THEMA:

Schöner Karton :up: :uboot: *wegduck*

Isn kaputter Monitorlautsprecher drin.....geht zur Reparatur. Musik, mein anderes Hobby.

Innere struktur noch mal überarbeitet....jetzt geht ein 1000ml-Tank rein. Das sollte dann reichen.

O.K., um das hier am Laufen zu halten. Der erste imrprovisierte Bausatz ging an einen Freund in den USA, der mir bei der eralisierung der Nautilus sehr geholfen hat. Ohne Ihn wäre das Boot nicht so schön geworden. Er schreibt einen Work In Progress Report und ich werde den hier nach und nach auch posten. Leider nur in Englisch. Ach ja, Ladies und Gentlement.....die Arbeit von David Merriman:

I first became aware of the model work of Andreas Schmehl a few years back while
checking out the articles at one of the few forums dedicated to r/c submarine model
building. His work-in-progress (WIP) -- a format of article writing that is heavy on inprogress
photos with supporting text -- dealt with the construction of a 1/23 scale, U-1.
Germany's first combat submarine. It was the most comprehensive and well laid out
WIP I had ever read.

That multi-part article had everything: CAD design, CNC'd hull masters; 3D printed
detail parts; hard-shell, GRP hull tools; RTV rubber tools for the small stuff; GRP lay-up;
resin casting; WTC design and manufacture; trimming; detailing; and painting.
As Andreas put it: "I mainly use CAD to create a virtual model of the hull and the interior
technical structure. From that I produce the 3D files for manufacturing 3D-printed parts
and for milling preforms for the GRP tooling". What Andreas calls 'preforms' we
American's understand these as masters, or patterns.
Once Andreas had worked out the 'plans' in CAD, he sent the files to a second party
fabricator who used them to cut machinable plastic medium via CNC milling machine,
and to poop out plastic parts via 3D printer. Those parts, back in Andreas' hands,
becoming the masters of off which he would produce the actual model parts.
Masters by robot. Tooling and model parts by the good doctor.
SkyNet, call your office!

His U-1 article showed me, in a very well laid out article, the use of computers and
mechanized subtractive and additive item manufacture as part of the model building
process.

Andreas has done the same thing with his current r/c submarine project: a dry-hull 1/87
scale model kit of the famous, USS NAUTILUS.
His first USS NAUTILUS, assembled from his kit -- as is the European practice -- was
configured as a dry-hull type r/c model submarine. With the exception of the sail and a
portion of the stern (where the stern plane, rudders and propeller shafts make up to
their respective running gear and linkages) the entire hull is dry.

Another European practice -- most suitable for dry-hull types r/c submarines -- is to
access the interior through a set of bayonet rings that seal with an o-ring. Set into the
forward and after sections of the model, the bayonet rings produce a radial break
between the two. To access the interior all that is required is a slight rotation of the hull
halves to free the lugs of the bayonet rings and simply pull the two hull halves apart. A
positive, quick, easy and pressure-proof closure method. Attaching the equipmentdevice
mounting structure to the stern exposes everything when the forward section of
hull is removed.

Unlike wet-hull type models -- which require opening the hull through a horizontal
equatorial break, removing the WTC, and only then gaining access to the devices by
removing the end-caps of that WTC -- the dry-hull bayonet rings make for excellent
access to the internals for repair, de-watering, adjustment and maintenance tasks.



The advantage of the dry-hull is that there is plenty of available volume in which to stick
all the propulsion, control, and ballast sub-systems.
However, as the superstructure and portions of hull above the waterline will displace so
much water when they are immersed, it takes a great deal of water weight --- taken into
an internal ballast tank -- to create the force needed to counter the buoyant force
produced by all that displacing structure. A big ballast tank takes up valuable real-estate
within the tight confines of the hull.
The need for such a large internal ballast tank denotes the major disadvantage of the
dry-hull type submarine.





Andreas followed the same manufacturing methodology with his NAUTILUS kit. A
second-party produced the masters from which he would make to tooling needed to
create the model parts. Here we see some of the CNC milling-machine cut masters.

Off those CNC cut masters Andreas laid-up these GRP hard-shell tools. A total of eight
tools required to render all the hull and sail parts. Those GRP parts rendered as very
thin section structures.

In addition to the resin and GRP parts he produced from this tooling, Andreas also
produced the art work from which he had acid-etched a fret of wonderfully detailed
deck, radar antenna reflector, other detail parts ... and even a painting mask needed to
produce the white '571' on the sides of the sail.
Also provided in the kit is a set of water-slide type decals containing the white draft
markings for the hull and upper rudder.

