Polaris Seaplane Parkflyer - Page 507 - RC Groups
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Jul 20, 2010, 04:46 PM
TonyS
Quote:
Originally Posted by mavlo77
Leaks found in my polaris.

I think I found the source of my problem with water inside the hull....

I pressurized the hull, poured some soap water... And found several bubble-generators... . The nacelle is not a big problem as it will normally not be covered with water. But the wing is frequently covered with water. So I think some capilary action will do the rest....

Do some more testing tomorrow (on the bottom).
mavlo;

I am amazed at the bubbles along the carbon reinforcement. It is almost as if the glue has formed a tube allowing air (water) to move along it.

Thanks for sharing!

TonyS
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Jul 20, 2010, 05:23 PM
unconventional :-)
kadil's Avatar
Quote:
Originally Posted by mavlo77
Leaks found in my polaris.

I think I found the source of my problem with water inside the hull....

I pressurized the hull, poured some soap water... And found several bubble-generators... . The nacelle is not a big problem as it will normally not be covered with water. But the wing is frequently covered with water. So I think some capilary action will do the rest....

Do some more testing tomorrow (on the bottom).
Your rig is ingenious!!! Well done.

I worked for a food manufacturing/packaging company many years ago, the way we tested for leaks was to insert the product into a clear plastic box filled with water, hold it down under the water and pull a vacuum on the air above the water. The air in the product expanses and would find it's way out any holes forming bubbles that stream to the surface. This only works fully sealed units with a small leak, not very good for this application.
Jul 20, 2010, 05:32 PM
Registered User
mavlo77's Avatar
Hi Thanks! I was really surprised. On one hand happy aswell, as I found the source of my problem (hopefully....)...

But this is a lesson for my next Polaris: seal the area around the CF which is inside the fuse... It's a small area you have to seal, and it's only on the bottom. Then there will be no path from outside to inside. Even if there are imperfections in the CF glue joint outside the fuse, or any damages in that area on the outside.
Jul 20, 2010, 06:28 PM
Registered User
Quote:
Originally Posted by mavlo77
Hi Thanks! I was really surprised. On one hand happy aswell, as I found the source of my problem (hopefully....)...

But this is a lesson for my next Polaris: seal the area around the CF which is inside the fuse... It's a small area you have to seal, and it's only on the bottom. Then there will be no path from outside to inside. Even if there are imperfections in the CF glue joint outside the fuse, or any damages in that area on the outside.
Mavlo, that is very interesting but I find it hard to believe water could enter the fuse from the carbon wing slot unless you are spending a great deal of time cruising around in rough water. Of all the areas of potential water ingress, that would seem to be the least likely. But, you have shown it may be possible.

Anytime I have seen water intrusion, it has been through the lower aft fuse bottom, where I typically only tape it in place. It's fairly simple to seal the forward fuse while building the plane.

Scott

www.ModelAero.com
Jul 21, 2010, 09:08 PM
Eric
doc_74's Avatar
Hey guys,

I have been lurking here on this thread since the early spring and have read through every post. The more I read, the more I wanted to build this plane. I finally got around to getting all the parts ordered and finished building up my Polaris a couple weeks ago. This was my first depron build and my second scratch build. I previously put together a Leadfeather designed 3D EPP Edge 540T that I have been attempting a little 3D flying with this summer. This build was just a little more complicated than that profile foamy though!
I basically followed Steve's build guide with a couple minor deviations. I like the strip aileron construction because I will be flying primarily off water in the summer so I wanted to have minimal opportunity for water to get in. I am running a 2212-06 motor with a 2200 mAh LiPo and a Turnigy 40 Amp ESC with a heat sink, HXT900 servos and a spectrum reciever all getting pulled around by the suggested APC 6X4 prop. It all came in a little on the heavy side at almost 23 ounces, but I did use a lot of white gorilla glue so that might account for the couple extra ounces.
Since I will be primarily flying off water, I made sure the hull was water tight (lots of glue) and I completely removed the heat shrink from the ESC and coated it with a couple layers of liquid tape to make sure it was waterproof too (you know....just in case!).
Once it was all built up I maidened my polaris at a local park. A couple clicks of up elevator and she was flying beautifully.....and FAST!! Wow, this is way faster than my other plane (E-Flight Apprentice that I taught myself to fly on and have since added floats and converted to a sea plane). This Polaris is SOOO much fun to fly. I have had it on the water for about 8 more flights since the maiden and am having an absolute blast with it!!
Here are a few construction pics and a couple of the final product. I finished it in a pseudo coast guard theme. Hope you don't mind Scott, but you have such a great looking design scheme and I was just trying to get it close!

