drawing the steam frigate Mississippi

didit

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#61
WHAM! BAM! ok all the frames are drawn from stem to stern except for the 1/2 cant frames at the bow and the stern those I will do a different way.

all frames.JPG



G'day Dave
I have read this log again. It's so informative and sometimes easy to read, but not too easy to digest for a person like me, CAD ignorant!
Dave, I don't know you doit mate to make all of these frames so quickly. How many hours have you done so far on the drawings?
Happymodeling

Greg

I can't give you a time because CAD does not keep time on the drawing only how long the file is open. What I do when I am working on a drawing is to keep the cad file open when I finish I just put the computer in sleep mode. I work on a file in short work sessions. Like when I am making dinner and waiting for something to cook I will sit down and draw a frame or two and I do this all day. So far the Mississippi file started May 22 and I finished the frames today that is a total time of 40 days 8 hours and 31 minutes. The actual time I spent drawing is about 22 hours.


The Mississippi frames were easy to draw because they are straight sides and bottom the only real curves involved is at the turn of the bilge.
Now take a hull like this one with all the complex curves this would take me twice as long if not longer.
I have been using CAD for over 30 years so I know the program up down and sideways and a lot of quick tricks which helps with speed.

curved hull lines.jpg
 

didit

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#63
and now for step two of the frame drawing.

once all the frames are drawn I will break them down onto floors and futtocks and that goes like this
starting with frame number 1

breakdown1.JPG

the drawings are exact measurements and if I cut out the parts to these exact measurements I have learned over the years of model building I would have zero tolerances when it comes to building. So I am going to add some wiggle room so if I am off slightly I can make adjustments.
What we are looking at to the left the blue line is the original frame drawing. Using the offset tool (blue arrow) I will offset the frame lines which are the black lines outside of the blue lines.
On the right side is now the pattern for cutting out the frame. Comparing the black frame to the red frame next to it you can see the added width of the frame.

breakdown2.JPG

next I added the black and red lines these lines are the breaking points of the frame. The frames are double frames that is two frames bolted together to form on frame. The red lines are one frame the black lines are the other. The breaks are like bricks in a wall and they will overlap. The frame to the right is a copy of left frame.


breakdown3.JPG

Here are the two halves of the frame broken down

breakdown4.JPG

Once you have a drawing you can change it to any scale. I will work the drawing in the scale I intend on building. The reason is I am able to set up cutting files on a known sheet size. The sheet below the frames is 3 x 30 inches so I fit the parts onto the sheet.
i can also figure out 66 sheets will require 23 board feet of 4/4 lumber.

this is another tedious slow process so figure another 40 to 60 days on and off of drawing.


breakdown5.JPG
 

didit

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#65
when you planning a scratch building project sometimes you need to rethink the plan.

plan A was to layout the frame parts for laser cutting well that may not be such a good idea because for one thing it will require 66 sheets of wood 3 x 30 x 3/8 The 3/8 thickness will require a powerful laser to cut that thickness in one pass and a couple technical issues with creating a cutting file will add a lot of extra time. figuring in the laser cutting time it was approaching $1,000.00 a big pricy.

on to plan b

because of the thickness of the sheet stock that will be pushing those small hobby scroll saws to their limits. I happen to have a 10 inch old bandsaw I picked up in a yard sale for 10 bucks and it works great perfect for this type of job. I laid out the parts on 2 x 48 x 3/8 sheet stock and that will do one frame with 2 inches at the end to spare. The difference between a laser cutting layout and a bandsaw layout is I can place the parts real close together, a laser has only .012 thousandths cutting beam with a bandsaw I will have to spread out the parts to give me enough room. This is at 3/8 = foot scale nice and big for fine details and X sections. The bottom layout is at 1/4 = foot scale and one frame will fit on a sheet 1 1/2 x 18

frames option 2.JPG
 

didit

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#66
I am going to break down the frames in the center blue section and build that part of the hull first.

outside profile.jpg

while I build the hull I will continue with the drafting of the bed plate that the two steam engines sit on.

