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View Full Version : Cooling air (but no water) to ESCs in Seabee.


Henry111
05-30-2010, 07:20 AM
I need some advice from you seaplane folks.
G and P Sales 72-in. TWIN Seabee is ready for ESCs and battery. The ESCs will MAYBE be located in the fuselage along with the batteries, perhaps attached to the wing just under the wing opening to the fuselage. Problem: How do I get cooling air flow to those ESCs without letting water in at the same time. You can see the build up to this point at:
www.electricflyermagazine.com (http://www.electricflyermagazine.com)
I considered putting the ESCs in the motor cowlings, but that would result in overly long wires to the batteries.
There is lots of volume in the fuselage, so maybe cooling will not be a problem--I hope--but I would appreciate your thoughts.

Larry3215
05-30-2010, 11:38 AM
You're going to need to cool the batteries too so one way or another you need to get some airflow in and out of that fuse.

I locate my air inlets forward of the splash line from the hull and up hi. Make the exit somewhere in the back or even in the wing bottom if you can make that work.

During normal flying, no water will ever get in. If you crash, water is going to get in around the wing anyway, so an extra air inlet hole isnt going to make any difference.

Larry3215
05-30-2010, 11:47 AM
Two other things I do on all my water flyers.

1) Treat the controller with CorrosionX to water proof it.

2) Mount the controller so its not at the very bottom of the fuse. If any water does get in, it will go to the lowest point. Also picture how the plane might sit in the water if it landed up-side down for any reason. Make sure the esc isnt in the lowest position for THAT attitude.

Henry111
05-30-2010, 11:50 PM
Larry, Himat, a gentleman over at RC Groups makes this suggestion for cooling the ESCs. Please tell me what you think. (Forgetting about the batteries for a moment or the air exits.)

Cut holes in the fiberglass fuselage. Glue the ESC cooling plates (My ESCs do not have fins.) to the inside of these holes. Atatch the ESC to this cooling plate (on the inside--if not already attatched. Water proof the hole. I would probably use hotmelt glue for this purpose.
What da ya think?

Larry3215
05-31-2010, 01:30 AM
That technique wont work for any of the name brand controllers like Castle, Jeti, Schulze, etc.

In fact it doesnt really work at all unless you use a very thin layer of heat transfer paste between the esc heat sink and the external heat sink. Hot glue sure wont do you any good. Those metal plates you see on the cheep esc's are not really properly installed to do much good as far as cooling. You still need good air flow.

If you're going to use a cheep controller and especially if your not going to give it plenty of cooling air, then your best bet is to over size it by a large margin and keep your fingers crossed :)

I dont know why people are so paranoid about letting cooling air in on water planes.

If you position the inlet and exit properly no water ever gets in. Really, it doesnt.

If you crash, water ALWAYS gets in no mater what you do. Having an air inlet isnt going to make any difference at all.

The best solution is to water proof the esc and rx to begin with so that it doesnt matter if water gets in. CorrosionX works great of properly applied.

I have deliberately run treated motors and ESC's - under power - while they were completely under water, with no damage.

CorrosionX works if properly applied.

I have built and flown literally dozens of my Capricorn flying boats and none of them make any effort to protect the esc from water. They sit inside a long open area that runs from front to back that is open at each end. When I crash, the esc is completely submerged.

On my smaller one the esc is completely exposed on the bottom side of the fuse. It gets splashed on every take off and every landing. Ive flown it dozens of times off the water.

I crash in the water a lot because I like to fool around on or near the surface a lot :)

All I usually do is wait for the wind to blow the model back right side up and then give it a minute for the water to drain out of the treated RX and take off again.

Ive had models sitting up-side down - with the rx and esc under water and still plugged into the battery - for over an hour. Once I finally retrieved the model all I did was shake the excess water out and start flying again.

If you treat the esc and rx you dont need to worry about water and all this trouble and worry can go away :)

Larry3215
05-31-2010, 01:54 AM
For details on how to use CorrosionX, check out post #3 in my Capricorn thread.

http://www.wattflyer.com/forums/showthread.php?t=26120

Larry3215
05-31-2010, 01:57 AM
I should fess up on one thing. In all the years Ive been using CorrosionX and all the water flights and crashes Ive had I did kill ONE esc.

It turns out I didnt get the CorrosionX to completely cover every single chip on the board. The BEC burned out when it got dunked.

I sent it in to Castle they told me what went wrong and then they repaired it for free even though it was my fault :D

Henry111
05-31-2010, 02:22 AM
Thanks Larry. I'll check out the instructions corrosion X.

Henry111
05-31-2010, 04:58 AM
Larry, will it help some if I remove the shrink wrap from the ESC before dunking? Then replace with new shrink wrap?

Larry3215
05-31-2010, 05:27 AM
Yeah, that will help. Ive taken to doing a full dunking these days, then flip over and repeat and turn and repeat and allow it to soak for a while.

Just spraying was how I killed that one esc.