Thanks to everyone who posted there experience and build tips on this thread and a HUGE thanks to Steve and Laddie for such a wonderful plane!! I definitely see one of Steve's park jets in my future too!
Jul 21, 2010, 10:51 PM
Registered User
Quote:
Originally Posted by doc_74
Hey guys,

I have been lurking here on this thread since the early spring and have read through every post. The more I read, the more I wanted to build this plane. I finally got around to getting all the parts ordered and finished building up my Polaris a couple weeks ago. This was my first depron build and my second scratch build. I previously put together a Leadfeather designed 3D EPP Edge 540T that I have been attempting a little 3D flying with this summer. This build was just a little more complicated than that profile foamy though!
I basically followed Steve's build guide with a couple minor deviations. I like the strip aileron construction because I will be flying primarily off water in the summer so I wanted to have minimal opportunity for water to get in. I am running a 2212-06 motor with a 2200 mAh LiPo and a Turnigy 40 Amp ESC with a heat sink, HXT900 servos and a spectrum reciever all getting pulled around by the suggested APC 6X4 prop. It all came in a little on the heavy side at almost 23 ounces, but I did use a lot of white gorilla glue so that might account for the couple extra ounces.
Since I will be primarily flying off water, I made sure the hull was water tight (lots of glue) and I completely removed the heat shrink from the ESC and coated it with a couple layers of liquid tape to make sure it was waterproof too (you know....just in case!).
Once it was all built up I maidened my polaris at a local park. A couple clicks of up elevator and she was flying beautifully.....and FAST!! Wow, this is way faster than my other plane (E-Flight Apprentice that I taught myself to fly on and have since added floats and converted to a sea plane). This Polaris is SOOO much fun to fly. I have had it on the water for about 8 more flights since the maiden and am having an absolute blast with it!!
Here are a few construction pics and a couple of the final product. I finished it in a pseudo coast guard theme. Hope you don't mind Scott, but you have such a great looking design scheme and I was just trying to get it close!

Thanks to everyone who posted there experience and build tips on this thread and a HUGE thanks to Steve and Laddie for such a wonderful plane!! I definitely see one of Steve's park jets in my future too!
That is a great looking Polaris and very impressive for your first Depron build. Way to go!!!

Scott

www.ModelAero.com
Jul 21, 2010, 10:55 PM
Did ya'll see that?!?
Tony A.'s Avatar
Quote:
Originally Posted by Model Aero
That is a great looking Polaris and very impressive for your first Depron build. Way to go!!!

Scott

www.ModelAero.com
Ditto!!
Jul 21, 2010, 11:45 PM
Registered User
Quote:
Originally Posted by doc_74
Hey guys,

It all came in a little on the heavy side at almost 23 ounces, but I did use a lot of white gorilla glue so that might account for the couple extra ounces.

I think maybe you got carried away with the glue. Start with square cuts on the depron, sand perpedicular if needed. For the fuse bottom and the wing to fuse joint use epoxy (I used epoxy most everywhere, except white Gorilla glue on the wing spar). Then go over the wing to fuse joint with a thin coat of hot glue as a seal.

I don't think a 100% seal is absolutely critical. A drop or two in the lower fuse won't hinder anything (receiver and ESC is above the wing). Any drops that do get in are easily shaken out.

