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Old Feb 01, 2013, 09:04 PM
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Originally Posted by genghiskt View Post
They are cool..no problem. 87A is total Amp draw for both fan..
I started looking if you said which motor you're using to push twin factory CR 70s on 29.86 V @ at 87 amps pushing 3.1kg.
I'm using more than 110 amps to get just above that with Wemo's but the battery weight is about the same, where you could come down some in battery weight if you wanted. So thats a good setup using the factory blades.
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Old Feb 01, 2013, 09:47 PM
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Max,
The setup are; 2x freewing 70mm units from SU-35, 2x inrunner, 2x Hobbywing 70A HV,2 x 4500mah 4S 30c batteries.
Everything runs cool. I will try to drop the batteries to <800g.
I do have another motors that push about total 3.8kg at about 115A.
I try to put up more testing videos.
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Old Feb 01, 2013, 09:56 PM
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Originally Posted by genghiskt View Post
Max,
The setup are; 2x freewing 70mm units from SU-35, 2x inrunner, 2x Hobbywing 70A HV,2 x 4500mah 4S 30c batteries.
Everything runs cool. I will try to drop the batteries to <800g.
I do have another motors that push about total 3.8kg at about 115A.
I try to put up more testing videos.
??? no I'm specifically asking which motors are they. Which inrunners make model etc?
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Old Feb 01, 2013, 10:04 PM
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I custom it. If you need one, PM me. Price about USD 80 without freight. It's can run on 10S. Weight 160g. 65mm can.
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Old Feb 01, 2013, 10:10 PM
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I custom it. If you need one, PM me. Price about USD 80 without freight. It's can run on 10S. Weight 160g. 65mm can.
K thanks. 28mm OD 65mm long but still only 160g and can run continious on 8S. There are so few 28s that can do 8S and the ones that do are heavy. What dia shaft? 4 or 5mm?
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Old Feb 01, 2013, 10:28 PM
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4mm shaft. I have problem with the higher power setup. The fan adapter cannot hold tight to the motor. At WOT the fan rotor will fly out. I m looking for a solution.
Next test will be 8S at CS10/70 twin. Want to put it in the ME-262.
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Old Feb 01, 2013, 10:30 PM
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This motor cannot do 5mm shaft. Factory said no space for 5mm shaft.
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Old Feb 01, 2013, 11:57 PM
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Originally Posted by SU-4ever View Post
Dave, welcome to the club!

I wouldn't fiberglass the nose, that's a lot of weight to add to the nose and will unbalance the plane. I take off from a bad grass field and yes, the foam behind the nose gear collapsed on the 3rd or 4th landing but you can solve it easier without adding so much weight. This is the solution I came up with: I built a balsa wall reinforced with fiberglass and attached to the back of the nose gear bay, right ahead of battery compartment. that stops the foam from breaking. It doesn't need anything else. I'll post pics this weekend if you want to see it.
Yes, I'd be curious to see pics of your solution!!!!

I'm always open to new ideas....................................
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Old Feb 02, 2013, 04:10 AM
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Originally Posted by genghiskt View Post
4mm shaft. I have problem with the higher power setup. The fan adapter cannot hold tight to the motor. At WOT the fan rotor will fly out. I m looking for a solution.
Next test will be 8S at CS10/70 twin. Want to put it in the ME-262.
This sounds dangerously serious...................

What's the KV of your custom motors????
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Old Feb 02, 2013, 04:59 AM
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Hey if you ever lose that 'kid' in you, your inner child its ALL OVER!!
I cannot agree with you more!!!!!!.............
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Old Feb 02, 2013, 05:11 AM
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You can do this 8S type setup on the Leopard 2860's. They have 1840kv and 1690kv. (1690kv for 'normal' power.... 1840kv for HIGH power)
1300W capable motors. So you will be running approx 46A each in CS10's/12's. You would need to use the 12bl for the 1840kv.
And if you wanted real 'balance and sound perfection' throw those into ExtremeRC housings - because those are the lightest (sme weight as the plastic), and greatly reduces reverberations etc.

Probably better getting a dedicated 8S battery for the Su as it can't fit things as easily as most other aircraft can (thus they can use dual batteries in those easily).
The 8S should help balance out the heavier tail end (motor weight) fairly well too.
Using more volts, less amps, means you can get away with lower C batteries too.

