Scratch build HMS Resolution Class SSBN

[Davidh]

thank you trout,

Good to see that something I'm doing is inspiring someone. I usually get on this forum and look at the cool stuff other people are doing and find soon enough that I then want to head into my tiny workshop and build something.

I have just realised that I don't have any pics of the top hull being moulded. I don't have pics of the part coming out of the mould. However I do have pics of the top hull reasonably finished and even weathered. I was not initially happy with the first attempt at weathering. I have weathered the waterline before attaching the top and bottom moulds together. Easier to get a scribing tool around on a flat surface. I have ended up going with a green algae scumline.

Once the top hull section has been finished to an extent I can then look at attaching the missile deck to the top hull section. I need to drill out some holes in the top of the hull beneath the missile deck for air to get out and access to the airline for the air pump in the subdriver. The joint area between the missile deck and where it fits to the back of the bow section requires some cutting and issues of access. I have had to grind out the back wall of the front hull in order to get to the underside of the missile deck where it mates. Once done I can then F'glass it together. I also need to make sure that there is a consistent gap between where the top hull deck ends and where the missle deck gap occurs and runs to the stern. There is a slight taper in the missile deck edge as it widens slightly to meet the front of the hull. I have had to wedge a small piece of balsa either side while I f'glass down the missile deck to the top hull section. Once that's done I will sand back the outside joint untill it's nice and flush then rescribe the safetly harness lines as they cross the joint area.

Anyway, enough for now

David H

[Davidh]

G'day all, very quiet...

After I've attached the missile deck I have re-etched and scribed where some of the harness lines would go over the area where the two parts meets and are glued. It's important that this joint is simply not noticed. I gradually go down with various levels of wet and dry and then give it a shot of the satin black that I have been using.

In the meantime I have been working on developing the surfaces that the boat needs. I would like to mould these out of a resin of some sort and want to experiment with different moulding techniques. This will come with time. So I will stick to the methods that I have been using ever since I started with model subs and that will be to cut these pieces out of a hardwood. (well, pine aint a hardwood I know, but for soo long I've worked with Balsa which by comparison feels really soft and yet Ironically is actually a hardwood) you get it. The only alternative that I have lying around is some Jarrah, which is an Australian native hardwood.

I carefull shape the two pieces that I will use to make the fore planes, making sure that they are the mirror image of each other. Once I am happy with how they have turned out I give them a coat of resin. Then plenty of wet and dry and then primer coats the ascertain the uneven surfaces that will need further sanding.

For the moving surfaces I use brass rod for the rotating shafts and then a brass tube as brackets where needed. This is the case for the rudder and the rear horozontal planes. The foreplanes are fixed. I have used a smaller diameter brass rod and drilled into the foreplanes and then into the sides of the plane mound so I can see how they look. I can pull them in and out untill I need to eventually glue them in.

As you can see from the upper moving rudder section I have glued a brass tube to the leading edge of the rudder. this is where the brass rotating shaft will fit up and into similar tube attached to the fixed fin section. I will then have a similar section of brass within the hull precisely aligned with the mounting of the fixed forward section of the fin. I also have to alight the bottom rudder because the both pivot off a "C" type bracket that a pushrod will come off. The glues brass tube will then be given a small layer of filler and sanded back. I have then scribed some detail on the rudder.

The horizontal planes are a similar proposition except that they wil have their own pushrods. They will however need a bracket at the outer end where they will attach to the fixed horizontal plane. This is a crampt little space.

Meanwhile I have also been drilling out the vent holes on the bottom of the hull. This can be a tedious process but necessary. My positioning of these drainage vents as mentioned previously is mainly speculation, there have been no released photos showing what the arrangment is.

I have been looking at the positioning of the shaft and screw mounting. I decided to make a small section for the shaft to rest on at the rear of the hull. I looked at the rear shaft mounting that Dave designed for the skipjack kit and liked it. So I have used casting and embedding resin to create a small 'dam' at the very stern of the hull and built a dam wall out of some thin fibreglass sheet, then poured in the resin and waited. Did this on both halves.
Once dried I simply drill and file out.

Anyway, enough for now.

please feel free to add comments, I consider all the advice I can get.

Dave H

[He Who Shall Not Be Named]

STOP USING WOOD!!!! Get some dense RenShape and you'll never look back.

http://www.freemansupply.com/MachinableMedia.htm

Do it now!