Just my thoughts...please don't flame!
Jul 22, 2010, 01:21 AM
Registered User
mavlo77's Avatar
Quote:
Originally Posted by gapagod
I don't think a 100% seal is absolutely critical. A drop or two in the lower fuse won't hinder anything (receiver and ESC is above the wing).
If you don't go inverted: yes ...
Jul 22, 2010, 10:10 AM
Airplane Killer
SumthinsFishy's Avatar
Quote:
Originally Posted by zhenfeng
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Jul 22, 2010, 10:42 AM
Fly now crash later
davecrash's Avatar
There's a new ESC at HK that may be perfect for the Polaris. It already has a nice looking heat sink, Just some brush on electrical tape to seal it and and it should be good to go and it's only $11.00

http://www.hobbycity.com/hobbycity/s...dProduct=11617
Jul 22, 2010, 11:34 AM
60 years of RC flying
Daedalus66's Avatar
Quote:
Originally Posted by davecrash
There's a new ESC at HK that may be perfect for the Polaris. It already has a nice looking heat sink, Just some brush on electrical tape to seal it and and it should be good to go and it's only $11.00

http://www.hobbycity.com/hobbycity/s...dProduct=11617
I still believe a good switching BEC is worthwhile insurance, especially if you intend to use the ESC inside the hull without ventilation. This ESC uses a linear BEC.

I've standardized on the Maytech 40 amp ESC w/SBEC available from Model Aero as I was so impressed with it when I tested it.

I'm also a bit worried about the impact on ESC cooling of the heat insulating qualities of the liquid tape that people are using. I'm sticking to CorrosionX to waterproof my electronics. For sure, I would not coat the heat sink with anything that lessened its ability to get rid of heat.
Jul 22, 2010, 12:23 PM
Eric
doc_74's Avatar
Scott, Tony,

Thanks for the kudo's. I took my time but I think it was worth it. I am pretty happy with the way she turned out.

Daedalus66,
I too was a little worried about the isulating factor of the the liquid tape. I just made sure I put the heat sink on correctly that I got from Scott at Model-Aero. I think a combination of a higher rated ESC (40 amp) and a higher C rating on the battery (25-30) is helping keep the ESC and battery a little cooler than a 30 AMP esc/lower C rated battery set-up would provide. Last week we had some hot days here in the mid 90's and I had absolutely no problems with my set-up. I set my timer for 10 minutes and that pulls very close to 80% of the capacity out of my battery while being pretty aggressive on the throttle. I can touch my heat sink right after the flight and it is not that hot. I can also reach the ESC by reaching in through the battery hatch with my fingers and can hold my fingers to the ESC with no problems. My battery is also not warm enough to give it any concern.
I may have over-engineered it a little but it doesn't look like I am going to have any thermal issues so I am happy with it.
Jul 22, 2010, 03:15 PM
Park Jet Guru
jetset44's Avatar
Quote:
Originally Posted by doc_74
Hey guys,

Thanks to everyone who posted there experience and build tips on this thread and a HUGE thanks to Steve and Laddie for such a wonderful plane!! I definitely see one of Steve's park jets in my future too!
Great story and very nice model, doc! Thanks for the story and pics, and you're welcome for the plans.

Steve
Jul 22, 2010, 03:24 PM
Dance the skies...
Tom Frank's Avatar
Quote:
Originally Posted by Daedalus66
I still believe a good switching BEC is worthwhile insurance, especially if you intend to use the ESC inside the hull without ventilation. This ESC uses a linear BEC.
...
I'm also a bit worried about the impact on ESC cooling of the heat insulating qualities of the liquid tape that people are using. I'm sticking to CorrosionX to waterproof my electronics. For sure, I would not coat the heat sink with anything that lessened its ability to get rid of heat.
I couldn't agree more, especially with the latter. Corrosion-X PLUS ventilation solves ALL the problems. No over heating, no water damage to sensitive electronics, no issues with a hull that might have a small leak (invert and drain after a flight). It's so simple and effective, but few seem to want to go that route.