With this picture I'm jumping ahead a bit -- this is Aundrea's initial assembly of his kit. I
include it here to point out the use of the very detailed acid-etched deck pieces.
Provision is made in the upper GRP hull to accommodate this. A slight step is provided
atop the hull to sit this .015" thick acid-etched item atop the hull so that it sits flush.
Though the USS NAUTILUS is distinctive of lines, it is a rather boring subject to look at
if the details that are there are not exploited to the maximum -- such is the case with the
deck: safety-track, slotted wooden deck, deck hatches, marker buoys, cleats, torpedo
loading skid, these and more are items captured by the brass metal deck pieces. Even
a bridge deck grating is provided on the acid-etched fret.

Andreas will be making this kit commercially available. What is pictured above is what I
would consider to be a more than adequate kit: right down to pages of exploded-view,
orthographic and isometric drawings outlining not only assembly of the kit proper, but
recommendations for the fabrication and assembly of the European style internals.
A preliminary kit. What I'm presenting here is likely not the definitive version -- note that
there is no bayonet rings to accomplish the water tight radial break between forward
and after hull halves; that the hull pieces (five of them) are provided split to suit those
wishing to assemble this r/c submarine as either a wet-hull or dry-hull type; and no form
of tech-rack (as the dry-hull guys would describe the internals mounting arrangement)
or water tight cylinder (WTC) is provided. Also, there may be material changes before
the production kits hit the street. So, regard what I've pictured here as a Beta test
article, subject to change.

The resin pieces are of exceptional quality. Right down to the bezels and gyro-repeater
that attach to the open bridge!
The items to the right include the bow plane foundation, anchor well, bow planes
(detailed right down to the universal cup joints that make up to the retract/deploy struts),
deck sonar faring, anchor, and deck hatches. In the middle we see the mast foundation,
open bridge well, sail top with all mast and bridge openings, antenna and snorkel
induction items, as well as the scopes and antennas attached to their respective
fairings. Items to the left are the two rudders and two stern planes.
The dark items are cast from epoxy, the lighter items are cast from polyurethane.

... And these two little jewels: the NAUTILUS propellers! Brass, no less. However, it is
prohibitively expensive to have these propellers cast in brass, so I'm working on
Andreas to consider a white-metal alternative -- any heart-burn about that in the future,
you can blame me. You do want a kit you can afford, right?....
It's obvious Andreas did his homework on these. The blades appear to be of a scale
thickness -- no small feat! And they are of the right shape. These two wheels are simply
gorgeous! Matched with the right motors and gear-train, these propellers should scoot
the NAUTILUS along at a very good clip.

The nominal GRP part thickness is about .050"! In the world of model submarines that is
as good as it can get! And the uniformity of the lay-up is even throughout the parts.
These two observations point to a fabricator who has been grounding in aircraft quality
GRP part fabrication. Which Andrea was. He studied at the feet of an FAI quality
contest r/c powered glider fabricator and flyer. The quality of his glass work is a
testament to this early training. You can't buy that type of training!
Note that the hull kit is presented in five pieces. This break-down offers the customer
the option of assembling this kit either for dry-hull or wet-hull operation. Now, that's
smart tool-design! And greatly increasing the market this project is aimed at.
A dry-hull would demand gluing the two long center hull pieces together, then bonding
the bow to the main hull, and making up a set of bayonet rings to the stern of the main
hull and forward end of the tail section. Access would be the radial break between
bayonet rings.

If configured for a wet-hull -- as I'm doing with the kit Andreas provided me -- you would
bond the forward and after hull pieces only to the bottom main hull piece, leaving the
long upper hull half as the removable element, providing plenty of internal access in
which to mount and set-up a removable WTC (Caswell-Merriman SubDriver in this
example).

An artifact of Andreas' lay-up process are the radial and longitudinal flanges at the
edges of the GRP parts. The flanges are beneficial in that they contribute a great deal of
rigidity to the parts, and offer considerable glue area when bonding adjacent sections of
hull together.
However, in those cases where you want a much stronger bond between the hull parts,
it's best to grind away the flange and to lay in reinforcing strips of glass tape on the
inboard side and saturate the tape with epoxy resin. Part-2 of this article will deal with
that and other kit assembly issues.

The two pieces that make up the stern section of the hull. Here you can see, to better
advantage, the radial and longitudinal flanges at the edges of the two pieces.
The lower pieces is a hatch incorporated in the dry-hull version of the hull -- needed to
access the linkages and running gear in the wet stern section. Not needed on the wethull
version I'm assembling, I bonded the hatch permanently to the after portion of hull.

NAUTILUS PART-2
Part - 2 to this article has got to be the most boring installment to this WIP! No flashy painting techniques. No exotic model building do-dads on display. No combination of kit parts to make this thing look like the eventual USS NAUTILUS.
BORING!
But, what I'm presenting here is a vital phase to the kit assembly task: the gluing together of the separate hull sections; the bonding of the bow to the lower hull main section, and bonding the stern section (itself made up of two separate parts) to the lower hull main section. The desired result will be a removable main hull upper piece that permits access to the models interior -- the huge equatorial spit in the hull making WTC installation and removal an easy and quick task.

