Overdue for an update, I've been too busy building over the past few weeks. Last week I abandoned hope to finish it for NATS, and with the fleets shaping up the way they are I decided to shift focus to the Rivadavia. Catching up from the last post, after Carl's battle I focused on the deck, water channel, rudder, and other structural items. Here is the first layer of water channel, I stuck with balsa because it was what I knew. Here was tracing out the subdeck, I used 1/4" plywood Test fit. More to follow
Yes it will be done in time for Ming's moat round 2, I think I could have finished by NATS, but I would have little room for teething issues. Here is the prep work for the subdeck installation. I made a painters tape flange to go under the deck to catch epoxy, as well as one to go under the wood support for the rudder post. The subdeck was complete here. This is post epoxy prior to removing the tape from the bow section. Moving on to the deck itself, the stern was pretty easy to cut based on the flat profile of the deck rim, but the bow took more time due to the Atlantic bow shape. This is the deck cut out, with barbetts placed on top. 2" PVC coupling pieces ended up being the correct diameter. From this point I moved to drag shafts and shaft struts. This is the wood for the rudder, 1/8" ply frame, filled with 1/4" balsa to shape. Everything in place, 1.5" nylon drag discs. The stern is narrow so they are far enough forward to be within the beam on the boat at that area. This shot shows the rudder profile. I ended up covering the balsa with a layer of fiberglass. Meanwhile I worked on the stern deck piece. The small section of superstructure on the deck served as a housing for the rotate servo. Shows the lineup of the servo with the barb. I'm using a chain drive from servo city
I used 2" PVC with the associated coupling piece for the rotate. A small piece of coupling is epoxied to the deck and acts as a bushing, and the rest of the assemlby rotates. Initial sizing of the plastic chain. I had to space the servo away from the turret to allow the top of the pump motor to fit between the sprokets.
Here is the aft deck pre epoxy And gun parts. This batch includes 4 guns for another boat, the California will have 6 guns for displacement and configuration options
Bigger props doesn't matter when you run brushless. 1" props on a Cali. 1000kv on a 12v system will do great. 1500kv on 6v
Very nice and interesting. I am very interested in seeing how the rotate system works. Hopefully you can post video of it . I am looking for ideas to set up a rotate system for my Montana.
Well I look at Brushless a bit different (big surprise), I think that it can do both and has the ability of spinning up way faster than brushed. Bigger screw and more torque in the hole, what is not to like. Oh yeh, the current is a issue when you go nuts.
I'm not sure I follow. Bigger prop spinning faster with more torque....... How do you keep it under the speed limit?
Putting 1" props on a ship this size is a huge mistake. Cruisers at 11lbs get a 1.25" prop. This ship should get 1.75" props. It's not about the top end speed. It's about starting and stopping. Something we do a lot of. Those little props are not going to stop or start your ship well enough. Making speed might be hard too as at some point the props spin too fast and cause cavitation. For example I built a Kongo, Hudson built a Kongo. I used 1.75" props, he used 1.5" props. We thought that the smaller props might help the ship turn better as the small rudders would get more coverage. When both ships were finished and we were both at speed we turned the same. My ship had a HUGE advantage in start/stop power. Hudson replaced the smaller props with 1.75". For a BB this size 1.75" four blade props are best.
Post Nats building has resumed. A few changes based on experience at Nats. I'll be shifting at least some of the voltage to 6.6V (2S LiFe) to support the Traxxas Titan 12T pump, the 14V version did not last long in my other ship. The other major change is that I think I will try brushless out before Ming's battle in august, since I have some time now. I will have to figure out everything I need. I can either use 4 20Ah LiFe bricks per battle (~6.6V, 40Ah), or I can use 2 LiFe bricks and 2 4S, 4200mAh LiFe zippy packs per sortie or battle based on how much juice the boat pulls. Any recommendations for brushless setup? In regards to the prop size, I ordered 1.6" and 1.7" Kort props the other night, which should be in about 4-5 weeks from now. The 1.6" should fit with the current shaft length, but I should be able to shorten the shafts very slightly to fit the 1.7" props in if necessary. I also ordered 3/16" SS drive shafts and oilite bushings As far as build progress, I have been focusing on getting guns installed. I started making gun pins yesterday using #10 brass wood screws cut down. My old SS BC gun pin is shown for comparison, back when I has access to a lathe and could drill out SS. I also got the triples and the rotate haymaker in, though I will have to play with the haymaker mount to give it clearance to elevate above the aft turret. Pictures with the haymaker haven't transferred from my phone, so here are the aft guns. I decided to make a turret mold to make fiberglass turrets to give more room on the inside, the mold should be done tomorrow. Goals for the long weekend will be getting the guns mounted, moving onto solenoids/expansion tanks, and the water resistant box plus wiring
The Annapolis boat house has a lathe and you can get rivets from McMaster Carr that fit your exact specs.
Drilled Pistons have worked for my boat, I did some testing in 2011-2012 with different hose arrangements, and found the drilled Pistons increased bb speed by around 30fps. There are probably other methods out there to accomplish the same goal, I plan to stick with it until I feel it's inferior to some other design
