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[MikeA]

its the same motor im telling ya, here is the turnigy version, look at the case size in the drawing.

http://www.hobbyking.com/hobbyking/store/__5145__TR_28_45_3600kv_Brushless_Inrunner_WaterCooled_.html

[Nige52]

That's it, I give up.......carry on Mike 

[MikeA]

Thanks again for the info, i may down grade my motor so i dont have to spend  out on a 120A esc. How do you work out the amp rating  needed for an esc? example, If i had a 2200kv motor & 14v lipo , what amp esc would i need? Whats the maths for this? I know how to work out r/p/m, kv X volts

Ralphy

sorry to argue with nige over your thread your motor and 60A esc match are fine, i use that combination and it works ok for me. The problem is you have a big and heavy boat, and in order to shove that boat you need a big prop, but the motor is too weak to spin the big prop required to get your boat to shift, so in order to save your motor and esc from burning out you need to down size your prop to about 32mm diamater at the most, secondly in order to stop cavitation you need to slow down the prop speed and run on 2s or 7.4v, thats probably a bit high still but would need a test.  As a result this combination in order to save your motor from thermal melt down with make your boat slow.

Now the the 2200kv motor that was mentioned is a bigger motor, a lot bigger! It has the grunt to turn the big prop and high rpm you need to get the boat fast, the one you have doesnt. Its normal for the increase in size of motor for the kv to drop. For example this larger motor, probably not suitable for boats but gives you an idea of the drop n kv as the size increases:

http://www.hobbyking.com/hobbyking/store/__5139__Turnigy_80_100_A_180Kv_Brushless_Outrunner_eq_70_55_.html

thats about 9.4 hp that motor.

these bigger motors require bigger esc's and the faster you run them underload determines the esc you need.  To match the esc to the motor you look at the specs of the motor and the operational current at maximum efficiency. The 2200kv leapord for example works at 90 amps max according to specs ive found, so you would select an esc to meet those requirements then give it a bit of headroom just in case the amps spike. Thats why hes selling both the motor and the esc togeather. 

[MikeA]

Nige i think well agree to disagree eh?

[MikeA]

ralphy im not sure youve understood which motor i meant, on that link i suggested that f1 madness is selling he has this gear up for sale for 80 quid.



excuse me for robbing your picture f1 madness

anyway if you went this route youl need to go surface drive and that means old prop shaft out and in with different hardware

[F1 madness]

@nige
hey bud no problem

@mike
No worries

@ ralphy
ralphy listen to me,nige & mike,we have slightly different opinions but niether of them are wrong.its just what works for us
You say your ESC is 60amp whats the burst current of the esc ????????????????????????????
you lose power after 20secs,i think you said right,take note
if your burst current is 120amp and your esc is cutting to half power on that motor,this means your spiking amps are above 120amps
unless you spend a fortune on data logging equipment you will never know fully how may amps your pulling.
That motor and esc are 2 small to move that weight of the boat and your prop is also too big for them
MY RULE OF THUMB for choosing amp rating esc to motor is go bigger.
The reason this set up works for mike is probably because his boat is lighter,smaller and hes running smaller prop

heres somthing to remember
the lower the KV motor the more volts required but amp draw is less and so are temps,but you can also run a bigger
the higher the KV motor less volts,more amp draw,higher temps and small props
The more poles a motor has got the more effeicent it runs and more torque
the lesser the poles the amp it draws,more heat and relies on rpm,but safly rpm is usually 30-35000 over this you risk your boat

changing to surface will be a better option,you could also use an X642 which is a higher lift prop allowing the 'bottom' end to air out,reducing the drag and creating more speed,with the right balance and setup

[Nige52]

Whatever you're on, I'll have a double.....


 

No, not you Daz, you posted at the same time as me....

[MikeA]

sorry to argue with you nige, it not like it matters really anyway.

