Efficient water cooling?

[FoxProGT]

Sup peeps....

I wanted to ask about the stock water cooling in the ul-1...... mainly just how easy should it be to blow air threw the tubes? im not totaly sure but i believe my esc thermaled even tho the motor and esc didnt feel that hot. i dont have exact temps but compaired to my cars esc/motor temps.....the ul-1s esc and motor were way cooler.


so i checked to make sure water was getting threw the cooling system and it was but when blowing in one end to let all the water out.... it felt......tight? i dont know if thats the best way to describe it... it was like blowing air threw one of them skinny red or brown straws you get when you order coffee or hot chocolate from somewhere. i would have thought it would be more like blowing threw a normal size straw. X)

[sewerpit]

it should just blow out pretty easy ,maybe you have something stuck in the rudder pick up, get an ose water jacket it works great and isnt that expensive

[FoxProGT]

iv pulled the hose off of the rudder and blew threw there so its not the rudder. ima take all hoses off and make sure there is nothing stuck in the esc and motor ports i guess.

[Kfoss1]

Check the nipple on top of the rudder, some times the threaded end has some blockage from threading. The hole should be the same size all the way through.

[FoxProGT]

all tubes are clear..the cooling is fine. thanks peeps

[Drag Boat Bob]

all tubes are clear..the cooling is fine. thanks peeps

Here is a link to what I did:

http://www.rcgroups.com/forums/showpost.php?p=12281523&postcount=487

I ended up drilling out the motor water jacket fittings to match the one on the right in the photo.

[FoxProGT]

oh thats a good idea bob....... i may have to do the same thing to my setup.. i wonder if you can do it to the esc fittings too ..

[Drag Boat Bob]

oh thats a good idea bob....... i may have to do the same thing to my setup.. i wonder if you can do it to the esc fittings too ..

The ESC fittings (for whatever reason) have a bigger hole than the water jacket fittings. I did not need to drill them out.

For the water jacket fittings, I just used a box end wrench and sat them on a block of wood and drilled down through them. It worked just fine.

[FoxProGT]

The ESC fittings (for whatever reason) have a bigger hole than the water jacket fittings. I did not need to drill them out.

For the water jacket fittings, I just used a box end wrench and sat them on a block of wood and drilled down through them. It worked just fine.

nice....thanks :D

[MT-Tank]

Improved cooling mods -- easy!

Took your advice and opened up each brass nipple to 1/8th inch inside diameter. Started with 7/64ths drill bit in a variable speed drill, held the brass in a pair of pliars (the vice was too far away) drilled slowly then repeated with the 1/8th inch bit. Did this with the ESC without removing the brass from the ESC. No problems. Easy. Safe enough for this newbie.

IMPORTANT!
The stock configuration of the tubing is a BAD choice. It creates what is known as a counter-current heat exchanger-- a great way to contain the heat in the system instead of losing it!
The water that has taken one pass through the ESC and then the motor is hotter than the ESC , obviously. So you do not want to put it back through the ESC and dump heat INTO the ESC. You should take this water out of the boat directly from the motor.
Best is to put water through the ESC, loop it back through the ESC then to motor then out of boat. This only requires one more piece of tubing than stock. Do it.

Question:
Wouldn't it be better to have the water come into one of the side plugs of the motor and exit from one of the top plugs?

Paul

[jcald2000]

YES, 10 to 15 degrees cooler!

[Drag Boat Bob]

Took your advice and opened up each brass nipple to 1/8th inch inside diameter. Started with 7/64ths drill bit in a variable speed drill, held the brass in a pair of pliars (the vice was too far away) drilled slowly then repeated with the 1/8th inch bit. Did this with the ESC without removing the brass from the ESC. No problems. Easy. Safe enough for this newbie.

IMPORTANT!
The stock configuration of the tubing is a BAD choice. It creates what is known as a counter-current heat exchanger-- a great way to contain the heat in the system instead of losing it!
The water that has taken one pass through the ESC and then the motor is hotter than the ESC , obviously. So you do not want to put it back through the ESC and dump heat INTO the ESC. You should take this water out of the boat directly from the motor.
Best is to put water through the ESC, loop it back through the ESC then to motor then out of boat. This only requires one more piece of tubing than stock. Do it.

Question:
Wouldn't it be better to have the water come into one of the side plugs of the motor and exit from one of the top plugs?

Paul

I changed the motor water jacket exit to the top of the motor and it dropped the motor temp by 10 to 15 degrees. From 136 down to 120 degrees. The m445 prop did get the motor up to 131 with this setup. Motor leads are another story.

