1/48 USS GRAYLING SSN-646 STURGEON BUILD

[rapidnadion]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

(Sorry if I got anyone's hopes up with this bump, but I had to chime in.)

What a great build this was! The level of detail was amazing! It's a shame Tom didn't stick around to complete it. Does anyone know why he stopped work?

[tommydeen]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

always the same....work,family or burnout......

[racer]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Well, actually none of the above.
The more I worked and looked at the hull, the worse it was looking to me.
It was full of huge waves and dips. Really bad.
So I took a hacksaw to it.
Need to start over with a different strategy.

[thor]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Tom,

Don't give up here. May I make a few suggestions and comments on your approach?

Matt

[racer]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Absolutely Matt. Lay them on me.

[thor]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Tom,

First of all, your approach and your skills are excellent. That is not the problem, in my opinion. The issue is the material you used to machine the pattern from. The foam is way too soft to machine in hopes of obtaining the type of accuracy that you are wanting to achieve. I am so pleased to see someone pursuing this type of technology as well to model. It is a lot of fun and a great challenge.

What is the Z travel on your machine? If possible, use the maximum Z travel to minimize the number of sections that you have to machine.

I would suggest using a more robust material such as MDF, renshape, good white pine, etc...your choice. Reduce the number of sections if possible. If you are really set on making a pattern to pull a mold off it this will work well. It will be a VERY heavy beast, but it will work very well and give you the kind of fit and finish you are wanting. If you are really adventurous, may I suggest doing just the negative of what you have done so far? flip your CAD to use the OML(outer mold line) and machine the mold cavity instead of the pattern. Provide a nice common datum for all sections and machine away.

I, myself, rarely machine a pattern any more. I go straight to machining the mold, pull out a glass hull after a rough finish of the mold, and then detail the part up from there. It cuts your time down by 75%.


Good luck, and please do not give up! You have a fantastic project going. If I can assist you in any way with the CAD or G-Code or anything else please let me know. I would be most happy to help!

Matt

[Guest]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

If I use soft foam for bulking out master I always skin the foam with a layer or two of glass matt and resin, and then finish off with polyester filler. This provides a nice tough master. I do find that polyester filler tends to shrink back a bit, resulting in dips in the finish, I leave the plug for a week, and then skim over any low areas, which rectifies that.

[racer]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Thanks for the reply guys.
During the time I had stopped on the project and now, I have made great strides working with Solidworks.
This program is MUCH better to design in than 3D Studio Max and will make the re-design much more enjoyable.
I have also progressed to the point with the Solidcam CNC program which makes this enjoyable and a hoot to work with.
I quite frankly enjoy the design and machining part of this very much and could not see doing it any other way.
It basically increases your skills in so many areas.
Matt, the CNC has a usable table cutting area of X=11" Y=4.5" and Z=10"
I had no issue with the width laying along the X. It is the 4.5" Y dictating the shorter sections.
Although, being this hull has an 8" beam, I could lay it down along the X and do the mold in quarters
which would be 4" wide each. Those could be made 10" long then and I would just have to join it together down the center line of each half of hull. At 10" long, that would drastically cut down on the number of mold pieces. 8 per quarter hull.
I see from your site you have one of the larger table size CNC's permitting these much larger sections.
Mine is more setup like a Bridgeport type table. Much narrower.
Clearly, the straight to mold cavity is the way to go here.
This would also allow me to machine in all the details which makes the Solidcam work challenging.
This is how you learn....
Alright, now where are those plans..

[thor]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Go get 'em! It sounds like we have a work plan now!!

[racer]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Here we go again....

[JWLaRue]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

...gotta love Solidworks!

-Jeff (who's 'stuck' using AutoCAD)

[racer]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Here I have divided up the hull into its modular components.
(colors for part contrast)
In this way I can concentrate on one section at a time before moving onto the next.
The plan is to have torpedoes, camera and moving conn tower components.
Instead of just jumping to the creation of a hull, I want to complete the interior component
designs as I go to insure proper packaging. (yes...it should have been done this way in the first place)

[racer]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Here is the hull tail cone section showing the M6 shaft sealed bearing and a Prop Shop
7 blade scimitar propeller. This prop is 4.0" in dia. with a 1" hub which fits damn near perfect for 1/48th scale.

[thor]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Outstanding work, Tom! Keep it up...

Matt

[racer]

Re: 1/48 USS GRAYLING SSN-646 STURGEON BUILD

Finished up the rudders and tail planes.
Everything that is movable is setup for animations and I will be using these
kinematic movements to check the feasibility of the design as far as full motion without having
things binding or crashing into other components.
Next step will be the U shape bell cranks that will provide the link to the surfaces.
And for a size reference, this module is 5 3/4" in Dia. and 13 1/2" long and I am still making my way
forward up the hull taper.