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Author Topic: Loyal Class - Prop Choice  (Read 2525 times)

turner

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Loyal Class - Prop Choice
« on: August 10, 2014, 12:49:27 PM »

Hi

I've not been on here for a very long time, my last post showed progress with my 1:25 Burutu - still got that and making very slow progress will post some updates soon.

While I've been away I bought an immaculate Loyal Mediator (approx. 1.00m long) It has a home made "scale" 3 blade prop measuring 50mm dia on an M5 shaft

It performs ok ahead but hardly anything astern  - I have read that fitting a coarse two blade prop will improve this (done this on my Waveney lifeboat)  but was wondering what the current thinking is - would one of the 5 blade Rivabo Brass 5 Bladed Propeller LH (A-Type Blades) offer any improvement ?  I guess there will be others on the market also.

regards

David
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Shipmate60

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Re: Loyal Class - Prop Choice
« Reply #1 on: August 10, 2014, 02:00:18 PM »

Any decent scale prop will be good on her.
I have had one of these and used the geared motor and a scale 3 blade prop, handled fine.
One thing to remember if ballasted deep and slightly bow high she will handle almost any sea but she is still a heavy model so will not stop in half her length.


Bob
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hmsantrim

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Re: Loyal Class - Prop Choice
« Reply #2 on: August 10, 2014, 07:14:58 PM »

Hi David.
 I have a plastic three bladed prop on a model forward is ok but very poor going astern.  In your case having a metal prop I recon the blades just needs a little tweak with the pliers to slightly increase the pitch.   This is old skool engineering O0
 
Frank   
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mudway

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Re: Loyal Class - Prop Choice
« Reply #3 on: August 11, 2014, 01:58:02 AM »

They carried a 3 blade prop.
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turner

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Re: Loyal Class - Prop Choice
« Reply #4 on: August 11, 2014, 10:35:12 AM »

Thank you Gents
 
Like the sound of old school - its cheap !  :-))
 
I am not looking to enter this into any scale comps - (principally as I didnt make it)  just want to sail it.
 
I would imagine that an owner of a full size vessel  might consider a prop upgrade to a four / five blade item if it gives them an increase in performance or manouverability or economy accepting of course any limitations due to engine size / speed
 
regards
 
David
 
 
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Shipmate60

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Re: Loyal Class - Prop Choice
« Reply #5 on: August 11, 2014, 12:51:21 PM »

Check to see if the blades are concave ahead.
If so just flatten them with a pair of pliers.


Bob
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dodes

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Re: Loyal Class - Prop Choice
« Reply #6 on: August 11, 2014, 04:35:21 PM »

Remember on a full scale vessel, it is estimated on average that the astern power is 65% of the ahead power, this is due to hull resistance and a prop is designed to give max efficiency ahead not astern.
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merseyferry

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Re: Loyal Class - Prop Choice
« Reply #7 on: August 11, 2014, 11:31:36 PM »

hiya dave  my loyal class is slighly smaller then yours but she has a 3 blade prop  handles quite well regards pad ]www.youtube.com/watch?v=4TzMFInD5C8&index=1&list=WL
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turner

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Re: Loyal Class - Prop Choice
« Reply #8 on: August 12, 2014, 07:42:17 AM »

Thanks gents
 
I appreciate that a boat is not going to go astern as well as it goes ahead - I would guess with the current prop I get about 10% performance astern.
 
Looked carefully at the prop last night - one blade is slightly larger than the others and all three are only slightly dished.
 
Took the plunge and ordered a couple to have a play with - will start filling the bath tonite !
 
David
 
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mudway

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Re: Loyal Class - Prop Choice
« Reply #9 on: August 12, 2014, 09:41:23 AM »

Just a thought, what speeed controller are you using? The "blue" ones are noted for giving a lot less power astern than ahead.
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turner

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Re: Loyal Class - Prop Choice
« Reply #10 on: August 13, 2014, 07:20:33 AM »

Had another look inside last night - the units are "Action Electronics"
 
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turner

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Re: Loyal Class - Prop Choice
« Reply #11 on: August 18, 2014, 02:41:09 PM »

New props arrived - went for fitting the three blade first.
 
Sunday morning in the water (millhouses) significantly better performance in reverse
 
Thanks all
 
David
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