Samer

[TC10] Classic Locomotive

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Eurobricks TC10 Classic Locomotive
 

Updates: click here for latest update on 23-Sep


Objectives

  • Model a Classic Steam locomotive that runs using LEGO pneumatic system.

pdc-railway-locomotive-vickie-emms.jpg


The Plan (best hopes)

  • Match an elegant locomotive as much as possible
  • Smooth run at decent speed



The Initial design
The idea is to create a pneumatic engine directly driving the locomotive's wheels. The engine receives power from a pneumatic compressor and can be supported by a fly wheel function to support smoother run. Other functions such as opening doors can also be implemented.



LocomotiveDesign%20(Small)%20(Small)%20(

 

Progress

My target is to first accomplish the main function, getting the locomotive to run. when it starts moving I then have to try to make the run smoother. Finally, if time allows and if my parts are enough, I may try to add some extra functions. For now I built an initial structure and started the struggle to have the engine move when pumped.



IMG-20160818-WA0001%20(Small).jpg

IMG-20160818-WA0000%20(Small).jpg

Edited by Samer

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Cool Idea,I hope this moc turns out well for you,as the cylinders are yellow could you put these in side the chassis?

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I am really curious if Lego pneumatic is strong enough to make it actually go. I hope so.

This looks totally interesting.

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Interesting to see what you will come up with, but I think that by using 4 cylinders you could make it go without flywheel.

Each cylinder would be at one of the four possible stages so the locomotive never stalls.

Edited by LXF

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Very good concept. This was on my own to do list so I'll be watching closely. I am fairly certain you will need a geared up fly wheel for smooth running. For a better connection between the link and the wheel you could swap the 1M beam/spacer with 2 3x0.5M pulleys. I think that could be reinforced with pins to better handle the torque of the pneumatics against the counter torque of a geared up flywheel.

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It is a good idea, but front troley with small wheels should be steering

steering? why? that is not how railway works

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steering? why? that is not how railway works

Nope it ain't indeed. But I think he meant that the front trolley needs to turn as a whole. Because that's how railway works

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Nope it ain't indeed. But I think he meant that the front trolley needs to turn as a whole. Because that's how railway works

sure, I understand now what was meant by steering. thanks.

I am sure it is just working stage, because wheels will have (when finished) same track gauge :classic:

Edited by J_C

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Neat idea. Certainly in line with the competition. I hope you get it to work.

What I think would work is mount the blue rods at 90 degrees relative to each other, so that when one rod is at a dead point, the other is perpendicular.

Then, you get a four-stroke kind of sequence:

cylinder 1 extends

cylinder 2 extends

cylinder 1 retracts

cylinder 2 retracts

It's the same as a V4 engine.

Then, you might even have the axle of the wheels drive a crankshaft that will control the pneumatic valves that will inturn drive the cylinders. Similar to what 8868's B model is doing. Maybe you should check that out, it's one of the most brilliant sysems in an official set ever.

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I actually had the same idea but I didn't have the parts to make it work I'm glad to see that someone else can do it. I would suggest using flex axles and liftarms for the body.

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Problem with great projects like this is now you have a following. So no pressure..... :wink:

I will also be following.... love the idea of the motorcycle rims being used here.....

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Flywheels are not necessary. Once the loco has forward motion it's momentum will provide the same function as a flywheel. The hardest part is to overcome it's initial inertia which is where maximum torque is required. Offsetting the pistons by 90 degrees, as real steam locos do, will, as has been already explained, prevent dead-spots in the power delivery no matter where in the stroke the loco is when starting.

As for the feasibility of the idea... click. Good luck with your own model.

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Great to see someone taking on this challenge - looking forward to seeing how your get on. Quick question though: do Lego pneumatics move quickly enough to make this work at a decent speed?

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Looks very challenging to me, hope it will work, you've got your work cut out for you!

Hope you didn't bite off more than you can chew.

Good luck!!!!!

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Hi guys and thanks for this great early interaction and I'm so glad many of you liked the idea.

Actually this is my second try with this project. I failed to do it in the first time when I wanted to make it for TC9 which allowed pneumatics but no electrics. What I did then was using a manual pump and 2 LEGO air tanks. The idea did work and the locomotive moved a short distance with a very nice take off ( and no flywheel). So the answer to the question does this work is a yes by experimental proof. The distance traveled however didn't make me feel it was good enough for a Eurobricks competition and after a lot of failed tries to enhance the travel distance using the same pneumatic resources I have and as the deadline of TC9 got close I decided not to put the entry. However in TC10 having an electric compressor allowed and having my inventory grown, including these 4 wheels which I got very recently, I felt I'm very interested in putting myself into the TC10 challenge and hopefully it will be a great experience with your comments and thoughts.

