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Author Topic: Props + Korts.  (Read 2285 times)

freko16

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Props + Korts.
« on: August 13, 2016, 05:24:39 PM »

Hi, I don't know if this has been discussed before but the price of Kort props is nearly twice the price of ordinary props, could you not buy a slightly larger prop and turn down the diameter to the Kort size , It seems to me thats all the difference is. perhaps you in the know will tell me different. Regards freko16.
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Shipmate60

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Re: Props + Korts.
« Reply #1 on: August 13, 2016, 10:12:59 PM »

In a word yes.


BOb
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freko16

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Re: Props + Korts.
« Reply #2 on: August 14, 2016, 03:44:06 PM »

Thanks for reply Bob, have you ever done it?. freko16.
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roycv

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Re: Props + Korts.
« Reply #3 on: August 14, 2016, 04:32:56 PM »

Not sure if this helps but American experience on the Mississippi according to 'Tow Boat Joe', passed away a few years ago, is that the original close fitting props in Kort nozzles were not replaced after damage, mainly by logs in the water.  It was found they were very susceptible to damage but when standard round bladed props were fitted, these chewed up the logs (sometimes) but were not damaged in the same way.
regards Roy
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freko16

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Re: Props + Korts.
« Reply #4 on: August 14, 2016, 07:15:19 PM »

Hi, Roy thanks for the info hopefully I won't be encountering to many logs on the norwich pond. Regards freko16.
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Shipmate60

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Re: Props + Korts.
« Reply #5 on: August 14, 2016, 07:30:24 PM »

No I haven't done it myself but have seen it done.
1 thing to be aware of is the size of the prop boss, the smaller the better.
But as has been stared the tight fitting Kort prop will increase thrust over an open prop the "normal" profile does increase maneuverability.
It also helps if the Kort is of an aerofoil cross section but most don't bother with this.


Bob
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NFMike

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Re: Props + Korts.
« Reply #6 on: August 14, 2016, 07:48:38 PM »

It comes down to how important appearance is to you. If you are happy with "near enough but working well on the water" then just stick a normal prop inside the nozzle. If you want it to look right when on display obviously you need the nozzles and props to look correct to your chosen prototype.

Fastfaz

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Re: Props + Korts.
« Reply #7 on: August 14, 2016, 08:31:18 PM »

    From my limited experience I am not sure if there will be a significant difference (I have experimented with a brass 4 blade Kort prop in a bowthruster which,not only was expensive but a complete failure) I replaced the expensive 4 blader with a cut down 2 blade plastic prop and bingo result both in price and performance. If you are towing try the normal bladed props I can't see it making that much difference in a model but unless you try it who knows?
      Cheers,
            Faz.
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Brian60

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Re: Props + Korts.
« Reply #8 on: August 15, 2016, 09:35:43 AM »

This is a prop taken directly from a working drawing of my latest build.

As you can see it doesn't conform to the shape of a standard Kort prop. The boss in the centre is so large due to them being variable pitch blades.

Nobody does this style blade that I have found so far, which leaves me to attempt to make them - I need five for my thrusters :o %%

Edit: the blade shape that is, not variable pitch. I'm good but I'm not that good, only the Germans it seems have the skills to produce variable pitch props that work O0

freko16

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Re: Props + Korts.
« Reply #9 on: August 15, 2016, 01:20:14 PM »

Hi, Thanks to all that replied to my question, I am going to buy some larger props and turn them down to the right size, can't be to far out to be like Korts. Regards freko16.
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