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Old Oct 26, 2012, 05:05 PM
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Ireland, Leitrim
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Hi fellas, and ladies if present.

I hate jumping in the middle of threads like this, but I gotta start somewhere. I've read through a lot of this info and info on RCU.

Here's the scoop. I want one of these, I've seen so many vids and they really do seem like a good bit of fun. I have a servo, radio gear and lipos. But even after all the reading, I'm not settled on a power train. So I'm hoping for some advice.

I have 3s lipos(1300-2200mah) that I use in my planes, so I thought I might as well utilize them. I was thinking a motor around 2800-2900kv as I'd like a bit of speed and that seems about what folks were recommending on a 3s.

So can I ask on what actual motor and esc you would recommend with the above in mind. I don't want to run the bare minimum and I'll go a bit overkill etc if it possibly means a bit more reliable(ie. 45A esc rather than 30A), same with motors. I don't mind hooking up water cooling, I actually think it's pretty cool how it works. I'm just outta my element so looking for a helping hand from those with the experience.

Many thanks,
Jon
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Old Oct 26, 2012, 05:33 PM
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Australia, NSW, Sydney
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Thanks guys, I'll throw a Nanotech in and see if that helps. I did read the stuff about the higher kv motors, but unfortunately, after I had placed my order with Hobby King!
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Old Oct 26, 2012, 07:01 PM
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Quote:
Originally Posted by Tiernan85 View Post
Hi fellas, and ladies if present.

I hate jumping in the middle of threads like this, but I gotta start somewhere. I've read through a lot of this info and info on RCU.

Here's the scoop. I want one of these, I've seen so many vids and they really do seem like a good bit of fun. I have a servo, radio gear and lipos. But even after all the reading, I'm not settled on a power train. So I'm hoping for some advice.

I have 3s lipos(1300-2200mah) that I use in my planes, so I thought I might as well utilize them. I was thinking a motor around 2800-2900kv as I'd like a bit of speed and that seems about what folks were recommending on a 3s.

So can I ask on what actual motor and esc you would recommend with the above in mind. I don't want to run the bare minimum and I'll go a bit overkill etc if it possibly means a bit more reliable(ie. 45A esc rather than 30A), same with motors. I don't mind hooking up water cooling, I actually think it's pretty cool how it works. I'm just outta my element so looking for a helping hand from those with the experience.

Many thanks,
Jon
Go back to page 37 and read posts 547-552; a few of us neatly summarized pretty much exactly what you are looking for, with some links to products. 2800-3000kV seems to be the sweet spot for 3S, and I would recommend you use your 2200mah packs. They will give you 15-20min of runtime bashing around in a creek.

The water cooling can be done with either a cooling sleeve sized for your motor, or a piece of aluminum tubing wrapped around your motor several times, which is what I did. The Turnigy SeaKing 35A ESC is waterproof and comes with a water cooling block installed so you don't have to modify it at all. I think the hardest part of the system is drilling a hole in your jet nozzle to install the cooling inlet pipe.
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Old Oct 27, 2012, 05:34 AM
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Ireland, Leitrim
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Thank you Firehawk,

I did read those posts and I suppose I was just looking to see if that's a general consensus etc. But I'm happy enough to go that route than. There's links to ebay for a motor, I'll have to see if they will ship to Ireland as they don't in their add. And all the motors on hobbyking are sold out around that kv range.

Appreciate the assistance,
Jon
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Old Oct 27, 2012, 05:48 AM
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Australia, NSW, Sydney
Joined Oct 2012
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This is my Tear with 3S 25C 1300 battery, what do you guys think, can it go faster?
NQD Tear Modified 35a ESC 1300 Nanotech Battery & 4800kv Motor (1 min 34 sec)
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Old Oct 27, 2012, 09:58 AM
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Ayrshire, Scotland
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Originally Posted by Tiernan85 View Post
Thank you Firehawk,

I did read those posts and I suppose I was just looking to see if that's a general consensus etc. But I'm happy enough to go that route than. There's links to ebay for a motor, I'll have to see if they will ship to Ireland as they don't in their add. And all the motors on hobbyking are sold out around that kv range.

Appreciate the assistance,
Jon
Try Giantshark (used to be Giantcod before it was taken over earlier this year). Stock and service not what it was in 'Cod' days (when it was a prime source of electroflight goodies for GB hobbyists wanting to avoid sourcing stuff overseas), but prices are still reasonable and being based in England, delivery is very fast. Still have some good stuff including useful 2040 motors. Would advise the Keda or Black Magic 2900Kv motors if you go for a 3s setup. You will struggle to find a cheaper source of motive power.
http://www.giantshark.co.uk/20mm-inr...t=2a&showAll=1
they don't do watercooling but there are plenty of sources for suitable 20mm metal or silicone jackets on ebay or through model boat shops. Or do as Firehawk suggests and 'roll your own' from ali tubing.

Regards, Iain
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Old Oct 27, 2012, 12:11 PM
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United States, IL, Chicago
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Letter back from the factory..

Cost if you buy em in 5 case lots is about 15 bucks a boat..

