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Old Oct 05, 2012, 09:02 PM
advanced n00b
xfatdannx's Avatar
United States, NE, Omaha
Joined Feb 2012
978 Posts
4s or 5s? and would you be willing to balance mine for me!?
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Old Oct 05, 2012, 10:25 PM
Scale Jet Driver
Rangerfan's Avatar
United States, TX, Grapevine
Joined Jul 2012
707 Posts
battery cooling and retracts

Quote:
Originally Posted by herk1 View Post
Just got back from test-flying the E-flite main-gear retracts in my F/A-18. Flew two batteries for two landings. The retracts worked great...landings were pleasantly uneventful. The E-flite retracts are the best, solid as a rock.

On another subject: is anybody doing anything to ventilate the battery compartment? There is an outlet (the opening for the wiring) but there is no inlet. My batteries are getting too warm.
Herk1: I had the same concerns on the battery cooling so I cut three vents on the fuse and painted them so they aren't so obvious.

You inspired me on the eflite retracts so I did the same thing. I found a way to do the nose (at least the taxi test showed success, we'll see when I fly it). Had to cut away the foam where the old retract was mounted. Put down ply to mount the new unit to and installed an eflite metal gear servo I had laying around and used a prebent pushrod (I think it came with the kit for the fixed gear maybe?). Had to epoxy a zip-tie to the side of the well to keep the pushrod out of the way of the strut. Seems to work well.
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Old Oct 06, 2012, 07:22 AM
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herk1's Avatar
Maryland, USA
Joined Oct 2006
1,700 Posts
Nice job, and I'm glad to see that the E-flite unit can be fit in there without too drastic surgery. So the stock servo position was not workable?

I think I'm going to borrow your cooling vent idea too (inlet holes tucked out of sight under the leading edge extensions). Except I'm going to locate them farther forward so that the incoming air will pass over the whole battery, for where I'm situating my batteries. And I'll tack on some plastic scoops, to scoop in more air. I'm using 2650 and 3300 size 4S batteries. The 2650 was getting especially hot.
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Old Oct 06, 2012, 09:24 AM
Scale Jet Driver
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United States, TX, Grapevine
Joined Jul 2012
707 Posts
Herk1- that's a good point on moving the vents forward. In retrospect, I wish I had made them about one inch forward. I'm using 2800's as far back as they'll go but if I use anything larger, the vents won't fully cover the larger battery.

Yeah the stock servo location was no good for getting much throw. Would be limited severely by the arm length.
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Old Oct 06, 2012, 09:56 AM
Defender of the park sky
Ispintechno's Avatar
London, ON Canada
Joined Nov 2009
1,123 Posts
Interesting point about the battery cooling. My Zippy 2800's get warm, not puffy warm but clearly not much air movement is happening there. I'm adding two Turnigy nanotechs into the mix though, much higher discharge and will be running a few more watts through this thing too soon. I wonder if turning the nose gun into a couple cooling holes would be enough or do much. Exiting air shouldn't be a problem, there is a huge exit where all the servo wires run back, it's getting air from the nose I think.

