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Old Dec 09, 2012, 09:57 AM
Yin & Yang
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Quote:
Originally Posted by JetPlaneFlyer View Post
It would rarely if ever be the bell itself that was bent, almost invariably it's the shaft bent inside the motor which causes the bell to sit 'wonky'.

I'd recommend to remove the shaft and check it for being bent by rolling on a smooth flat surface.
Yea that's what I was thinking too but,
New shaft already. Put both new and old on razor edge and granite counter and no bend. At 5mm it's one tough shaft.
Motor running clamped tight, I used the tip of my exacto knife at the base of the bell until it touched. Shut motor down the razor left a mark only on about 1/3 of the bell. I'm sure it's the bell.
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Old Dec 09, 2012, 10:33 AM
Grumpy old git.. Who me?
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I've bent 5mm shafts before. But if you have tried a new one and it's still running out then you must be right, the bell must be bent.

I think that it's going to be really hard to straighten it unless you have access to machine shop facilities that would allow you to put a dial gauge on it and 'tweak' it back into alignment.
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Old Dec 09, 2012, 12:41 PM
Yin & Yang
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United States, VA, Sterling
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Quote:
Originally Posted by JetPlaneFlyer View Post
I've bent 5mm shafts before. But if you have tried a new one and it's still running out then you must be right, the bell must be bent.

I think that it's going to be really hard to straighten it unless you have access to machine shop facilities that would allow you to put a dial gauge on it and 'tweak' it back into alignment.
I was thinking the same thing. I used to have a drill press but sold it for lack of room to set it up here. I've been thinking of getting a smaller bench top drill press. I may try it at some point but for now I guess I'm ordering a new motor. Given that the razor point touched the bell for 1/3 my guess is it's only a few thousandths out. If this was a beater I'd probably try it but it's a new fuse cowl canopy and right wing so it's almost a new Edge.
As smart as I think I am at times It's always good to seek other opinions because somebody somewhere has probably got a good or better idea. What better resource is there than here. Tons of really smart people that have been working on the electrics far longer than I have.
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Old Dec 09, 2012, 02:59 PM
Not as Good as The Kid
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Originally Posted by bryansifsof44 View Post
Ok finally got my 20x8 props in and was able to do some testing with my 4330-216. All tests were static on the bench 70degrees F @ 140 feet ASL. Readings were with the Castle logger at 10 readings per second (10Hz), so numbers were more accurate.
Thanks for the data, Bryan. Static thrust is calculated and you can use the PropEngine to get the calculated difference. Here's a few observations:

The reason I like bigger props on these planes is simply the higher thrust and power along the entire throttle curve. Smaller props need the higher end RPM of the motors to achieve the same effect. The 20x8 Xoar at WOT is producing about 273 Watts per pound and about at 10.5 pounds.

If I compare, the:
14x7 prop on a 683Kv on 4S and a 56 oz airplane
16x8 prop on a 480Kv on 6S governed to 65A on an 88 oz airplane
22x10 prop on a 215Kv motor on 10S on a 215 oz airplane

... all produce over 240 Watts per pound and a static thrust to weight ratio of 2.15 to 1 or higher. This also means that at 66% RPM, they are still producing about 90 Watts per pound. Your setup is well over these results (273W/lbs and a 2.44:1 thrust to weight). I will also add that the reason I did not buy a plane in this size yet is because I had been considering the A60-7S on 10S with the 20x8, but it fell short of these expectations. The 20x10 added Amps and cut into the flight time.

