Model Boat Mayhem
Mess Deck: General Section => Beginners start here...! => Topic started by: Ralphy on October 25, 2011, 12:25:41 am
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Hi, i have recently bought a "Tornado 80" hydroplane as a ready to almost run. The shop where i purchased it sold me 2 7.4v overlander batteries 3600mah , a Robie outrunner motor & a 47mm X prop. I was told it would go 3 times the speed of my Pro boat Volere. Well it was a bit faster but not impressive, cavitate.d on every turn & listed to one side at full speed. I went back to the shop to be told i needed a bigger prop & the trims i thought would help were a waste of time. I fitted trims against the shops advise & cured the cavitating problem. Unhappy with the performance i took the boat to another more race like shop. After they had stopped laughing at the apparently unsuitable motor & hugh prop they recommended a 3600kv motor (a purple one) with a water jacket, a decent mount & 40mm X prop, speed controller was an Overlander 60A. Couldn't get this running as i use a pistol grip control & the thing wouldn't centre as it had no reverse. Now i like reverse. So i asked them to get me one. A"Fusion Hawk 60A" & a couple of 9.6v 5000 mah batts in series. That will do about 40 mph , 69000 rpm mate! even faster with two 11.1 li-pos.
So there you have my story. Thing is i took the boat to my local pond all excited like i was 14 (im 45) put in the 2 x 7.4s gave it a bit of a run. Mmm, not as fast as the Volere, cavitateing power dropped after 40 seconds of use, rested 20 seconds power returned for 5 seconds. Mmm, i'll change the batts. Now with 19.2v this should shift! Nope. Kept on cutting out & still not quik. Took the boat out the water, checked the batts, not even warm. So i gave it a little rev out of the water to see if the batts were ok, my uni-joint exploded, doh. Looked at the speed controller - Ooops. It had got so hot that the heat shrink had split open & i could hardly touch it, hence why it was cutting out.
Now after this long winded story my questions are this........
1. What should i put in this boat to make it quik? I only want to run electric.
2. What size prop should i use?
3. What speed controller will be best for use with twin 11.1v li-pos? & twin 9.6v?
4. How do i work out the Amp rating for the speed controller?
5. Has the shop miss sold me the parts or was it set up wrong?
6. KV of the motor X volts = r/p/m is this correct?
7. What is max r/p/m of a 60a speed controller?
I hope to hear from someone soon before i go back to the shop all unhappy. I'd appreciate some knowledge before hand.
Thanks for reading
Ralphy
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What should i put in this boat to make it quik? I only want to run electric.
What size prop should i use?
What speed controller will be best for use with twin 11.1v li-pos? & twin 9.6v?
How do i work out the Amp rating for the speed controller?
Has the shop miss sold me the parts or was it set up wrong?
KV of the motor X volts = r/p/m is this correct?
What is max r/p/m of a 60a speed controller?
1) how big is the boat?
2) prop size depends on the capabilites of the motor and what type of drive your using. from the set up you have described your are using too many volts and too big a prop on a 3600kv motor. i have that motor and use 11.1 lipo with a 37.5mm surface peircing prop. The ideal magic rpm is 30,000 so why the shop is telling you to go to 69000 rpm is stupid because one it will burn out your motor and two just make foam if the motor doesnt melt it self trying to do so.
3) i would say that the shop probably has missed sold you the parts or they dont know what they are talking about, dont hold me to that though lol
4)rpm = kv X v so yes your right
5)depends on speed controller but if you get the rpm right it wont be a problem anyway :-))
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Speaking from actual experience....
The Tornado 80 is a very heavy boat and in all honesty it's more of a showpiece rather than an actual fast electric. I also own the Riva 80 and the Gold Coast 100, all made by Equipage from Viet Nam.
None of these boats can be made to go fast with the set up that comes with them, the propshafts are alloy with cheap plastic bushes, the shaft itself is an easily bendable one, they are also submerged drive which doesn't help.
