Hey Guys,
So been working on this for a while now and normally I post updates as I tune and test at the lake, but this time the modifications came one after another without even leaving the work bench because, hey, that's just the way it goes sometimes, you look at what you've done, immediately see a way to improve it, rip it out and start again... at least that's the way I work sometimes.
My aim from the beginning was to add extra functionality to a one of my favourite boats, it has amazing presence on the lake and performs well in all conditions, I'd be really worried if it didn't being a lifeboat n' all!
But unfortunately, even with all the best intentions, I completely ruined that majestic glide that a Trent has across the water and turned it into a big orange tug, so it was back to basics, out came everything I had added and I reset the boat back to it's last good sailing trim, then out with the scales to see what kind of all up weight I had to stick to and in last good trim the max dry weight was 5970g, (minus batteries) I have removed the batteries as the scales can't cope with the added weight and thy are also a constant in this equation, not going to leave them out after all.
One of my first modifications to the boat was to do a brushless motor upgrade to replace the twin 3 pole 850's that had zero low speed manoeuvrability, they are also really heavy at half a kilo each, so heavy in fact, that when I did the swap, I had to add 1470g of ballast to get the boat to sit back down in the water, (when I bought the boat it was ballasted very lightly and sat too high in the water) so as I am adding a ton of kit, if I can get everything to work within my budget of 1470g, give or take, all should be right in the world again, so out with the scales again to make a list of each component I had installed on a quest to ether improve or junk it, major savings had to be made somewhere:
- MK1 Vapor Tank (includng fogger, float switch & fan) 650g
- Power Distribution Board 420g
- Pump & Mounting Board 180g
- Speaker & Mounting Board 355g
- Multi Function Decoder Board & Relay Board 80g
- Mounting Board for Above 140g
- Relay for Pump 20g
As we can see from the above figures, that is a whole lot of weight, 1845g of stuff and that is not even including the water for the vapor tank which holds around about an additional 250g, savings have to be made, in the above list, anything that is green cannot be reduced in weight, so I have to decide to keep it, junk it or replace with something better and lighter.
Looking at the original install pictures I posted, I realised that my placement and use of space was very poor, partly due to the very rushed nature of the install to prep the boat for a cub event, I had the speaker and pump right up in the bow, a great open space for bulky kit, but a terrible choice of placement in regards to trim, as the extra weight was pushing the bow down into the waves instead of letting it rise above them, next for judgement was the size of the vapor tank, it was gargantuan, great for a puffer, terrible for a lifeboat, it held too much water and really needed re-thinking, for some unknown reason I had also elected to construct the tank and all the other mounting boards from 6mm thick clear Acrylic, obviously a poor choice on my part and a major source of potential savings.
Right, to work, I re-designed the vapor tank, not only shrinking the size I also decided to 3D print it which would make for a strong yet light weight construction, opting for a wall thickness of 2mm, the new tank was a considerable improvement over the old one, weighing in with an all up dry weight of 332g, (including hardware) no sooner had I finished bench testing the new tank, I thought, "Hey, the float switch in this tank is huge compared to the one in my Clyde Puffer, why don't I get another one of those and that will allow me to make the tank even smaller an if I decrease the wall thickness to just 1mm, I can save even more weight, with the added bonus that it will take less time to print"
One swift print and a delivery from Mr. Postie later, the new and improved MK3 tank was ready and weighed in at an all up dry weight of 232g, saving 418g over the MK1 tank and 100g over the MK2 tank, happy with the savings so far I turned my attention to the water distribution system in the boat, which originally had a 12v pump sucking water out of the lake through a pipe in the keel, this was then pumped through both ESCs before filling up the vapor tank. The original idea was that the boat would have a combined cooling water / exhaust smoke effect coming out of the exhaust ports, this is great in theory, but alas the water only ever dribbled out of the exhaust ports, completely blocking the vapor from escaping and on the first outing to the lake, the pump nearly sank the boat by over filling the tank, clearly a re-think was in order.
In my Clyde Puffer I have a pump, that like the lifeboat, draws water from the lake and fills up the vapor tank, except in this instance, there is a float switch driving a relay, which turns the pump on and off as is necessary, the vapor system consumes very little water and the pump runs mostly to replace water escaping out of the tank back through the pump when it is switched off.
Even though the ESCs in the Trent are water cooled, even without water cooling, they have never gotten hot, even on extended high speed runs, so this time I am going to take a slightly different approach, this time doing away with the pump altogether and instead placing the cooling inlet pipe just behind the prop, taking advantage of the high positive water pressure produced to cool the ESCs when they need it most, before the water is dumped back into the lake back through the original keel inlet, a pair of one way relay controlled solenoid valves will divert cooling water to fill the vapor tank as and when the float switch demands it, now this does mean that the vapor tank may take a little time to prime at the beginning of a run, but I can always over come that by pre-filling with a drain syringe.
Other small improvements include relocating the speaker to a new thinner mounting plate in between the motors, so as to preserve the original trim's centre of gravity, all of the mounting panels have also been re-cut from lighter 2mm Acrylic and last but not least, as part of the complete rewire, I have started on upgrading all of the lights on board with LEDs as well as making all of the feature lighting functional.
Hopefully more to come tomorrow after much successful tinkering in the Shedshop!
Alex