Seppo43

Hi,

As the title says. I've built my first boat and am searching for information on the elctrics to use. Since I'm totally new to rc stuff I could use some help with the electrics.
Sofar know I need a motor, an esc, servo, reciever / transmitter and a battery.

I've been looking for parts on hobbyking and have found things like these:

HobbyKing 30A Boat ESC 3A UBEC
http://hobbyking.com/hobbyking/store/__24567__HobbyKing_30A_Boat_ESC_3A_UBEC.html
Fits the motors needs??

XK2845-B-2000kv Brushless Inrunner
http://hobbyking.com/hobbyking/store/__17725__XK2845_B_2000kv_Brushless_Inrunner.html
Don't really need speed, maybe 15km/h(9,3mph) max.

Turnigy XGD-11HMB Digital Mini Servo 3.0kg / 11g / 0.12
http://hobbyking.com/hobbyking/store/__25455__Turnigy_XGD_11HMB_Digital_Mini_Servo_3_0k g_11g_0_12.html
To move the rudder.


Hobby King 2.4Ghz 4Ch Tx & Rx V2 (Mode 2)
http://hobbyking.com/hobbyking/store...2_Mode_2_.html
Just a basic radio with forward/reverse and left right steering.


Are these items compatible with eachoter? What voltage should the system use + LiPo > NiMH? Also, is water cooling for the esc and motor a must, every boat esc seems to be water cooled on hobbyking.
I'm not aiming for fast speeds. Maybe 15km/h(9,3mph).
Are there better sites that you'd recommend me to take a look? Haven't ordered anything yet, the parts listed above are just for example.

Length: 60cm / 23,6inch
Width: 17cm / 6,7inch
max size for prop: 3,5cm / 1,4 inch
weight: maybe 200g / 7oz. It's made out of lightweight plywood
Here are some pics of the boat.



More pictures in this imgur folder.
http://imgur.com/a/rpCTg

Thanks in advance
Sepi

canabus

Hi Seppo43
The Xk2845B-2000kv is low powered (280watts) a 2858-2650kv(700watts) with 60A car ESC would be better.
I do not water-cool my motors but Hobbyking had water cool motor mounts.
Why the 60A car ESC(with programming card) because it's small, no plumbing and with a cooling fan for all speeds.
Handles 2-4S batteries for the motor.
Battery 3 or 4 S 2650mah( too bigger battery to much weight).
Prop 32mm x 1.4 pitch 2 blade(from the Sprint F3 outboard).
What's the plans for the drive line solid or flex drive??

Seppo43

Thanks a lot for you answer canabus!
So using a bigger motor with lower speeds would cause less heating right? A "car" esc can be turned into a "boat" esc with a programming card? http://www.hobbyking.com/hobbyking/s...w_Reverse.html. You meant this esc right? Also, which programming card should I use?

Both flex and solid drive would fit the boat. I'd rather go with flex drive cuz it'd fit the hull better.
edit. fixed the link for pictures: http://imgur.com/a/rpCTg

canabus

Hi Seppo43
The bigger motor will be less heat at low speed and the 2000kv would be OK for a kids boat.
Also on the first run you would be looking for a better motor.
The program card is ID HKProg-card.
Setup:- 1. 9.9volts for 3S and 12.8 volts for 4S.
2. Start power 10%(good slow speed start also helps in reverse speed).
3. Advance Timing 4(less kick at slow speed and max. at the top end(.
4. Run mode 2 (less braking).
5. Brake force 1.
6. Drag 1.
7. Neutral 2.
8. Initial brake 1.
9. Reverse force 1 (25%) controllable slow speed reverse( handy for de-weeding props).
I like the car ESC's for the on/off switch to power up the receiver and size.
ALWAYS TURN ON THE TRANSMITTER FIRST AND NEXT THE RECEIVER.
ALSO TURN OFF THE RECEIVER FIRST AND NEXT THE TRANSMITTER.
ESC's get a little mixed up and do not work until they are reset(you have to reprogram the ESC again and it goes to default).
Drive line have a look at Hobbyking ID BP22-S PROP and BP-22 Sleeve( drive line kit from motor mount to 3 blade 30mm x 1.4 pitch prop).
I have installed one in my Sea Hornet 25 and half inch boat(see Model Boat Forum Sea Hornet 2015 Album).
Boat balance point start with a third of the boat length from the stern.
The battery is the biggest weight so allow room to move it forward and back as far as possible.
As for a radio the Turnigy TGY-I6 is a better radio(supports up to 20 models) program each model to you requirements(reversing servo direction) and on my throttle channel I have changed the servo curve for better low speed on one of my other boats.
I have a cheap radio from Hobbyking and to reprogram you require a computer with XP(it's a pain in the rear).

mfr02

If you intend to use a flex drive, you won't want reverse. Flex shafts tend to unwind in reverse.
On the other hand, with a more general purpose rather than pure speed boat, reverse is desirable. It helps get out of situations, and it is also your brakes. On water, 15KpH is quite fast, especially when approaching something unexpected, like a concrete bank or a rock or another boat.

Seppo43

Thanks again both of you guys for your responses!

@canabus
Thanks for the specific tips. Pretty much collected all the items you recommended. Could you double check the list if they're the right ones and are compatible and all I need. I'm ordering the rudder from another website, couldnt find a good one at hk.
Can I adjust the voltage input to the motor from the transmitter or the esc to control the speed of the boat?

http://hobbyking.com/hobbyking/store...r_2630kv_.html
http://hobbyking.com/hobbyking/store...w_Reverse.html
http://hobbyking.com/hobbyking/store...r_Car_ESC.html
http://hobbyking.com/hobbyking/store...r_Mode_2_.html
http://hobbyking.com/hobbyking/store...eve_255mm.html
http://hobbyking.com/hobbyking/store..._Prop_Set.html
http://hobbyking.com/hobbyking/store...12sec_19g.html
http://hobbyking.com/hobbyking/store...Lipo_Pack.html
http://hobbyking.com/hobbyking/store...t_Charger.html

@mfr02 what you said about the flex shaft made me think. Got enough room for a solid one, going with that one instead of the flex one. Te prop will have a slight angle down but that shouldnt be a problem right. http://i.imgur.com/qsMn9XI.jpg

mfr02

Electronic Speed Control, ESC. The job of the ESC is to take the signal originated by the throttle stick on the transmitter and control the speed (and direction) of the motor.

Seppo43

I mean, arent all escs programmed to set the speed of the motor linear from 0 to 100% when moving your throttle stick. I dont want the motor to use all of its power aka go fastest. Can I program the esc with the programming card to only use like 50% of the max speed with my battery setup? I don't want to cause too much heat on the motor nor do I want the full speed.

crispyspa

Exercise self control with the throttle finger. If you only want 50%, only pull the trigger halfway. Keeping the 100% is not a bad thing. Say you are out on the water and a jet ski comes by. You may need that full throttle to get out of the way quickly...or to jump the wake. Go big or go home LOL

To answer your question though, the only ESC's that I know of that will do what you ask is Castle and Traxxas car esc. Probably others too, but those are the only ones that i KNOW of.

canabus

Hi Seppo43
Looks like a good setup, but, you will require a XT-60 connector for the battery to ESC.

As for mounting to\he motor, mount it the full length of drive shaft and low in the boat.
This will get the drive angle low.
You may require some spare drive line bearings(always handy).
Regrease after each run day.