M

[Subculture]

Renshape may not be available over there. Trade names tend to vary from country to country.

Look for polyurethane tooling board. It comes in varying densities. The stuff in the 240-500 range would be most useful for model work, at least when makign the smaller parts.

However it can be difficult to find in smaller quantities- you usually have to buy a big sheet, which costs a lot of money, and it's difficult to justify if you're only building the odd project here and there. If you know some other modelmakers you can do a group purchase, and cut a sheet up into bits.

I tried that some years ago, got a two or three people interested, but it wasn't really enough. Easy composites here in the UK sell smaller chunks now.

[trout]

I am in for a group purchase, if we want to do that!
David,
what do you use RenShape 5030?

[Subculture]

I should have added that the weight of the higher density material (similar to plywood) would make it very uneconomical to ship internationally.

Having said that, I have to be honest and say I haven't used this stuff. I use plastic sheet, metal, MDF or epoxy glass sheet for making parts. These are all no doubt harder to work than the tooling board. If I was doing it for a living where time is money, then I'd probably go straight for the expensive stuff, as it is I'm a hobbyist and use what materials come easily to hand.

[greenman407]

David, that is one smart looking boat

[He Who Shall Not Be Named]

I am in for a group purchase, if we want to do that!
David,
what do you use RenShape 5030?

This one, Tom:

http://www.freemansupply.com/RenShape450MediumD.htm

Use of low and high density RenShape:



M

[Scott T]

Wow! It comes with fig newtons.

Scott T

[He Who Shall Not Be Named]

I'm a weak, weak man.

Smart ass!

M

[Davidh]

I think I've annoyed dave...

I would love to get some renshape If I could find a local supplier who could give me a price and a straight answer. Found one in Perth, (4500kms away) Also I produce one new model every 2-3 years so I don't know if it's feasable. I am certainly curious to try it though...

Anyway,

David, block you ears, wood involved.

Tail feathers. I have built all the pieces for the stern assembly, coated them with resin, fillered them if necessary and sanded and then repeated whole task untill they were how I liked them. (Dave, unblock now) Glued the brass pushrod shaft sections in place to the various rotating pieces. Cut out small sections of brass tube to act as the bearings or collars for the rotating shafts. Supported one drilled holes in the fibreglass of the rear hull. Making sure at the same time that the top and bottom collars line up precisely with each other.

Iwould take the brass shaft attached to the rotating surface and then file a flat section in either side so that it created a rectangular profile. The horns that I use are made from a tiny rectangular piece of printed curcuit board with a rectagular cut out for the brass shaft to fit up into. I then glass this down making sure that none of it gets into the collar that the rotating shaft is supported by.

Originally when I produced my earlier boats I would glue the stern top section of the hull to the bottom which meant it was difficult getting into the tail area. I liked the idea of Dave's where you assemble all the horizontal bits without the top of the hull onto. Makes total sense really, he's an ideas man this Dave Bloke. That made things so much easier. Could work any problems as they arrise and made sure that the movement of the horiz feathers are good.

The connection between the top and bottom rudder is a flat piece of Aluminium plate (AL You Min E um) could'nt resist, for you americans. (I'll probably get a tirade for this one) Bent in a sideways 'U' shape. Then glued.

Once all the rear connections are done although it is hard to align the top and bottom rudder with the top hull at the stern not joined. This required concentration and fine adjustment during gluing to get right.

enough for now,

Dave h

[Davidh]

Wow, I must really have annoyed dave, and everyone. It's been quiet..

Anyway back to it.

After I have assembled all the stern structure it was time to assemble the linkages. I was going to get a die for 2'56 or whatever that is in metric, to thread a rod and then wind the nylon clevice onto the end. then I saw those little Du-Bro brass extension pieces that you simply solder onto the end of a smaller diametre brass rod. Brilliant!

Initially when I worked on the electronics for the Subdriver I was concerned about how small diameter the pushrods are coming out of the back of the Subdriver. In my home made WTC's I use bigger diametre pushrods as they would be less likely to bend under load. Jury still out on that one. I guess that a smaller dia brass rod puts less load on the smaller servos were using..

