Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[Liverbudgie2]

Stewart,

You will probably find that that you don't need as much power as you think so, with that in mind I would probably use a Mabuchi 555 motor running on 12 volts if this is not enough then the voltage can be increased to 18 or even 24 volts. I would also consider using a single 12 volt battery and perhaps a smaller one as well if you require the extra power. For couplings I would use the rubber insert ones from Model Boat Bits.

Don't forget also that the props turn outboard when running ahead.

LB

[16-21]

Stewart,

I believe Phil aka kiwimedic on another forum used
Buehler motors for his 1/72 Bismarck.
I think they where 4400 Rpm.
So maybe you could use
Bosch car fan motors Similar to these
http://engel-modellbau.eu/shop/en/Electric-Motors/E-Motors-Brushed/High-Torque-Electric-Motor-EPX-1236-12-36V.html

[Mark T]

I can't help with the motors but I'm finding this build absolutely fascinating.  Loads of research and planning which shows some real tenacity and dedication.  Keep the updates coming 

[Rob47]

Stewart,

You will probably find that that you don't need as much power as you think so, with that in mind I would probably use a Mabuchi 555 motor running on 12 volts if this is not enough then the voltage can be increased to 18 or even 24 volts. I would also consider using a single 12 volt battery and perhaps a smaller one as well if you require the extra power. For couplings I would use the rubber insert ones from Model Boat Bits.

Don't forget also that the props turn outboard when running ahead. looking from bow, inboard from stern, inboard more efficient for slow moving warships and is prototypical for most.

LB

[16-21]

At 140+ inches long i think there is more than sufficient space for Sla batteries
In parallel or if you need more power in series
If the speed is too much throttle back.

[bfgstew]

Tenacity and dedication.......more like lunacy and stupidity..........


Looks like the 555's are getting the thumbs up, good as they fairly cheap. May have them set as direct drive, just need to figure out how to mount them as the plans show a 2° inward angle (bow to stern) and 1° downward angle on the shafts. Looks like making an Aluminium mounting plate then bolt that to an appropriate bulkhead....on ward ti the drawing board.


Cheers for the help guys, much appriciated


Stewart

[Colin Bishop]

Toothed belt drive might be a good option. Gives you more flexibility in mounting the motors, much quieter than gears but allows the motors to run more efficiently with a lower power consumption for the same speed.
Colin

[Liverbudgie2]

On the real ship the propellers turned outboard (the top of the blade is turning away from the centre line.) when the ship was running ahead, whether your standing at the stern, or the bow for that matter. see: http://www.hmshood.com/ship/hoodspecs3.htm

In fact this applies to all, or virtually all, ships built for the Royal Navy since the mid 1890's, as well as most merchants vessels with multiple shaft arrangements apart from the Lusitania and Mauritania, which had a combination of both, until fairly recently.

As for mounting the motors at the correct angle. If you are unable to mount the motors and maintain the correct angle at the same time in the conventional manor, then a simpler method then using a belt drive might be to mount them upside-down; a simpler method still would be to extend the shaft into the hull until you can mount them correctly.

Other notes that maybe of interest can be found here: http://www.hmshood.com/ship/handlingnotes.htm & http://www.hmshood.com/reference/written/asnejournal32.htm

LB

[raflaunches]

Have a look at my HMS Invincible- The First Battlecruiser build regarding a toothed belt drive. The are smooth and very quiet when running. I got some made by SHG Models, all they need to know is the distance between shaft centres to get a belt and ‘cogs’ made.
My system would be very similar to what Hood requires if you go that route.

[bfgstew]

Thanks guys, invaluable info as always.


Nick, I like your set up, very nifty.
My thoughts though are having 4 motors, direct drive, motors mounted 'nose first'......may have to make my own prop tubes due to the length of them. This has to be 'right first time' as therd will be no way of getting to these tubes once installed.........will get my inventors hat on, got a few ideas!
This is such a mad idea.............but fun.


Cheers again guys.


Stewart

[Rob47]

On the real ship the propellers turned outboard (the top of the blade is turning away from the centre line.) when the ship was running ahead, whether your standing at the stern, or the bow for that matter. see: http://www.hmshood.com/ship/hoodspecs3.htm

In fact this applies to all, or virtually all, ships built for the Royal Navy since the mid 1890's, as well as most merchants vessels with multiple shaft arrangements apart from the Lusitania and Mauritania, which had a combination of both, until fairly recently.

