Bismarck props?

Discussion in 'Propulsion' started by jstod, Jun 15, 2012.

  1. jstod

    jstod Well-Known Member

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    Ok this is a little early for my build as the ribs arent even cutt yet but were would I be able to get 3 props (and reliable stuffing tubes for that matter) for a big gun formatted bismarck?:cool:
     
  2. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    They're pretty easy to make :)
     
  3. jstod

    jstod Well-Known Member

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    haha Tug i get the impression that you are one of the master do it your self craftsmen in this hobby and beyond. For my first boat I would prefer on propulsion at least to go with the expeirenced makers of both props and stuffing tubes. On a later build I will most definitely build em my self. :)
     
  4. jstod

    jstod Well-Known Member

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    So what size props would be ideal for the bismarck?
     
  5. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    Hmmm... some people have run big honking 2 1/4" 5-blade props. I max out at around 2" because I like a flat drive angle, but that's personal preference. I also like flat pitch, direct drive, although that's not a hard and fast rule' both of my current combat-ready ships are geared. Go figure :)

    As far as making things oneself... some things are what I would call 'Easy', which is either you can read a simple how-to online, or see it done once, and do it again for yourself without too much bother and basic tools. Driveshafts, stuffing tubes, motor mounts are in this category. 'Involved' would be read a fairly in-depth, step-by-step method online, or spend an hour or two with someone who knows how, have some more tools (like a vise, a drill press, blowtorch, etc), and maybe have a few failed attempts before succeeding with a basically functional unit. I put guns, pumps, props, and gearboxes in this category. Maybe a solenoid setup for multiple guns. 'Hard' would be reading and re-reading a somewhat complicated howto online, until you think you get it, or spending several hours with a master (maybe more) and making several examples of whatever you're trying to make that are acceptable but not AWESOME. Could in certain cases require power tools that are usually found in a shop (scrollsaw, bandsaw, mini-mill) I put improved versions of 'Involved' items in this category. Brian K learning to make better guns from Bob H. one year at the Brouhaha is an example; And even after several hours (I was asleep for most of them), Brian still made several guns that worked fine but weren't AWESOME. AWESOME takes know-how and practice. (Disclaimer: I suck at making guns) Wooden hulls are a special case. A WW2 US cruiser hull (about as easy as it gets) rates Involved, but might take some tools under what I rate as Hard (Ex: not everyone has a scrollsaw). A WWI Deutschland class predread is Hard, because it takes a lot of mental heavy lifting (relatively speaking) to lay out the various parts and stringers and make them all slot together. Other ships are easy looking but hard because of poor plans or lack of plans (the Russian Gangut class comes to mind). WWI destroyers and all submarines are V.Hard, because on top of everything else, you are under severe weight and space limits that require advanced improvising and a fair bit of green stuff to buy higher-end micro components.

    These aren't hard-and-fast, but I think that they're good generalizations. Of course, the old Navy rule applies: Anything's easier if you know how to do it. :)
     
  6. jstod

    jstod Well-Known Member

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    I would agree with what your saying generally. But for stuffing tubes Id rather get the ones that are going to work at least for the first ship and props i like the cool look of the ones you can buy.

    As for the size 2" seems a little to big. Does it make a difference I am building to Big gun rules?
     
  7. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    Oh, I wasn't meaning that I'd think less of anyone who bought them. I bought them before I got a shop and learned how :) I still pay good money for guns, because they're good, and I suck at making them :) So I can't really look down on buying things.
     
  8. jadfer

    jadfer Well-Known Member

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    I have a prop shop 2.25 5 blade for mine. I use the same version but smaller on my Baden and love it. I broke so many blades on props in my FIRST battle alone..Personally I will never use soldered props if I can avoid it.

    http://www.prop-shop.co.uk/index.php?section=store&sub_section=product_detail&id=1077&product_type=37

    We got together and ordered a bunch and split the shipping...

    I love the way they look and so far its been more cost effective than buying soldered props. I had gone through several sets of those soldered props. In the end my cast props (I bought 2) were the same price as 2 pairs of props (I only needed 1 but they are sold in pairs so I was overbuying anyway).

    Granted if you find the blade you can solder back on .. but I wasn't going to search the pond for a little prop blade.

    Life is easy now.
     
