Tugboat
Veteran
Admiral
Posts:4438
 | | 04 Oct 2009 12:54 PM | | I know very well that ships that come with 4 props typically are run with only the 2 center shafts being driven. If I was going to be building, say, a Baden, would driving only the center shaft give me a noticeable advantage over running 3 screws close together? I know that I'd lose the turning advantage of the drag discs on the outboard shafts if I drive all three. But my acceleration and braking/reversing should be better if I run all three. Advice from battlers who have operated three-shaft ships before? | | | |
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Stokamoto
Stokomoto
Vice Admiral
Posts:3730
| | 04 Oct 2009 01:47 PM | | That's a good question Tuggy. Both versions will come with their advantages and disadvantages. I ran Bismarck side by side with Ralph's Tirpitz. We were using identical rudders and both ships were ballasted at the same weight. Tirpitz had all 3 shafts powered. Bismarck had ony the center shaft powered and the outer shafts had drag props only. I did not observe any noticable difference between the 2 when turning and driving. Both could stop really fast and accellerate about the same to get up to full speed. Tirpitz had the advantage in reverse in that it could hold it's course in reverse and actually have some turning in reverse whereas Bismarck would pull immediatly to the one side so you have to offset your angle ahead so that you line up to the target with stern guns. This takes some practive to get used to. I had lots of practice that way and became very adept at operating Bismarck this way but it's not for everyone. On the other hand if you have either motor on the wing and one stalls well then you got issues. So in a nut shell no noticable difference in turning ,stopping or accelerating, but reverse the 3 shaft has more control. My Konig will be operating off one motor center shaft. For Bismarck I could manuever with a North Carolina very well and stay with the cruisers no problem.
Warspites and anything like that can out turn me. | | | |
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Stokamoto
Stokomoto
Vice Admiral
Posts:3730
| | 04 Oct 2009 01:47 PM | | That's a good question Tuggy. Both versions will come with their advantages and disadvantages. I ran Bismarck side by side with Ralph's Tirpitz. We were using identical rudders and both ships were ballasted at the same weight. Tirpitz had all 3 shafts powered. Bismarck had ony the center shaft powered and the outer shafts had drag props only. I did not observe any noticable difference between the 2 when turning and driving. Both could stop really fast and accellerate about the same to get up to full speed. Tirpitz had the advantage in reverse in that it could hold it's course in reverse and actually have some turning in reverse whereas Bismarck would pull immediatly to the one side so you have to offset your angle ahead so that you line up to the target with stern guns. This takes some practive to get used to. I had lots of practice that way and became very adept at operating Bismarck this way but it's not for everyone. On the other hand if you have either motor on the wing and one stalls well then you got issues. So in a nut shell no noticable difference in turning ,stopping or accelerating, but reverse the 3 shaft has more control. My Konig will be operating off one motor center shaft. For Bismarck I could manuever with a North Carolina very well and stay with the cruisers no problem.
Warspites and anything like that can out turn me. | | | |
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Tugboat
Veteran
Admiral
Posts:4438
| | 04 Oct 2009 03:14 PM | | Thanks, Curt... Question: how close (or different) are the Konig's turrets from Baden's? Brian K is going to make me a set of high-detail Baden turrets, so if they're close you might want them, too... | | | |
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Greg McFadden
Rear Admiral (RDML)
Posts:1416
| | 04 Oct 2009 03:38 PM | | Hey tug, what do the high detail turrets look like (and where did he get the documentation)?
-Greg | | | |
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Gascan
Veteran
Commander
Posts:777
| | 04 Oct 2009 04:30 PM | | The 28cm turrets and the 30.5cm turrets are very close with the same shape, so you could probably exchange those with nobody noticing. However, the 38cm turrets show some noticeable differences. I don't think you can exchange those. The cross-section of the 28cm and 30.5cm turrets is square, but the 38cm turret's upper corners are chamfered. They are also wider for roughly the same height.
Bayern's 38cm turrets:
Konig's 30.5cm turrets:
Moltke's 28cm turrets:
edit: that outta do it. | | | |
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Tugboat
Veteran
Admiral
Posts:4438
| | 04 Oct 2009 04:30 PM | | He is still working on them, so no pics of the turrets yet. The documentation is a mix of plans and pics. I forgot that you're doing one, too... I'll post on here when he's got them ready (could be a month or more, as we have a battle in 2 weeks and a scout campout after that. The Baden is a winter project so there was no rush to do it. | | | |
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Greg McFadden
Rear Admiral (RDML)
Posts:1416
| | 04 Oct 2009 06:41 PM | | Yep.. I am still deciding what to do on her. Last one I built had two outer shafts powered, free wheeling inner shaft. I think I will go the single powered central shaft this time... | | | |
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Iceman
Rear Admiral (RDML)
Posts:1186
| | 05 Oct 2009 09:03 AM | | I just got mine going with a 970 running the center shaft, direct drive, drag discs on outer shafts. It turns well, starts and stops ok and yes it does pull a bit in reverse. I find that to be a tactical advantage. You can go straight back by holding the rudder all the way or make a turn in reverse holding the rudder the other way. It really turns vs a normal set up which barely turns and it just happens to turn the way of my rear gun  Not an accident.... | | Rob A.