Bed Plate Plan, Etevations.jpg

there are extremely tough durable plastics available so I am going to attempt to machine the bed plate on my drill press with an X Y table with end mills. A machinist I am not so it might be harder than I think. Plan B is to 3D model the bed plate and send it out to be printed. There is no plan C yet

I am thinking using a black plastic or a clear plastic for the engine parts
 
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#67
Beato lei che usa il CAD è può modificare come vuole il suo lavoro, in italia viene chiamato (modellismo arsenale) le posso dire che sono lavori stupendi tutti rigorosamente fatto a mano posto una foto di un modellista (Matiz) ogni singolo pezzo e in scala dell'originale

1046.jpg
 

didit

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#69
Beato lei che usa il CAD è può modificare come vuole il suo lavoro, in italia viene chiamato (modellismo arsenale) le posso dire che sono lavori stupendi tutti rigorosamente fatto a mano posto una foto di un modellista (Matiz) ogni singolo pezzo e in scala dell'originale

Blessed she who uses the CAD is can modify as she wants her work, in Italy is called (modelling Arsenal) I can tell you that are wonderful jobs all strictly handmade place a photo of a modellist (Matiz) every single piece and scale of the original


CAD is a very powerful modeling tool

Sì CAD è uno strumento di modellazione molto potente


non riesco a visualizzare cio che avevo postato vedo solo la foto

I can not see what I had posted I see only the picture
 

zoly99sask

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#70

didit

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#71
there were 2 types of marine steam engines being used around the 1840 the one used in the Mississippi was of the European type. This is the frame that held up the shaft that turned the paddle wheels you can see where the shaft goes on top.

steam engine.jpg

this is the 18 ton bed plate everything was bolted to. looking at the profile view it shows the plate is not just flat. There is a the blue area below the plate. not knowing how such an engine works or what one looks like assembled I am at a loss as to what the blue area is. reminds me of an oil pan on a car engine. Look close at the top view and you will see 2 sets of dotted lines running the length of the plate. That seems to suggest the blue area is running down the middle of the plate leaving a lip on either side. but that is just a guess.

Bed Plate Plan1.jpg
 

didit

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#72
the pink part I would say is what houses the level shaft and you can see where it bolts to the plate. From the side view you can see the raised area where the housing sits in. Now the question is the gray colored rings are they set into the plate or are they above the plate like a ridge? what is the blue part and where does it go and what is that to the left. Besides the rings in the top view what are the other areas indicated?


Bed Plate Plan2.jpg
 

didit

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#73
loosing count of the amount of Emails sent to steam engine museum over the last few months i am batting a big ZERO so far not a single reply. My thought is no one knows how this was built.
this is only the bed plate there are 66 more drawings of various parts to this engine.

building models that come in a box is a nice relaxing hobby scratch building quickly turns to frustration when you get no answers and you hit a dead end over and over. but then again this is the reason in the end those models from a box have little value because there are thousands of them. A model built from scratch is a one of a kind and that is where the value comes in the model itself becomes a reference source for future study. Over months I managed to find 2 know engines similar to this one in the world and no model of one.
 
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didit

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#74
road trip

not exactly like the engine in the Mississippi but close enough I might get some understanding of this type of engine and how it works. Maybe even answer some questions. I can see in the photo the bed plate is quite big like a box. Is that part of the engine OR is it just something the engine is sitting on? I will soon find out
so in a couple weeks Ev and I will go see it.



the-henry-ford-museum-gothic-steam-engine.jpg
 

didit

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#75
the issue with scratch building is there are no instruction everything you do you have to research it or find supporting information. Even when you find information like say the drawings for the engine, if you do not know how a steam engine cira 1840 works you have no idea how to build the engine. I do have text books on steam engines 1850 reading that you need a back round in engineering.

I can see why kit builders expect "instructions" and blame the manufacture for poor instructions or no instructions or instructions that are not clear. Building a ship model either from scratch or from a kit requires a basic understanding on how a ship is built before you even start your build. An intermediate builder should be able to open any kit box and without a word of instructions be able to build the model from experience and basic knowledge of the subject. A beginner gets this knowledge from either learn by your mistakes, learn as you build and or get the needed information from forums that support the subject and not to expect a kit maker to provide everything you need to know. The larger a forum grows the more information get buried and lost resulting in frustration of finding what you need to know.

so with being said looks like I will need to learn what I can about a steam engine in order to build an accurate model. This will require a lot of information so I will start a new topic on steam engines.
 

didit

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#78
Un lavoro eccezionale è certosino,seguo con interesse

An exceptional work is Carthusian, I follow with interest
 

didit

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#80
So where did that guide come from? When I contacted Philly, they denied knowing anything about anything.

odd they know nothing about it, here is the Email sent to me by Debbie
I do not know if this a publication sold by the museum OR if it an internal library reference guide. I would copy the above cover and contact Debbie


Hi. Thank you for your request for information regarding the USS Mississippi. Attached is some more precise information on what we have in our John Lenthall Collection pertaining to this frigate. Please let me know if this is helpful and how I can further assist you.

Best wishes,

Debbie Lovell
Interim Archive/Library Assistant
library@phillyseaport.org
 
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