What with Christmas I've got a little less done over the past few weeks, but I have made progress on the pump. A while ago, Shapeways had a free delivery sale, so I bought one of these: www.shapeways.com/model/234810/gen-x-pump-kit.html, not necessarily thinking I'd use it in the Golo, as I was hoping to find a pump small enough to fit between the propeller shafts (i.e. < 30mm diameter). When I got the pump I realised that it would just about fit in the bow of Golo, so I decided to use it. I don't have an ideal brushless motor around -- that is, something with the shaft extending from the stator mounting plate, so I built a support to hold the motor in place. You may call it Heath Robinson (or Rube Goldberg on the other side of the Atlantic), but I prefer to think of it as a bit steampunk. The mount consists of a brass plate and a lot of M3 Nylocks. The origianl motor mounting holes on the pump have been filled with epoxy. I've drilled some holes in the bottom of the hull for the three vertical bolts. It pumps a lot of water -- I can imagine replacing it with something smaller in a future refit.
The hardware is all stainless steel of course. Yes, the bow is the best place as I can't fit it anywhere else My stuffing tubes are a bit longer than they really need to be, and the battery takes up the rest, so bow it is (unless I could find/make a narrow pump, which I may try to do in the future)
I think it is designed to compression fit a 2.3mm shaft, and my motor has a 2mm shaft, so it is attached with thin CA.
If that wobbles too much, something I've had good luck with is buying some aluminum tape from NAPA or other auto parts place. Couple of layers will make up a small difference in diameter
Here are some photographs of the engine mountings and universal joints. Some things to note: The engine mount is a length of aluminium angle -- it was the only size I had lying around, so it only fits three of the motor mounting holes, which I think is enough. I epoxied the mototr mount to the bottom of the hull. In hindsight I wish I had bolted it to make it easier to move later. If I had the skills/tools to make a gearbox I probably would have used one, but duplicating the motor/ESC is actually simpler and cheaper -- arguably. The motors are unnecessarily large, I think -- they are these: www.hobbyking.com/hobbyking/store/uh_viewItem.asp but I think these 18mm diameter motors would have enough power, while being lighter and smaller: www.hobbyking.com/hobbyking/store/uh_viewItem.asp I've used double universal joints as my alignment was not perfect -- they are from this range from Cornwall Model Boats: www.cornwallmodelboats.co.uk/acatal...tml#aC8000 The stuffing tubes are too long -- I thought I had plenty of room (as this is a merchant), but in practice more latitude for battery placement would have been nice. I've attached the stuffing tubes with epoxy putty. I found I was getting some vibration, hence the extra support at the forward end. The stuffing tubes are from Cornwall Model Boats too.
My two Golos, M/V Gwai Lo and M/V Gaijin aren't even brushless, and have no gearing. Just a convenient way to retire my NOS brushed 280-size motors and 15A speed controls from warship service without throwing them out. So comparatively speaking, you're way in front of me convoy-tech wise
It is *extremely* high tech (edit -- that assertion needs a smiley ) -- all brushless, 3D printed pump, no wood (except for the skinning and the original skin) -- no 6mm ply soaked in resin for me -- the decks and subdecks are all Sintra and Styrene. And I have great plans for telemetry[1] Nothing laser cut, unfortunately, or CNC milled. Just have to see how it stands up to combat... [1] Plans depend on free time
Thanks for the pics, looks great! I like how you mounted the motors. I had considered using that type several times, since they seem to be in stock fairly often - I just never wanted to put the effort into mounting them The dual u joints is a good idea if things aren't lined up pretty darn good, keeps everything in the proper angles, like the drive Shaft on a car.
Decided on red for the decks -- apparently a common colour. Some more progress: Got some PVC tubing for the pump Fitted battery straps -- I just epoxied them to the bottom of the hull, I think the hooks on the back will work well with epoxy. I think I'll still need something to center the battery precisely -- how is that usually done? Finished the software for my pump controller (bitbucket.org/tdavies/pump-controller) -- I'm not running my pump from a radio channel, so I need a way of setting it to a legal pumping rate. The controller is an attiny84 which allows me to set the control signal sent to the ESC appropriately. I have a little programming board which plugs into the controller and has two button, allowing me to adjust the pump motor speed. Random notes: Finally got my crimping tool working reliably -- I think I had the tension set too high. I wish I hadn't decided to use XT-60 connectors for everything -- they are too big, and far more heavy duty than I need. I'll be surprised if I draw more than 6 amps from my battery.
