Scratch build Soviet Project 661 Anchar "Papa" Class SSGN K-222 1/120 Scale.

[Davidh]

Hello all,

Turning the tail end down to the right diameter wasn't too difficult. As mentioned I needed to make it around the same diameter as the out dia of the last PVC pipe. I had a small section cut out and fitted around the face plate on the left of the lathe. A section of about 50mm would be lower diameter to fit within the pipe. This chunk of timber is long enough to have the tailstock engaged to support it. Once I had a constant diameter on the stern section I would need to have a slight tapering towards the very stern. This section would only taper in by a small amount but would signify the gradual transition between the main round hull section and where it then branches off into two tapered round shaft sections that culminate in shafts and screws.

Once the stern section met the PVC pipe at the right diameter then subtly reduces down about 5mm before the main transition I would gradually make my way through reduced sandpaper to get the wooden block smoother and smoother. Once this was done I couldn't give it a layer of polyester resin simply because this is where the symmetry would end.

At this point the stern section would come off the lathe and I sat down and measured the overall dimensions. This is where I would have to mark out and make two cuts to create a flattened section top and bottom on the rounded stern section. This tapered cut section would lead down to where the transition to the twin tapered sections would start. before making this cut I worked out the diameter of the two cone sections that I would need to turn up on the lathe separately and then needed to make sure that they would coincide with the diameter of the stern main section. These two diameters would actually overlap so I would need to eventually make an angled cut along the length of the cone section once turned to the right dimensions.








The challenge was making sure that both tapered "cones' are identical. If not then there would need to be a lot of eyeballing later on. As mentioned at the stern end of the main section
the square surface area wasn't big enough for both cones to sit side by side. There would need to be equal cuts down the length of each cone to get them to sit aside each other and make sure they didn't go over the edges. The side of the stern section would have to gradually curve towards to the very tip of each 'cone/boom' on either side.

David H

[gantu]

Here we go i send you an link with more stuff and plan.

Gantu

[gantu]

https://www.youtube.com/watch/?v=fqvuLFEHlOs

[Davidh]

Hi Subculture,

thankyou for for the link, will be making enquiries...

david h

[Subculture]

Wonder if these guys can help you?

http://www.rezco.com.au/contact-us/

[Davidh]

Hello All,

Once again I used the usual method of turning up the stern and bow sections. The bow section of the Project 661 is quite straightforward. It is not quite perfectly round in cross section. There is a slight elliptical aspect to the curve, however it is subtle. So once again I cut out several blocks of scrap from the bin in the school woodwork room and glued them together overnight before drilling 4 holes and mounting it to a faceplate. to mount on the lathe. This bow section is about 50mm longer than it needs to be so that it will slide under the innermost layer of the PVC pipe that makes up the middle hull section. Once mounted I then turned it down to round making sure that the diameter didn't go under the outer diameter of the PVC pipe. I marked off a section of 50mm and took this down to the diameter of the inside of the PVC pipe. Once taken down I made a small section of the 3 rings of PVC and slipped it over the faceplate (this is the white section in the photos) and then slide it over the 50mm section that would sleeve in underneath the main hullsection. This would then indicate where I would take the rest of the bow section down to.

As mentioned previously, I would love to use Renshape or Sikaboard, however it seems to be devoid on the East coast. I found a supplier in WA of all places and for a board of about a metre by half by 100mm thick it was going to be $700 or so. Forget it. This limits me to wood. The wood I have mainly been using is pine. I know, I should look for something with a better grain. I have got good results so far.
after turning down this bow section the grain has become really evident in this example and getting the shape right hasn't been hard. as I've come very close to the outer diameter of the PVC tube ive had to be careful with the cutting tool to just take off enough to make the diameter level with the pipe. I made up some simple profiles to get the curve just right. Moving through various grades of sandpaper have allowed me to smooth off this bow section. I will then give it a layer of Polyester resin and stink out the workshop. Comments form the year 10 boys. Oh, Mr Hughes are you building another submarine? Leave the resin coat over night and then give a sanding back with about 240 grade paper. this allowed for a reasonably smooth surface. Once sanded another coat will then thicken up the layer. then once again sand back the next day to get a really nice smooth consistent bow section. I did as much of this as possible on the lather to make it evenly sanded and it would be more accurate and quicker.





Once this has been smoothed down I applied wet and dry and really fine grade to bring up a really smooth finish. I gave it a shot of primer just to show up the imperfections.