During my prop testing, I have been watching all temps. The ESC has always been much lower than the motor. Since I have not experienced a temp problem with the ESC (always <110 degrees; caps ~92), I would hesitate to change to the "loop through the ESC" design. I have 2 additional caps installed however.

I did add a cpu heatsink (passive) to the top of the ESC (attached with Arctic Silver). It goes the full length and is against the water jacket lines on both sides. I am uncertain just how much this helps, but I am positive it is removing some heat.

Just a reminder; remove the Aquacraft decal before attaching a heatsink.

[MT-Tank]

heat removal

...The m445 prop did get the motor up to 131 with this setup. ... The ESC has always been much lower than the motor. Since I have not experienced a temp problem with the ESC (always <110 degrees; caps ~92) ...

I have forgotten more of my medical training than I wish to admit but I do remember this about physiology. A counter-current heat exchanger is crucial to the survival of many cold weather mammals and is similar to the osmotic exchange in a kidney.
HUH? What does this mean?
Running the hottest water (leaving the motor) into the ESC and alongside the coolest water (the fresh water from the pickup) effectively helps conserve the heat in the motor and ESC. NOT desirable.
As you said, the water coming out of the motor is 131. Why would you want to run that through the ESC which is 110? You're not trying to heat the ESC. Don't run the motor outlet through the ESC! Yes it works as stock but, please trust me, it is cooler with this mod.

"Trust me , I'm a doctor" is an old line, I know...

If the idea of running the water twice through the ESC worries you then consider: Which is better to run through the second tube of the ESC, the water which has just left the ESC after one pass (less than 110) or the water coming out of the motor (approx 130)?

OK, the original post is a simplification. It only adds one line. If you really want the most efficient cooling without a second pickup then you can put a WYE in the pickup line, put the two tubes through the ESC, run two tubes to motor then one tube out of boat. This assumes that it is a higher priority to keep ESC cool than the motor. This would be a marginal improvement in this set-up so I did not mention it earlier for simplicity. In a set-up that is approaching ESC temp limits it may be worth considering.

Respectfully,

Paul

(Now, if I understood prop mechanics as well as thermodynamics....)

[FoxProGT]

water coming out of the boat is 130?

man that water sure heats up quick huh? X( i wouldnt have thought that the water passing threw that quickly would heat up that quickly too. i could see if its the same water running threw the system over and over again and eventually it will heat up .... but its always fresh new water that enters the system.

Ima have to put the temp gun up to the out going water or the water thats left in the system when im done running the boat to check that out.

[Drag Boat Bob]

I have forgotten more of my medical training than I wish to admit but I do remember this about physiology. A counter-current heat exchanger is crucial to the survival of many cold weather mammals and is similar to the osmotic exchange in a kidney.
HUH? What does this mean?
Running the hottest water (leaving the motor) into the ESC and alongside the coolest water (the fresh water from the pickup) effectively helps conserve the heat in the motor and ESC. NOT desirable.
As you said, the water coming out of the motor is 131. Why would you want to run that through the ESC which is 110? You're not trying to heat the ESC. Don't run the motor outlet through the ESC! Yes it works as stock but, please trust me, it is cooler with this mod.

"Trust me , I'm a doctor" is an old line, I know...

If the idea of running the water twice through the ESC worries you then consider: Which is better to run through the second tube of the ESC, the water which has just left the ESC after one pass (less than 110) or the water coming out of the motor (approx 130)?

OK, the original post is a simplification. It only adds one line. If you really want the most efficient cooling without a second pickup then you can put a WYE in the pickup line, put the two tubes through the ESC, run two tubes to motor then one tube out of boat. This assumes that it is a higher priority to keep ESC cool than the motor. This would be a marginal improvement in this set-up so I did not mention it earlier for simplicity. In a set-up that is approaching ESC temp limits it may be worth considering.

Respectfully,

Paul

(Now, if I understood prop mechanics as well as thermodynamics....)

Well doc I am sure you understand that the fast moving water through the system does not remove ALL of the heat generated by the components. All I know is that the residual water that drains out when the boat is lifted from the lake is not even close to being warm. I suppose that I could capture this water and check the temp, but right now I am more concerned with the component temperatures.

With all of the talk about a 'weak' ESC in the UL-1 I can understand why that is your priority. The cap is the weak point in the ESC and its generated heat is not removed by the water (it extends out of one end). Capacitors expel heat mostly from the top of the can. If you add a couple of caps, their respective temperatures drop significantly and they are outside of any water cooling.

Right now for me I choose to attempt to keep the motor temp within reason.

Bob