So this was the first of what were going to be many proper detailed upgrade parts for the Engel Nautilus radio controlled submarine I was going to build, or rather I still will at one point. However things have gotten in the way at this stage in my life and itís been put on hold.
While not one of the major things, but quite important, the local council do not keep the local boating pong in good order and on closer inspection when the water was quite clear a while back showed in places it is very shallow, meaning you would only be able to run on the surface, but there is a lot of rubbish that it could still get caught on.
So for now my dream of owning a scale radio controlled Nautilus have been put on hold, till such time I have the money spare, and the pond is in better shape.
After spending many hours looking through the Disney Nautilus forums, it seems although the Engle version was a good price and came with all the bits needed to get it up and running, the detail level left a lot to be desired. Only the top half had rivets showing, and a lot of the finer details were missing. The other options worked out at almost twice the price, but came much better detailed. Not being able to justify nearly twice the cost for work I could do myself, I decided I would go for the Engle version, and make my own super detailed parts to fit it. I would also offer these parts to fellow Engle owners who wanted to upgrade there own subs.
My first job as it was one of those bits I could build from plans once I knew the correct size was the propeller. With help from the Disney Sub forums I got the correct dimensions, so set to work.
This was going to be made in three basic parts. The main spindle, the end cap and the blades. The reason the end cap was made separate was when finished and cast, being used for radio controlled meant it would need to be drilled and taped to take a threaded shaft, something that couldnít be done with the end cap on. By having this separate if could be placed in the chuck of my lathe and drilled and tapped dead straight, something that is important if it is to spin at any rpm.
I had pictures of what it needed to look like when done, and dimensions, so it was just a case of turning it from a rod of plastic on my lathe, which was more time consuming than hard.
The next job was to make one of the five blades. I cheated here slightly as I only made one, then made a mould of it and cast the five I needed. It saved a lot of time and produces five identical blades, which was the most important thing.
I knew the shape from drawings, so printed out a 1:1 scale picture of one blade then set about making it. I used carbon fibre rod as the base, then added thin styrene sheet to creat the flat surface, then is was just a case of adding model filler and sanding and adding till it was correct. The longest part was waiting for the filler to dry between sanding.
With the blade finished and correct in dimensions, the main spindle was put back in the chuck and five holes drilled equally spaced round the sides to fit them in. When that was done I made a mould as mentioned before of the one prototype blade and made five copies.
Getting the correct angle for each blade was a bit tricky as you had to compare each one to the scale picture to make sure they were just right, however I have to admit I was pleased with the finished prototype.
Next it was time to mould the prototype so copies could be made. This needed a bit of thought as each prop was going to be reinforced with carbon fibre to make sure it was super strong and up to the riggers of being used on a pond.
The mould was made in two halves so the join was on the edge of the blade so there would be minimum clean up work. It also needs a resin fill hole to the lowest point and air escape holes on the highest. Even though this was to be pressure cast, the high points without escape holes could still get air bubbles in so just by adding the escape holes you make sure its bubble free.
The finished cast is in grey resin, as this way if at any point the paint comes off, all you will see is dark grey, oppose to casting in white or another colour.
So as you can see from the finished painted propeller, it came out rather well and a vast improvement over the standard brass propeller Engle use.