So I then looked at how I would arrange the top and bottom halves of the hull. I needed to create a lip that would hold along the endges of both pieces at they mated. Firstly having to sand down the long edges of both pieces to make sure they are as close to flat and straight as possible. Once done I cut a long straight piece of Fibreglass sheet into a long strip that I could glue to the inside of the lower hull on both sides. These would act as lips for the top hull section to slide onto and register. I ran this from about 205 from the stern to about 70% up to the bow. Then once glued I would file away at the inner edge just to make sure that the mate would be flush and as tight as possible.

I usually separate the bow, underneath. Why show the part line on top of the boat. I make a cut underneath the bottom of the bow underneath the planes. This will be held on by an aluminium plate with a thread put in and a brass bolt that will cunningly hold the whole ensemble in place. I mark ou thte cut line on the bottom of the forward hull and then work out where to put the aluminium plate. The plate will cross the cut line with the hole forward for the screw to go through the forward section of the hull, into the aluminium plate. The plate stick forward of the rear lower section. I then glass it into place but behing the separation line and then drill a small pilot hole where the bolt will go. I can then cut the lower bow section off and fibreglass it to the top half.

I sand around where I will glass at the equator between the two pieces, then glass inside and out. Mostly inside. Clamp it in place. Then sand back and make look good. Once this is complete I will then put lips on the front edge of the lower hull as it meets the bow lower section as it slides in under the aluminium plate. |I also do the same at the back where the stern top section slides in underneath the stern top section with the surfaces.

These photos show the general arrangment and the last couple show the overal final impression. Still lots of small details and then some further write up on the installation of the subdriver and all that bizzo.

It's getting on, it's been a darn hot day here in straya. Please feel free to give me some commentary.


david H

[He Who Shall Not Be Named]

You are progressing at a high rate. You will finish it. There are so, so many WIP's threads that don't see completion. You have. Congratulations -- this thing is going to see the water. Welcome to a very small fraternity, Dave.

I think you'll find the 1/16" pushrods to have sufficient strength to move your control surfaces.

I've been following your thread with interest and a touch of pride. Keep at it, Tiger.

M

[Davidh]

Thanks for the words dave,

Still very quiet.

As you can see from the last pics she is mostly finished however I would eventually add the towed sonar array bulge that runs down the port side of the stern from the back of the missile deck to the port side stern plane. I have tried to get photos of the arrangement but have not got much. I think that it is similar in design to American Towed sonar array housings. Reminds me of the Sturgeon class boats and I think that some of the 41 for freedom (boomers, I can't stand how the british have this annoying habit of calling their missile boats Bombers. The VULCAN was a bomber!) were also fitted with this design. I assume that the array line snakes around the leading edge of the stern plane and comes out the side of the plane and runs behind the boat.

To do this I would split a piece of dowell in half length ways. Then cut notches at equal lengths to allow the dowell to curve around the slopeing shape of the stern. This would run from the back port side of the missile deck and then runs down to the bottom corner of the top half of the hull. Then I would extend the moulding around the front edge of the stern plane. I would use filler and then sand back to complete the shape.

I sanded a section of the top hull that the dowell would be glued down to. This would make it easier for the glues to grip the dowell onto the fibreglass shell. Tapeing around the rest of the hull area as to not get glue or resin on the rest of the hull.
Once I glued this down I could then use filler around the edges of the dowell and once sanded down would allow me to give a light coat of resin.

I thought about moulding the towed sonar array bulges into the top half hull mould. However this would create some tricky undercuts and I simply did nt want to go there.

Once the array is down I would then scribe some hull lines into the shell. Once this was all completed then it could be pained over and given the tricky scumline detail. I will get some more detailed photos soon.

One of the other photos show the brackets made out of F'glass sheet. these would be mounted in the hull and raise the subdriver off the floor of the lower hull. This allows you to get ballast undeneath the driver and also allows the drive shaft to not have to deviate too much below the centreline.

The last photos show the day that you work hard for...

Dave H

[He Who Shall Not Be Named]

Boats looking good, Dave. Hey, the rational for the towed aray fairing is a sound one: it worked.

Another way to make those circular bulkheads for you, Dave

Try this idea next time you need to make fairings for the hull -- a linear varioution on the screeding technique shown above. You screed them out of Bondo or other such automotive two-part filler -- this material (polyester based) is a bit thermoforming, so after you take the cured part and subject it to heat, you can bend it to conform to the hull and even the tight radius where the fairing jumps off the hull and meets the tip of the horizontal stabilizers.

M