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Author Topic: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?  (Read 2015 times)

Offline Kevin Muckleroy

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Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« on: December 19, 2018, 02:07:40 PM »
I am not sure who designed this plane But it flew great with the specs listed.
Just need to install new motor for it.
Will the Brodak Arrowind 2820/7 920kv be a decent choice spinning a 12x6E tractor
or should I go with the Brodak BH-2076 3548 950kv?
I will be using the ZTW 45 ESC and KR timer, 4S-3300 battery

Skyraider Profile
Wingspan: 56"
Length: 40"
500 sqin
Wieght: 54 oz w/Motor, ESC & 4S 3300 Battery
E-POWER
Original Power: RSM .46 System
Motor: Black Tiger 3548 950kv
ESC: ZTW 45a
Timer: KR-2 Compact Profile
APC- 12x6E Prop Tractor
9600RPM

Offline jfv

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #1 on: December 20, 2018, 10:35:36 AM »
I've used the Arrowind 2820/920 on a 54 oz plane turning a 3 blade 11.5 carbon prop.  Pulled OK but the bearings didn't last very long even though it was front mounted.  I also use an Arrowind 2826 turning a pusher 12x6.  Probably the better choice with the 12x6.
Jim Vigani

Offline Keith Renecle

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #2 on: December 22, 2018, 10:51:24 PM »
Hi Kevin,

What happened to the original BT 3548 motor? That is a nice size of motor for your model. It weighs 160 grams so it is in between the Arrowind 2820 (.40 size) and the 2826 (.55-.60 size)

A good replacement is the Cobra 2826/10 which is a close copy of the AXI 2826/10 and weighs 171 grams so it is a medium size motor and will fly your model well turning an APC 12 x 6 E prop.

Keith R
Keith R

Offline Kevin Muckleroy

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #3 on: December 23, 2018, 03:18:13 AM »
Hi Kevin,

What happened to the original BT 3548 motor? That is a nice size of motor for your model. It weighs 160 grams so it is in between the Arrowind 2820 (.40 size) and the 2826 (.55-.60 size)

A good replacement is the Cobra 2826/10 which is a close copy of the AXI 2826/10 and weighs 171 grams so it is a medium size motor and will fly your model well turning an APC 12 x 6 E prop.

Keith R
What Happened? had a nose over wreck.
I all ready have a Brodak 3548 I will use it w/11.5 x 6 APCE Thanks for the info.
Be out flying it on Monday.

Offline Kevin Muckleroy

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #4 on: December 23, 2018, 12:42:34 PM »
OH MY! Bench tested today. Got almost 4 minute run. Went into complete shutdown.
Battery too hot to touch. Cell voltage 3.7v equal on all 4 cells
Two questions
1-Would the battery being completely covered cause thermal shutdown?
2- Would having flat side of ESC mounted to fuselage cause thermal shutdown?
Specs:
Brodak BH-2076 3548 950kv
ZTW Mantis 45a ESC
KR Governor
Cut down 12x6 APC Prop to 11.5x6
9600rpm
3500 4s 30c battery

Offline John Rist

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #5 on: December 23, 2018, 01:43:47 PM »
It the RPMs of the motor drop below a cretin point the KR timer will  stop the run.   If your battery is getting hot that is not good.  Could be your setup is overloading everything.   You need an inline amp meter  to see how much current you are drawing.   Also running the setup on the ground is not a good thing.  We are running our setups at there upper limit.  When you launch an aircraft the motor unloads and the current drops to a safe level.  I smoked a perfectly good motor by running it on the ground.  Mounting the ESC  on the fuselage should not be a problem.   Install a very small prop and see if you a full time run.  Electric is fun when it works,  a big mystery when it does't.

PS make sure the motor is not rubbing on anything.
John Rist
AMA 56277

Offline Russell Bond

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #6 on: December 23, 2018, 02:06:23 PM »
Yes, NEVER run the motor on the ground for more than 10 to 15 seconds as you will overheat EVERYTHING!  n1
Bandolero

Offline Fred Underwood

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #7 on: December 23, 2018, 02:33:34 PM »
In addition to the above, 3.7v is getting low unless there is a 4+ following the 7.  My typical end of flight voltage is 3.73(+) and after setting several minutes 3.75(+).  That is close to 80% use.  Did you hit low voltage cutoff?  When was that voltage measured?  Batteries also get warm is overdrawn.


 
Fred
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Offline Kevin Muckleroy

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #8 on: December 23, 2018, 02:43:41 PM »
Yes, NEVER run the motor on the ground for more than 10 to 15 seconds as you will overheat EVERYTHING!  n1
Well dangon thats nice to know. And over heat it did. Scratch 1 ZTW 45a ESC.
Got a ZTW 65a installing now. Same setup I have on my Brodak P-40E

Offline Kevin Muckleroy

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Re: Arrowind 2820/7 920kv vs. Brodak BH-2076 3548 950kv?
« Reply #9 on: December 23, 2018, 02:49:23 PM »
In addition to the above, 3.7v is getting low unless there is a 4+ following the 7.  My typical end of flight voltage is 3.73(+) and after setting several minutes 3.75(+).  That is close to 80% use.  Did you hit low voltage cutoff?  When was that voltage measured?  Batteries also get warm is overdrawn.


 
3.70-3.69-3.70-3.70 about 5 minutes after shut down. Lipo cut-off at 3.2v. Rpm never slowed just stopped.
Now I know not to bench test anymore. Thanks everyone for the input.


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