Our particular Tornado has gone through 3 members hands, all of us trying to make it faster than a tugboat, with little success. We have tried 600 race motors, 700BB Turbo motors, brushless motors and in the end given up.....even getting it up on the plane is a job in itself. Sorry about the bad news but we have all come to the conclusion that due to the weight and design, the boat is nice to look at, but......... :((
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Speaking from actual experience....
The Tornado 80 is a very heavy boat and in all honesty it's more of a showpiece rather than an actual fast electric. I also own the Riva 80 and the Gold Coast 100, all made by Equipage from Viet Nam.
None of these boats can be made to go fast with the set up that comes with them, the propshafts are alloy with cheap plastic bushes, the shaft itself is an easily bendable one, they are also submerged drive which doesn't help.
Our particular Tornado has gone through 3 members hands, all of us trying to make it faster than a tugboat, with little success. We have tried 600 race motors, 700BB Turbo motors, brushless motors and in the end given up.....even getting it up on the plane is a job in itself. Sorry about the bad news but we have all come to the conclusion that due to the weight and design, the boat is nice to look at, but......... :((
Obviously you felt compelled to have a dig at me then, i was just trying to help after all this forum has helped me and i just wanted to put something back. I will admit i do not have as much experience as you obviously do nige but i do know the 3600kv motor as i have one myself and know when its starting to push its limits. I have not suggested what motor to install in his boat but i feel my contribution so far will help avoid further dissapointment and failure.
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Thanks for both of your replies, i shall try a smaller prop & quiz my dealer.
Mad Mike the boat is 32 inches long & a little on the heavy side. Nige if i get a decent speed out of it i'll post a film on you tube. (towed by jet ski)
How do you determine the amp rating of the speed controller, whats the formula?
Thanks Ralphy.
ps MM don't think Nige was having a dig
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well i felt like it was a dig, and cant deny that im not insulted. Despite my lack of personal knowledge for this perticular boat you are referring too, i do know that the 3600kv is too small and underpowered for your boat size. my boat is 2/3rd the size of yours and even then its at limits. However im not going to recommend another motor as its been allready covered by nige's post.
Usually the amp rating is labeled on the esc. I have found this thread anyway and it gives you an explanation of how to work it out:
http://www.rcgroups.com/forums/showthread.php?t=436720
hope it is of some use to you.
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It was not a dig at you Mike. Somebody replying to a post that has actual experience of the problem asked about, in my opinion is worth far more than uninformed suggestions that might cost the originator even more money.
Ralphy, I look forward to any video you can produce which shows this particular boat actually performing as good as it looks :-) We have tried but failed miserably and so have given up....it is a heavy lump of wood, albeit a very nice looking one (Except for that awful bilious green trim line) {-)
Best of luck in your endeavours mate!
:-))
Oh, and as you know Mike, I have a 3600kva motor in my MFA Spearfish which is a bigger boat than the Tornado and the Spearfish flies along on the plane......?
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ok fair enough no more said about it. I would agree with you that actual experience is better than an educated guess.
i also forgot that you had the 3600kv, i seem to remeber you posting a pic of the cooling system. i still feel that the motor is too small but im talking about surface peircing props.
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Yes, to be honest I still can't see why you thought I was having a go at you, I was merely answering Ralphy's question about the Tornado, which I do have experience of, anyway...
Here is a pic of the 3600kva motor along with the ESC inside the Spearfish's hull, you can see just how big this boat is compared to the Tornado, much bigger, but also a lot lighter :-)
Unfortunately I don't possess any photo's of the Tornado, I sold it to a club mate who just brings it out occasionally for a tootle round the lake :((
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And here is the exact motor/esc I bought :-)
CLICKY HERE (http://www.ebay.co.uk/itm/3600-Water-Cool-Brushless-Motor-SEAKING-60A-ESC-CA061-/270793024308?pt=UK_ToysGames_RadioControlled_JN&hash=item3f0c85a334)
In fact, I've just got the boat down from upstairs to give it a run this afternoon, hasn't been out for a while so the 5 and 6 cell Lipo's are charging up nicely :-))
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thats the kit i bought. i wasnt happy with the coolant flow threw the motor it just wasnt happening. i bunged up the original nipples on the back and then drilled and fitted new ones to the outer case. do you use 6s at once? :o arnt those prop speeds a bit high for a 3600kv with submerged drive??