Speed costs money ralphy and even though the combination you have works for me, my boat is 1.2kg fully laiden and only 60cms. In order to get your boat to go like the one in the vid you will need to get
that motor and esc f1 is selling £80
a strut surface drive, flex cable and coupler £30-40
rudder £15
prop £10-15 

it will add up im afraid

you could possibly try the cheapy chinese ebay hardware though many people on here would steer away from it, i might not though but thats because im awkward

[F1 madness]

Ralphy
i just googled them esc'c and not 1 is watercooled,are the 1s you have watercooled ??????????????

I agree with mike,speed costs money
i spent loads on my cat to get  it to break the 60mph,ask nige LOL

[Ralphy]

Thanks again for your input, F1 you have some interesting points about kv over amps = prop if you get my drift. I ran my Tornado this weekend , 36kv motor, 11.1v lipo, 60a esc (70a peak) & 32.5mm prop. A huge difference in speed, loads better, (sounded good too) however at full throttle  it sounded like it was over reving, my guess the prop is a tad small, i have a s35 i can try. The esc was warm near to hot after 4-5 mins, should i get a cooler for it? I am thinking about dropping the kv down to 22kv, will this save my esc? From whats been said on this thread i think it should. However i think then i could up my  power to 14.4v lipo & increase the prop to around 40mm , F1 what do you think?   (its quite a learning curve)
Also, who makes the best lipos for the money? What C rating & mAH is best?  I have "Overlander" 11.1v 25c 2200mAH, but they seem pricey against a brand called "Turnigy" any feed back on "Turnigy" would be good or any other quality brand.
Lastly i have seen some low volt warning alarms around £5 on the web. Do they work & are they worth it?

Thanks, hope to hear back soon.

[Nige52]

I can answer some of your questions Ralphy as I have a box full of lipos and esc's....

The Mah is purely the capacity of the battery, 2200 is good for a short while but 5000 will give you more than double the running time.

The 'C' rating is how fast the battery wiil allow the current to escape. Think of it as a bottle of water, the smaller the C rating, the narrower the neck, so when you tip it up to empty the water the slower the water will come out. 25c isn't bad and better than 20c or 15c but still not best. A 30c rated battery would really be the minimum you need for the set-up you propose. Don't forget, the higher the C rating, the wider the neck...the faster the water will flow out.

A lot of people will only buy 30c batteries or higher nowadays, because the demand put on them by the drive train sucks the life out of the batteries very quickly 

As for the low volt warning alarms, yes they do work and if you are using a brushed motor/esc, they are essential to stop the voltage dropping below 3v per cell on your lipo's. But if you're using a brushless motor, the esc 'Should' have an automatic low voltage sensor, and will either slow the boat down or stop it completely, depending on which way you have it set.

Hope this helps,
 

[F1 madness]

Hi ralphy
going down to 2200kv is a good and uping the volts to 4s,as for esc depends on the motor 2pole motors are less effiecent and draw more amps but run hotter,a 4pole motor is way better or even a 6pole motor.
The thing you need to understand about choosing a motor,size of motor,number of poles and KV,they all have different amp ratings aswell,then choose the esc and batts to suit
BUT you gotta think of the drive line,will it take it as putting on a bigger prop on puts strain on it all
This would be my main concern.
It is a big learning curve but youll get there
now for batts,what nige said is right,but mah and c rating make up the amperages that can be drawn
For example a
11.1V 3300mAh 25C continuous discharge
82A continuous, 126A burst.

but the c rating still the same but bigger mah and look at the difference in amp that can be drawn
11.1V 3600mAh 25C continuous discharge
90A continuous, 135A burst.

Now the batts i would use minimum are these,im currently running these batts and had no trouble at all with,they are excellent for the money
http://www.ebay.co.uk/itm/110733977629?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
hope this helps

[Ralphy]

Ok, thanks again.

@ F1.  Now i'm concerned that if i do get a bit of power i'm going to tear my boat to bits. Whats all this about submerged drives? Whats the fix for that, a surface one? How about a flexi drive? Or shall i just build a new boat after all winter is nearly here 

@ Mad Mike, you posted a link for a Turnigy motor, was that a recommendation for my boat or just "Hey look at the size of that" type thing? Hope you were kidding 

Hear something soon.