Dan, testing the Turnigy L2855-2800 on 4S hooked up to the CS10 70mm, probably on Sunday or Monday. Just need some connectors for my 80amp ESC. Might grab those today at the LHS.
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Old Oct 06, 2012, 02:02 PM
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United States, NE, Omaha
Joined Feb 2012
978 Posts
awesome man. let me know what you get. i am thinking with mine i am gonna have to go 5s to get anyhting out of it. I really don't want to cuz that would render my pretty much brand new batteries useless, and i would need a new charger that can do 5s. The point of staying 4s for me was to do 2s batteries so my 2/3s charger could handle it without a new one. ALTHOUGH!!! i am thinking of getting a second so i can charge my batteries faster. I guess i will just have to play it by ear.
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Old Oct 07, 2012, 06:33 AM
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Maryland, USA
Joined Oct 2006
1,700 Posts
I swapped over the stock power system to my HET fan+motor+ESC (HET 6904 fan, 2W-20 motor, HET 75A ESC w/switchmode BEC). It was nearly a drop-in fit....just a little sanding and trimming. I was surprised when I took out the stock ESC that there are slots under the ESC that open to the interior intake area, I presume for cooling the ESC. So they mounted the stock ESC with the heatsink facing the inside. I'm not sure how effective that will be for cooling though, since they made the slots perpendicular to the airflow instead of parallel, and the foam is pretty deep there. But I followed suit and put the HET ESC's heatsink to the inside too. I made the plastic cover for the ESC and wiring removable with four screws...so after my first test flight I will take that off and check the temp of the ESC. It got pretty hot when I used the same power system in my Habu.
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Old Oct 07, 2012, 10:18 AM
Defender of the park sky
Ispintechno's Avatar
London, ON Canada
Joined Nov 2009
1,123 Posts
Quote:
Originally Posted by xfatdannx View Post
awesome man. let me know what you get. i am thinking with mine i am gonna have to go 5s to get anyhting out of it. I really don't want to cuz that would render my pretty much brand new batteries useless, and i would need a new charger that can do 5s. The point of staying 4s for me was to do 2s batteries so my 2/3s charger could handle it without a new one. ALTHOUGH!!! i am thinking of getting a second so i can charge my batteries faster. I guess i will just have to play it by ear.
Dan, get this charger, it's only $40 now and it is awesome! I have been using it for 3 years. 1-6 cell lipos, quick charge, balance charge, lipo storage mode (I use this to properly store my batteries at the right voltage each winter). This charger works a real treat. I charge multiple single cell lipos at one time for my pkz p-51 micro to doing my 3 and 4 cells at a pretty speedy amp rate to get out the door.

http://www.hobbypartz.com/thac6smbachw.html

http://www.hobbyking.com/hobbyking/s...dProduct=10621

http://www.hobbyking.com/hobbyking/s...apter_Set.html

What ever brain is in this charger in balance mode I have found it to even fix some turnigy 3 cells that had off balance cells. After many cycles later those batteries are still good after almost throwing a couple away. Anywho, just my 2 cents there.


Herk, sounds like a great set-up. Those HET parts seem to be top quality. Wouldn't mind seeing a pic of how you are mounting that ESC cover too. I figure I'll get one more flight off with mine stock than rip it apart after I get a motor/esc combo to work right on the bench.
I need a new soldering iron. It's really crapping out. Just need to add motor connectors to my Turnigy superbrain ESC without heating up the whole damn thing.
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Last edited by Ispintechno; Oct 07, 2012 at 10:38 AM.
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Old Oct 07, 2012, 11:39 AM
Progress with the process...
M3ATpl0w's Avatar
NE Alabama
Joined Feb 2011
141 Posts
Quote:
Originally Posted by herk1 View Post
I swapped over the stock power system to my HET fan+motor+ESC (HET 6904 fan, 2W-20 motor, HET 75A ESC w/switchmode BEC). It was nearly a drop-in fit....just a little sanding and trimming. I was surprised when I took out the stock ESC that there are slots under the ESC that open to the interior intake area, I presume for cooling the ESC. So they mounted the stock ESC with the heatsink facing the inside. I'm not sure how effective that will be for cooling though, since they made the slots perpendicular to the airflow instead of parallel, and the foam is pretty deep there. But I followed suit and put the HET ESC's heatsink to the inside too. I made the plastic cover for the ESC and wiring removable with four screws...so after my first test flight I will take that off and check the temp of the ESC. It got pretty hot when I used the same power system in my Habu.
If you find that your ESC is getting too hot, you may want to try what I did. I am using the HW 80A platinum with the aluminum heatsink, so I cut the foam out in that area so that I could recess the ESC where the heatsink would be slightly protruding into the intake area. Only done bench testing so far, but it seems to work really well. Keep us posted on your new setup!
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Old Oct 07, 2012, 12:16 PM
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Maryland, USA
Joined Oct 2006
1,700 Posts
To make the belly cover removeable, I cut four small rectangles of 1/8" plywood measuring 7mm X 14mm. Then with a #1 x-acto knife I carved out corresponding chunks in the EPO to fit the wood pieces at the spots shown in the photo...and for extra security, part of that cut goes underneath the "lip" in the EPO at that curved part (about 3mm of the wood piece slides under the "lip"). I then Gorilla-glued in the wood pieces. Then I punched four holes for the screws in the plastic cover using the punch attachment of a pin vise, then put the cover in place and poked thru those holes into the wood pieces to make starter holes for the screws. Photo attached...which also shows numerous other mods I've done so far (and I'm not finished)...including the pass-thru connecting skewer spar, CF tube sleeves for the elevator pushrods, better control horns with screw-down backplates, twin battery compartment inlet cooling vents with air scoops, and a more secure battery tie-down that loops around the outside.
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Old Oct 07, 2012, 05:18 PM
Defender of the park sky
Ispintechno's Avatar
London, ON Canada
Joined Nov 2009
1,123 Posts
Well today was a mixed bag. Got my LED system working but I broke the CS10 fan... on my hand
Thought I had those 4 little screws on tight to the shaft but the fan flew out the front sideways hitting me in the hand. Lost a little blood.
Well this sets me back a few weeks...

