1/72 Scale Akula
Below is a series of pictures showing the evolution of my 1/72 scale Russian Akula nuclear attack submarine. I opted for this scale as I was not pleased with the smaller 1/96 scale and was not up to a back breaking 1/48 scale. The design of the model is based on Greg Sharpe's (Deep Sea Designs) drawings and readily available photographs of Akulas on the surface; most notably from Jane's Fighting Ships Edition 97/98.
-- Jerome
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Bondo Sub: The master plug for the submarine started out as two 4x8 boards of oak. They were turned on a lathe about two years ago. Unfortunately, the wood was quite green and when I got back to working on this project there had been significant shrinkage. To bring the surface back to where it needed to be, a template was cut from sheet metal to match the profile of the submarine and held up against the side of the master. The master was then revolved and Bondo added to the surface. The template worked the Bondo to the correct profile. Next time I will only use good kiln-dried wood!
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Sails Galore: I went through three different versions of the sail. The bottom left sail was built according to the plans. When I discovered the prototype was quite different than shown on the plans, I cut it off the hull. The bottom right was another attempt. I finally used some air drying clay to sculpt a half scale version. Once I was happy with it, I sliced it up and with a copier and some transparencies, built a set of cross-sections to create the skeleton shown on the hull. |
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Another view of the hull and sail. The sail shape is complete but not yet attached to the hull. |
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Finished Top Hull: An overhead stern view of the final master for the top half of the hull. Twelve coats of automotive primer sanded down with 1200 grit sandpaper and polished ten times with Bounty paper towels gives the surface a shine you can see yourself in. But more importantly, with the proper application of release agent, this master will also literally drop out of the molds. It is ALL in the prep work! |
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Masters Prepped: Here the masters have been prepped with 10 coats of parting paste wax followed by 7 coats of thinly sprayed on green PVA release film. They are now ready for mold walls and fiberglass. |
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Fiberglass Materials: Everything I used for fiberglassing is straight out of Fibreglast's catalog. If you are going to put this much time and effort into building a hull, go with epoxy. You and your health will be pleased with the results and your spouse, kids (or pets), and possibly neighbors will be pleased with the smell. |
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Mold Curing: It will be hard to do, but wait 5 days while the molds cure. Just find something else to do. Here is the top mold prior to removal of the master. The botton hull mold can be seen in the background. Just a little careful prying was all that was needed to remove the master. Here is where extra effort in the prep work will pay great dividends. |
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Mold Prep: The molds received that same number of coats of wax and paste and then they were ready for hull lay-up. The two lamps offered plenty of light as well as 3 extra degress of warmth. The work area was always kept between 76 and 78 degrees. Note the thermometer in between the molds. It cost me two bucks. Buy one! Dont guess! Keeping the temperature up and thoroughly mixing the resin yielded a set of molds and hulls without a single tacky spot in the surface. |
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Hull Lay-up: The layers of cloth have been laid into the hull with careful attention to remove all extra resin after each layer was added. Actually this picture was taken some time after my initial hull lay-up. After pulling the hulls from the molds, I found them to be a little too flimsy for my taste so I placed them back in the molds for support and added two more layers. The yellow cloth is 5oz Kevlar. I put it in the bow and stern for extra rigidity. It sure did the job but the material was so #@%$! hard to cut that I am not sure I will do it again. |
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Fresh hulls: Here are the hull just prior to removal from the molds. The extra cloth was removed with a dremel tool and a stack of cutoff wheels. Again, there was much cursing at the Kevlar. |
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The Results: The hard work pays off! The masters for the control surfaces and molds for the towed sonar array pod can be seen inside the cabinet. |
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Conrol Surfaces: The rudders and planes were constructed from high grade airplane plywood. After cutting and sanding to shape, they were tacked in place on the master and Bondo was used to create the fillet between the hull and stabilizer. |
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Some Conrol Surface Molds: The masters were used to create a set of RTV rubber molds. The small circular mold was used to fabricate some of the sensors that protrude from the hull of the Akula. A casting resin, along with carbon fiber reinforcement was used to cast the final control surfaces. I used RTV rubber and casting resin supplied by MicroMark and was very pleased. I had virtually no air bubbles in the RTV molds without pressurizing. The casting resin cured more like ABS plastic than fiberglass resin. The stabilizers actually give some instead of being too brittle. The movable control surfaces were cast with epoxy resin for increased rigidity. |
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Scribing: Each scribe line was first marked with a thin permanent marker. It is time consuming, but saves a lot of headaches. The hull in the upper right corner is Matt Thor's 1/72 Alfa. I bought this hull prior to building mine to see what top notch fiberglass work looks like. Thanks a million for you help and encouragement Matt. |
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Equipment Rails: A pair of 1/2 inch aluminum angle brackets make up the support for the internal equipment. Six thumbscrews fasten the equipment rack to the rails. The design is almost identical to Dave Merriman's original setup in his 1/96 scale Akula. |
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The Akula Out Sun Bathing: This shows the current state of the model. The equipment rack is installed. The notch in the sail is for the removable escape pod that is present on the prototype. On the model it will act as a teathered releasable locating marker should the sub 'go down and stay'. A solenoid latch will be tied into the failsafe circuitry. |
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The eqipment rack removed from the hull. The empty section of the rack will hold the ballast tank and CO2 system as well as the periscope mechanics. |
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Bow Close Up: The yellow battery will power all the electronics while a seperate larger battery will be used for propulsion. The 4-1/2" diameter pressue hull will hold the servos, radio receiver, fail safes, depth & pitch controllers, and anything else I come up with. |
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Stern Close Up: The motor is held in a seperate pressure hull. A 7AHr battery supplies the motor power. The output shaft contains a simple ball joint that mates to the propeller shaft. There is no need to fiddle with shaft screws will inserting or removing the equipment rack. The shaft rides inside two ball bearings and couples to a 3-1/4" seven bladed brass scimitar propeller. |
On to Part II of the Construction Process