  9. jstod

    jstod Well-Known Member

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    interesting... I will definitely keep that in mind when it comes to actually getting the props.
     
  10. Quintanius

    Quintanius Member

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    Thanks for the great info, and the link to those very nice props. At scale, the Bismarck should have 3 bladed props, 1.25" dia. What pitch though? The Port and Center prop spun counterclockwise, and the starboard one clockwise. That be 2 LH and 1 RH or did I get that backwards? I'm building the H-39 (Hindenburg) and assume that the props were (to be) somewhat larger, although I dont have any data, but my guess would be about 1.5" props at scale when considering the larger scale of the H-39.
    Suggestions or comments be most welcome - the price is steep but I'll definately buy them. I'm also making the assumption that the props from that place in England there fit on a 1/8" steel shaft? Just have to thread it for the proper size?
    Thanks,
    Thomas
    http://www.kbismarck.com/propulsioni.html
     
  11. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    Scale props are nice appearance-wise, but the physics of the water don't change with scale so I'd recommend the largest you can conveniently mount :)
     
  12. jstod

    jstod Well-Known Member

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    I believe my two outer props are going to be 1.25" but my center prop i think I will make it 1.5" I dont want to go to much larger then that but I also think I will go with the 4 blade props
     
  13. Quintanius

    Quintanius Member

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    1-1/2" Props is about it for the H-39. I wonder how much these propellers cavitate. Be cool to watch it with a submersible camera or when its in a big aquarium or something.
     
  14. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    My Vanguard had 2" props and I wouldn't go smaller on a big ship. Someone else WILL, and you'll be at a disadvantage.
     
  15. Quintanius

    Quintanius Member

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    Hmm...how, so as long as speed is set to the proper knot to scale ratio: asside from the time it takes to come to speed, which I believe having all three props operational should provide enough thrust to compensate for the size of the hull and accellerate the H-39 just fine. And besides, Big Gun rules mostly allow a up to 50% surface area increase in the propeller size, and Treaty only allows to scale props.And using more blades than the ships propellers were equiped with seems strange as well, especially since most rules do consider the historical build and form of a vessel. To ignore something as elementary as using propellers that were not mounted (such as 5 bladed vs 3 bladed) is certainly (to my mind) more prone on the side of deviation from that premise than - say - adding 2 smoke stacks when the vessel clearly had only one smoke stack. One wonders. So how about that pitch...still having trouble finding the pitch for the Bismarcks propellers. :confused:
    Thomas
     
  16. jstod

    jstod Well-Known Member

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    Im going with the25pitch props with the middle at 1.5" and the outer 2 at 1.25" the Bis had 3blade props but i think i may go with the four but havent made that decision yet. as for the 2" prop idea id rather not because of space between the prop and center keel of the ship above it
     
  17. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    You guys are free to do what you want :) But it's not like I have any experience or anything ;) My thought for you is this: The people who have driven large warships have (as a group) tried a LOT of combinations of props in actual practice. Do you really want to go with what 'should' or 'ought to' do well, when it flies in the face of that experience?

    With your top speed fixed, you can get some tactical advantage from being able to GET to your top speed quickly. For the same amount of power transmitted from a given ship, a small prop (or props) will cavitate easier than a large one (or ones).

    Full disclosure: I don't make nor sell props, nor get kickbacks from anyone that does. (Altho I am TOTALLY willing to sell out if there are kickbacks to be had; contact via pm with offers)
     
  18. jstod

    jstod Well-Known Member

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    I hear you Tug my only concern is i do not want to alter the hull to accommodate a larger prop. from what i am gathering from the guys in my club is that at least for the Bis with its dual rudders having the center prop be the most powerful is key to turning better.
     
  19. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    I agree with them 100%. The center prop is crucial. If you don't want to alter the hull, you could put a little bit of downangle on the stuffing tubes. 10 degrees down won't hurt. Short of that, get as many blades as you can on a 1.5" prop, probably 4 unless someone can custom make you one with 5.
     
  20. jstod

    jstod Well-Known Member

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    thats what i was thinking. the problem with a down angle is the stuffing tube has to fit under the accumulator for the aft guns. (big gun format)
    What I am thinking of doing is shortening the stuffing tube as short as i can and havein the motor lay on top of it faceing forward.