Rudder water pick up and cooling problem ??

[JonD]

I don't know what I am doing wrong here, and hope you guys can help me. I am having trouble getting cooling water flowing through the ESC and motor - at least, I don't think any water is getting through, but I am new to RC boats so the problem is most likely me

I bought the Genesis boat new, and after blowing up the stock motor on the first run (I put that down at the time to overheating due to no water flow) have rebuilt with Leopard 4082 1550KV, T180 ESC and using 2 x 3S LiPo in series. I am using the stock rudder/pick up, but with 5/32 inch tube right through from rudder to outlet. I am starting out with a M445 prop for now.

I have attached photos showing how I have the water cooling tubes run.

Water cooling layout1.JPGWater cooling layout2.JPG

Does this layout look OK, or have I screwed something up ?

I can see no water coming out of the outlet on the side of the hull. I had assumed that it would be very visible. At slow speed - certainly nothing. At higher speed (say 50%) I still can't see any water coming out, but the boat is traveling quite fast by this stage and it is difficult to see. I have only been game to give it around 50% throttle and in short burst of a couple of seconds at a time for fear of burning out a second and much more expensive motor. I have checked motor temp (just by hand) after these brief runs and it is barely warm.

There are no blockages and I can fairly easily blow air through it. I even disconnected the tube from the top of the rudder, expecting to see this big plume of spray squirting out the top where the tube normally connects - but nothing (only tried this a fairly low speed - say 20% throttle). Rudder looks fine - inlet hole on either side near the bottom - passage ways to the outlet at the top seem normal.

Can someone please point me in the right direction and tell me what I am doing wrong? Or doesn't any water start flowing until the boat is really screaming through the water?

Cheers,

Jon

[CHUD]

Sound like everything is ok,bud,If you can blow in the exit port on the side of the hull,And feel water commin out the rudder your ok,Just keep your eye's on the side exit port when running mid speed, But don,t run around the lake to slow to long.your speedcontrole need;s water flow,You can move one water line ,Here;s the setup///Rudder// inT180//OUT T180//into big Motor can//out big motor can// into face motor cooler//And out face motorcooler //and out the boat//I have that motor and T180 in my df33 and I love it,,I hope this help;s you out,O YA welcome to OSE ,

[BHChieftain]

I have seen cases where the actual rudder portion gets blocked-- so check both. Disconnect the waterline at the rudder and blow through it to test the flow through the esc and motor, then also blow through the top of the rudder to check for blockages there.

It is also a good idea to take a mouthful of water and blow it through the system to check for leaks.

Chief

[LarrysDrifter]

Dont use the mount for cooling. Doesnt do anything anyway. Only cool the esc and the motor cooling jacket. Cooling more than needed only creates more restriction, something thats not wanted or needed in a cooling system.

[properchopper]

The rudder in your setup has an inlet on both sides; it should pick up a decent amount of water. If no plume was noticed when the line was disconnected, there may be a blockage due to machining residue left behind. Try reaming it out ; a servo rod is good for this. Another blockage that commonly occurs is caused by the hose barbs on the motor cooling jacket being screwed in so far as to bottom out on the motor (this just happened to me). Back them out one turn ( use sealant on the threads) OR notch the bottom thread. You have lots of resistance in your setup- I'd bypass the motor mount cooling ; it's used mostly for outrunners and has little effect on your inrunner.

Make a leak & flow checker DSC02822.JPG that attaches to the kitchen sink. Blowing through the lines won't give an accurate picture of flow. Air travels much easier than water. Let us know what you find & good luck !

Tony

[dana]

I agree that you should check rudder for blockage. You could go to higher pitch prop with that motor btw

[larryrose11]

Seasoned members,
Uppon reading this, I did a quickie search on the web for a water pump that could wirk.
I fpound this:

http://www.youtube.com/watch?v=P9T5PayVRR0

and this product:

http://www.ebay.com/itm/DC-12V-Mini-Electric-Water-Coffee-Pump-24-GPH-P-25A-/260895901599?pt=Small_Kitchen_Appliances_US&hash=item3cbe9b879f

Rated voltage: 12V DC
Rated current: 0.34A
Capacity: 1.5L/Min (24GPH)
Pump head: 1.6M
in the video, it look pretty good. Any users have experience with this? Sesme like it would be really easy to wire up. Power it drectly from the 3s or 4s pack. You could easily have a micro relay driven by 3rd channel to switch it on/off.

[JonD]

Thanks Guys, for your comments and suggestions.

You've been really helpful and I appreciate it. I will certainly be taking it all "on board". I'll let you know how I go.

Cheers,

Jon

[Mattwarner]

One of the things I have done (and i will post some pics later) on my Genesis is replace the rudder hinge pin with a 4mm brass tube which makes an excellent prop wash water pickup, i have two bulkhead fittings with one cooling line going to the ESC and the other to the motor (supplied by the standard rudder pickup).

This is a very quick and easy mod to do which hopefully give a decent cooling improvement over a single pickup/single cooling line setup.

[JonD]

Hi Matt,

Thank you for the suggestion.

Pictures would be great, if you get a chance.

Jon

[JonD]

OK, so this is what I have done :-

1/ I removed the front motor mount cooling so it now goes from water jacket direct to the outlet.

2/ I enlarged the inlet slots in the rudder (by quite a bit) by grinding with a Dremel, to create a larger "capture area" for the water. Not sure if this is OK to do, but it seemed a good idea at the time. Photo attached comparing original with modified.



It's a bit quick and rough - I could have done it a bit neater, but I thought it would be interesting to see what difference it may make, if any. (I had a spare rudder in case I stuffed it up)

I could then see water coming out the outlet, even at low to mid speed, so after a few runs gradually increasing the speed each time, and bringing it back each time to check temps etc., I was happy to take it up to full throttle. That seemed fine regarding cooling, but for some reason I sheared the nylon screw pin in rudder and the rudder pivoted up. I may have hit something in or under the water (the lake is large but very shallow). I just hope it didn't shear because of the extra drag I have added by increasing the water inlet size

Cheers,

Jon

[Mattwarner]

Pics as promised!

P1000178.jpg

P1000179.jpg

Couldnt be easier, cut some 4mm brass for the pickup, the rudder has an allen key securing the pivot rod in place undo it and the rod slides out and just replace with the hollow brass, tighten up tthe allen key and done!

[JIM MARCUM]

Same thing happened to me yesterday at Professor Joe's lake. I just finished the build of an Apparition and this was it's first run. Setup was stock 380 1620KV motor, 6S1P, 150A Sky Wing ESC, and X632 prop. It ran like a raped ape until the motor fried. STUPID STUPID STUPID!!! For the second time, I ignored Tony Propperchopper's golden rule. Make 2 passes, bring it in & check it out. I didn't. Was having too much fun. IDIOT!!!

To figure out what went went wrong, I popped the cooling line off at the rudder & tried blowing air thru it. NFG. Took the supply line off of the ESC & connected it straight to the cooling jacket - bingo. Air flowed nicely out of the through hull exit. The problem was blockage in the ESC. ESC lived. Motor died. Tony recommended drilling out the ESC's water nipples to clear the blockage. Will do it today.

The Apparition comes with a water cooled motor mount, as well as a cooling jacket. Tony said all that does is add more tubing, more resistance to water flow & complicates isolating flow issues. This time I listened. Better "air" flow instantly. THX, Tony. Good luck - JIM

[JoeOvercoat]

How tall should that plume be, in this boat/typical deep-vee/cat/hydro, with the rudder hose disconnected and the boat running at half, and at full speed?