Subject:
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Re: MOCs: incl German WWII Railway gun
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Newsgroups:
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lugnet.trains, lugnet.build
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Date:
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Wed, 2 May 2001 13:34:48 GMT
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Viewed:
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27 times
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Mattias Martensson wrote:
> Congratulations Shaun to another fantastic mastermodel.
Thanks :)
> Fascinating that the gun is motorised also. Do you use the pneumatic
> pressure as a counterweight for the gun barrel. I wish you could take same
> pictures of the interior design.
The pneumatic pressure is the actuator that lifts the gun. The motor only
serves to run one air cylinder as an air compressor. That pressurized air is
then fed into one of the large pneumatic air pistons, which is pinioned to the
gun barrel quite close to its axis of rotation. When the air piston is in the
fully retracted position, the gun barrel lays flat. In the fully extended
position, the gun is forced to rotate up to accomodate the expanding picton,
which pushes it up to the maximum angle shown in the pictures.
I used one of the geared motors to pump the air cylinder, and ran that further
through another 1:3 reduction using the large crown gear. The large crown is
then attached to one of the crankshaft pieces, so that each rotation only
provides a small stroke. This slow pumping provides the slooooowwwww rise to
the gun.
Next time I borrow the camera, I'll try to get some pictures of the inner
workings.
One disadvantage to the design is that it is all built inextricably linked
together. The electric cords actually run through the interior of the black
wheelbase platforms, and connect the railgun to the freight car. Consequently,
the two cars must be moved together. When on the track, this is no big deal,
but lifting the cars or transporting them is best accomplished by two people.
> I have also a few more general building question. When you design a build a
> Lego model, do you make some kind of sketches or drawings first?
Well, the first step is always an intense research period. I scour the web and
Barnes and Noble and my own collection of WWII reference books for every and
all pictures of my project subject. Based on those, I can usually get an idea
of what features are essential to the design, and waht areas are absolutely
crucial to convey the details of the subject.
I do do a good deal of sketching. I've actually taken to carrying a LEGO
concepts notebook with me everywhere, and jotting down everything: lists of my
pending purchases or needed bricks for my current project, web addresses of
interesting ideas, and lots of development sketches. Sometimes, I fear that my
job is just a place to figure out LEGO solutions without having the bricks in
front of me [disclaimer to any other employees of my company reading this ...
JUST KIDDING ;)] There are also a large number of sketches and calculations.
> Do you
> make many prototypes before the final construction? I have myself found it
> practical to keep the last prototype as a 'drawing' for the next more
> detailed prototype.
For some reason, I very rarely end up having prototypes ... there are only two
real exceptions to this that I can think of; my AT-ST (which I have since
scrapped and am in the process of redesigning), and the BR52 locomotive (which
was my first foray into tranis, and after it was finished I realized it was
just way too small). Except for those two exceptions, I'm really building the
final item the whole time. I'll rework parts of it as I go along, or
occasionally try out an idea with random colored bricks first before finalizing
it into the design, but I hardly ever build entire prototypes, and never with
that intent.
Interesting ....
Thanks again, Mattias!
-shaun
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Message is in Reply To:
 | | Re: MOCs: incl German WWII Railway gun
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| Congratulations Shaun to another fantastic mastermodel. Fascinating that the gun is motorised also. Do you use the pneumatic pressure as a counterweight for the gun barrel. I wish you could take same pictures of the interior design. I have also a (...) (24 years ago, 1-May-01, to lugnet.trains, lugnet.build)
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