About this specific kit: Most manufacturers produce GRP hull pieces that arrive warped out of shape, pieces that demand of you the design and creation of specialized holding fixtures, weird hand contortions, and other means of coaxing the parts into proper alignment as you bond them together.

Not the case with this model! Andreas has produced GRP parts of very, very tight maintenance of original tolerance. Near zero warpage. This model kits GRP hull parts rigidity owed to his incorporation of longitudinal and radial flanges. Those flanges both a blessing and a curse: the flanges kept the GRP parts true of form, yet most of those flanges have to be ground away to permit application of internal layers of reinforcing glass tape and resin as the parts are bonded together.

The end game her e will be the permanent bonding of the bow and stern sections to the lower hull, leaving the upper hull to be removable in order to access the interior of this wet-hull type r/c submarine.

To insure correct alignment of the hull sections to one another I first secured them into a coherent hull assembly with the aid of brass straps, those straps bolted to adjoining hull sections -- three straps per adjoining parts sufficient to insure a secure, non-slipping union. By making the holes in the straps a sloppy fit to the machine screws, enough slop is present to permit adjustment to me made as the parts are brought into symmetric alignment with one another.

First task was to drill and tap holes needed to pass the 2-56 machine screws used to hold the straps tight that pulled together adjacent GRP model parts. Initially I used masking tape and hand pressure to hold a pair of parts together, but only long enough to work out strap placement and where to drill the holes.

Use of a three-foot straight-edge -- placing it to the sides, top, and bottom of the central 'main body' portion of the hull -- was used to check symmetrical alignment between the bow and stern sections to the main body. Loosening the involved straps, repositioning the fit between the sections, and re- tightening the straps was all that is involved to move things around till they are in proper alignment.

To ensure all elements of the hull lined up correctly I included the (eventually) removable upper hull section to the assembly. Once a proper fit between the parts was achieved the upper hull half piece was unstrapped, and the process of bonding the bow and stern pieces to the lower hull begun.

For the moment, the radial and longitudinal flanges are left on all the parts, and the hull sections are strapped together. Once the hull is assembled, the individual straps are identified with a number, that corresponds to the same number printed on the hull. The assembled hull was then taken apart so I could go about the nasty work of grinding off the radial and longitudinal flanges, with the exception of the flanges between main hull halves and the bow and stern part radial flanges that would mate with the upper hull section.

The longitudinal and radial flanges at the edges of all GRP hull parts -- to be joined permanently with epoxy saturated fiberglass strips -- were ground away with moto tools equipped with sanding drum and carbide cut-off wheel. The objective is to present a uniform flat internal surface upon which the reinforcing strips of fiberglass cloth can lay and soak up resin, without the internal 'bump' of a flange getting in the way.

The after hull piece has a 'hatch' which has utility on a radially broken hull, but is useless when you are making a wet-hull with the big upper hull half made removable for access. So, you see the flanges between this after hatch and rest of the stern piece being ground away in preparation of bonding.

In some cases, like this, it's a good idea to remove the straps before getting into the glass bonding chore. The strap screws projected into the hull a bit and would interfere with the lay-up of the fiberglass tape used to lap over the seams between hull parts.

So, to keep things together, I tack glue the hull parts together with CA adhesive, then remove the straps and screws. The machine screws cleared away it was a very simple matter to mix up some laminating epoxy and lay in the fiberglass reinforcing strips within the hull assembly.

Four-ounce weight (fiberglass cloth/matt density is expressed by weight per square yard) cloth tape was cut into inch-and-a-half wide strips. Those strips cut to a length that would girdle, from the inside, one- half the diameter of the hull. These strips, when saturated with resin becoming the reinforcement that would permanently bond adjoining hull sections together.
A neat way of working out developed length of the strips is to use a malleable item, like solder wire, as demonstrated here, to determine the required length of strip needed within the model, then to straighten it out and use that to determine the length of the strips required. Fiberglass matt and cloth is best cut out with a disc-blade knife as seen here. A cutting board of wood works very well, as long as the direction of cut is in line with the grain of the woods surface.

The reinforcing fiberglass tape is laid within the model after first brushing on some catalyzed laminating resin. Note the long handle to the disposable brush here -- it permits easy application of resin to those areas not easily reached by hand.

The many holes used to secure the metal straps were first covered from the outside with pieces of tape. Once resin was laid up within the hull it filled these holes -- the hardened resin restoring the outside of the part ... no more pesky holes to fill and be bothered with later.