1:10 RC Boat
Packing:W/B

Products size:5cm Advanced Aero Boat 21" Long
The Lightning Ready to Run Out of the box can handle rough water with its powerful water blowing built in fan. High Performance boat feature a single large torsion propeller, make turns by high torque servo and comes with a 700mah Ni-Cc rechargeable battery pack with charger unit.
The Lightning RC Speed Boat is Powered by 390 Type Racing Motor which can produce tremendous racing power. Brightly colored trim scheme makes this offshore rc boat look as good as it goes! High performance design and state of the art running gear makes this boat fast and cool at the same time.

Specification:
Boat Size: 21.2"
Single Professional style Ducted propellers
Super high speed motor, capable of pushing this boat to 27 knots (31 mph)
Radio Controller with 3 functions providing forward, port and starboard control
Large high capacity battery

Included in the box:
Ni-Cc 9.6v 700mah rechargeable battery pack with charger unit.
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Old Oct 27, 2012, 04:28 PM
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Canada, ON, Whitby
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Originally Posted by nckmat View Post
This is my Tear with 3S 25C 1300 battery, what do you guys think, can it go faster?
Here's mine with a 3200kv motor and 3s2200mah pack:

Tear into - lunch fun! (2 min 28 sec)


I think you're running too much voltage for your motor, or you have something else wrong in the setup.
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Old Oct 27, 2012, 04:32 PM
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Ireland, Leitrim
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Originally Posted by madbugger View Post
Try Giantshark (used to be Giantcod before it was taken over earlier this year). Stock and service not what it was in 'Cod' days (when it was a prime source of electroflight goodies for GB hobbyists wanting to avoid sourcing stuff overseas), but prices are still reasonable and being based in England, delivery is very fast. Still have some good stuff including useful 2040 motors. Would advise the Keda or Black Magic 2900Kv motors if you go for a 3s setup. You will struggle to find a cheaper source of motive power.
http://www.giantshark.co.uk/20mm-inr...t=2a&showAll=1
they don't do watercooling but there are plenty of sources for suitable 20mm metal or silicone jackets on ebay or through model boat shops. Or do as Firehawk suggests and 'roll your own' from ali tubing.

Regards, Iain
That's perfect, ordering one from there! Thanks!
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Old Oct 27, 2012, 05:01 PM
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Originally Posted by nckmat View Post
This is my Tear with 3S 25C 1300 battery, what do you guys think, can it go faster? http://youtu.be/EwXENDeGGks
For speed, i can only think of to much rpm like wparsons noticed before me.. i thought you where running 2S lipo.
can't you trim your trottle channel?
I did that with my 4300kv on 3s.. mine did not even move on wot without limiting the trottle, only making bubbles.

For cavitation, maybe you can move the prop a bit further to the back if you have some space left, in my case that solved the problem. As close to the stator as possible.

btw, this is mine before i mounted the prop a bit back, now its a bit better..
NQD Tear Into on Curacao beach ( short version ) (0 min 24 sec)
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Old Oct 27, 2012, 05:50 PM
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To end my little jet build, today I finished tuning the boat, worked out better than I expected, it turns much harder than I thought I could make it do, its so little, it cavitates so easily..

Using unequal trim tab length fixed it, as I said, its gonna be used primarily as a sprint boat, not just a rock climber..

The vid will make you sick, but, its ABOUT the turning...and the keychain cam, vibration and all, puts me IN the boat, cant really judge what its doing from the shore...

PICT0002 WMV V9 (3 min 0 sec)
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Old Oct 28, 2012, 07:37 AM
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Ayrshire, Scotland
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Originally Posted by Tiernan85 View Post
That's perfect, ordering one from there! Thanks!
Just 'happy to be part of the industry of human happiness', as they say
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Old Oct 28, 2012, 07:56 AM
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Ayrshire, Scotland
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Originally Posted by nckmat View Post
This is my Tear with 3S 25C 1300 battery, what do you guys think, can it go faster?
wparsons' video shows how it should perform - hence my earlier comment about only being able to use 1/2 throttle most of the time in rocky streams, if it was going like that on WOT.

Assuming there is not a mechanical fault (for example a loose coupler, a shaft which is binding in the bushes, or not having greased the shaft) then I would suspect the problem, as I said before, is too high a motor kv. Read RimRC's latest comment about how his cavitated and just blew bubbles, until he limited throttle movement.
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Old Oct 28, 2012, 12:19 PM
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4800kv? did you listen to it? no rpm..thing should SCREAM..it aint cavitating, it aint REVVING..

nqd rc jet boat. sickly powerful. brushless 14.8v PART 2 (0 min 37 sec)
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Old Oct 28, 2012, 01:33 PM
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Originally Posted by chidago View Post
4800kv? did you listen to it? no rpm..thing should SCREAM..it aint cavitating, it aint REVVING..

http://www.youtube.com/watch?v=JcmYoqS-H1c
Ok, did you listen to it?.. it revs too much when it cavitates and the drive is without water.


@nckmat:
Could be a slipping shaft, i had that too trying out the shaft without flat spots and without water sounded ok, but in the water the shaft skips. Or something like that.
Like, is the end of the shaft really inside the bushing of the stator?
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