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Old May 09, 2012, 10:24 PM
What's up with that?
cubcrafter60's Avatar
United States, CA, Clearlake Oaks
Joined Jul 2011
1,791 Posts
spencer1 - I also faced this dilemma. I purchased the recommended set up, I took it to a club meeting and got the "you know how much you could have got that for thru HK" and you’re going to run a UBEC, right? I'm like, what's a UBEC? (I know now). Anyway, One of our more experienced members said, running 6 servos you should have more than a 3 amp BEC, so get a UBEC OR use the stock radio battery to power your radio! He showed me how to modify the plug (to remove power) and I simply use the radio battery to power the radio and the speed controller controls motor function! Yea, I have to charge it (I have to charge my transmitter also) and it's additional weight, but the FunCub has no problem hauling around that NiCad and I can also turn on the radio without arming the prop! ~ Robin

PS - It's real simple, if you want I can post directions, but bounce it off the other guy's first and consider all your options!
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Last edited by cubcrafter60; May 09, 2012 at 10:31 PM. Reason: Added PS
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Old May 09, 2012, 10:28 PM
Registered User
Prof100's Avatar
Canton, Michigan USA
Joined Jul 2007
16,653 Posts
Quote:
Originally Posted by cubcrafter60 View Post
spencer1 - I also faced this dilemma. I purchased the recommended set up, I took it to a club meeting and got the "you know how much you could have got that for thru HK" and you’re going to run a UBEC, right? I'm like, what's a UBEC? (I know now). Anyway, One of our more experienced members said, running 6 servos you should have more than a 3 amp BEC, so get a UBEC OR use the stock radio battery to power your radio! He showed me how to modify the plug (to remove power) and I simply use the radio battery to power the radio and the speed controller controls motor speed! Yea, I have to charge it (I have to charge my transmitter also) and it's additional weight, but the FunCub has no problem hauling around that NiCad and I can also turn on the radio without arming the prop! ~ Robin
Non-electric guys have been doing it for years.

Which radio are you running? If Spektrum make sure your pack is charged. a 3.5 volt or less input to the receiver and it will reboot.
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Old May 09, 2012, 11:59 PM
Bay Area Prop Buster
Bluhammer's Avatar
Bay Area CA
Joined Jan 2011
4,019 Posts
As another side of the UBEC question, I fly the PZ P-47.
It has a mild 15 size motor and has a stock 30A ESC with a 3A SBEC, 2 aileron, 2 flap, rudder, and elevator servos plus electric retracts.
The manufacturer has stated many times that the system has been tested and certified to work with in this configuration and most fly it this way on 3S. I don't think the FC is anymore tasking then this.

So unless your flying with a questionable ESC, 4S, or a really hot setup, I think you'll be fine without adding more. But if you feel better, peace of mind is worth the effort.

Blu
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Old May 10, 2012, 01:36 AM
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baumerm's Avatar
USA, OR, Carlton
Joined Aug 2009
178 Posts
Quote:
Originally Posted by Bluhammer View Post
As another side of the UBEC question, I fly the PZ P-47.
It has a mild 15 size motor and has a stock 30A ESC with a 3A SBEC, 2 aileron, 2 flap, rudder, and elevator servos plus electric retracts.
The manufacturer has stated many times that the system has been tested and certified to work with in this configuration and most fly it this way on 3S. I don't think the FC is anymore tasking then this.

So unless your flying with a questionable ESC, 4S, or a really hot setup, I think you'll be fine without adding more. But if you feel better, peace of mind is worth the effort.

Blu
+1. A built-in 3A switching BEC has worked for me in the Funcub with 7 servos for more than a year. It doesn't even get warm. Some Multiplex power packs include the Thunderbird-36 with a linear 3A BEC. That would not be a good choice.

Martin
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Old May 10, 2012, 06:13 AM
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Del-Dredd's Avatar
Near Aberystwyth - Wales
Joined Aug 2004
2,119 Posts
That is the point, most cheaper ESC come with Linear BEC which is what produces most of the heat in an ESC.
(it has to lose energy somewhere to drop 12.6V to 5V and it does that as heat)

If your ESC comes with a Switching BEC you should have no problem if its 3A.

I use a Switching UBEC which stays cold the ESC (just supplying motor) gets barely warm in my Funcub after a hard flight, which proves the point.
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Old May 10, 2012, 07:56 AM
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planex's Avatar
Australia, VIC
Joined Jun 2011
1,538 Posts
Was finishing up my funcub last night and the motor mount screws were too long. I suspected they would be but then thought they were fine. Ended up damaging the windings on my brand new NTM 1000kv

When putting the throttle up with the prop on and the motor in the plane, the motor splutters and doesn't want to spin. Sounds like its jamming.  When you applying more throttle it eventually starts to spin nice and smooth. Once you get to about half throttle it developed a severe vibration, when more throttle is applied it just dies. 

