David's Prinz Eugen has differential steering, which is reported to allow tight turns at high speed with no loss of speed in the turn. I know how differential steering works on a tank (reduce speed to one tread and the tank turns in that direction), but is it the same for a boat? How does it effect the turning radius, rate of turn (or time to complete a turn), and speed when exiting (or speed lost during the turn)?
It is the same for a boat. This is done a lot in subs to get tight turns. However, I'm pretty sure it slows down the vessel, since one prop (or more on 4-prop ships) is going in reverse. Hope this helps, Carl
In MWC, we cannot slow down or affect the speed of the props in any way to assist turning. What I do is turn the rudders different amounts, the rudder on the inside of the turn turns at about 50 to 60 deg, the outer rudder at 30 deg. As you can see in the pictures. The inside rudder acts as a drag force, while turning the ship, while the outer rudder keeps the ships speed up, since the water flow is not as restricted. I did not know if this would work as envisioned, some of the MWC old hands basically told me it would not work. But with testing in Rick's canal, it works great. Don and Rick were both amazed that it turns so well, and you can not see any slow down at all. Of course it has to slow down some, but its not noticable that we can tell.
I don't think it's done in subs anymore, as Other than Typhoon, I can't think of any modern subs with two props. Modern surface warships can change prop pitch on the fly for this purpose. Variable thrust Dave, post a pic from above of your rudder setup!
Thanks for the info guys. Dave, you don't change the speed of the props, but you have the rudders at different angles so one produces less drag than the other? It would be interesting to try setting the rudders to be parallel and seeing how that changes your performance.
Sorry, I was refering to the older diesel boats. Nearly all of them had two props. You're absolutely right about the modern subs. Carl
My Roma has the rudders turn the same amount, when you make a sharp turn, which it can do, the speed of the ship slows down to the point of stalling, its just turning, with little forward motion. And the speed of the turn is also slower. I see all the ships doing this on a tight turn. So while they go into a stall, my plan, if it works, is to just power around their turn, and since my turning circle is about 60% of theirs, My bow should be pointing at the forward side of the other ship at the end of my turn. Just right for me to rip off 3 or 4 shots with the triples, before I start into another turn. Again this is all theory, but we will see next weekend. Don and I will just practice some manuvering against each other. Looking at my PE pictures I spent alot of time making sure the rudders gave me as much prop coverage as possible. I wanted the inner to be as close to 100%, the outer at 60 to 70%. I think I acheived my goal. I have a picture posted of it, but here it is again. It has dual throw arms, and by putting the 2 bends in the rods, when it pushes out, it goes further, than when it is pulled in. Both rods have the bends, the one at the angle it is you just do not see it.
I don't understand why differential steering would be illegal. The real ships could and did vary the speed and direction of individual shafts so, why forbid it in scale models? I didn't find a direct statement about this in the IRCWCC rules. Is it allowed?
Nope. I just double checked the rules that are on the site. Section D makes no mention of varying propeller speeds or directions being disallowed. The part about "only rudders shall be used to steer ships" is nonsensical. Rudders are useless without props or sails unless, one's ship is being towed : P
D. RUDDERS 1. Only rudders shall be used to steer ships. No "turning motors" or other systems may be used to assist in turning.
We've made a game with semi-scale toy boats boats. Water is involved. That's about the limit of the intersection of the real ships and us.
I was waiting for that. That wording is attrocious. I think it is meant to state that bow or stern thrusters are not allowed but, it's very unclear. What is a "turning motor"? Unless one counts solenoids, nearly all electric motors turn. Again nonsensical. If one can't use the props and shafts the ship had then, one can't turn the ship. period.
Turning motors refers to using varying the speed of one prop relative to the other to promote turning ability.
Nope. We're using propellers and rudders that are semi-scale too. There's a bunch of rules about them : ) Why not use them the way they were intended to be used?
We have semi scale location and scale number of props, but no scale or semi scale requirement on the shape and dimensions. Given that I honestly believe we have an excess of turning, to the detriment of the game, already... I'm going to say 'no' .
It doesn't refer to anything. There is no footnote nor citation of that any where in the document. I like the way you've stated it and I propose we change it to read similarly next year.
If you ask any "oldie" in this hobby what turning motors means he will tell you something along the lines of what I've stated. It's a definition native to this club you might say.
We do have rules about the dimensions (area) of rudders. We just got done voting on them : ) I see your point that, perhaps, turning needs to be limited but, the limitations need to be made clear and none of that is made clear in those two sentences.