Unfortunately currently I have personal time stress and these days I seem unable to update the project soon. I hope next update would be some time in September and hopefully by then I would be able to dedicate myself on almost daily basis.

Thanks again to all your encouraging comments that put me in further challenge which I like :-)

Cool Idea,I hope this moc turns out well for you,as the cylinders are yellow could you put these in side the chassis?

I will see what to do with the looks once the main function is successful

Interesting to see what you will come up with, but I think that by using 4 cylinders you could make it go without flywheel.

Each cylinder would be at one of the four possible stages so the locomotive never stalls.

I already did make it go with 2 cylinders which I will stick to unless a problem happens. But even then I don't have 4.

Very good concept. This was on my own to do list so I'll be watching closely. I am fairly certain you will need a geared up fly wheel for smooth running. For a better connection between the link and the wheel you could swap the 1M beam/spacer with 2 3x0.5M pulleys. I think that could be reinforced with pins to better handle the torque of the pneumatics against the counter torque of a geared up flywheel.

Noted, once my hands are back on will be looking into this. It is indeed very early almost concept model. I will have to experiment with so many options including ideas I get here and what I remember from my 1st try.

Edited by Samer

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This is a very original entry, and if finished could well be a winner! I don't know if you have come across this MOC, but here is a smaller brother of what you are trying to create:

I also found a couple more versions of the same idea, but nothing else. This is a very unique MOC!

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I am really interested in it. Hope it will have enought pressure to make this locomotive moving. :)

Looking forward for next progress. Good luck :)

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Hi guys I just came back to work on this yesterday. I'm trying hard, hopefully I'll be able to show something very soon. My main issue isn't lack of torque like some expect. In fact I'm getting a "damaging" torque. For me the main issue I'm facing now is the need to balance pressures in the desired directions to obtain continuous rotation. There are several problems that cause that and I'm still experimenting with the various options.

This is a very original entry, and if finished could well be a winner! I don't know if you have come across this MOC, but here is a smaller brother of what you are trying to create:

Thanks, I always follow ISOGAWAYoshihito but never saw this before. And who can beat this expert. He has 40+ years of Legoing and his books are our references :-)

I am really interested in it. Hope it will have enought pressure to make this locomotive moving. :)

Looking forward for next progress. Good luck :)

It does have a lot of pressure like said above, just bring that pressure under control and GO! :-)

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I came to update this but seems there is a problem with media?

Anyway. I will post the links to pictures and videos. To see please copy and paste each to your browser address bar.

First, after a lot of experimenting one notice that the way this model is connected introduces a lot of friction and a lot of power wasted in undesired direction. This is clearly seen by noting that the valve pressure is transmitted to the wheels only at one side of the valve, unlike most pneumatic engines which picks the valve power evenly on both sides. I could try to modify the design to connect the valve from both sides, but still, the resistance of the wheel comes only from one side whatsoever.  

The above problem with the problems of dead locks (position of which both valves have no desire to move or have little collective pressure to overcome the friction), made the model hard to realize but after a lot of trials I finally had the model work (continuous rotation)  by using this configuration:

800x633.jpg

So this implies:

- Valve had to be directly coupled with the wheel to avoid angular pressure loss causd by the fact that LEGO valves has only one connection point.

- The 40 tooth Gear has 4 stud displacement arrangement, which is perfect for the amount of displacement needed for this valve.

- The system worked by making 2 step displacement between the 2 valves (quarter rotation). This and feeding each switch to the opposite direction valve served to overcome friction and deadlocks very well. 

The pneumatic compressor is made up of a pneumatic pump (the old on from set 8462) run by 2 XL motors. This produced sufficient pressure to move the model semi-smoothly. 

After that, I found a nice method to shape the boiler, but I spent later some days experimenting with different motor configurations :

Configuration 1 (the chosen conf) 2 parallel motors with a single battery.

Advantage: single Battery needed, can place the pump inside the boiler

Disadvantage: As seen, big motors are visible.

Configuration 2 2 opposite motors, 2 battey boxes

Advantage: motors can be hidden inside boiler while the less bulky pump is only partially visible

Disadvantage: 2 battery boxes, the boiler will shake hard and may disassemble because of the alignment of the pump, and boiler is very long.

So after observing the 2 configurations I decided to live with the first one which makes the model lighter, more stable, and really better looking. I will try however to make the motors look like the accessories locomotives have on their top.

I tried L and XL motors and L motors did work but sometimes struggle. So I stayed with the XL.

I hope to bring the next update soon. Thanks for spending the time reading all this :-) 

Picture1:

 800x450.jpg

Picture2:

 800x450.jpg

Video 1: 

Video 2 : 

Video 3: 

 

Edited by Samer

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