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[Ralphy]

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

[MikeA]

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 

[Nige52]

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.........

[MikeA]

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.

[Ralphy]

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

[MikeA]

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.

[Nige52]

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......?

[MikeA]

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.

[Nige52]

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 

[Nige52]

And here is the exact motor/esc I bought 

CLICKY HERE

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 

[MikeA]

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? arnt those prop speeds a bit high for a 3600kv with submerged drive??

[Nige52]

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.
 

[MikeA]

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

[MikeA]

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

[Ralphy]

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

[MikeA]

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.

[Nige52]

Mike,
Please don't go into a sulk again 
The 3660 kva is REVS PER VOLT......NOT the dimensions of the motor.......please get your facts right when advising somebody......

[MikeA]

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.

[F1 madness]

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
            

[F1 madness]

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

[MikeA]

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

[F1 madness]

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

[MikeA]

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.

[Ralphy]

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

[Nige52]

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...............