Hello everyone!

I have a couple questions:

1) Imodded a Rio Ep with a brushess setup. It's a Turnigy watercooled 3600KV motorand 5A 3S batteries. My problem is that I have alot of prop walk, the boat rotates to the right whenIget up to a decent speed. It will flip if Ipush too hard. I've been messing with the stabilizers on the back to get it right but It's not quite there. Is this the only way to stabilize the boat? I've tried putting the battery on the left of the boat and that does help a bit.

2) My friend built a boat with me at the same time. It is the NQD arrow wind and has the same setup as my Rio EP. However, I've noticed that it runs faster than the mine. Why would this be? Mine is lighter, but maybe he has less of the hull in the water. What do you all think?

3) How can Iget some more speed out of mine if Ican stabilize it better?

Rigger sponsons help reduce effects of motor torque while the boat skips along with minimal contact with the water. Also, the stuffing tube is off-center to help alleviate prop walk. Your Rio needs a certain amount of contact with H2O for stability and will suffer more from these effects. Adjusting the cog (battery placement, etc), trim tabs and prop choice will help the Rio, but may not catch the rigger!

I kinda thought that might be the case. Where would you recommnd putting the battery?

Sorry, I'm not familiar enough with that boat, but I would try adjusting the right trim tab down slightly and put the battery on the left to trim a boat that rotates to the right.

I beleive I saw it suggested to try a smaller diameter 3 blade prop with this. I know my SV27 handled better with the 3 blade (turns were smoother/more predictable, but it didn't suffer from the problem you describe. If you rudder is not perfectly strait it may create an "airfoil effect" that would cause the boat to lisp under power. Check that as well.

I wonder if that's why it has 2 rudders. I see no need for 2. Well..... The SV has a rudder that is offset to the right side of the transom and this is typical of oval racing boats. It's been stated that the SV was really designed for racing but I'm sure they found that most are purchased for sport runnng. So it was a big complaint among alot of new owners that the boat really didn't turn left well. With the rudder and turnfin on the right, it wasn't supposed to. This may be a lesson they learned and the built this boat to turn both directions well at the cost of some additional resistance. All the same the effect of the rudders would be double so it's all the more improtant that they are straight.

I will have to try a smaller prop on it and see what happens. I have a 3 blade that I tried that was something like 37mm instead of the 42 stock but it ran alot slower. I'll have to try out a few different configurations then.

I have been putting the battery on the left at least so that's a help.</p>

Here's a thread that's like 7 pages long about your boat. I don't have time to skim it now but you should to see if somone else has experienced the same problem and found the solution.

http://www.rcuniverse.com/forum/m_94...tm.htm#9460137

yes a smaller 3 blade prop will help, and keep in mind you have right at 40,000rpm..
even running 2s would be plenty with this boat say running a 38-40mm prop.
stut angle should be set more to 0* will help some to

So, I tried the boat again today. I tried a 38mm two blade and it was really slow. It just ran the prop fast but got no push behind it.

I tried the three blade 38mm and it worked quite well however I was using my 3,000 mAh 20C battery and it ended up puffing it a little bit.
 Why would it do this if the motor is only a 40A motor and a 60A ESC?

Then along the same motor battery esc combo I have another question:

I am thinking of building another boat this summer and was wondering if the 5000 mAh 20C batteries would work well with the following motor and ESC?

70A motor:
http://www.hobbycity.com/hobbycity/s...idproduct=4284

120A ESC:

http://www.hobbycity.com/hobbycity/s...idproduct=8946

a couple things..
one boats can pull much amps than what the motor is rated to, second even if a esc is rated at 60Amps it can and will allow much much more than that
the motor you are running is spinnig 40,000rpm unloaded, and that's alot!
how many Mah did you put back into the pack when you charged it?

the motor you listed is not a 540 motor and has way to much KV for any boat
if you want to run 3s choose a motor that is more in the 2500kv to 2900kv range..

with your Turnigy 3600kv motor, this hull should be pushing mid 40s with the stock prop

I have no way of judging the speed unfortunatly, I don't have a GPS that will fit in the boat.

I charge my batteries at 1C always.

my guess is you may have a mid 20s boat?
and for the battery, how many Mah are you putting back into the pack that was a little puffed?

SRT,
I'm confused you said he should be seeing 40's with the 3600 and then you said 20's. can you clarify?

Yeah, I was wondering that too.

Also, what do you mean by how many mAh are you putting into the pack? I always charge at 1C ~ 3000mAh.

Also, does a smaller prop put more draw on the system or does a larger prop do that?

when you charge does your charger let you know how much you are putting back into the packs?
like 2800mah 2700mah 2900mah into your 3000mah pack
smaller prop draws less amps

when properly setup, this boat should see 40's with that KV on 3s, but it sounds like it is going much slower than that and to me it indicates that there is something wrong with the setup...

My charger doesn't show me what is being put into individual cells but it does display the current Amps running into the battery and it always runs at 3A until it gets very close to the final voltage then it drops down low to finish off the battery.

I understand what you mean about the lower speeds of the boat. I have a video of it running if that will help analyze it.Just to throw out an idea,I've heard from another sorce that thehull design is not a good one and that it has limitations of barrelrolling at higherspeeds. I dont know if this is truely accurate or if there ismore to it than thatBut in the meantime what could be changed to get the speeds your referring of?

Here is my video:
http://www.youtube.com/watch?v=imjanAk4BmQ

Thanks for the help on this!!

the reason I was asking how many Mah you are putting back into the 3000mah 3s battery is if you take them down to far on volts they can puff..
the video looks like it is doing low 20s
check to see how your rudders are set, make sure they are not towed in or out, better yet take the left one off
also check the trim tabs and see if they are at 0*
next check you turn fins and see if they are straight
and check your strut, I know mine is angled down and that causes the boat to want to plant the nose down.. I need to move it to 0*
I hope this helps you out.. [:-]

I'm going to try a Trinity P2K pro motor this weekend with the stock prop and see how that goes on 2s

SRT said:

OK. I agree. Honestly It doesn't sound like you are tuning the revs you should with that motor. Are you shure it's 3600kv? To clarify I have a charger like what SRT is speaking of. If you were to have to stop mid run when you charge you would see that you only put back 2300 mah. It steadily increase as the packs charge like you are filling a bucket. Nice indicator for when your packs are cooked.

Yep right on man, that's what I ment..
this motor should be at 40,000rpm unloaded and it sounds like its only 1/2

Hmmm, That's interesting. I wonder why it would be running at half speed....

Also, I have set the turn fins and trim tabs even and then I have been adjusting the right one to compensate for the right rotational prop walk. It works ok but when I switched to a smaller three blade prop it had no problem with the prop walk. However, that was when it drew too much from the battery, which was odd since it's a smaller prop.

I have been planning on ordering another 5Ah battery from hobbyking, a 120A ESC and A new motor. But which one? I have a couple ideas, see what you think:

http://www.hobbycity.com/hobbycity/s...200kv_Inrunner

http://www.hobbycity.com/hobbycity/s...900kv_Inrunner

http://www.hobbycity.com/hobbycity/s...idproduct=6527

Or

http://www.hobbycity.com/hobbycity/s...r_(WaterCooled)

Not sure if you are reading through your post?
you have a 3600kv motor on 3s that is not performing good, and this is to much rpm
look at the sizes you have listed. the first two are two small with high kv's.. they will get hot, specially the last one you listed
this one would work great on 3s with plenty of unloaded rpms
http://www.hobbycity.com/hobbycity/s...idproduct=6527

But I believe he wants to use a 2s lipo. [8D]