Motor $75.... CS12 $16..... HV ESC's, can use HK 'cheapie' SS 190A if you wanted, $33 (because it is 8S capable and cheap... others will cost $100 area!!).... ERC housings $45 for the 4 stator, or $70 for the 7 stator
X2
$244 + ....$90 or $140
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Old Feb 02, 2013, 05:36 AM
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Originally Posted by PeterVRC View Post
You can do this 8S type setup on the Leopard 2860's. They have 1840kv and 1690kv. (1690kv for 'normal' power.... 1840kv for HIGH power)
1300W capable motors. So you will be running approx 46A each in CS10's/12's. You would need to use the 12bl for the 1840kv.
And if you wanted real 'balance and sound perfection' throw those into ExtremeRC housings - because those are the lightest (sme weight as the plastic), and greatly reduces reverberations etc.

Probably better getting a dedicated 8S battery for the Su as it can't fit things as easily as most other aircraft can (thus they can use dual batteries in those easily).
The 8S should help balance out the heavier tail end (motor weight) fairly well too.
Using more volts, less amps, means you can get away with lower C batteries too.

Motor $75.... CS12 $16..... HV ESC's, can use HK 'cheapie' SS 190A if you wanted, $33 (because it is 8S capable and cheap... others will cost $100 area!!).... ERC housings $45 for the 4 stator, or $70 for the 7 stator
X2
$244 + ....$90 or $140
Hey PeterVRC,

You're really into this, aren't you?????

It's interesting talking to people who know exactly what they're talking about, and that's why I enjoy this thread so much.........

ALL OF YOU are educating me about things that I have never known before!!!!!

As I said before, you're NEVER too old to learn......................
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Old Feb 02, 2013, 06:07 AM
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Originally Posted by PeterVRC View Post
You can do this 8S type setup on the Leopard 2860's. They have 1840kv and 1690kv. (1690kv for 'normal' power.... 1840kv for HIGH power)................
So at 29v and 1840kv, you'd theoretically be cranking about 53,000 RPM. It will not get there due to electrical, friction, and windage losses, but it would be interesting to get a tachometer on it to see exactly how many RPM's you're actually getting. The motor will unload a bit once airborne and at speed, but a bench test result would be a good starting point!

That's why I ordered a 99,999 RPM tach.
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Old Feb 02, 2013, 06:24 AM
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Multiply CS10/12 numbers by 0.8 to get a rough guide as to real RPM to expect (and it will even be a bit less really).
29.6 (if your battery CAN even sustain that) x 1690 = 50,024 x 0.8 = 40,019 RPM
Fine for both CS10 and CS12

29.6 (if your battery CAN even sustain that) x 1840 = 54,464 x 0.8 = 43,571 RPM
CS10 = explode. CS12 would be fine.
But this is really getting into high power territory!

The whole 8S idea would be a costly venture anyway......
I would think you would really only even do it it IF you were wanting to get that high power end of results!
Doing the 1690kv would probably be a bit more efficient system than 6S CS10/12 (but probably still not better than the stock 6 blade 6S!) so the high cost is well short of worth it anyway really.

I will dig out my meters and scales etc tomorrow and re-test all my Su numbers...... 6S 2200KV HET 2W30's in CS10's.
I am tossing up on changing them to CS12-70's I have here. But I don't want to go through all the changing/testing just to compare them..... though maybe I will do that too..... sigh (I will be very tempted).
I made up a new Static balancer unit today, and will finish making up a Dynamic balancer stand tomorrow (hopefully), Android phone based, so then those CS12-70's could be the first real test case..... (in the Su)....
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Old Feb 02, 2013, 06:33 AM
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Well, here are the pics.

The wood attached to the foam wall as a layer of fiberglass reinforcing it.
The whole piece distributes the effort on the side foam walls of the battery compartment using two extra pieces of balsa wood glued to the main with epoxi. The same pieces are covered in epoxi to avoid the wood from tearing apart in its weak points. It still ends up very ligtweight and does te job fine.
The oter pics are the stand I use for the SU. It's the original foam protection. Just need to cut open holes for nose, tail dome and stabs, and makes it easier to carry to the field. I also use it as a workbench for the airplane.

Cheers!
Jandro.
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