So, DavidH, is it a 1/144 scale Typhoon?
Scratch build Soviet Project 661 Anchar "Papa" Class SSGN K-222 1/120 Scale.
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Next time I make a statement here I'll temper it a bit -- taking into account the mind-set of my audience (you people!).
I figured out how to make a model of that beast work … other than having it flaying around palm trees, that is.
David
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I would vote for a Typhoon in 144th scale (makes a perfect scale to travel with!Leave a comment:
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Hi Trout,
thanks for for the comments. She has been a really fun boat to run for the last couple of days. I think most of the bugs have been sorted. The tanks works exactly how you described it. You essentially force water into the tank compressing the air above it. The pick up line goes to the bottom of the tank and will suck up probably 95% of the water. There is always a little in the tank. It’s reliable, not quick, but I do like having an on board air reservoir. Tanks fills to about 60% water, 40% air.
DaveLeave a comment:
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Sweet! That looks wonderful cruising underwater!
I do have a question, if I understand what you are doing, you are pumping water into the ballast tank and causing pressure to buildup in the tank. Then reversing that process to surface. Right? If I am tracking o.k. here, from your design there will be a little water left in your tank, because of the shape of your pick up line, when your tank is fully blown. At the end of the day, how do you get the rest of the water out?
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Thankyou Peter,
I haven't spent time talking about the internals of the boat. However earlier on in the build I did spend a bit of time going over the cylinder and ballast system. I have decided to use a pump system based on the sheerline design that has been around for decades. I have used this system for over ten years now and although I have used a subdriver and continue to do so with Mike, I really like the sheerline set up.
The major departure in design for me is the fact that I have decided to put the pump on the outside of the cylinder. This will make for one less giant hole in the front endcap to have to waterproof. It will simply meant a different plumbing arrangement. I have also decided to make a stand alone ballast tank that will sit in front of the cylinder. Unlike my previous designs it will not be an integral middle part of the cylinder. It means that each boat I build will need it's own ballast tank bolted down. But made out of PVC pipe with PVC endcaps they are really cheap and easy to seal. That green PVC cement stuff is awesome.
For Papa I have had to make a custom made PVC tank. The Diameters available are either way too small or too large. So I have created essentially a short but wide tank. I took a 90mm pipe, cut it and split it down the centre. Removed a section and bought it down to about 85mm . Repeated the process so created two layers and sealed it good with the green stuff. After reinforcing the ends I then drilled a hole and placed pickup made out of nylex garden nozzle pipe with a bend to touch the bottom of the tank. The other end going through the rear baulk head and out to the cylinder behind it. Seal it all up, give it an hour and blow air in , pinch and stick it underwater, no leaks, Yay!!
This ballast tank was then fitted with two pvc brackets made from flattening out two strips of PVC plastic and heating them flat. Then heat bending them to an "L" shape and drilling a hole. I them made up some small brass brackets that were fixed to the side of the hull at front and back and then a stainless steel bolt secures the tank front and end. I initially had the concern that the ballast tank being a little forward of the c of G could cause problems however I had no ability to move it any further backward. As it is the cylinder is as far back as I can put it.
This pic shows the rear of the ballast tank snugly fitted into the hull with the silicon tube coming out of the pick up that will connect to the outlet of the pump as it exits the forward endcap. Forward of the tank is as much foam as I could load and the rectangular placing for the big SLA 12 v battery to sit. Then the front of the boat is just foam, foam, foam. The raised curved fibreglass piece in front of the tank is the cradle to sits the front of the cylinder so that it is sitting level with the hull.
There is sheet lead up front. Being my first twin shaft boat I am not accustomed to not having to deal with torque roll. I am guessing that it probably shouldn't be an issue. I am hoping that I am not going to have to use lots of lead to counteract this. Placing the boat in the water soon revealed that I would need a lot of foam down the back end. She sits low at the back as photos will attest. Problem is that there is very little space in the back end for foam. It's pretty tight down there...
Testing is often fixing heaps of little things, and one big thing, TRIM. Papa has been full of surprises, Trim has turned out to be easy. It took very little extra lead and foam. I must have guessed well to start with and the concern about the ballast tank being slightly forward did not eventuate. She dives beautifully. No, the pesky problems involved pushrod connections that kept coming loose, a loss of ballast tank pressure and a few glitchy connections inside the cylinder along with a drive shaft coupling that slipped. Now fixed due to crimping a brass shaft. This boat seems to want to work. She has to date had the fewest bugs to iron out of any boat I have built so far. Fingers crossed.. As mentioned before, she's quick...
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Thanks Trout, Peter W and Scott T,
So I've added the fine green algae finish just below the waterline and also sanded back and finished the props. Then gave them a good spray of a bronze tint. Then took some photos.
As you can see she's already been in the water. I have still some bugs to iron out, including a recent issue with the prop shafts of the new cylinder. refer to thread in tips N tricks. One thing is for sure, she's like her full size,. Quick.......
David H
Enjoy.Last edited by Davidh; 10-02-2018, 03:38 AM.Leave a comment:
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To give you an idea of what color it is in water....Here is a nest of Kilos
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