I would say that you got it right, and Kenís got the right motor for the 10 to 11 pound 3D airplane. The 12S lets me use the 6S batteries I have for the 60 EXPs, keeps the Amps down at peak power, keeps me from adding 7.04 oz, and swings the big disk for the higher torque at lower RPMs we need for 3D.
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Old Dec 09, 2012, 03:14 PM
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Thanks for the insight and great analysis, makes me feel better about the setup. Now to go try it out... I will report back with how it compared to the 19x8 in flight.
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Old Dec 12, 2012, 06:41 PM
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I could use some help please, I am looking to buy a ZTW B-Series ESC for my 4315-480. Most likely a 84A but am considering the 115A as it weighs the same. I will be using a Castle external BEC because I have HV servos. I have never had an OPTO and don't know if that is better or worse. What surprise me about the ZTW Opto's is that they do have an internal BEC. I always thought most OPTO's did not have a internal BEC.
Thanks in advance.
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Old Dec 12, 2012, 06:55 PM
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Originally Posted by Ohio AV8TOR View Post
I could use some help please, I am looking to buy a ZTW B-Series ESC for my 4315-480. Most likely a 84A but am considering the 115A as it weighs the same. I will be using a Castle external BEC because I have HV servos. I have never had an OPTO and don't know if that is better or worse. What surprise me about the ZTW Opto's is that they do have an internal BEC. I always thought most OPTO's did not have a internal BEC.
Thanks in advance.
I would go with the bigger if you intend to run the 16x8 prop. As far as ZTW's opto ESCs... I'm pretty sure it doesn't have the internal. I believe there site says it has one in the features but in the spec it says none.

As far as my 4330-216 on 12s the 20x8 is what I am sticking with... more power and low and slow stuff is much easier.
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Old Dec 12, 2012, 07:12 PM
They Call him Dead!
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I thought that OPTO meant that is was an ESC ONLY. No BEC. I thought that is what OPTO meant?
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Old Dec 12, 2012, 08:15 PM
Not as Good as The Kid
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I would say that this is the correct ZTW: http://www.altitudehobbies.com/brush...sc-opto-no-bec

There is no BEC no matter what the description bullet-points say. And I have no idea why the confuse the issue by calling it a Land ESC. Someone should fire their marketing guy. Nothing like having to educate your prospects.

Also, you don't need an external U-BEC for this setup IMO for two reasons. First, you are creating another failure point, and second, no one I know has yet to have an issue with running the 2S lipo right into the Rx, unregulated. I've done it with 2S Lipos at 7.4v to 8.4v, as well as 2S A123 LiFe to 6.6v plus on new and old Rx's.

Put a 3 inch extension in the Rx and plug and unplug the battery into the extension, or add a switch in between the battery and the Rx, which is what I did on the 78.
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Old Dec 12, 2012, 08:20 PM
Not as Good as The Kid
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And glad to hear about the 20x8 on 12S. Very cool setup, Bryan. Thanks.
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Old Dec 12, 2012, 08:41 PM
Not as Good as The Kid
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Sorry... one more thing. They make JR switches with a charging plug, which is just a third wire that you can mount to the side of the fuse with an included Ernst Receptacle and charge the battery while it's in the plane. I would never recommend charging a Lipo in the plane. Please don't do that. Buy the switch without the third cord, or tie/tape off the third cord, and remove the battery to charge it. As always, buy deluxe switches, and change them every two years, or if they ever start to feel weird in any way.
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Old Dec 12, 2012, 08:44 PM
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It was out dragged my parter with his 20x10 prop on a 4325-380 6s setup in the vertical climb, and was identical in the top speed pass side by side.
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Old Dec 12, 2012, 09:09 PM
Not as Good as The Kid
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so are you saying that the two setups performed virtually the same, only you were pulling 68A and he was pulling 105A, right?

I think he has better batteries than you do.
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Old Dec 12, 2012, 09:14 PM
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Not at all... I had a 20x8 and he had a 20x10.... My plane is slightly heavier and I was quite a bit faster then him in a vertical drag race. And even with a prop two pitches smaller I was Identical in top speed in a high speed pass. My wording up top was supposed to say "It out dragged my partner".
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Old Dec 12, 2012, 09:21 PM
On loan to Texas
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Quote:
Originally Posted by Aeroplayin View Post
I would say that this is the correct ZTW: http://www.altitudehobbies.com/brush...sc-opto-no-bec

There is no BEC no matter what the description bullet-points say. And I have no idea why the confuse the issue by calling it a Land ESC. Someone should fire their marketing guy. Nothing like having to educate your prospects.
Thanks I have not considered that version of the ZTW because the caps look so vunerable sticking out like that. I was looking at the B-Series like this.
http://www.quantumhobby.com/product-p/b-ztw115aopto.htm

Are you using the land version and if so are the caps more secure than they look?
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