USS Alabama
USS Arizona
USS Saratoga
DKM Bismarck
USS John Brown
http://groups.yahoo.com/group/NYBG/ | |
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Tugboat
Veteran
Admiral
Posts:4438
| | 05 Oct 2009 05:27 PM | | What size center prop are you using, and why so big a motor? I'd expect that a 28 sec DN could be pushed by one 550-size motor (for that matter, what's a 970 size? Sounds huge!) Also are you using a gearbox or direct drive? | | | |
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bb26
Rear Admiral (RDML)
Posts:1642
| | 05 Oct 2009 09:50 PM | | I think the Iceman is running the Bismark on 1 shaft. For a DM a 550 should be sufficient. | | | Just when you think you know the answers, I change the questions. | |
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Chris Easterbrook
Rear Admiral (RDML)
Posts:1391
| | 05 Oct 2009 09:54 PM | | Paul a 550 is not big enough to push a Biz. Look at the engines me and Criag both put in ours really big gropners on direct drive with really big props. You really need two 550's for that ship. | | | That which does not kill me, makes me stronger. | |
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Iceman
Rear Admiral (RDML)
Posts:1186
| | 06 Oct 2009 08:41 AM | | Yes, a Bismarck, I should have stated that... 5 blade 2 inch prop, direct drive. A large motor is the norm. A set of 550's will do it, especially with gears but a 970 or a big motor gives it power without stressing the motor too much. I have a 34 pound 6 foot carrier and the two 550's work at moving that... You will find this is a common motor for these ships. | | Rob A.
USS Alabama
USS Arizona
USS Saratoga
DKM Bismarck
USS John Brown
http://groups.yahoo.com/group/NYBG/ | |
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bb26
Rear Admiral (RDML)
Posts:1642
| | 06 Oct 2009 02:57 PM | | The BIS might need 2 550's to push her but a 28 second DN (Dreadnought) running on a single center shaft should have no problems running on a single 550 motor. | | | Just when you think you know the answers, I change the questions. | |
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Tugboat
Veteran
Admiral
Posts:4438
| | 06 Oct 2009 03:36 PM | | That's what I'm hoping | | | |
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Knight4hire
Captain
Posts:885
| | 08 Oct 2009 09:27 AM | | Those 550's, what voltage are they running on?
BC shows that the motors are rated for 6-12 volts.
My question really is: What voltage is required for one 550 to get Bismark up to 28sec?
Then my next question is: What voltage is required for two 550's to get Bismark up to 28sec? | | | I am from the Government, and I am here to help.
www.mabg.org | |
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crzyhawk
Rear Admiral (RADM)
Posts:2130
| | 08 Oct 2009 10:12 AM | | Posted By bb26 on 06 Oct 2009 02:57 PM
The BIS might need 2 550's to push her but a 28 second DN (Dreadnought) running on a single center shaft should have no problems running on a single 550 motor. You might be surprised, depending on the dreadnought. Bob Amend used to run a Bayern with a single 550 driving the center shaft and said it got hot enough to sizzle when a bead of sweat dropped on it. He said he then touched it and burned the crap out of his finger because he didnt believe it should be that hot. | | | HMS Invincible
USS Salem (CA-139)
USS Belleau Wood (CVL-24)
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Chris Easterbrook
Rear Admiral (RDML)
Posts:1391
| | 08 Oct 2009 01:25 PM | | I would think an engine sgould not get that hot, that much heat means the engine is running way too hard and this will ruduce the life of the engine. | | | That which does not kill me, makes me stronger. | |
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JustinScott
Founder
Rear Admiral (RADM)
Posts:2176
| | 08 Oct 2009 02:54 PM | | I'll be running this very torque-y brushless motor with my Tirpitz if it helps... I wasn't planning on using such a large prop.. but if iceman is running with one; and I do have a 2" 5 blade on hand... hmmmmmmph.... still very tempting. Kv : 800 rpm/V within 10%
Current capacity : 55A/60s 
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jks
DKM Tirpitz | |
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jadfer
Lieutenant Commander
Posts:570
| | 08 Oct 2009 03:36 PM | | I am thinking of trying some rock crawler motors. I am sure that they can run the ship at speed but the low end torque should really get it up to speed fast. I am not sure and they are around $40 each. | | | |
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