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Jul 11, 2019, 02:56 PM
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Joe 1320's Avatar
Total amps usually can be divided equally between motors, but that’s not entirely accurate. i’ve seen twin motor airplanes where one motor pulls more amps than another. I generally try to match components so that the motors are as close to each other as possible.
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Jul 16, 2019, 05:30 AM
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Flyer4God- thanks. Glad to see all my hours of work appreciated.
Beanie - the ESCs are 20 amps each. As far as not wanting to mess up the scale looks, I painted everything under the MiG grey to match the grey underside color and blend in. The previously -blue servos and wiring all look like they belong there now. From a few feet away you can't really see anything under there.
If you need to add nose weight, when I scale -modded my nose and cut some off, i hollowed out the center area behind the nose cone so you can access inside the nose cone from inside the fuselage if needed. I haven't tried balancing mine yet since I don't have the batteries I'll be using yet.
Jul 16, 2019, 12:25 PM
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so i tried a 4s setup this weekend using 2x 2s950 turnigy graphenes. unfortunately, i was underwhelmed at the outcome. actually, i crashed the first time after about 16 seconds. i was afraid to go full throttle and burn out the esc, so i didn't throttle up enough and she stalled in the first turn. broke the canopy and one taileron detached. i glued her back together and flew her again... this time being a little more liberal with the throttle. she had more ooomph to her, but i don't think she liked the added weight. granted, my batteries are pretty old, so that probably contributed. the extra 1/2oz of lead in the nose i'm sure really didn't help... but that was only way i could balance her with those batts. i may try again this weekend, but fast losing interest in her abilities.
-beanie
Jul 16, 2019, 05:23 PM
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Beanie- don't be afraid to use full throttle. The airflow when she's moving will cool the ESCs. Even if you somehow burn them out you can replace them with 30amp ESCs for about $18-$20 total. The plane flies decently on 3s, so will fly well on 4s. Did you hollow out the nose up to the nose cone? I can install batteries all the way into the nose cone until the tip stops them. When painting mine I removed the fuselage piece below the canopy and re-installed it with magnets, like the canopy /battery access hatch. I hollowed out extra foam. By having it removable I can access the receiver and wiring easier. You can remove enough material in there, and cut off some of the too-long nose to get it back to scale, to not have to use lead in the nose. Just get those batteries way up front. I installed a strip of velcro the entire length of the compartment so I can adjust CG with the batteries.
Jul 16, 2019, 05:24 PM
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I'd also try at least 35c batteries, 45c would be better.
You must be using weak batteries. When I tried full throttle on the bench with two decent 2s batteries it really wanted to take off. Very good thrust. Unloaded in the air, with 1200-1500 mAh 35c or 45c batteries this plane should be a rocket.
Jul 16, 2019, 06:22 PM
yank and bank!!
[QUOTE=beanie;42310829]so i tried a 4s setup this weekend using 2x 2s950 turnigy graphenes. but i don't think she liked the added weight. {/QUOTE]


If you're talking about the 49g turnigy 2S 950 graphenes, I'm surprised it got in the air at all.... of course it won't fly well with that much battery weight.

I fly a dual 30mm edf plane with a 55g 3S battery in it and I wouldn't call it a floater.....
Jul 16, 2019, 09:05 PM
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yes, they are the 49g Turnigy 2s 950 (but 2 of them to get 4s), but to get the CG right, i had to add yet an extra 1/2oz (what's that... another 15gm or so!). she flew, though not great, with a 3s1000 that weighed 105g, but because it was compact, i could move it far enough forward that i didn't need to add extra weight.
yes, the turnigy 2s batts are old, so i'm sure they are not able to pump out the amps as some of the newer batts.
i hate how the battery companies all overrate their C output and turn it into marketing hype.
-beanie
Jul 17, 2019, 05:03 AM
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I haven't bought batteries for the MiG yet because I've been shopping for two 2s batteries with around 1500 mAh and at least 35c-45C without too much weight. When you start looking at batteries the weights are all over the place. Some don't tell you weight. Plus you have to get configurations that fit into the compartment. It should be easier to find two 2s batteries that weigh less than one 4s battery of the same power,though.
Jul 17, 2019, 05:09 AM
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Beanie - are you flying without the landing gear and hand-launching? That gear will add weight and drag and make it fly more brick -like.
Jul 17, 2019, 07:10 AM
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wing no- yeah, i’m flying without gear. please lemme know if u find a batt that works.
-beanie
Jul 18, 2019, 04:59 AM
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The best one I've seen so far is the Kinexis 2s 1200 mAh 30C battery at Horizon Hobby for $9.99. At 30C and twenty bucks for one setup it looks good but they don't list weight. I'd also like to get closer to 1500 mAh. But if I don't find anything better I'll probably go with ten of these to give five flights. Blitzworks recommends 25C , so 30 is better, but there are 35C and 45C batteries out there. Still looking...
Jul 18, 2019, 05:16 AM
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Joe 1320's Avatar
Something here doesn’t seem right.... a micro that takes a 1200mAh+ ? Instead of all this nose weight, I would be looking at ways to remove weight from the tail.
Jul 20, 2019, 12:19 AM
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AntiArf's Avatar
Quote:
Originally Posted by Joe 1320
Something here doesn’t seem right.... a micro that takes a 1200mAh+ ? Instead of all this nose weight, I would be looking at ways to remove weight from the tail.
Yeah the battery weight in itself is self defeating. I'm flying a twin with these fans on a TP3s around 800mAh. Decent flight time and nowhere near the need for full throttle. This model sounds like it needs the LG stripped and 2 gram servos installed, to start with. Haven't had any fail yet on models up to 1m span.
Jul 20, 2019, 05:08 AM
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You could probably lose 8 grams in servo weight that way but there's nothing else you could really lose in the tail.
I'd never use landing gear, and I'm guessing that using two 2S batteries in series will be lighter than one 4S battery.
I don't know if lighter servos would handle the air loads on those control surfaces , especially the elevons.
The video of the stock plane flying with landing gear on and 3S battery looks like it flies okay. Deleting the gear and the extra mass from the too-long nose, plus running 4S should make it fly better, even if the two 2S batteries weigh slightly more than the original 3S did. I don't have any weight info since I don't have any 3S or 4S batteries. I'm just guesing that a 3S or 4S battery weighs the same or more than two smaller 2S batteries. Does anyone have a weight for the 3S batteries used to fly it stock?
Last edited by Wing No; Jul 20, 2019 at 05:14 AM.
Jul 20, 2019, 06:33 AM
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Wing No- my first 15 flights were with a 2s1000 at 105g. my single attempt at 2x 2s950 was with each batt weighing 49gm plus the adapter plus 1/2oz lead in nose. hope that helps.
-beanie


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