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Author Topic: 1/24th scale Fairmile D help required.  (Read 3826 times)

john44

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1/24th scale Fairmile D help required.
« on: February 25, 2014, 07:05:36 PM »

Hi guys
have any of you wise and wonderful people built or run a 5 ft Fairmile D
I am at present restoring one to its former glory and require help with the
running gear. At the moment she has 4 off 500 size motors fitted powering
38mm 2 blade plastic props,from a 12v lead acid battery.
All the props are the same hand, Should they be on this type of boat or should
the 2 nearest the rudders contra rotate outwards.
I was thinking of fitting 32mm 3 blade brass props.
What do you think?

thanks in anticipation

john
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cdsc123

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Re: 1/24th scale Fairmile D help required.
« Reply #1 on: February 25, 2014, 08:16:03 PM »

Hello John


The real boats had all props turning the same way, the props would have been 3 blade. For the sake of realism that would be the way to go, but it will make the model hard to manoeuvre and it will not perform as well as with the 2 blade props, it will lose some speed.
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john44

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Re: 1/24th scale Fairmile D help required.
« Reply #2 on: February 25, 2014, 08:50:11 PM »

Thank you Christian,
I want the boat for sailing,I was going to use a mixer on the
2 motors nearest the rudders, on the left stick,for general sailing,
 and the 2 outer motors on the right stick for additional speed when required.
I will use the 2 blade props and forget about the 3 blade type.

cheers

john
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cdsc123

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Re: 1/24th scale Fairmile D help required.
« Reply #3 on: February 25, 2014, 09:02:51 PM »

Hi John


Sounds like a plan, try contacting Mudway here on the forum as he has been conducting in-depth tests using different prop/motor/battery combinations using one of my 1/24th scale BPB MGB hulls and he may be able to offer you more advice on the subject. For example one tip courtesy of his testing is to be careful the skegs are not too close to the props otherwise you will get cavitation on the sharper turns with certain props. Also note 3-blade props may improve slow-speed work and reverse operation.
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gra2

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Re: 1/24th scale Fairmile D help required.
« Reply #4 on: February 26, 2014, 08:19:29 AM »

Hi John

My 1/24 scale Fairmile D runs great using four 35/36 mm three blade props.

Gra2
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gra2

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Re: 1/24th scale Fairmile D help required.
« Reply #5 on: February 26, 2014, 08:38:14 AM »

Sorry meant to add photo.
<a href="http://s1358.photobucket.com/user/gra28/media/DSCF1520_zpse2db8825.jpg.html" target="_blank"><img src="http://i1358.photobucket.com/albums/q776/gra28/DSCF1520_zpse2db8825.jpg" border="0" alt=" photo DSCF1520_zpse2db8825.jpg"/>

Gra2



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gra2

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Re: 1/24th scale Fairmile D help required.
« Reply #6 on: February 26, 2014, 08:58:57 AM »

Hi John

Boat in action.
<a href="http://s1358.photobucket.com/user/gra28/media/MTB62306.jpg.html" target="_blank"><img src="http://i1358.photobucket.com/albums/q776/gra28/MTB62306.jpg" border="0" alt=" photo MTB62306.jpg"/>

Gra2






Hi Gra2,

Please use the  IMG reference  rather than the HTML one, as I have done for you above.

Regards

Ken


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john44

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Re: 1/24th scale Fairmile D help required.
« Reply #7 on: February 26, 2014, 11:34:22 AM »

Hi John

My 1/24 scale Fairmile D runs great using four 35/36 mm three blade props.

Gra2
Hi gra2
she looks great on the water. Are the props all the same hand,
& what motors/batteries are you using?

john
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morley bill 1

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Re: 1/24th scale Fairmile D help required.
« Reply #8 on: February 26, 2014, 05:00:44 PM »

Hi Gra 2 it appears to have right and left hand props on the same side of the boat is there a reason for this as ive never seen this before regards Bill....
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derekwarner

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Re: 1/24th scale Fairmile D help required.
« Reply #9 on: February 26, 2014, 09:24:38 PM »

Gra2....might be some turbulent water there....lets see if I have it correct

as shown....for fwd direction

stdb outer = anti clockwise
stdb inner = clockwise
port outer = anticlockwise
port inner = clockwise

should be

stdb outer = anti clockwise
[take the port outer & install in stdb inner] = anti clockwise
stdb inner = anti clockwise
[take the stdb inner & install in port outer = clockwise
port outer = clockwise
port inner = clockwise

I think that should work......... %) please confirm your thoughts.........Derek
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Derek Warner

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gra2

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Re: 1/24th scale Fairmile D help required.
« Reply #10 on: February 27, 2014, 05:12:07 AM »

Ken.
Sorry have not posted photo for some time lost my way again.

John,Bill,Derek.
Have l/h and r/h props motors are two Graupner speed 600 eco and two 545 motors.
I use two 8.4 v nimh 5000 ma batteries one battery for each pair of motors.
Props are set up as Bill and Derek indicated this was how I first trialled boat during build boat ran nice and straight
and I was to lazy to change configuration.

Gra2
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mudway

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Re: 1/24th scale Fairmile D help required.
« Reply #11 on: March 02, 2014, 06:54:15 AM »

Hi John


Sounds like a plan, try contacting Mudway here on the forum as he has been conducting in-depth tests using different prop/motor/battery combinations using one of my 1/24th scale BPB MGB hulls and he may be able to offer you more advice on the subject. For example one tip courtesy of his testing is to be careful the skegs are not too close to the props otherwise you will get cavitation on the sharper turns with certain props. Also note 3-blade props may improve slow-speed work and reverse operation.

A quick bit of history for the tests. 3 of us are building Christianís semi kit for the 71í 9Ē MGB. People I spoke to in the UK recommended the Graupner 600 Eco and a 35mm 2 blade prop.

I bought what I thought was a 600 Eco from a UK model shop which arrived in a plastic bag with a black & white Graupner attached to it rather than the usual Graupner box with instructions etc. I asked the shop what it was, and they never bothered to reply. What I got sent was a Mabuchi RS550 in a Graupner bag. Finally got an original boxed one made by Graupner and tested that.
 
I was surprised by how many amps it pulled but put it in the water. Nice and fast but, with a 2 blade prop, would not stop at all when an idiot yachtie went straight across my bows. Didnít hit him but scared the hell out of both of us. 
After that I went and test tank tried a Raboesch 30 & 35mm 3 blade WW2 style prop. Much better. Nice and fast on 8.4 volts & very fast on 9.6 volts.
Then one of the guys in the club mentioned Glynn Guestís article on crawler motors. I had a read and bit the bullet and bought one. Much better, more rpm and less amps. The Integy one I have been testing is a 12 volt motor compared to 9.6 for the Graupner/Mabuchi.  On the MGB, the 35mm seemed better suited to the hull. 
I did actually try it with 10.8 volts in the water and the boat went like stink. So much so that I wasnít game to try it on 12 volts. Sucked too many amps anyway.
I did also try a 45T and a 65T Crawler by Integy but the 45T just pulled too many amps compared to the 55T and the 65T just didnít give enough rpm in the water.
Two shots attached from yesterday when I got to run her in calm water. As you can see, nowhere near built yet. I never glue a deck down until Iím fully satisfied about how the model performs and turns. On 9.6 it actually maintains its speed in a turn, on 8.4 it slows down.
 
 
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