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If you recall, I had the very same problem :-)
I found that one of the nipples was bunged up, so drilled it out as in the pics. Although I use 5 and 6 cell Lipo's, I very rarely open the throttle up to max, the boat can't really handle it, but I find that having a BIG battery keeps everything cool, a bit like having a 2.5 V6 engine in a small car, you never really need to open the throttle up, whereas a small battery gets hot quick and works overtime trying to keep up with the demand put on it.
ok2
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well first i drilled the holes, i still found that the water flow threw the esc then into the water jacket was pathetic, the outlet flow was a dribble well not even that it was just weeping. I decided to do away with the standard nipples alltogeather and construct my own with a bit of aluminium 6mm tube drilled and epoxied into the case. The results were more than sufficient which eased my mind. i use a 3s lipo on my 3600kv at full throttle on surface drive. i get about 40k rpm unloaded and loaded i think itl be around the 30-35k region. i presume you all talking about 6s in parrallel configuration then? as 6s is about 80k lol
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ok im not sure if your boat is made by equipage ralphy but it seems like this is a good resullt on rc groups. theres a youtube video link to it performing:
http://www.rcgroups.com/forums/showthread.php?t=872481
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Thanks to you both. Both links are usefull & the you tube vid is as fast as i'd like my boat to go.
Yes my boat is made by Equipage.
Odd, i still dont understand how my 60A esc nearly melted & only gave me 30 secs run time before cutting out.
Ralphy
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they recommended a 3600kv motor (a purple one) with a water jacket, a decent mount & 40mm X prop, put in the 2 x 7.4s gave it a bit of a run. Mmm, not as fast as the Volere, cavitateing power dropped after 40 seconds of use, rested 20 seconds power returned for 5 seconds. Mmm, i'll change the batts. Now with 19.2v this should shift! Nope. Kept on cutting out & still not quik. Took the boat out the water, checked the batts, not even warm. So i gave it a little rev out of the water to see if the batts were ok, my uni-joint exploded, doh. Looked at the speed controller - Ooops. It had got so hot that the heat shrink had split open & i could hardly touch it, hence why it was cutting out.
with 2 7.4 batts in series you have made 14.8v multiplied by 3600 you have 53000 revs. The 40mm prop on this motor is way oversized. See the manufacturers in china class this motor as a size 3660 but in reality it is a 2845!! These numbers are the dimensions 28 being the diamater of the can and 45 being the length. Normally brushless motors and their manufacturers rate there size of motor BEFORE they put on the outer cooling jacket whereare in this perticular motor they have classed it afterwards. Firstly the motor on this voltage is SCREAMING and secondly its trying to spin a huge submerged prop at this stupid speed. 40mm prop is way too big for a submerged drive, it would want to be 30mm at the most and even then at these rpms could do with being smaller. The bigger the prop you install on a motor and the faster its required to turn the more the motor has to work and thus draws more amps. The motor has drawn so many amps its litterally flattened the battery instantly, the overheat protection has kicked in on the ESC cos the load on it was melting. I dare say your motor will be burnt out too.
with this motor and prop that you have the ideal speed wants to be in the 9 to 11,000 rpm range. Beyond this its gonna get a sweat on and will risk being damaged. But at these safe prop speeds your boat will be slow, if it was me i would buy this from a fellow member on here:
http://www.modelboatmayhem.co.uk/forum/index.php?topic=33401.0
theres an 3674 motor with a 120A esc. spin this with a 36-40mm prop on it, uprated drive train and 2 be safe 2s lipo you should get a shift on, put in the 4s you will get more speed but mind the temps. This is my oppinion bare in mind and what i would try so dont hold me responsible if it dont work after all the boat is heavy.
