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Jul 21, 2019, 05:12 AM
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So your 4S attempt weighed only 12 grams more plus the adapter.
You said 15 flights on 2S. I'm guessing that's a typo and you meant 3S. If it was 2S the plane would barely fly, if at all.
If it was 3S, how did the 15 flights go? With only 12 grams more weight and 4S power you should have seen a big difference in performance.
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Jul 21, 2019, 08:30 AM
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sorry, yes u r right, i meant 15 flights on 3s. performance was anemic. she’d fly but definitely not fast and could barely loop. she’d fall out of a loop at the top and could only get into a partial loop by diving into the loop. she would be flying at full throttle the entire time. on 4s i wasn‘t full throttle but about 75%. she could loop but she really didn’t like turns. that extra weight really made her dive in any bank. i’d have to go to full throttle just to keep a level turn. it wasn’t much fun to fly. she definitely lost her floaty feel. but the 2x 2s950 batts were definitely older and lower C (for whatever that is worth since most companies exaggerate C value).
-beanie
Jul 21, 2019, 09:33 AM
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Joe 1320's Avatar
My guess is this was one reason for the extended nose. A lighter battery, but pushed forward to get the right CG. This bird might be a good candidate for a pusher prop conversion. There would be a significant weight reduction in the tail. More power too!

If retaining the edf, any chance of moving the edf units forward an inch?
Jul 22, 2019, 12:19 AM
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AntiArf's Avatar
Not sure where the ESCs are, but moving them forward would help too, if possible. I'm running light weight Emax 12A units on 6 of these fans on 3s, with no failures so far. The quad Victor het has an SBEC, but the twin airliner simply has diode isolators so the second BEC can come online if the first one shuts down. Both have ballistic power at full throttle. I'd be reluctant to run 4s on the 7000kv motor, as that puts it in the rpm territory of the higher kv 2s version, which has some documented bell explosions. The bell is simply wrapped sheetmetal with what seems to have a spot weld seam on an L type overlap joint. I added aluminum rings cut from lipstick tubes fitted tightly around my bells, to provide a little added assurance so they don't explode. You get a grenade effect, when the magnets fly off in random directions.
Jul 22, 2019, 05:04 AM
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I think the older lower C batteries are the problem. They recommend 20C but I'd use at least 30C, preferably 35-45C.
We should be able to find 1200mAh or so batteries light enough and small enough to sit forward.
I bought a couple 5000 kV motors just in case the 7000s grenade.
I'm attaching a photo when I had her apart to install the orange motor LEDs. You can see where the ESCs are. The wiring is tight so you'd have to do some splicing to move them. They are tiny and weigh nothing, moving them wouldn't do much. You could move the motors /fans forward toward the cheater holes, but I'd rather try finding the right batteries and moving them around first. When I cut off a few inches from the nose area to make it more scale I left a hollow area going into the nose cone where you can move batteries forward to the tip inside the nose cone.
I think the secret is finding the right batteries.
I also left the ESCs in the open so they get cooled by airflow under the fuselage.
Jul 22, 2019, 07:03 AM
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wing no- where did you source the 5000kv motors?
-beanie
Jul 23, 2019, 05:46 AM
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Got them on Banggood. Brushless outrunners just like the stock 7000s. I think they were about $9 each if I remember correctly. I bought them along with two 30mm 8-blade fans but decided to keep the stock 6-bladers. The 5000 motors will come in handy if the 7000s explode...


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