would really like to see them.
maybe a couple bushings, with the lighter rod and some bushings it may rev higher with the lower rotating mass
Still worked though bro. Great job
These things need to be tried. Will it be possible in the future that we will have plastic engine internals?
I highly doubt it, but it would be cool. If they can make the parts as strong as the aluminium ones and the manufacturing process is faster, then there are some chances.
Lots a fun, I bet that head was scared of that piston the whole time though :) Great vid.
Had you made clearance the rod to accept brass bushings the rod would of resisted a bit longer before heating up and disfiguring the rod ends.
could I suggest you consider using the 3d printed conrod and do a last wax type of casting
in aluminium by building a gas forge would also open up a new world of projects for you
surprised it lasted that long lol, pretty cool though
CNC would be pretty interesting too
He blew that shit up
Lasted longer than I thought with no bearing
I prefer bubble gum connecting rods when it comes to nitro. They flex more. Bazooka Bubble gum works the best and I can read the comix inside.
Hey Johnny! Long time fan! If you are interested, I could print this connecting rod out of nylon for you to test, if that is something you are unable to print. I'd be willing to ship it to you at my cost as well, just to see it tested!
Try the plastic filament with metal particles in it
I was like: this is only a matter of time until it fails
nice vid Johnny! Since you are the best with the lathe, I would like you to introduce brushless motors to your channel (high KV motors to be exactly), Could you make a big gear with 5 brushless motor around connected in parallel to convert 50k rpm to 5k rpm? those motors are really powerful but not really efficient at 50k rpm and would be a great idea to move a large prop or to use it on a go-kart or e bike, there are plenty of 3750 KV motors on internet and they are powerful and cheap! but a big brushless motor is really expensive !
gartt 3700kv (330w) for a large prop or gartt 1600kv (1700w) for a gokart
Now try CNC delrin with brass bushings
well it lasted more than I expected
you should try and make a fully 3d printed engine
That leaves the question was it thermal expansion because the friction or just the surface of metal to plastic without enough Lube that caused the failure?
1+ trying brass bushings.
The drilling, you can see on 1:52, is missing. so there is no lubrication in the rod bearing.
Looks like it may have worked with little bushings.
I wonder if material PEEK would succeed. Its plastic resistant to high heats.
Would be cool if the whole engine would be made out of carbon. Pretty expensive
This was the first time that I laughed instead of the knot in the stomach upon seeing an engine fail. Intuitively I knew it would slowly break down and stop, just pop a new rod in. If direct injection and a few other methods of known and accepted cooling were used you might be able to make the entire engine out of plastic. Then if you knew how to make a proper geet pipe, well those who know know what I mean.
Would it have worked better with the brass bushings fitted in the con rod holes? Like you had on the metal one? The brass might reduce the friction heating of the plastic moving on metal at such high speeds. Also what plastic filament did you use? Some of the low temperature plastics like PLA would get soft with that level of friction. Nylon might be a good choice.
i bet if it had small brass bushings in the conrod it would last alot longer
I think if u place brass bushings in the connecting rod it will last more hopefully o and hi temp filament if you're not using it here
That was certainly interesting to watch.
It would be interesting to see if the nitro fuel destroyed the PETG plastic in addition to the heat.
I think if you were to put the brass bearings in the plastic arm, it would actually work.
Did you balance out the crank after printing the con rod? And is the rod any lighter? Carbon Composite might work better. Plastic why would anyone use plastic in a 18,000 rpm engine that runs at around 200 to 260 degrees Fahrenheit?
Sounds like a snowmobile on idle
Takin it to the next level
Would be nice to see other materials as well.
Hey JohnnyQ90, .2 or .3 @ 100% ? Was waiting for catastrophic failure. Loved the heads up annotation. Cheers, JAYTEE
It would be interesting to try the other connecting rod with metal bushes to see if that way holds more. a greeting
Would it have failed if it had a brass bushing?
This isnt a fair comparison. there is no bronze oil lite bushings on the plastic rod.
Yep true that
All is fair in love and RC engines...
Spawny eyed wazzock but with high temp plastic u cant 3D print thats the problem
This is such a simple part that I wonder why he doesnt just cut it out of a block of plastic. I guess when you have a hammer...
lolatmyage the idea is to experiment with the longevity of the part made from that material. Those tiny cheapo tire inflation pumps use plastic rods, so why not try an RC motor? Hand crafting that tiny dog bone would be much harder, and probably not much faster than printing one
You should try casting a rod out of a low temperature metal alloy like aluminum or maybe even pewter.
Yes indeed... Perhaps... Metals would be better suited for engine parts...
It seems to fail from heat distorting the crank end under load. The contact with the cylinder is an indicator. Was that your diagnosis?
It needs a bush pressed into each end of the con rod.
i wonder if the fuel is having an effect like acetone with abs were it gets soft and falls apart.
Try carbon fiber?
Carbon Fiber melts at 900°C(I think correct me if wrong) so it should work, great idea!
MacTalk i dont think a nitro engine will get to 900°C😂😂😂
Try metal.
Matthew Godwin 😂😂😂 yeah
Carbon fibres dont melt at all (unless you get to over 4000°C while in an oxygen free enviroment), they will only burn at high enough temperaturs in contact with oxygen.
If anything melts its the matrix ^^
It lasted longer than I thought. Might of done better with carbon fibre filled nylon or peek. But the cost of them is far to high.
Still cool experiment.
Great video. Keep up the good work.
It may not have failed , if you had drilled the lubrication ports and put bushings in the rod or even better a bearing ..on both the wrist pin and crackshaft connecting points ..how ever I think the plastic used for a 3d printer are engineered to get soft at a certain temperature.. it's probably possible to manufacture a connecting for out of a piece of a Teflon kitchen cutting board ..as Teflon is rated for higher temperatures .. plus just the general properties would make Teflon less likely to create as much friction , I had a buddy make a piston ,rod and sleeve in his dad's ceramic shop , whitch actually worked out better then he expected , I believe he still uses that engine today in one of his plane models ..
I have the same screwdrivers mate. Bought them from Lidl :D