I usually glue a couple of 1/4" square rods parallel to the centerline to remind the battery where it belongs, with velcro straps holding it down. Doesn't go anywhere. I've standardized with the XT60 conecctors, they're not thatbig and it's very convenient. I can grab any battery if I'm doing bench testing, without worrying about connections.
Progress report: Pump has been mounted. I discovered the folly of putting any fixed decks on a ship, and had to cut out a hatch in the forecastle deck to get at the pump. I've assembled the basic blocks of the superstructure -- still plenty of detailing and painting to do. The superstructure is made from Sintra, which is rather brittle, so I'm prepared for it not to stand up too well to gunfire. Each block of superstructure is filled with a lump of closed cell foam, with West epoxy poured around it, to try to give a bit more strength. I've started on the blast shielding, which would have been five times easier if I'd done it before sheeting and before installing engines and steering gear. I'm using 1mm polycarbonate, space with Sintra strips glued to the ribs. Each strip has two M3 bolts countersunk into the face glued to the rib. The bolt has a spacer made of PVC tube pushed over it, and the polycarbonate is attached to the bolt with a nylock nut. I took the ship for a long run at the last AusBG Sydney Battle Squadron meeting -- not in combat because of the lack of blast shielding, but for long enough to feel hopeful about reliability and to get a feel for her. I've decided that my 8400mAh 2S LiFePO4 is overkill -- and while I do have the displacement to carry it, it doesn't leave me much leeway or choice about where I put the weight. I've ordered a 4000mAh battery which will still give me plenty of runtime. Handling is rather twitchy -- I wonder if distributing the weight more evenly as a result of a smaller battery will help? Now to finish the blast shields, add some detail, and, at the next meeting, get sunk!
I've finally got my Golo ready for action! All wiring changed from XT60 to EC2 -- takes up much less space. Blast shielding completed. Battery downgraded to 4500mAh from 8400mAh, and extra ballast added to compensate. And finally just enough detailing work that I won't feel embarassed having her on the pond. I will add more masts, boats, railings, ventilators, portholes and crew in due course. Still to do (there's always one more thing): fill the rudder servo with mineral oil. I'm not going to bother potting the electronics to begin with.
Bad idea! I had my first battle and first sink (went down like a stone with a splintered panel) and the electronics were not happy. I've now cast the ESCs and RX in blocks of West epoxy (actually I think just dipping them would have been fine -- I did one that way and the viscosity/surface tension of the resin gave a good coat). My servo failed because I had not got the mineral oil into the lower section of the servo -- where it is actually needed. My fellow club members got me going for the next battle, which I survived. So plenty of lessons learned. My cosmetic work so far has been restricted to applying some laser printed waterslide decals, which look pretty good. (I need to find the right matt varnish to protect them) Bridge windows and the Captain's wife. That is some ugly fibreglass. The ship is named "Petersham Castle" because it is painted in Union Castle Line colours, and I live in Petersham. Port Botany is my nearest port. For safety, I added a Plimsoll line -- not sure why it came out jagged like that, but it looks OK (in fact it's nearly invisible) in real life.
Hi Mark -- it was looking at the laser etched details on the kit you sent to Kevan Morgan that inspired me to do it. Incidentally, why do you leave the little uncut sections? The surrounding wood will hold everything in position during cutting without that, won't it?
The tabs on the parts make the sheets easier to handle since you don't have to worry about losing parts. Additionally, the bed of the laser is a coarse honey comb that they pull vacuum through to hold the wood. Parts small enough that are not attached can go straight to the vacuum or they may "tombstone". A tombstone is when a part is partially sucked down by the vacuum, but the rest of it tips up above the board. Since the laser head is very close to the board, it can hit the tombstone and cause the machine to do an emergency stop and need to be reset. At one point I was having some Golo kits cut and had a full 4' x 4' of 1/8 lite ply on the laser. On the last blank, after almost an hour of laser time, a part tombstoned and shut down the laser. After that I didn't complain about the tabs, even the ones that are only holding interior pieces that are scrap.
