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Old Mar 21, 2012, 04:30 PM
roooostinnn
angrycat's Avatar
United States, NY, Glens Falls
Joined Mar 2012
57 Posts
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new here and have some projects

hello everyone, the name is neil and ive been into rc cars for a long time now and just recently started getting into some boat projects and what do ya know im hooked.
my first builds are going to be some boats that i recently bought off a family member who hadnt used them in over 15 years. the first one and my main project is an old graupner systems with the orrigonal 606 twin hydrospeed. the hull is in amazing shape and has a very nice paint scheme. i would like to switch this boat over to brushless but as more of a reliable/ affordable set up. i want it to be quick but i dont want to dump all of my money into one project.

my next project is an old MRP fast-cat twin motor which is also in amazing condition and had the optional spin fins and trim tabs from MRP. this boat i plan to keep twin because of the dual drive shaft set up unlike the dual into single like the graupner. this was his old race boat, it had twin octura x430, one reversed and one normal, i am considering keeping it brushed due to how expensive and pain staking it can be with dual brushless set-ups.

and lastly i plan on buying the 32.3" EP Fibreglass RC Godspeed-U Catamaran from r-hobbies, this is to be my summer project and the one i hope to hit around 50-60 mph easy. just wondering what other peoples views on this hull were and what they would suggest, i have looked at all of the other eletric cats this size and am still considering mrs geico as an option but if i plan to build a boat the way i want to it might as well start with a decent priced hull with the driveline already taken care of.

my goal is to have the graupner and the fast cat back in action by this summer (paychecks permitting) allthogh i will most likely be building the fast cat for my cousin while he is away at college for a few more weeks and left me in charge of getting all of the parts. hope i didnt scare anyone away by typing this essay but just figured id say hi and let everyone give me feedback on these projects since i will need alot of help finding the right motor/esc/batt set up.

neil
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Last edited by angrycat; Mar 22, 2012 at 06:39 PM.
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Old Mar 22, 2012, 06:30 PM
roooostinnn
angrycat's Avatar
United States, NY, Glens Falls
Joined Mar 2012
57 Posts
so here is the graupner. i have no ideah what size or make this prop is, i measured it from prop tip to tip and it was 5cm or 50mm, still dont know the pitch or make tho. i removed everything from the hull to sand and seal the wood to prevent mold/rot, and also swapping out all of the components and running water lines. any suggestions for this hull? im open to all opinions and ideas. id love to restore this boat and its german roots paint scheme. and remember this hull was set up to run the graupner 606 twin hydrodrive.

ps ill be posting up pics of the fast cat soon also to see what direction you guys think i should take as far as brushed/brushless set-ups
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Old Mar 22, 2012, 07:01 PM
I feel the need for speed!
scorpion1's Avatar
Southern U.S.
Joined Jun 2008
7,086 Posts
Good looking Graupner!! The length would help..................

I'll throw these out without knowing:

20-26" 3650 or 2860 motor, 2500-2900kv on 3s Lipo

27"-34" 3660-3674 1800-2200kv on 4s Lipo.
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Old Mar 22, 2012, 07:09 PM
roooostinnn
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United States, NY, Glens Falls
Joined Mar 2012
57 Posts
its a 32 from bow to prop, and 30 from bow to stern
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Old Mar 22, 2012, 07:17 PM
I feel the need for speed!
scorpion1's Avatar
Southern U.S.
Joined Jun 2008
7,086 Posts
I'd try something like this on 4s for a "bargain" type setup:

http://www.hobbyking.com/hobbyking/s..._Inrunner.html

http://www.hobbyking.com/hobbyking/s..._w_5A_BEC.html

and two of these in series:

http://www.hobbyking.com/hobbyking/s..._2S1P_40C.html
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Old Mar 22, 2012, 07:42 PM
roooostinnn
angrycat's Avatar
United States, NY, Glens Falls
Joined Mar 2012
57 Posts
awesome! ive been trying to figure out the whole prop thing tho, like i said i have no idea what brand/pitch it is and what motor to choose for it. this been my main problem with choosing a set up for this boat, its a nice prop and it looks like its been balanced/sharpned/polished and like i said when i measured from prop tip to tip and it was 4.9- 5 cm and i didnt know how i should choose a motor and esc set up to match it.