[F1 madness]

Hi Ralphy
your drive line at mo consists of a solid shaft through the bottom of the hull with prop on the end of  it,this setup is submerged drive,meaning your prop is fully submerged in the water.
Now surface drive consists of strut,flexi,stuffing tube,dog drive and surface drive prop,surface drive props work by only havin half of the prop in the water.
To change yours to surface shouldnt be that bad,but a case of being carefull and patience,you need to get yourself new hardware including rudder as the 1 you got will be useless
the transom of the boat is not very wide making it difficult to fasten the strut and rudder so heres a solution
Etti strut & rudder combo,cant post link at mo site is down
ill finish when i can post link and explain how you can change to surface drive

[F1 madness]

Ralphy
somthing like this will work
http://www.astecmodels.co.uk/catalog/product_info.php?cPath=1_79&products_id=557
the rudder bolts to the strut bracket so no worries about mounting it all on the transom
what you need to do is strip everything out the hull,carefully remove the solid driveshaft and mounting bracket & rudder,you will have some holes to fill and touch up
you need mount the the strut so the bottom of strut is level with the bottom of the front sponsons,place masking tape over the transom are and mark the bolt holes for the hardware make sure you get the elongated holes in the strut center of where it bolts through the bracket,this will allow you to adjust strut height to set your prop depth
you can use the original slot in the floor of the hull for the the stuffing tube,what i do is place the stuffing tube with teflon liner and flexi in it and very carefully bend it so the stufing sits just inside the back of the strut and through the floor and inline with where the motor shaft is
you wanna keep the bend at a nice radius so it a nice smooth line for the flexi to run in
You will also need a new coupler to match upto your motor and flexi so you can cut the flexi to the right length,to cut the flexi mark where you need to cut then wrap some tape about 15mm either side of the mark,next is to silver solder the flexi before cutting this stops the flexi for fraying up when cutting and when you push it into the coupler.
Once youve got everything lined up and connected together and everything is freerunning,use some quality epoxy resin and epoxy the stuffing tube into the hull making sure it fully seals the area,what i do is rough up the stuffing tube where its goes through the hull with some 60g snadpaper this helps the epoxy to bond with the tube,i alos use electrical tape under neath t,overthe area to stop the epoxy from flowing every else where you dont want it
once cured pull it apart again,flip it over and tidy up any mess the epoxy might of caused,i also use the epoxy to fill any holes by mixing abit a talcon power in it
hope this gives you some idea of whats involved,its not hard but on a boat like that time consuming and being carefull not to mess it up
 

[MikeA]

Ok, thanks again.

@ F1.  Now i'm concerned that if i do get a bit of power i'm going to tear my boat to bits. Whats all this about submerged drives? Whats the fix for that, a surface one? How about a flexi drive? Or shall i just build a new boat after all winter is nearly here 

@ Mad Mike, you posted a link for a Turnigy motor, was that a recommendation for my boat or just "Hey look at the size of that" type thing? Hope you were kidding 

Hear something soon.

it was just a hey look at the size of that type thing. i just explaning how the as the motor sizes increases the kv rating goes down. The motor you have is too small and doesnt produce the torque to turn a prop large enough to get your boat to shift. you need a bigger fatter motor which will mean bigger esc and because its a slower motor you will need more batteries to make it a fast one. The motor you will need might not be quite as big as that turnigy but you will be getting in that league.

what you did with the 3600kv, 11.1 lipo and 32mm prop is about as far as it goes with that motor and submerged propeller. The reason why it was cavitating is because the prop was too fast, up sizing prop what make any difference except burn the motor and probably still cavitate anyway.  to do get the speeds you want F1 has pointed you down the right road.

[Ade the Blade]

Hi all i have to say this but it is is with the greatest of  respect for both Mad Mike and Nige52 you guys bring a smile to my face on an otherwise grey work day you remind me of statler and waldorf of the muppet show .I know you have  great respect for each other but without both of you life would be a duller place Thanks guys you make my day

Regards Ade

[MikeA]

lol I still think hes wrong 

[Ade the Blade]

Hi Mike thanks for all the advice you have given me and as for who,s right it would be a shame if one of you was right as i would miss my daily laugh.

Regards Ade