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Author Topic: What prop do I need ??  (Read 7491 times)

Drkomen86

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Re: What prop do I need ??
« Reply #25 on: October 07, 2010, 05:14:53 PM »

here is a link to the kit Ive seen, I dont mind waiting aslong as it is good kit at a very good price  :-))

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=120629530229&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en
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John Mk2

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Re: What prop do I need ??
« Reply #26 on: October 07, 2010, 05:59:00 PM »

I deal with P.M.B Fast dispatch 2/3 days ok2
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w3bby

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Re: What prop do I need ??
« Reply #27 on: October 08, 2010, 07:24:28 AM »

I would question whether a 4mm flex will cope with the propeller size I suspect you are going to need. As Martin said at that size of boat we (gas boaters) are looking at 65mm and upwards in diameter. But as said no idea when it comes to electric so the props in use might vary enormously. I would seriously try contacting people that are dealing with electric in that size of boat to see what they recommend before buying.

John Mk2

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Re: What prop do I need ??
« Reply #28 on: October 08, 2010, 07:47:43 AM »

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Drkomen86

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Re: What prop do I need ??
« Reply #29 on: October 08, 2010, 08:59:35 AM »

ok, thankyou people
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Drkomen86

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Re: What prop do I need ??
« Reply #30 on: October 10, 2010, 01:48:00 PM »

ok little question, I'm fitting a 3/16 flex-shaft with drive dog.
what I want to know is can you get a 65mm prop in anything but brass, I want a cheap prop so I can swap and change very cheaply.
any ideas?
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w3bby

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Re: What prop do I need ??
« Reply #31 on: October 10, 2010, 02:07:34 PM »

Carbon propellers from MHZ http://www.mhz-powerboats.com/shop/shop.htm in the larger sizes. You can also use a bushing to allow the use of 1/4" drive propellers.

Drkomen86

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Re: What prop do I need ??
« Reply #32 on: October 10, 2010, 07:13:16 PM »

ok so what prop size would you start with?
the boat is 34.5" long and weighs about 7.5lbs with a 3600kv motor running at 11.1v and a 60A ESC.

Any ideas ?
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brodjack

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Re: What prop do I need ??
« Reply #33 on: October 10, 2010, 08:21:19 PM »

42mm,X442. any larger is gunna use a ton of amps in your setup and burn.
http://www.prestwich.ndirect.co.uk/octurapropellers.htm
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Drkomen86

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Re: What prop do I need ??
« Reply #34 on: October 10, 2010, 08:31:33 PM »

ok thanks, atleast its a start position  :-))
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w3bby

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Re: What prop do I need ??
« Reply #35 on: October 10, 2010, 09:10:18 PM »

I'm in total confusion at the moment, I have just fitted a 3600kv brushless motor, a 60A ESC and a 3cell 5000mAh Lipo to my 42" Cat.
ok so what prop size would you start with?
the boat is 34.5" long and weighs about 7.5lbs with a 3600kv motor running at 11.1v and a 60A ESC.

Totally confused!!!!!!!!!!! What size is the boat????

F1 madness

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Re: What prop do I need ??
« Reply #36 on: October 10, 2010, 09:19:43 PM »

That motor and esc will not work in that hull the hull is to big for that set up,i ran the same in a 24" F1 using a 34mm prop and the esc kept shutting down to half power as the motor drawing more amps than the esc can cope with,any bigger prop will simply fry all your electronics
I have a video which shows this if you wish to see it.
also would defo change that hardware for more adjustment and better controlabilty otherwise will be a right pig to get right
Cg on thses hulls should be between 27%-35%.
Also start with small props and work your way up in size checking the temps but you wont be able to run any bigger than a 30mm on that setup and all you will have then is cavitation and the boat wont move.
If i was you i would get a lower Kv motor and bigger esc,swing a bigger prop on more volts,less amps,cooler running and longer run times and reliabilty
Hope you take note otherwise you ll be throwing your money away
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Drkomen86

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Re: What prop do I need ??
« Reply #37 on: October 10, 2010, 09:57:03 PM »

its a 34.5" hull, memory is rubish sorry.