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Mike,
Please don't go into a sulk again :embarrassed:
The 3660 kva is REVS PER VOLT......NOT the dimensions of the motor.......please get your facts right when advising somebody...... ok2
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well firstly 3600kv and the dimensions as described for this motor are 34.5 X 58mm buy this chinese seller:
http://www.ebay.co.uk/itm/RSC-3600-KV-RC-Model-Water-Cooled-Brushless-Motor-IM294-/300584201306?pt=UK_ToysGames_RadioControlled_JN&hash=item45fc36ec5a
this british seller has classed the same motor as 2845:
http://www.ebay.co.uk/itm/BL-2845-3600kv-Brushless-Inrunner-WaterCooled-Motor-purple-/250906837924?pt=UK_ToysGames_RadioControlled_JN&hash=item3a6b3683a4
i got to admit i cant currently find a seller that has classed this SIZE of motor as 3660 i cant remeber where i got it from, think it might have been on here. The point i was making though is that some sellers class the size of the motor by the outer cooling jacket dimensions rather than the can itself.
so if i was more exact then the dimensions they give us for it would make it a 3558 size motor at 3600kv.
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Hi mike
The motor and esc you mentioned need to run 4s,and 442 or x445 prop.
I ran this setup on an 32"F1 no probs and also run it in the rocket thats advertised
Ralphy
Iv just googled this hull,seems very heavy,the submerged drive will not hold upto the power you crave for speed
you were sold and told stuff that is not suitable for that hull or the driveline
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Also you mention that you lose power for ex amount of time then have full power,this is the esc's way of saying your drawing to many amps and the esc cant cope with it and cuts off to half throttle usually
the biggest prop i would on that motor is 32mm and a 100 amp esc on 3s which means your boat wil just sit there and cavitate
surprised you didnt fry the esc and destroy the motor and bearings.
Also the CF props wont take over 32000 rpm before shatering leaving your boat stranded
use my rule of thumb for esc,if the motor says 60amp double it cos as soon as you load it with a prop it will draw more than there rated amps
also do the the same for your lipos,i wouldnt use anything less than 5000mah and 30c
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Hi mike
The motor and esc you mentioned need to run 4s,and 442 or x445 prop.
I ran this setup on an 32"F1 no probs and also run it in the rocket thats advertised
Ralphy
Iv just googled this hull,seems very heavy,the submerged drive will not hold upto the power you crave for speed
you were sold and told stuff that is not suitable for that hull or the driveline
wouldnt the motor your selling run on 2s with a 36-40mm prop. I was refering to using it on a submerged drive not peircing mind :o
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Hi mike
You could run it on 2s on that prop but it would real slow been only 2200kv of
Even on submerged drive it would still spin 42mm prop
This is a 4pole motor and been 3674 has alot of torque without the big amp draw
Hope this helps
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when i think about it at those prop speeds and sizes it pointless waste of a brushless motor like that leopard when a 700 motor could do the same job. I suppose if you were to use your motor then you might aswell go all out surface drive on 4s.
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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
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Hi Daz,
Thanks for your expert input :-))
Morning Mike,
Those 2 ebay links you supplied....they are for 2 different motors my friend. The only similarity is the KVA rating, they both spin at 3600 revs for every volt you put through them. Oh, and the colour purple of course.........
The physical sizes of them are different, one is a 28mm wide case and 45mm long, whereas the other is 34.5mm wide and 58mm long.
I have both of these motors and many many more....I have tiny outrunners no bigger than your small fingernail which I fly very small planes with, and a wide range of both inrunners and outrunners all in different sizes...............
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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
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That's it, I give up.......carry on Mike %)
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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.
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Nige i think well agree to disagree eh? :-))
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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.
(http://s7.postimage.org/vux0kbi2v/DSC01475.jpg) (http://postimage.org/image/vux0kbi2v/)
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
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@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
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Whatever you're on, I'll have a double.....
%% %% {-)
No, not you Daz, you posted at the same time as me.... {-)
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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 %)
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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
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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.
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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 ok2
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,
:-))
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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
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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.
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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
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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
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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.
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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
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lol :} I still think hes wrong ;D
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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