Author Topic: A gearbox for a little locomotive  (Read 14394 times)

Offline Zephyrin

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Re: A gearbox for a little locomotive
« Reply #30 on: November 04, 2022, 06:36:09 PM »

And now the engine...always my favorite point in model, even if I choosed this model owing to the gearbox !

the  plan of the engine is extracted from the same original picture, lot of infos, but really confused (the first picture of the thread)
it is a small 4 stroke engine with 12mm x 20mm bore & stroke, i.e. 2.2cm3, with spark ignition (coil and contact breaker) and carburetor.
the original engine had a magneto and a pump intake, (if I understood correctly), but I gave up the fuel pump at this scale.

the machining from bar stock is fairly conventional since I don't have any good aluminium castings with my 3D models...

<a href="https://www.youtube.com/watch?v=TtRIWxtQ6IQ" target="_blank">http://www.youtube.com/watch?v=TtRIWxtQ6IQ</a>



Offline Admiral_dk

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Re: A gearbox for a little locomotive
« Reply #31 on: November 04, 2022, 07:43:35 PM »
Looks really old fashioned - and one German caption mentions that is was originally a Mine-Shunter - so do you plan to run it under ground  ;D

No matter - I really like the Looks and Apperance  :Love:   :cheers:

Per

Offline Roger B

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Re: A gearbox for a little locomotive
« Reply #32 on: November 04, 2022, 07:54:07 PM »
Excellent  :praise2: The crank and camshaft look to run freely. I have done fuel injection down to 6 cm3 cylinders however 2.2 cm3 is another challenge. The pump would need to be 1.5mm bore and the injector needle 1mm  :headscratch:  :thinking:  ::)
Best regards

Roger

Offline Zephyrin

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Re: A gearbox for a little locomotive
« Reply #33 on: November 05, 2022, 07:37:47 AM »
You are right, Per, this shunter is pretty ugly, but not so ugly that she has to be hidden underground!
I chose her only for the engine and the transmission; and most of the pictures I gathered show the loco without the bonnet, fortunately !


Roger, with all that I learned by following all your experiments, testing a fuel injection system was my intention at the beginning of the project, this engine dates from right before the diesel and was a good model to have a go...
 But I had to leave this project this summer, and since I have lost its ambition and direction, and now, I'm trying simply to finish this small engine to the simplest and wishes that my model run like this stationary version of this 1905 Deutz engine.

<a href="https://www.youtube.com/watch?v=0-nAtXU8AO4" target="_blank">http://www.youtube.com/watch?v=0-nAtXU8AO4</a>





Offline Admiral_dk

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Re: A gearbox for a little locomotive
« Reply #34 on: November 05, 2022, 06:14:29 PM »
I don't know about 'Hidding it Underground' .... as much as the fact, that it was presumeably meant to do almost all it's work underground -> not much point in 'Prettying it up' ....

I don't know how important it is to you, to make your models authentic - but if not (and you have a succesful roling chassis, w. Engine) - you could always put a more 'Atractive Top' over it  ;)

No matter what - I find your project very interesting  :cheers:

Per

Offline Roger B

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Re: A gearbox for a little locomotive
« Reply #35 on: November 07, 2022, 09:52:26 AM »
I'm happy that you were thinking about trying a fuel injection system  :) however life dosen't always go the way we want  ::)

I look forward to seeing it running along the track  :ThumbsUp:  :wine1:
Best regards

Roger

Offline Zephyrin

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Re: A gearbox for a little locomotive
« Reply #36 on: November 11, 2022, 09:37:43 AM »
Thanks for your interest folks, a much appreciated nudge !

Here is the progress of the model, at this stage I still have the most difficult part to do; the cylinder head with the valves, the rocker arms and the cams...and then to make the engine alive!
I don't get tired of looking at all these little gears, in fact it's mostly for that reason that I'm making this model!

<a href="https://www.youtube.com/watch?v=n3JMKeJZ750" target="_blank">http://www.youtube.com/watch?v=n3JMKeJZ750</a>

Offline Johnmcc69

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Re: A gearbox for a little locomotive
« Reply #37 on: November 11, 2022, 07:11:04 PM »
 :ThumbsUp:
 That really is some GREAT work. You're right about the gears, it's poetry in motion. I feel like a cat chasing a laser pointer when I see all those motions.  :Love:

 John

Offline Zephyrin

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Re: A gearbox for a little locomotive
« Reply #38 on: March 24, 2023, 05:26:12 PM »
  warning says that there are more than 120 days since my last post , how quickly time flies when building models...