I bought the motor and ESC for a smaller boat and when I put it on this it did as you said and shut down quite quickly, I guessed it was draining the battery having never use this type of system before {:-{
what hardware would you use?
I think I will keep the motor but buy an ESC with about 125A, what do you think?

Chris

PS thanks pal your a life/ESC saver  :-))
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F1 madness

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Re: What prop do I need ??
« Reply #38 on: October 10, 2010, 10:03:05 PM »

its a 34.5" hull, memory is rubish sorry.

I bought the motor and ESC for a smaller boat and when I put it on this it did as you said and shut down quite quickly, I guessed it was draining the battery having never use this type of system before {:-{
what hardware would you use?
I think I will keep the motor but buy an ESC with about 125A, what do you think?

Chris

PS thanks pal your a life/ESC saver  :-))

Defo need a bigger esc as for hardware i would get 1 of these and youll be set,but you will still only be able to run a smaller prop or it will just burn the motor out i would say 36mm max but this would also let the motor rev due to the high Kv.

Hardware:
http://www.astecmodels.co.uk/catalog/product_info.php?cPath=1_79&products_id=748
hope this helps
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Drkomen86

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Re: What prop do I need ??
« Reply #39 on: October 10, 2010, 10:09:51 PM »

Cool, what would I need to get the highest speed possible out of the hull ?
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F1 madness

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Re: What prop do I need ??
« Reply #40 on: October 10, 2010, 10:20:19 PM »

Cool, what would I need to get the highest speed possible out of the hull ?

you need to run lower kv and more volts to spin a bigger prop.
What hull is it and have you got more pics of the hull,then i would be able to be a little more specific
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Drkomen86

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Re: What prop do I need ??
« Reply #41 on: October 10, 2010, 10:34:03 PM »

The same design as this just 34.5" not 42" http://www.prestwich.ndirect.co.uk/Mercury.htm

And I have just noticed that the motor says      Kv
                                                                 3600Rpm/V

does that help?
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w3bby

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Re: What prop do I need ??
« Reply #42 on: October 11, 2010, 08:28:08 AM »

Maybe a trip here http://www.rumrunnerracing.com/feforums/ would be of further help. Just electrics..... Here's a 36" mono for instance http://www.rumrunnerracing.com/feforums/showthread.php?t=30766

F1 madness

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Re: What prop do I need ??
« Reply #43 on: October 11, 2010, 09:08:28 AM »

The same design as this just 34.5" not 42" http://www.prestwich.ndirect.co.uk/Mercury.htm

And I have just noticed that the motor says      Kv
                                                                 3600Rpm/V

does that help?

The kv rating is is 3600 pre volt you put through it,for instance:
3600 x 7.4 volts = 26640 rpms unloaded or
3600 x 11.1 volts = 39960 rpms unloaded
The motor is 2845 so is a small motor,to small for what you want really.
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F1 madness

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Re: What prop do I need ??
« Reply #44 on: October 11, 2010, 09:18:48 AM »

Cool, what would I need to get the highest speed possible out of the hull ?

Right i would use  (option 1) Leopard 4074 2200kv 0r 2000kv on a 150 amp esc or bigger spinning a 42mm prop on 4s 14.8 volts.
(option 2) leopard 4074 1500kv on same esc as above on 6s 22.2 volts on 45mm prop maybe bigger depending on temps of motor and esc.
(Option 3) scorpion 3026 1600 or 1400 on 6s 150 esc,on 6s 22.2 volts and 45mm or 47mm prop.
I have run the scorpion setup in a 37" mono and must say i had longer run times and cooler running and is reliable punchy and quite fast.
Iv just ordered the leopard motors iv not run them yet but know some1 who is and said the motor for the money,ill let you know how i get on with them
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