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Post by panicbutton on Jan 16, 2013 3:03:40 GMT 1
Alright, well i have the stock supercub and she works but shes been through some pretty severe crashes.
So i bought a second supercub body and began to modify it.
I bought a dx6i controller and it came with a esc and 4 servos so i plan on using those for the plane.. I also purchased a 370 brushless motor... hoping that will be better then the stock supercub.
I think this will work? ( kind of winging it) Not very technical with all the electronic numbers.
Advice is welcomed!
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Post by flydiver on Jan 16, 2013 4:40:54 GMT 1
Saying 370 brushless is about as useful as saying I have a 4 cylinder car engine.
More specific info needed. The game is about watts and KV. Watts = power and KV lets you figure out the general prop and battery sizes to use.
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Post by panicbutton on Jan 16, 2013 5:29:00 GMT 1
Alright fair enough, ill get back to you on that sir. Its all so new to me still learning
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Post by panicbutton on Jan 16, 2013 6:19:06 GMT 1
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Post by flydiver on Jan 16, 2013 6:36:03 GMT 1
I can see your problem. There's about nothing useful for that combo.
(I've gotten so I don't like combos that shout how wonderful they are and don't give you any useful information at all)
Based entirely on what it looks like and the 18A ESC I'm guessing the power will be a little more than stock, the weight will be a lot lower (you are going to have CG problems getting weight forward), and the long shaft is going to be a noodle that bends if you look at it wrong.
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Post by panicbutton on Jan 16, 2013 7:15:59 GMT 1
SO shes not going to fly better then the stock sc?
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Post by flydiver on Jan 16, 2013 16:37:11 GMT 1
By useful, I meant useful information. Without more info it's hard to tell for sure. People get to thinking the word 'brushless' automatically means more power. The stock power system in the Cub isn't half bad, but it's heavy (132 gm with gearbox). To keep the CG right, and avoid adding lead, people put in fairly large brushless motors (along the 450/480 size) so they end up with a lot of power, WAY more than scale. Remember, the Cub was originally designed for NiMh as a cheap trainer so there are some design compromises when going lipo+brushless. I'm guessing that's a much lighter motor so ends up in a similar power range. Since it's light you'll need weight to compensate up front. End result > probably more or less the same. Take a look at this chart paying attention to the power (in the Continuous/Max-Burst) section for the Park Outrunner 370, 400, 450, and 480 motors in the 1000-1300KV range. Also look at the weight. Weight is important-bigger motors are more powerful. www.e-fliterc.com/PowerSystems/Motors/BrushlessCharts.aspxThe STOCK Cub brushed motor is a 400 rated brushed. Folks replace it with 450 to 480 brushless. That's a big jump in power, from around 10-12A stock to 20A or more. The Gamma is a stock 370 brushed and is replaced with a 370 brushless for a modest jump in power. I'm guessing it's ~ 10-12A motor, similar to the stock Cub. (see Note below) Fly better? Depends on your goals and how you build it. If you wanted a power and speed demon, no. You getting the picture that it's worth doing your homework before buying stuff based on being a 'good deal'? Note: found this in the Gamma 370 thread:
www.rcgroups.com/forums/showthread.php?t=1790673There's not a lot of info on the brushless motor in the Pro so I went out and bought a Watts up meter today. Tested with a SkyLipo 2s 1300 25c and 3s 1300 40c.
On 3s the 8x6 drew 13.85 Amps WOT so I figured that was the safe point since Ares recommended that setup.
A 9x3.8 drew 14.94 (getting a little to high Esc is rated at 18 amps)
On 2 s 9x3.8 drew 8.9, 9x4.7 drew 9.16, and a 10x4.7 drew 13.64.
Notice the guy did not watch for heating up. Getting hot is a sign of over propping and wasted energy. I doubt that motor is very effective at 15A, it's making heat, not power. People over prop on a routine basis thinking they are getting more and more power. Beyond an optimal prop size for a given motor+battery what you get is a little more power and a LOT more heat. It's like driving your car at 100mph thinking you'll improve your gas mileage by getting there faster-simply doesn't work well. You may see a small but accessible power boost if you don't make SC #2 too heavy with additions. If you build like this you could end up with something totally different. Personally I think it would be an improvement over the seriously overpowered options that seem to be the rage here. (If you want a jet, get a jet) HZ SuperCub, Brushless Parkflyer/Slowflyer Mod www.rcgroups.com/forums/showthread.php?t=830383 |
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Post by panicbutton on Jan 16, 2013 23:35:30 GMT 1
It should fly forever though, Yea i am learning slowly Im thankful for your help
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Gohmer
Squadron leader
Posts: 113
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Post by Gohmer on Jan 17, 2013 17:51:21 GMT 1
Looks to me like the stuff you have chosen will work fine. I like my light weight Cubs a lot. Hang your ESC and RX under the motor mount and shorten the motor shaft to get your weight as far forward as possible. Consider mounting the battery forward or making control surfaces from depron instead of adding weight to balance it. Attachments:
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Post by flydiver on Jan 17, 2013 18:44:59 GMT 1
That's a 24g motor pictured. The Ares is probably somewhere around 45g I'd guess.
FWIW you can use the formula of ~ 2.5-3 watts/gram of power for brushless electric motors. Sites claiming a lot more than that are likely full of it.
Sometimes they give you claimed efficiency too. If that's more than 80-85% it best be a pretty darn good motor or that's a fabrication too. The cheapies are often down in the 65-75% range. But they won't tell you that since it won't sell product.
Note-that motor pictured can be improved by 15-20% by a decent rewind job, and it's fairly easy on THAT motor. Most cheap motors have a lousy wind.
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Post by panicbutton on Jan 19, 2013 19:15:25 GMT 1
Ordered a motor mount off ebay.. still waiting for it to arrive. Ill take pictures of the cub after. My first Cub is so heavy from layers of paint and all. Its nice though because i can take it up on pretty windy days! This new cub is alot lighter and its even been painted.
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bizzyb
Flying officer
Posts: 5
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Post by bizzyb on Jan 21, 2013 1:16:46 GMT 1
So...what is the optimal brushless upgrade ?bigger motor = bigger battery = more weight. Also, the export under side fuselage.... can that be used for my led lites? Or if I disengage the A CT can I use hat terminal or switch for lites or servos?
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