Here are the first tests of my little 4 stroke engine, in its final version for my 1910 Deutz loco...I even tested it in place on the loco!
Note that the original engine was not a true diesel, not yet common in those days, but a conventional 4 stroke engine, hence my choice for this model.
it respects the dimensions of the original, he also has a hopper for cooling water and a spark ignition through an electronic box. it uses plain car gasoline with 2% motor oil.
Break-in took about 2 hours of actual running to feel both a free rotation and a high compression, the best moment in the making…

It is a small engine (2.25 cm3) with a very long stroke, 20 mm for 12 mm bore and a volumetric ratio of only 4.3 owing to a large combustion chamber, it also has 2 "large" cast iron flywheels; then I was hoping for a slower running than my previous ones, but no, it isn’t, once again in the 4000 rpm idle, ie, about twice as expected. I will see how the speed changes upon different loads.


I have not yet been able to correct this surging running, an ignition failure at high rpm cannot be excluded, but it seems to me to come rather from a poor carburetion and atomisation, the air/petrol mixture is not stable with this small needle mixer...
A fuel injection at this scale is out of my competence, as well as the beautiful centrifugal speed governor present on the original...alas.

<a href="https://www.youtube.com/watch?v=sSqc76KTdtw" target="_blank">http://www.youtube.com/watch?v=sSqc76KTdtw</a>

Once again it's going to be a struggle to fit everything on my loco… :hammerbash:


Offline Johnmcc69

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Re: A gearbox for a little locomotive
« Reply #39 on: March 24, 2023, 06:21:42 PM »
 A great running engine & a great project!

 John

Offline Admiral_dk

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Re: A gearbox for a little locomotive
« Reply #40 on: March 24, 2023, 10:00:59 PM »
Quote
A great running engine & a great project!

I agree completely  :praise2:

I do not think that you should expect to get it to run much slower .... it is a question of the combined friction and power loss, compared to the produced power ...!
All in All - Very good for such a small Engine  :ThumbsUp:     :cheers:

Per

Online Kim

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Re: A gearbox for a little locomotive
« Reply #41 on: March 24, 2023, 10:28:00 PM »
Congratulations!  That is very cool! She seems to run great! 

Kim

Offline Roger B

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Re: A gearbox for a little locomotive
« Reply #42 on: March 25, 2023, 07:47:09 AM »
Excellent  :praise2:  :praise2:

My 3cc four stroke also tends to surge. I found that the carburettor temperature was quite critical and added a plastic insulator between it and the cylinder head.

The loco looks good, you seem to have the gearbox sorted  :)  :)  :wine1:
Best regards

Roger

Offline Zephyrin

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Re: A gearbox for a little locomotive
« Reply #43 on: March 25, 2023, 03:00:19 PM »


Thanks for the appreciations, much welcome !

Quote
I do not think that you should expect to get it to run much slower

yes Per a sort of cold shower, i was assuming, from what i have read and understood, (model engines are far from my academic degrees!) that with a longer stroke, my engine will give its peak torque at lower rpm, nearer from the wished "put put put put" and not the usual screaming note.

I will make soon tests with loads to check...(electric test would be the simplest)
 
Thanks for the tip Roger, a thermal insulator is easy to add...and test

Offline Zephyrin

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Re: A gearbox for a little locomotive
« Reply #44 on: May 16, 2023, 09:43:44 AM »

the construction is going slowly...

I made a small muffler for the engine, placed under the floor of the loco, as on the original.

The exhaust pipe is simply cut in 2 and both parts connected through a expansion chamber, of about 5.5 times the displacement, I made a measurement with Audacity, (a free and powerful audio editing software)
and I note 9 dB of sound attenuation without even screwing the muffler in place, just put in front.
I show you the exhaust tests

<a href="https://www.youtube.com/watch?v=KIuTBrT-p6k" target="_blank">http://www.youtube.com/watch?v=KIuTBrT-p6k</a>


And still in the sound domain, the engine noise starts to have some realism when the engine is running at low speed while keeping enough power to move the loco!
the noise is low enough to allow the hearing of each of the put put put put... which was the secret goal!

I still have to fit and hide somewhere the ignition and all those ugly cables.

<a href="https://www.youtube.com/watch?v=_FlUNDl14cg" target="_blank">http://www.youtube.com/watch?v=_FlUNDl14cg</a>

and by the way, I've dropped my personal electronic ignitions, definitively, very similar to the commercial ones, except for the way they work.

 

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