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Old Aug 24, 2014, 05:23 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
8,220 Posts
Burned my motor about 1.5 minutes into the first flight today. Was able to belly in , out in soft brush so there wasn't any damage. Looks like just the motor at this point. Almost snapped it several times while getting it turned back into the wind, but didn't. It's a very forgiving airframe, even at almost 12lbs. She'll be back.
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Old Aug 24, 2014, 09:07 PM
Registered User
United States, AL, Northport
Joined Apr 2010
201 Posts
Join the club. Going to replace the whole thing then tweak the castle to run better than last.

Glad you got it down.
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Old Aug 28, 2014, 12:28 AM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
8,220 Posts
Turned out that the main thrust bearing worked it's way out of the base on my outrunner which caused the shut down. I've put the fan back together with a 1180kv version of the same motor to run on 10s.

Initial tests show about 120a for about 4.4kw. I have several different packs that I can use for 10s..... 4000 mah 65c for an AUW of only 10.5lbs......10s2p 8000mah 25c for AUW of 12.25lbs............and the granddaddy 10s2p 65c 8000mah, AUW of 13lbs. All of them will offer about the same power of course, the difference will be flight times and weight of course. Should be interesting. A 10s 6000 mah would come in handy, but no gotta that one.

Also I got the fan running a little smoother, so maybe the sound quality will improve some.
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Old Aug 28, 2014, 03:46 PM
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United States, AL, Northport
Joined Apr 2010
201 Posts
How are you getting 2 packs of 8000 in the nose?

My 2p for 5cell 5000 won't fit unless end to end.
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Old Aug 28, 2014, 05:08 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
8,220 Posts
10s 2P 8000mah is 2 x 10s 4000 mah packs

The 2P is there just to designate that the cells are not 8000mah, but 2 x 4000 mah in parallel.
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Old Aug 28, 2014, 05:44 PM
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Joined Mar 2005
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Anybody have a new spare motor. Let out the blue smoke 1.5 min into maiden flight ?

Tony
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Old Aug 28, 2014, 06:56 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
8,220 Posts
I'm planning to sell my motor/fan. It's brand new. I just rerouted the motorlleads through the fan shroud instead of out the back.
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Old Aug 30, 2014, 03:14 PM
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Well Lee really helped me out should have a motor here Tuesday morn. Hope this one doesn't burn out. I used all my luck on the 1st landing.

Tony
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Old Aug 30, 2014, 03:48 PM
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Canada, QC, Gatineau
Joined Jan 2011
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Sounds like the motor in this one is a little iffy!
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Old Aug 30, 2014, 03:59 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
8,220 Posts
Tony's is the first one to burn on the first flight as far as I know. I'd say that it's righton the edge though. No head room on the motor, so throttle management is a must. The strength of the lipos and the air temperature need to be considered.

Also with motors like this you will get a clunker sometimes.

I hope this one works well for you Tony.
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Old Aug 30, 2014, 04:08 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
8,220 Posts
On my motor problems......... I got the fan back together and sure enough, the motor issue knocked out the esc. So I've finished installing a CC120 ICE2 hv. At full 37v, it pulls 110a for roughly 4kw. So I have almost the same power on 10s @ 110a as I didwwith 14s and 80a. Running just a 4000 mah my flight time will be about 2:15 on the timer then it will be time to land. With 8000mah, total flight times should be close to 6min from take off to touch down.

I plan an afternoon of flying tomorrow.
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Old Aug 30, 2014, 04:43 PM
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Monaco
Joined Dec 2006
132 Posts
Flap control on 3 position switch or slider ?

This is my first EDF with flaps. Am I better off using a 3 position switch to operate the flaps, or using a slider where I can vary the flap angle continuously ?

I fly full house gliders and I like having the butterfly / crow on the left stick and fully variable. However I can also see the merit of having just 2 fixed flap positions so that the Cobra's flight characteristics are consistent for each position, and I learn to control the sink rate with the throttle and the speed with the elevator / angle of attack
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Old Aug 30, 2014, 04:55 PM
Mulit-Platform Pilot
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United States, FL, Jacksonville
Joined Sep 2004
3,298 Posts
I use two flap positions, about 15 degrees or so for takeoff and everything you can get for landing. It makes it easy to setup the compensation though I dont remember it needing much.
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Old Aug 30, 2014, 04:55 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
8,220 Posts
I'm using the switch, I think that most guys go that route, with 2 options for the amount of flap deflection. Even at almost 12lbs 15 to 20 degrees is plenty. I tried full flap once on a no wind landing, and the Cobra seemed to just stop in midair. I pulled it up to 1/2 flap. I prefer some speed for landing. I can't imagine 45 degrees of flap on a 9lb Cobra. It would probably VTOL with a 10mph breeze.
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Last edited by Knife Liddle; Aug 30, 2014 at 05:02 PM.
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Old Aug 30, 2014, 05:21 PM
Mulit-Platform Pilot
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United States, FL, Jacksonville
Joined Sep 2004
3,298 Posts
I used to do that thing like the Blue Angles do with their 18. Full flaps, nose up about 20 degrees and come across the field about 5 mph using about 1/3 power. Most folks are amazed how slow this thing will fly with full control.
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