also i wouldnt mind putting a quality motor/esc in it, im not looking to race it but i do want it to be quick enough to be in the 30-40 mph range if at all possible and i want it to be my reliable "honda" boat that i can build and just run it
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Old Mar 22, 2012, 07:55 PM
I feel the need for speed!
scorpion1's Avatar
Southern U.S.
Joined Jun 2008
7,086 Posts
You can trim the prop down, it too large and most likely has too much pitch. A graupner prop you can consider is an x440
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Old Mar 22, 2012, 08:08 PM
roooostinnn
angrycat's Avatar
United States, NY, Glens Falls
Joined Mar 2012
57 Posts
well was it oversized for the twin set up? more torque and less rpms from the motors and same speed? should i just go with a lower kv motor? id kinda like to keep it the way it is if at all possible, im not trying to be stubborn about it just trying to keep it the way it is and trying to understand the whole prop thing because it seems to be a big mystery to most people including myself. please be patient as i am slightly brain dead and tend to ask alot of questions
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Old Mar 22, 2012, 09:44 PM
I feel the need for speed!
scorpion1's Avatar
Southern U.S.
Joined Jun 2008
7,086 Posts
You can use a 3660+ motor in the 12-1400kv range on 4s i guess..............

http://www.hobbyking.com/hobbyking/s..._Inrunner.html
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Old Mar 23, 2012, 12:11 AM
roooostinnn
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United States, NY, Glens Falls
Joined Mar 2012
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hell yeah thats what i was thinking lol, i wanted to run a few different brands of batterys to see which ones last and which ones suck. but im mainly in the 4s 2p or 6s 2p and 5-5500 mah with bullet connectors and put a nice water cooling jacket and water cooled stand. now would i have to go with a 200+ amp esc for that or could i just run 4s 2p and stick with a 180amp for now, like i said not lookin to break any records here haha
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Old Mar 23, 2012, 12:58 AM
roooostinnn
angrycat's Avatar
United States, NY, Glens Falls
Joined Mar 2012
57 Posts
and im also strongly considering that r2 hobbies godspeed catt hull, its an a-rtr so i could just switch the motor and esc over as a temporary set up, id like to be able to swap parts if i ever have to while im out running stuff ya know? lol but thank you for those options

this motor dosnt seem too bad and i could still stick with a 180 esc comfortably i believe, ohh and a 36mm can is basically the same size as a 540 outside diameter wise right?
http://www.hobbyking.com/hobbyking/s..._Inrunner.html

or
http://www.nitrorcx.com/96m811-3674--1300kv.html
i am liking the tacon at the moment but im not sure if its better over the 1400 turnigy, id probly switch to ceramic boca bearings down the road either way.
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Old Jun 06, 2012, 09:21 PM
roooostinnn
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United States, NY, Glens Falls
Joined Mar 2012
57 Posts
soo i hate to bring up an old subject guys but ive been buisy with work/school lately. i am in the process of building the fast cat and have ordered a traxxas twin 12t set up with that as more of a budget build. now back to the graupner........ i still have not decided on a motor and battery set up and i would really like to get it going soon. i am thinking something 4s2p and something i can crank to 6s if i ever wanted to down the road, i herd turnigy put out a line of aqua star water cooled motors? and i am still considering the tacon if anyone knows where to get the genuine ones and not the cheap knock off versions.

neil
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Old Jun 07, 2012, 06:05 AM
Thermite + ice = Big boom.
boaterguy's Avatar
Canada, ON, Ottawa
Joined Apr 2009
2,257 Posts
You';ll have to change the prop to get a reliable setup, 50mm is too big especially because it looks like it has lots of pitch. That's because brushed motors spin slower so they put on a bigger prop to compensate.
This on 6S:
http://www.hobbyking.com/hobbyking/s...er_1600KV.html
with a 40mm prop shouldn't draw too many amps, you would be fine with the 180 ESC
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Old Jun 07, 2012, 07:23 AM
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wparsons's Avatar
Canada, ON, Markham
Joined Aug 2008
8,791 Posts
Quote:
Originally Posted by boaterguy View Post
That's because brushed motors spin slower so they put on a bigger prop to compensate.
There are lots of brushed motors that spin faster than most brushless motors... a more accurate statement would've been that the high turn stock motors through a gearbox are the reason for the big prop.

The big benefit to brushless motors is that they are more efficient so they produce less heat making the same amount of power.
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Old Jun 16, 2012, 10:14 PM
roooostinnn
angrycat's Avatar
United States, NY, Glens Falls
Joined Mar 2012
57 Posts
well what would be a good prop/motor set up? i am trying to get things moving soon so any input helps
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