After looking at the original plans for the IJN Fuso and other ships, I've noticed that some have their rudders at at angle (from vertical): What was the purpose in this, and has anybody done this on their boat? I was wondering what the effect would be at our scale; I'm thinking it would induce some (inward) roll as the ship turns - would this be good, bad, or indifferent? It might also allow the top of the rudder to travel closer to the hull, as the hull is at an angle at this location. Thoughts...?
I'm not sure about the purpose on full-scale ships, but at our scale it would certainly significantly increase complexity. Most steering systems are done with gears, or chain-and-sprocket systems. Even when using tiller arms, most of those setups don't like having different parts at different angles.
This is just a guess, but I would imagine at least on the ship you posted a picture of that the angle of the rudders was done to try to get the center line of the rudder behind the center line of the prop and the ship's stern wasn't wide enough to just move the rudders sideways to make it happen.
Yeah, just not sure how to make it work quite right with our equipment. I'm assuming Kongo hull? Most guys just get them close enough and call it good.
@McSpuds did angled rudders on his Mutsu build here on this site. I think he used specially shaped gears if I remember right. The only thing you'll gain is a little scale accuracy. Performance won't be any better I doubt.
Performance would most likely be worse since you'd be using some of the energy in the flow to go into roll instead of yaw. You can't really "bank and yank" one of these ships. Rigging it up probably wouldnt be too hard to do, just two servos mounted at an angle. Give it a try and let us know!
I was envisioning something along these lines, using GT2 Pulleys/belts: Yes, this is conclusion I was coming to - I might gain some space, but it would cost in performance. Another question I was pondering: what would happen if the rudders were not centered on the props, but moved slightly closer to the center line? Yes, I am the proud new owner of a @modelshipsahoy Kongo hull, just asking a lot of questions before I cut into it....
If that takes them out of the flow from the prop you're not going to be able to redirect it as much and you wont turn as well. The goal is to capture as much of that flow as possible and redirect it somewhere else in order to turn. For big turns it's more thrust vectoring than hydrodynamic lift that you're after.
I like the out of the box thinking and the sketch up, but that looks like a reliability nightmare. There's enough room to get the rudders about 1.625" apart which will give good coverage. I'll be printing a rudder/servo mount and can post files once I get there
Yes, those were about the numbers I was getting with my trusty 6" scale, so using 1.75" props, I figured my rudders would fall short of aligning with the center of the the props (@ 1.75" center-to-center). I realize I am probably overthinking this, but that's half the fun for me... Looking forward to all your postings, BTW, @Kevin P. Also, how far above the hull bottom did you cut your windows?
Most Fast Gun ships don't even really get the props or rudders in the 100% scale locations or sizes. Just put your inboard props close enough together that the rudders cover them, and you're good. Actual turning performance is much more affected by your weight distribution, power train, and rudder shape than the angle of your rudders. Heck, even Big Gun ships rarely get the details on props and rudders right, and they're at least required to make an attempt.