Bill G
07-11-2010, 08:47 PM
I have the same concerns Henry. My ESC in the engine cowl causes the batt wire length to be maxed out, but there is a scale grille that allows for prop drawn cooling air to the ESC. Castle claims that their input caps will allow a 14" max batt cable length, if I remember correctly. We'll see. I will probably parallel more caps also. I assume that you want the battery to be mounted in front, for ballast, thus length to the motor. I would look into increasing cable gauge and adding caps. Irregardless, with a UBEC, ESC failure will still allow control of the plane. I'm sure you'll be staying over water, away from trees and land, just in case.

Not the thread topic, but another that often comes up:
Pretty tough also to cool the batt, and keep a sealed cab, like I have. One good thing however, is that the latest low IR lipos can run amazingly cool for a resonable period of time, with no cooling. In my
EDFs, the difference in temp has been substantial. With ample batts, I think you will get reasonable flight time, without air movement for cooling. One good thing is that the fuse itself is large, and has a substantial volume of air to heat. It's not like as if it's wedged in a tight foam EDF batt compartment. Cooling lipos with air movement is not very effective to begin with, especially with more than a 2-cell batt, with a cell stuck in the center. It also takes some time in flight before air movement begins to really help in reducing batt temps. Depending on your desired flight time, it may not be that much of an issue.

Henry111
07-12-2010, 05:01 AM
Here is what I finally did with the Seabee:
After looking at photos of full scale Seabees I saw that a lot of them have cabin cooling louvers right above the cabin. So I added some to the model. The ESCs are located on the underside of the wing directly behind the louvers. I raised the battery pack so it, too, is behind the louvers. If you care to have a look you can see it at:
http://www.electricflyermagazine.com/seabee-completion-page1.html
Note that I did not move the batteries for better cooling. I did it for CG balance. A bonus was shorter ESC-to-battery wires. I think the need for cooling air to batteries is an over concern. To have any real cooling effect on 8 cells you;d have to be blowing ice cold air.

E-Challenged
09-01-2010, 05:38 PM
New Hi-C-rated lipos run cool in confined spaces ( buried in my ME-262) at fairly high amp draw for a while then start to warm up as they are stressed over time. Relatively low average amp draw/ample capacity should keep them running cooler longer as in a cruising Seabee.

I am a Seabee fan, have Cleveland plans, will probably carry lipo(s) in the forward cabin area with ESC close by and extend ESC-to-motor wires. I would keep flight times short and remove packs to cool as needed. Of course this necessitates removing wing to change packs. Challenging subject.

road king 97
02-06-2011, 01:12 AM
I know you should have air going over your esc but in my electrict sea planes i dont . I have plenty of room around them and do not run at full throttle all of the time to over heat and mine have flown fine so far. I hope you do a build thread of your seabee I have always wanted one. joe

Jim Casey
02-06-2011, 03:27 AM
>>I think the need for cooling air to batteries is an over concern. To have any real cooling effect on 8 cells you;d have to be blowing ice cold air.<<

I Agree completely. If battery cooling were so vital the manufacturers would not seal them in a sleeve of shrink-wrap. The shrink-wrap acts as an insulator. On 3S LiPOs, the middle cell gets next to no cooling.

Bill G
02-07-2011, 05:28 AM
>>I think the need for cooling air to batteries is an over concern. To have any real cooling effect on 8 cells you;d have to be blowing ice cold air.<<

I Agree completely. If battery cooling were so vital the manufacturers would not seal them in a sleeve of shrink-wrap. The shrink-wrap acts as an insulator. On 3S LiPOs, the middle cell gets next to no cooling.
Absolutely as for the center cell/s, and even more so, we don't generally fly long enough to reach a steady state condition, where we could really consider the effect of the cooling air. As the batteries have continuously lower IRs, the issue is even less important. In the past, batteries that I overheated would have overheated with good cooling or not. They were simply pushed too hard, period.

When I finally fly my Seabee somday, I'll be happy that the newer lipos should easily give a 4-5 minute flight, while also being able to fit, and keep the weight down. I have no cooling for my Seabee batt, as it is not an easy plane to provide cooling for the battery, and keep things sealed.

road king 97
02-07-2011, 02:46 PM
I agree with you bill ,and alot of being pushed to hard is the right prop size and to many watts being pulled to over heat. I do not know all about electrict planes thats why i sighned up here to learn ,but i do know when a motor is working harder than it should be and the esc shuts down. flying at full throttle all of the time when the batterie are getting low ,will cause a esc to shut down too. joe

E-Challenged
04-18-2011, 03:11 AM
I sent an e-mail to Park Zone suggesting that they produce a foamy Seabee. I think that foam would work nicely to make the bulbous cabin and a light rear fuselage even though I am primarily a balsa model builder. Getting the cg right while keeping overall weight down is a major challenge with the Seabee.

kenchiroalpha
04-18-2011, 03:32 AM
I sent an e-mail to Park Zone suggesting that they produce a foamy Seabee. I think that foam would work nicely to make the bulbous cabin and a light rear fuselage even though I am primarily a balsa model builder. Getting the cg right while keeping overall weight down is a major challenge with the Seabee.
Hi
Have you seen the Robbe version:$:tc::ws:
http://www.harbormodels.com/site08/info_pages/robbe/seabee.htm
Do enjoy:D
http://www.youtube.com/watch?v=8NOo3Ic8QUg
She on my want list:D
Take care
Yours Hank