Would the damaged windings on the motor be causing these problems?

I'm hoping the prop isn't out of balance that's why it's vibrating at half throttle, was told by someone that the vibration starts when more power is applied because a phase is damaged and it's overloading?
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Old May 10, 2012, 08:00 AM
You can't take the sky from me
copperbricks's Avatar
United States, OH, Cincinnati
Joined Aug 2011
1,081 Posts
That sounds like you're only getting intermittent contact on one or trek of the wires, brushless motors sputter without all threes wires attached. Sounds like as you spin up, it regains contact.
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Old May 10, 2012, 10:55 AM
Big Jim
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United States, ID, Mountain Home
Joined Jun 2011
2,958 Posts
Quote:
Originally Posted by copperbricks View Post
That sounds like you're only getting intermittent contact on one or trek of the wires, brushless motors sputter without all threes wires attached. Sounds like as you spin up, it regains contact.
+1 on that Check the solder joints and that the wires are clear of the motor.
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Old May 10, 2012, 10:56 AM
Registered User
east central ohio
Joined Jan 2009
341 Posts
Quote:
Originally Posted by Kimber View Post
With the weather we have had and the family situation we are in right now
we have not been able to do much flying of late.

Brad flew the Sensei and the Tower trainer a couple times and that is about
it. He flew the FunCub in the street, but just a little ways and it was sort of
an accident...

We got a new V-camera so we are ready when we get the chance..
Post pics of your fun cub. Pics of the whole plane.
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Old May 10, 2012, 11:43 AM
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planex's Avatar
Australia, VIC
Joined Jun 2011
1,538 Posts
It seems one of the wires from the ESC was lose
I re-soldered it and plugged it in but the spluttering is still there very slightly
It only does it if you put the throttle stick up about 1mm
If you move it say 3mm the prop just spins up as normal
Turns out the half throttle vibration was the prop adapter
It was WAY out of balance, switched to another one from my FunJet 800w + and its dead smooth
BUT all the vibration must have damaged the motor shaft..
I spun it up full throttle and at 315w the shaft broke clean off from where it enters the can of the motor on the front
Lucky I did't get hit by the 13x4 prop it was swinging
Now we wait for the new motor to arrive..
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Old May 10, 2012, 12:49 PM
Big Jim
RTF Thumper's Avatar
United States, ID, Mountain Home
Joined Jun 2011
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getting closer lol hope it all goes well with a new motor. A friend of mine Notsogood is going through almost the exact same issue.
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Old May 10, 2012, 02:00 PM
Grampa Tony
annarelli's Avatar
Lawrenceville, GA - Northeast Atlanta
Joined Jan 2009
1,489 Posts
The night flying pics didn't turn out, but here are some towing pics from SEFF:

Grampa Tony
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Old May 10, 2012, 02:04 PM
Hobby King Hater
Kimber's Avatar
USA
Joined Mar 2005
4,593 Posts
Quote:
Originally Posted by rcairboater View Post
Post pics of your fun cub. Pics of the whole plane.
Don't have a picture with the wing on it. It is at the other house now.



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Old May 10, 2012, 02:45 PM
Life is simple Eat, Sleep, Fly
Timewarp's Avatar
Germany, RP, Kaiserslautern
Joined Oct 2011
123 Posts
Quote:
Originally Posted by Kimber View Post
Don't have a picture with the wing on it. It is at the other house now.



that is a sweet setup, I would love to have something like that!!!
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Old May 10, 2012, 02:47 PM
Registered User
United States, CA, Pleasanton
Joined Apr 2002
540 Posts
Another Fun Cub Ready For Maiden !

Guys and Gals..

Here's my FC ready for its maiden !

Pretty much a generic build:

Turnigy 35-30 1100KV Motor
Sotog Motor Mount
APC 13x4 EProp
HS 82 MG (2x)
HXT 900 (4x)
Turnigy Plush 40 ESC
Turnigy Servo Reverser / Speed Controller for Scale Flap Deployment
Trunigy 3S 2.2 Batteries

Mods:
Motor mounts were reinforced with epoxy and glass cloth and landing gear brace added.

Trunigy Servo reverser / Controller was covered in heat shrink and then self sticking aluminum duct sealing tape was applied to reduce what some have reported as RF interference. No issues on the bench so far...

Painted with Krylon Fusion and then coated with Future Acrylic for a nice even shine.

Just need to mount the receiver and set the control throws and check the CG and she'll be ready to go.

Thanks to Everyone on this great forum for the great ideas and mod suggestions.

:harry
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