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AirmanAirhead
08-19-2009, 03:49 PM
BEFORE YOU SEAL UP YOUR POLARIS RUN A WATT METER TEST!!!

For those of you building a Polaris, if you have read much about it you will discover that some of us had or have over heating issues related to ESC's and or Motors partly due to lack of air flow, etc.

Before you seal up your wires, esc's and motor connections I urge you to run a watt meter test and make sure you are within good margins. I would assume this is good practice on any plane, but especially on Sea Planes where things get sealed in to protect them from water.

If you don't have a watt meter, then I suggest you borrow or buy one. I've learned the hard way how important this is. Lastly, I think it is also wise to tape the top panel or bottom panel on and test fly it before you seal it. Fly it on GRASS of course since things will not be sealed, and make sure you are not having any over heating problems. Trust me it is much easier to trouble shoot stuff before you glue this puppy together. I was sooooo excited to fly this great plane that I glued it up, testing only the control surfaces, but never thought about the motor and speed control!!! Like most good lessons, I learned the hard way. And like most good lessons, I'll never forget it!!

Of course it's not impossible to cut in access panels after the fact and then re glue them, but it's a drag and not the final look most of us want.

Having said all of that, I found this added information on another forum which I think is a great suggestion on the Polaris. The access panels are very helpful, not so sure about the placement of the esc in the nacelle

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Originally Posted by SGTalon
I built mine with access panels all over the thing. Mainly because i didn't want to get stuck with my hardware buried in a plane.

I put an access hatch on the top of the engine nacelle (i also put my speed control here) Not sure this is such a good idea, longer battery leads can cause ESC problems.... JN

Over the servo bay at the back of the fuse and in the front for the battery. I covered the top surfaces with tape then put a second layer of thinner tape to hold everything closed. Not i don't have to worry about peeling my paint off too.

Larry3215
08-20-2009, 07:00 AM
Hi Jeff,

Thanks for the tips! Excellent advice!

More guys need to build a Polaris. They are very cool planes and awesome on the water!

I will add one - long - comment on the cooling and the need to "seal it up".

I never bother to seal up any of my water planes since I discovered CorrosionX.

I have 8 routinely flying off water at the moment (5 Capricorns, XXL Polaris, BatBoat, 4Q, BUFY) plus maybe a dozen or more old Capricorns and maybe 6 or 8 different "Hydros" of various types that Ive built and crashed over the last few years as well as more than a few "normal" float planes.

Ive dunked my gear in the water - motor, rx, esc, servos, BEC's etc, litterally hundreds of times. Sometimes they have sat under water for as long as an hour or two while I tried to get them back.

All with not one single damaged bit of electronics.

The single exception was one time I did NOT use enough CorrosionX. I burned up the BEC unit on a controller when it got dunked. The tech from Castle told me I had missed the BEC controller chip. I dunk my stuff now instead of just spraying them.

My giant scale Polaris has a 1350 watt power system. It must have lots of cooling air or it will die. I added a large open air intake on the top front with an open air exit near the tail plus a huge battery access hatch that is not sealed in any way and no water ever gets in during normal water flying.

Even if I did crash it on the water there would be no reason to worry - so I dont :)

Use CorrosionX and leave an air intake and air exit and you wont have any issues with cooling or water damage :)

Some guys treat their servos but I dont. If you do treat the servos - just do the circuit board and do not get it in the motor or the pot. The servo will slow down or may not work at all.

If its a new brushless servo you could do the motor but normal servos have brushed motors and you never want to treat brushes with CorrosionX.

Its good for the motor bearings though. Keeps them from rusting and adds some lubrication.

I agree on the need to keep battery leads short. My xxl Polaris has the esc up front where it can stay cool and have short leads to the battery. My motor leads are almost 4 feet long! Works perfectly.

AirmanAirhead
08-20-2009, 07:42 AM
Larry,

I have a question for you regarding Corrosion X I used it on my motor after reading your recommendation, I figure you gotta know what you are talking about with all your Sea Planes. I didn't dunk my motor in it, instead I sprayed it real good using the red spray tube. Then I sealed things up and did the maiden. Long story short I had an over heating problem right way. I checked the ESC even swapped it out with another one, both 40 AMP. Still had over heating. I added scoops and that seemed to help. Then I started testing and retesting on the bench using a watt meter. I thought my motor extension leads might be too small of a gauge so I bypassed those for larger ones. Finally I went back to my origianl ESC and same wires.

All this to say that the more I tested the motor the more I started noting the numbers coming down. I dropped a little over 100 peak watts at WOT. I went from 40 amp draw to 27. The only thing I can figure is that the Corrosion X had clogged up something on the motor. Have you ever had that kind of an issue? I assume not, but I want to figure out what the heck is going on here. Have any ideas?

Thanks,
Jeff

Larry3215
08-20-2009, 08:38 AM
Ive never had any issues at all with treated motors.

A drastic drop in watts after running for a while sounds to me like something is heating up. Resistance will increase in the motor when it gets hot which will lower the amp draw and the total watts. The problem is, that just makes the motor run hotter as the resistance goes up.

You may have a poor connection somewhere - bad connector for example. That can also cause a drop in current flow. If the lead wires running back to the motor are too small they will also heat up robbing you of power.

If any of that is whats going on you will also note a drop in full throttle rpm when the power drops off.

If the CorrosinX was gumming things up and then things were "loosening up" after running for a while, then the rpm would increase as the power draw went down.

Do you have any way to check rpm? If so, test it when the motor is cold and power draw is at the max, then re-test it after things warm up and the power drops off.

It could also be a speed controller issue. If its over heating or if just the BEC circuit is over heating, it may be limiting the current flow.

If you can, check rpm like I said and let us know what you find. That may give a clue to whats going on.

AirmanAirhead
10-18-2009, 12:34 AM
Hey Larry,

OK, months later, I've had a couple of mishaps on the water. I've lost a couple of ESC's in the process due to water. I've been spraying the C. X not dunking. Mainly because I can't find the stuff locally in anything but spray. I've now concluded that dunking must be the way to go. Your note on missing the "chip" in your Castle ESC is a good point.

Any suggestions?

Jeff

Larry3215
10-18-2009, 01:13 AM
First a question for you. Are you cutting the throttle the instant you hit the water or befor if possible? If you try to run the motor while the prop is under water it will draw huge huge currents and likely burn something up almost instantly. Also, if your reciever isnt treated it could go nuts and cause the motor to power up and that could burn up the controller.

When I can only get the spray can, I cover the top of a large tall jar - like a 1 quart canning jar - with some paper towels or an old cloth of some type. Stick the plastic spray tube down inside the jar a spray until the jar is 1/2 full of liquid.

Its a bit waistfull and messy because some will get out and or soak into the paper towels. But at least then you can dunk.

AirmanAirhead
10-18-2009, 01:27 AM
Thanks for the point about cutting the throttle. Honestly I never really pondered that. Good point. I guess the very best practice is cut it and then retrieve it. Then do you let things dry out on their own, do you used compressed air or a blow dryer. What's the story on making sure things are dry before you try to power up the system again? Thanks Larry, you are tons of help!

Jeff