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[Dan-109]

I have built this boat from plans I got from building-model-boats.com for my son (my first attempt). I have used a motor from a 14.4volt cordless drill, It has no markings to tell me any stats on it, the speed controller is the trigger attached to a servo. the battery packs are 2 X C cell 9500mhA 6volt packs in series. the prop is D40 x P1.2 whatever that means. A 2.4Ghz radio FS-GT3B from E bay. It weighs, hull and electrics 1650grams plus battery packs 700grams.
I would like to know is there anything I can do to improve its performance before I continue with guns and tubes etc?

 I am looking to put this brushless motor and esc, will it push my boat? http://www.ebay.com.au/itm/Water-Cool-motor-BL2856-2300KV-150A-ESC-Brushless-Boat-/220826952204?pt=UK_ToysGames_RadioControlled_JN&hash=item336a4fe20c

All opinions welcome (be gental) 

[MikeA]

awesome use of drill!! ok as far as speed goes that motor should be more than sufficient to get your boat on a plane. i dont think you need to bother with a brushless. do you know what size the motor is? if you measure the lenght of the can you get the size for instance. 50mm = 500 motor, 60mm = 600 motor simples. 50mm motors are actually called 540's but you get the idea. see juding by the motor size from the pick youl get overheating problems with that prop.

with servos, if you you lose signal the servos in the boat do not reset to centre. that means that if your cruising round the lake and you accidently lose signal or drop the transmitter and the batteries fall out the throttle will stay wide open and boat will keep going while your franticly trying to put the batteries back in the regain control !! i have the fs gt2 and it uses the same receiver as the gt3. in the back of your gt3 manual there should be an instruction for fail safe funtion. youl need to do that to avoid catastrophe!

[MikeA]

by the way those bty rechargeables are so **** it goes beyond human comprehension. ive had 5 packs of those 2 of those were replacements cos i complained they didnt work and even they didnt work. they state there about 3000mah or someting yet there close to 300!! all the ones i had couldnt run an led light bulb for a minute. when it comes to batteries escpecially transmitter and receiver batteries get quality. youl see what i mean 

[Dan-109]

Mike the can is not quite 60mm so i guess its a 600. Is the prop to small? should i get a 3 blade?
I have set the fail safe, with experiance from RC nitro buggy where i had to chase it to regain control  . so when I started this boat i took into consideration my swimming (dog paddle  ) is not that good, fail safe was what i made sure the radio had built in. I have made the battery packs up myself they seem ok but I will take your advice when these give up and get name brand batteries.   

[MikeA]

What i was reffering to was the BTY 4AA batteries to power your receiver, they will let you down.

 so from what i gather you have used 2 seperate packs to give you 12v total at 9500mah? did the 9500's come out of the drill or did you buy them seperately?

secondly if that motor is a 600 then that prop is too BIG!!  if you run that prop your boat will smoke and your trigger speed controller will be molten plastic. You need a 30mm minimum or a 34mm diameter at the most to be safe. general rule of thumb when using a direct drive like you have is to have the diameter of the prop roughly the diamter of the motor. a larger prop could possibly be used but will need to be a slower rpm.

[Dan-109]

Yes 2 X 5 C cell packs gives my 12 volts, I have purchased the cells separately and soldered them together in packs, see pic second from the bottom, one pack on top and the other tucked under deck. The C cell batteries have 9500 mah printed on them so I gather it has 9500mah or is this wrong.

The motor is a 555  http://marksmodelbits.com/

It planes well, just digs in when it turns so i have to adjust the linkage on the rudder horn.

Do you think water cooling is necessary after prop reduction?

[treeboa]

trim tabs on the back may lift her bum out the water and stop it digging in

[MikeA]

so youve run it then. was there a heat issue with the motor when you ran it?
If those 9500mah are from china they wont be anywhere close that, but if they charge theyl do fine.
are you sure its a 555? not a 540? thought it was a drill motor you was using

[Dan-109]

I have run it yesterday, the motor was hot to the touch, I have a point and shoot thermometer I will have to check it next time we take it out for a dip.
I am only guessing its a 555 as you can see in the pic its not 500 or 600 but in the middle. 
Yes I think you are right about those BTY AA batteries they seem to be lighter than the other ones I have. 

Treeboa I think the rudder control is set too hard, when in full lock left or right it almost rolls, after i adjust the servo linkage and if it still digs in, trim tabs it will be. 

[MikeA]

well your motor is either one of these:

http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_550pcvc

http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_555pxvx

if you can remeber weather or not the motor you installed had vent holes in the front. if it does its a 550 and if it doesnt its a 555.  i doubt its a 555 its max rpm is 5k

either way prop too big, need a 34mm diameter at most. You should also be able to limit how much your rudder moves on your transmitter, its called the dual rate. you wont need to manually do it. 

by the way D40 x P1.2 means:

Diameter 40mm Pitch 1.2 X 40 = 48mm

the pitch is a multiplication on the diamater. 48mm is the distance the prop travels forward per revolution. If the water was solid like a screw in wood then it would be exact but water slips so its more of a guide. the higher the pitch the steeper the angle of the blades the more forward movement it produces. however the steeper the pitch more torque is required and thus more amps is drawn.

[Dan-109]

Mike It looks like its the 550 vc.

I was not sure what the dual rate was for, thanks for that. 

Now just have to get a smaller prop and then start on the guns tubes and deck fittings.

 

[MikeA]

yeah that should be it, at speed you dont want to be hard steering the boat anyway. i dont think youl need motor cooling either, especially with a smaller prop. have fun !!

[MikeA]

have you got any more pics of the progress of this build?