Help Determining Prop Size and Motors for Fictional Ship

MechTech · Post by **MechTech** » Wed Feb 15, 2006 11:35 am

Hey everyone,
I'm new to this forum, but I've been model building for some 25 years to include R/C installations. Most of the ships I have built were smaller hulls and an actual model of something exhisting so prop type and motor matching was easy. I'm scratch building a fictional ship that is six foot long, bulbous bowed, flat bottomed for the most part and 10 inches at the beam (this is about three feet in section by itself). It's from an animated TV series and there is actually a shroud over the drive system. I'm having a tough time determining what motor size to use, how many motors, and prop diameter. The ship is futuristic so I was wanting to go 6 blade scimitar, probably Raboesch or Prop-Shop. I'll build the rest of the running hardware. The only limit is that I decided to use 6volt gel cells to simplify power for all electronics and to use exhisting bells/whistles. Does anyone have a clue or computer program/formula of what would work best? I even contemplated using multiple smaller motors/props to increase power efficiency. Thank you for your help!

Victorious · Post by **Victorious** » Wed Feb 15, 2006 1:34 pm

It depends what you want from the model, if you want scale speeds, then go for smaller props, rather than large ones. Again, it depends on how many prop shafts you are using.
Iron Duke & Marlborough will eventually run with four props of 30mm which will give a realistic scale speed. ( see the build articles on these ships)

Guest · Post by **Guest** » Wed Feb 15, 2006 5:21 pm

Thanks for a clue about prop pitch. I am looking for scale speeds. The upper superstructure is basically a box which means a sail when a breeze comes up. A little extra "umph" would come in handy. I'm tossing around 4 shafts, smaller motors vs two shafts, bigger motors. I'll split them up for the control factor.

TommyL · Post by **TommyL** » Wed Feb 15, 2006 7:45 pm

Wich aminated movie? Submarine 707r? Space Battleship Yamoto? Blue Sumarine?

Guest · Post by **Guest** » Thu Feb 16, 2006 4:44 pm

It's the SLV-111 Daedalus from "Macross." I have all the mecha models and plans worked out. About 60% of the lower hull is rough built (not filled). Working on the bow section now.

MechTech · Post by **MechTech** » Thu Feb 16, 2006 4:46 pm

Ooops. I forgot you have to log in to post...
It's the SLV-111 Daedalus from "Macross." I have all the mecha models and plans worked out. About 60% of the lower hull is rough built (not filled). Working on the bow section now.

psships · Post by **psships** » Thu Feb 16, 2006 5:01 pm

It may help if we mere mortals knew what this thing looks like to start with, I have built a few odd balls in my time, But, don't have a clue what you are on about here matey? C'mon give us a clue?
Paul...

ddp · Post by **ddp** » Thu Feb 16, 2006 7:22 pm

sounds like it has a freighter/tanker type hull which usually only has 1 prop. if ship was real, what is the speed of it?

MechTech · Post by **MechTech** » Fri Feb 17, 2006 5:18 am

Note: no running gear (props, shafts, or rudders!) Now you know why the lack of information

I would give it the same speed as modern warships, 30+ knots.

http://www.macrossworld.com/macross/art/mcr374l.jpg

Thank you everyone. There are two shrouds in the back, so propulsion would have to be in pairs, either two props, or four. Three won't work. I'm thinking four 500 sized motors would be enough power.

ddp · Post by **ddp** » Fri Feb 17, 2006 3:07 pm

the top half of the ship will have to be made of light weight materials or your center of gravity has to be low as she will capsize easily

Guest · Post by **Guest** » Fri Feb 17, 2006 3:45 pm

You got that right ddp! The bottom is being made out of 2 and 3mm styrene (lots of it) and the top will be much thinner. In fact, the lower hull will act like a skeleton so I can thin out the top. Two massive 6volt batteries should help ballast it out too

ddp · Post by **ddp** » Fri Feb 17, 2006 5:11 pm

going by the picture, the water part of the hull is narrower than the top part of the hull so will have a stability problem unless waterline was raised til bottom of overhang of upper hull

MechTech · Post by **MechTech** » Fri Feb 17, 2006 5:34 pm

I understand. I'm just going to build it like an aircraft carrirer (those have massive overhang). The main part of the hull is flat bottomed, so that will help. The overhang will only be an inch on either side, so this shouldn't be a problem. Unlike a battleship, this won't have much detail on it topside so I'm sorta cheating there.