Hull 2 - 1/20th MDF Skeleton Kit
1/20th scale (4') MDF (Medium Density Fibreboard) economy Hull Skeleton Kit.
Hull-2 Skeleton Kit is now available in a much lower cost version.
For every shipment of marine ply that I buy, I also buy a couple of sheets of 3mm MDF as protection during shipment. The sheets of ply are about $80.00 Australian whereas the MDF sheets are only $5.00 so I have been making lots of stuff such as model houses and experimental stuff from the MDF sheets and it cuts both quicker and cleaner than marine ply and also etches very well so I thought I would introduce a much lower cost Hull-2 kit for those that can't afford the cost or complexity of the marine ply version. Much of the cost of kits is postage as well, particularly as most of my customers are around the other side of the planet, I can't do much about that but if I can knock off some cutting time and $70 worth of material that is a good thing.
I also cut a few ribs and left them to soak in a bucket of water to see if they would fall apart and they stand up fairly well and if the hull is painted inside it should give years of service. I can also cut this out of less expensive water resistant grades of plywood such as "Gaboon" in 3mm thickness but this would cost a little more.
So I have finished the design of the Hull-2 1/20th scale MDF Hull skeleton kit.
This hull is based on the more complex Hull-2 design but I have redrawn every piece to allow it to be made from 3mm material and I have used spruce deck runners like on the original Hull-1, again a laser cut set of ribs but not as many as Hull-2. I have kept the bow the same as it doesn't use much material anyway and left out every second rib towards the stern and added a couple of extra 4mm square intermediate runners half way down the sides and also between the keel and the chine on the bottom.
This kit includes ribs, transom, laminated main keel, laminated wing prop shafts and separate rudder keels, triple motor mount, servo mount, a large battery box and a laminated stand. These parts are cut from 3mm thick MDF and are supplied on 5 separate sheets that are 300mm x 400mm (1' x 1'4"), this makes a 15mm (5/8") thick stack that can be shipped as a flat post pack by airmail and will weigh around 1.3Kg (3 pounds). weight is an important consideration as I am in Australia.
The long keels when made up, are laminated as 2 thicknesses of 3mm ply with 4 thicknesses at the prop shafts and rudders, the individual short pieces are fitted together end to end with staggered jigsaw like joints. All individual kit parts join together into slots or recesses and make for a very strong but lightweight hull frame that is easy to build, in fact I built up the laser cut parts in around an hour and a half, however I designed it and I have done it before a few times. The motor mounting board is designed to take every type of motor that I currently have or have previously used in Hull 1 or Hull 2 and can be set up as either a geared or direct drive arrangement.
You will need to supply the long deck runners, chine, gunwale and intermediate runner timbers and the hull covering materials as well as the running gear. The chine, gunwale and intermediate timbers are 4mm (5/32") square section material as full lengths (1200mm plus or 4' plus) of balsa or harder wood such as Ramin or Spruce and you can cover the hull in whatever you like, on the 1/35th scale hull-2 I used 1 layer of 0.8mm (1/32") Balsa wood in about 1" strips and then covered with narrow strips of 0.8mm Birch ply which I laser cut into 1/35th scale 6" wide planks, just like the real thing which was covered in two layers of 1/2" Mahogany planks with waterproofed muslin cloth between the layers. This method is probably the most efficient in time and materials and the balsa superglues extremely well.
(There is still quite a lot of waste material left so I am adding extra pieces that I can include that can also be cut from 3mm mdf.)
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