As for mounting the motors at the correct angle. If you are unable to mount the motors and maintain the correct angle at the same time in the conventional manor, then a simpler method then using a belt drive might be to mount them upside-down; a simpler method still would be to extend the shaft into the hull until you can mount them correctly.

Other notes that maybe of interest can be found here: http://www.hmshood.com/ship/handlingnotes.htm & http://www.hmshood.com/reference/written/asnejournal32.htm


LB still disagree with you on prop rotation, my Bristol's turn inboard as do all my warships, better handling quality at the speeds expected from grey funnel, outboard give better handling at high speeds, this from ships manuals.  By upside down motors I assume you mean if it has a base, if not then not sure how you mount a round motor upside down  I am going to go the belt drive way as although it is 10 foot it is split at centre so cant extend shafts..
Bob
BTW prop rotation has gone on and one for younks, don't want a war of words, it works for me and boy can she shift if she has to, fastest ship in fleet at one time

[ballastanksian]

Hood is one of the few ships were you don't have to worry about the length of stuffing tubes as you have a lot of hull to play with!


Even the electrics will be dwarfed by the sheer capacity of her. I hate to think what her ballast will have to weigh. Even having four 12 volt car batteries may not be enough 

[bfgstew]

It's beginning to dawn on me Ian.......gulp!

[ballastanksian]

You may have an ideal opportunity to design water ballast tanks based on the drawings you have done for the hull which will save hours of CAD (Cardboard Aided Design :)

[bfgstew]

Just an idea, drill holes on the bottom of frames and fit lengths of 25mm conduit, cast some lengths of lead to fit in tubes these can then be removed for transport. 1.4M length of 20mm dia lead is equal to 10lb, got to see how many I can get fitted.
Looks like the hull will have to be in 2 halves, 12+ feet long is just far to big to transport and build......

[Bob K]

Just to get some appreciation of the numbers we are dealing with here,
At 1/72 scale this model will be 3.64 meters long, almost 12 feet.
Even cut in half that is around 6 feet per section. 
See the build of my 7 ft HMS Agincourt on how to build a very large ship in two halves.

Next you need to calculate the displacement for the model.
47,340 tons x the cube of 1/72, then convert answer (in tons) to kilos. 
Be prepared for a shock!

Next you are going to have to figure how to lift that weight.
Suggest use pumped water ballast for as much as you can, which will define where the bulkheads go.

[bfgstew]

290Lbs..........131kgs

[Bob K]

Sir, you are a brave man 
(That's 100kg more than mine, and I thought that was pushing my luck)

I shall continue to follow this with interest.   

[bfgstew]

Daft......not brave!

[Plastic - RIP]

290Lbs..........131kgs

And that will be awkward to carry too so fumbling hands will likely damage the detail work every time.

[bfgstew]

It will be broken down.
Superstructure off.
4 main guns off.
4 SLA batteries out.
Ballast out.
Hull in 2 halves.
Probably get it down to an acceptable amount for transport, handling.

[Colin Bishop]

But how often will you actually want to take the boat out given all the assembly, disassembly and transport procedures? And it will take up a lot of storage space as well.
Colin

[ballastanksian]

On a positive note  If you know what you are going to end up with you will be able to prepare at each stage-pretty much like you are with your sub assembly breakdown, hull split and consideration of ballast required. As mentioned before, you will have loads of space to plan and set out your ballasting requirements, even if you try out Geoff and Bob K'C3PO's T.A.R.G.E.T system. You could do novel weight additions such as making the very bottom of your turret 'Handling rooms' out of lead, as you know you will be removing them and so know where some ballast is placed and located.


It will be a challenge, it will be a bruiser, but by golly your Hood will be a sight to see on the lake when complete. Please bring her to Wicksteed when done 

[16-21]

Stewart,

I know you have done your research and that you have selected 1/72
But just in case you decide the 1/72 is too big
MTB Hulls Gibraltar
Lists in there 1/96 coming soon
Hood and Kgv

[bfgstew]

Batfish.........seen that on their website when researching, not sure how much longer that will be. Same with DeansMarine, there were rumours of a large Hood hull. A Massive commitment on their part to produce huge hulls that not many will be willing to build. Hence this build, but never say never, still a long way off cutting any timber for a while yet.


Ian, the old saying, fail to plan, plan to fail. The beauty of CAD is seeing how it will look, you can model it, change it, adapt it, build it, before spending hard earned and it going 'orribly wrong........