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Subject: 
Re: "Big Blue" Pneumatic 4-6-4 engine and tender
Newsgroups: 
lugnet.org.ca.rtltoronto, lugnet.trains
Date: 
Wed, 1 Nov 2006 17:13:39 GMT
Viewed: 
3166 times
  
In lugnet.org.ca.rtltoronto, David Koudys wrote:
An idea forming in the mind many years ago was to take the pneumatic cylinders
and actually make a 'steam' engine.

Inspired by Trevyn a few years back at hte hobby show, when he showed up with a
pneumatic engine that ran on the duplo tracks, I started formalizing an idea.

Well, the idea, in it's very limited glory, took shape this week--

http://sandysparky.net/gallery/20061026_pneumatic_train_1

Yes the website is very slow--I'm presumably working on it.

Anyway, I'm uploading a movie of the engine sorta working--

http://sandysparky.net/lego/big_blue.mpg

It's 71 meg so it's a little big (and it's stipp uploading so you won't find it
'til later :) )

I'll try to compress it soon.

This is why I was asking about fly wheels--the wheels running off the cylinders
don't spin smoothly, but eh, not too worried.

As well, I thought the small pneumatic cylinders could handle the weight, but
alas, not so much.  On a striaght piece of track, and with a little coaxing,
it's fine.  Anything else and it's the little engine who couldn't.

Yes it's a hybrid--the wheels are pushed and pulled by the pneumatic cylinders,
but the pneumatic switches are moved by an electric motor--couldn't figure out
how to flip the switches via the small cylinders.

Anyway, have plans for a 'better' one, this time using the large pneumatic
cylinders, but will wait until I get more BBB wheels 'cause I don't want to take
this one apart.

Let me know what you think, including any suggestions for improving the
functionality/looks of Big Blue

Dave K

That is just too cool.  I've watched the movie many times now, I love the sounds
your engine makes!  I hope you're able to get it to run reliably, I'd love to
see it on a loop of some kind.

I have a suggestion for the performance issue, but I'm no engineer so please
forgive me if it won't work.  Have you tried adding more weight above the
drivers?  I don't know how much those cylinders weigh, but they're full of air,
which can't help things any.  Perhaps the slippage is caused too little of the
engines weight is being distributed over the driving wheels.

I had a similar problem with a small train MOC of mine where I had the motor in
the tender, which was little more than the motor itself.  There just wasn't
enough weight on the motor and it kept slipping.  Troy has told me he sometimes
adds rolls of pennies to his MOCs to make the motors more efficiant.  Granted,
this is all about 9v motors, but the theory seems to be the same, at least to
me.

--Tony



Message has 1 Reply:
  Re: "Big Blue" Pneumatic 4-6-4 engine and tender
 
In lugnet.org.ca.rtltoronto, Anthony Sava wrote: <snip> (...) Great ideas Anthony! I did put a LEGO boat weight right on top of the drivers, and the 9v motor is pretty close as well. I haven't looked at it in a few days, but plan on modifying it (...) (18 years ago, 1-Nov-06, to lugnet.org.ca.rtltoronto, lugnet.trains)

Message is in Reply To:
  "Big Blue" Pneumatic 4-6-4 engine and tender
 
An idea forming in the mind many years ago was to take the pneumatic cylinders and actually make a 'steam' engine. Inspired by Trevyn a few years back at hte hobby show, when he showed up with a pneumatic engine that ran on the duplo tracks, I (...) (18 years ago, 27-Oct-06, to lugnet.org.ca.rtltoronto, lugnet.trains)  

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