Well at least I still have fancy afterburners...
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Old Oct 07, 2012, 06:14 PM
advanced n00b
xfatdannx's Avatar
United States, NE, Omaha
Joined Feb 2012
978 Posts
Ill send u mine fan and motor to finish your tests if you balance it and send it back when you are done
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Old Oct 08, 2012, 09:35 AM
Defender of the park sky
Ispintechno's Avatar
London, ON Canada
Joined Nov 2009
1,123 Posts
Quote:
Originally Posted by xfatdannx View Post
Ill send u mine fan and motor to finish your tests if you balance it and send it back when you are done
I can't tell you yet if I'm any good at balancing the fan
It kinda flew off the motor shaft before I could detect any vibration lololol
I ended up using just a tiny bit of CA, I really couldn't find much wrong with this rotor which bums me out even more as I destroyed it.

I did use a simple trick, found this on you-tube:

Instruction on How to balance a EDF fan (5 min 35 sec)
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Old Oct 08, 2012, 10:06 AM
Registered User
United States, TX, Grand Prairie
Joined Nov 2005
5,720 Posts
Quote:
Originally Posted by Ispintechno View Post
Well today was a mixed bag. Got my LED system working but I broke the CS10 fan... on my hand
Thought I had those 4 little screws on tight to the shaft but the fan flew out the front sideways hitting me in the hand. Lost a little blood.
Well this sets me back a few weeks...

Well at least I still have fancy afterburners...
Believe it or not it's worth it, this is one of the best 70mm models out there in so many ways..

I use the 2500kv CP 480 motor and fly mine on 4, 5 and 6s...
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Old Oct 08, 2012, 02:46 PM
Trash Hauler emeritus
herk1's Avatar
Maryland, USA
Joined Oct 2006
1,700 Posts
I got a couple of flights in this morning with the HET power system that I just installed. Wow it really woke this plane up! Better speed, better vertical, and it has a great "whoosh" sound that is very reminiscent of a real jet (simultaneous with the usual annoying EDF "whine" sound). The Habu didn't make that "whoosh" sound with the same power system, so it must be something about the ducting on this plane. With all the changes I've made, I'm starting to like this plane now...

Flight times were a little disappointing though. The 3300 battery was almost sucked dry on a 3-minutes-and-50-seconds flight (I think this plane is draggier than the Habu). So I ordered some 3600 batteries to bump up the time a little. It should still work out OK for CG, since the HET fan/motor is heavier than the stock one (I had to move the 3300 about an inch forward of full aft to restore the CG).
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