Reply To: Los Angeles Submarine scratch build

[John.RedearthParticipant @john-redearth]

The next step is to use a nice piece of brass rod (1/8^th in this case) and a snug piece of brass sleeve. I drill through the hull with a drill of ‘rod’ size and put the rod through and work it until it is square. Hot glue is a good idea to hold it in place. Then I took the hydroplane and used the profile of the hull to mark onto it the centre which is to be removed, cut it out, and now we have two matching hydroplanes, port and starboard. Then drill out the fulcrum slot with rod thickness drill and slip them onto the shaft and grind the planes till they fit snugly to the hull. Once they are fitting I use a set square, and marking opposite to the fulcrum, mark where the planes will be cut so that I have a ‘stub’ which will be glued to the hull.

Then I use a drill that fits the outer sleeve, and drill partway into the planes, past the spot they will be cut, and also open out the hole in the hull. Then I cut the planes along the cut off line, in this case by hand using a fret saw) and then start assembly. I have already turned down my little linkage for the centre of the hull which looks a little like a dog bone. It is drilled out to fit the rod. So then, taking two pieces of sleeve, and the dog bone, the stubs of the planes and the rod, I glue the whole lot in, in ensuring the rod and the dog bone turns freely, but the stub and the sleeve is glued in. The sleeve protrudes out of the stubs, and will fit into the planes. In this process I use a long piece of rod and make the final adjustments to ensure the planes will be square (bow stern, topside and keel).

Then I have generally drilled and tapped a grub screw into the planes alongside where the shaft will travel to enable a fixing once I am happy with it, and then slide the planes onto the assembly and check out the movements, fit and slide.

The next step is to work on the dog bone to make it miss the prop shaft. I have done this by silver soldering onto the middle of the dog bone a piece of rectangular brass, and then putting the assembly into the vice and using a round file, filing through the dog bone to get a clearance for where the shaft will go. This is a process of trial and error but eventually I get a nice c section with a perfectly lined up top and bottom. I then solder (using ordinary solder) a ball joint for the servo arm at an opportune place, and then drill and tap two grub screw holes in the top of the dog bone. Phew!

Then it is off the fit and file and fix. In doing this I used apiece of brass and silver soldered in the end of an allen key to get better reach onto the grub screws, attached a servo arm rod, the cup for the servo arm and eventually got it working. Tried out adding the prop shaft and ‘oila,’ the first set were in. (In this case, I started with the rudders, as they are the ones that are further back in the hull (Remember the 10 mm off centre fulcrum)

Then it was off to tod exactly the same with the hydroplanes. Then it was off to connect the arms to the servos. In doing so II cut the servo linage arms and fitted a couple of sleeves with grub screws so I can remove parts easily, and also make fine adjustments to the length of the arms.

I have now made a very nice intro as I have finally worked out what I and doing here!

Also if you click here for the blog you will see the pics of the build.