I then repeated the process with the back. This section is a lot longer and is quite complex in that I will be turning along section then tapering it slightly toward the rear of the stern and then cutting off 'wedges' along the top and bottom to create the tapering sections when looked at from each side but from above the width sees little change. Effectively the stern section due to its size would need support from the tailstock and dead centre. Once again I turned down a section to the internal diameter that would allow the stern to slide into the pipe. On the second photo you can see the sample ring to get the diameter just right. The left end of the piece will fit up into the hull. As it turned out I had taken the diameter to slightly under the 96mm needed at the inner end. So I pasted on plenty of filler to make up the difference. I would then sand it back on the lathe.`



Gantu, Have you got any new pics?



Enough for now.

David H

[Davidh]

Hi John,

The Scale is 1/120. that puts her slightly shorter than the Mike. Her hull diameter comes in slightly under 100mm. She will be able to take a 90mm Dia cylinder. As mentioned she is the widest boat that I have built even though she is shorter. I have wanted to do this boat for a while. No it isn't really consistent with what we talked about, but then again I tend to build models, offer them on the market and get the odd sale. If I wanted higher sales I'd just build LA's or skipjacks or mostly American stuff, seems to be what most people want.


I know what you're saying makes sense, I suppose the urge to build what I want to build gets the better of me over building to increase market share. I know there is more of a market for a certain type of boat.


Was good to see you at the Subregatta.

David H

[Slats]

Scale David? And is it consistent with what we talked about at the regatta - re size and the punters?

[Davidh]

Hello all,


Once again the cycle repeats itself, and I can't resist building something. It's been a little while since I pretty much finished development of the Borei class (project 955) and have now got all the tooling completed, first prototype out of the moulds and one already sold. So planning has started for me on my next boat. In the time as Borei approached the end of the development cycle my thoughts were already turning to the next boat that I wanted to build.

I had the Project 661 on the radar earlier than that. I initially though about building a 661 before the 955, but something said 'build a big boat' and something with a pump jet. Well the 661 aint the biggest boat that I have built, it's going to be slightly shorter than Mike (project 685) but slightly wider. It will be the widest boat I have built but the biggest challenge is that it's my first ever twin screw. If you look at the shape of the boat, the front end and overall hull is very straightforward. It has a really bluff bow and a really round straightforward hull length. The back end is where the business is and where I will spend the most of my time. The back end has twin booms that support the twin screws and looks like it was the inspiration for the Oscar class. This will require a lot of eye balling and profiles, bog and sanding.

The Papa class was the worlds fastest submarine, based on publicly available info. In 1970 she got up to 44.7 knots that's over 82 km/h. Fast little sucker. Yep, she wasn't a large sub. Smaller than an Akula. Story is that when she hit top speed grates came flying off and she had a hernia.

Once again I seem to gravitate to subs of which there is little info available. What is interesting about Papa is the fact that there aren't many photo's of her, but online you will find for the Papa, the most detailed internal layout drawings of virtually any nuke around. Pity I don't want to build and internal diorama....
What is with this. This submarine was in service from 1969 and was finally decommissioned around 1980 and scrapped I believe in 2012. Plenty of time for some decent pics, but once again, no matter how much I search, even Russian Google, still the same pics. So GANTU, surprise me!














I have also started looking at fabricating a twin shaft cylinder. I am looking at a direct drive module with two motors side to side and am going through the fun of working out seals and motor mounts. This is going to be a tight boat. However as mentioned she will be wider at about 96mm. She will fit a 90mm dia cylinder. One upside will be that making the rudder connections should be really easy. I wont have to go around any shafts!.

Turned front end and PVC pipe. You are probably saying, "why didn't you just use 100mm PVC.?" Good question I suppose, I didn't want a boat that was too wide and look at little to disproportionate to the mike. The 96mm is created by 3 layer of 90mm PVC pipe inside each other. The inner most one being one continuous piece. The two outer ones are split and wrapped around the rest of the hull. The outer one has the split at the top, This split is wide enough to create a trough in which you can paste down a layer of filler and is about the same width as the flat deck section on Papa.

The rear section is turned and tapered ever so slightly rearward. then cut flat just forward of where the rudder is. Then this part is cut on the Bandsaw and tapered down creating a really rounded rectangular cross section of sorts.

Anyway, more later.

David H





P.S the Hernia business didn't really happen...