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Old Jan 12, 2009, 10:14 AM
HAL... Open the damn doors!
jfetter's Avatar
Miramar, Florida
Joined Jul 2007
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Quote:
Originally Posted by dag214
No watt meter, know where I can get one???

I will be testing to night the motor with the 20-14 running for 10 minutes at 55% power to test the bearings. And I will then check to see how many Mah the batteries used.

Thanks, DAG
You can get a Whattmeter from any online retailer but your LHS should have one too. Without it, how will you test @ 55% power?

Jack
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Old Jan 12, 2009, 10:18 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,002 Posts
Quote:
Originally Posted by jfetter
You can get a Whattmeter from any online retailer but your LHS should have one too. Without it, how will you test @ 55% power?

Jack
I was wanting to just take a setting at where my RPM was 55% of my max measured. I should have said 55% RPM test .

I a new to this electric stuff, who would have thought 10 years ago I would have a plane that has no fuel tanks for gas.

Thanks, DAG
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Old Jan 12, 2009, 10:28 AM
HAL... Open the damn doors!
jfetter's Avatar
Miramar, Florida
Joined Jul 2007
8,471 Posts
Quote:
Originally Posted by dag214
I was wanting to just take a setting at where my RPM was 55% of my max measured. I should have said 55% RPM test .

I a new to this electric stuff, who would have thought 10 years ago I would have a plane that has no fuel tanks for gas.

Thanks, DAG
Lithium Ions my friend, trillions of them!

So was 4,100 the max RPM?

Jack
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Old Jan 12, 2009, 12:07 PM
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United States, AZ, Mesa
Joined Dec 2008
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why Yes I do........
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Old Jan 12, 2009, 12:12 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
26,747 Posts
Hi Dag...

I have a very nice set of Don Smiths RC Plans B-24 plans (also for about 10' wingspan) that you are welcome to. When I ordered the Connie plans, I was accidently shipped the B-24 plans instead. When I contacted them about it, they said keep them and they sent me the connie plans. I would like them to have a good home, so, as I said, you are welcome to them. Just PM me with your address...

SteveT
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Old Jan 12, 2009, 12:26 PM
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Hepdog's Avatar
Stonewall, MB, Can
Joined Jul 2004
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Quote:
Originally Posted by dag214
You know it's funny. I thought I was hearing the same thing, but what I think is going on is the motor sound being transmitted thru the shaft and the shaft producing some kind of a noise. I am using some fairly big Boca ceramic bearings and they still feel great. But I am going to run a test later right at the point that sound is the loudest and run a full cycle from the batteries. About 24 minutes worth at 55% power, that is where I here the noise the most.

Thanks, DAG

Sounds good. It's definatly a growl and not harmonics right around 55%. It is true that every prop motor has a sweet spot and a bad spot - this is a different sound. I've heard it before on Snowmobile Idler wheels - the little guys that spin real fast to keep the track aligned. When they start to growl failure isn't far behind. I think the growl sound is likely a chatter type response to vibrations at certain freqs. Even a few thousanths can vibrate to destruction.


I would also encourage you break in all your Lipo packs on the test rig to accomplish more of the same. Not only will your Lipo's perform better and you get assurances the packs are all good PLUS you can put some serious time on the driveshafts and bearings. I would log the time to see how many hours they are good for.
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Old Jan 12, 2009, 12:40 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Quote:
Originally Posted by Draknkep
Hi Dag...

I have a very nice set of Don Smiths RC Plans B-24 plans (also for about 10' wingspan) that you are welcome to. When I ordered the Connie plans, I was accidently shipped the B-24 plans instead. When I contacted them about it, they said keep them and they sent me the connie plans. I would like them to have a good home, so, as I said, you are welcome to them. Just PM me with your address...

SteveT
Thanks Steve,
PM me about Don Smith plans

DAG
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Old Jan 12, 2009, 12:45 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,002 Posts
Quote:
Originally Posted by Hepdog
Sounds good. It's definatly a growl and not harmonics right around 55%. It is true that every prop motor has a sweet spot and a bad spot - this is a different sound. I've heard it before on Snowmobile Idler wheels - the little guys that spin real fast to keep the track aligned. When they start to growl failure isn't far behind. I think the growl sound is likely a chatter type response to vibrations at certain freqs. Even a few thousanths can vibrate to destruction.


I would also encourage you break in all your Lipo packs on the test rig to accomplish more of the same. Not only will your Lipo's perform better and you get assurances the packs are all good PLUS you can put some serious time on the driveshafts and bearings. I would log the time to see how many hours they are good for.
I will check something tonight. The mid-shaft bearing fits the shaft well, but does not need to be pressed on. I wonder if I am just a little to loose and the shaft at RPM is moving just a little. I have checked the bearings and they are not binding or loose, but that shaft may be just a 10,000th off.

Thanks, DAG
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Old Jan 12, 2009, 12:55 PM
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Stonewall, MB, Can
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Quote:
Originally Posted by dag214
I will check something tonight. The mid-shaft bearing fits the shaft well, but does not need to be pressed on. I wonder if I am just a little to loose and the shaft at RPM is moving just a little. I have checked the bearings and they are not binding or loose, but that shaft may be just a 10,000th off.

Thanks, DAG
Thinking outside the box, you know how on 2 peice industrual drive shafts they mount the steady bearing in hard rubber to isolate inevitable vibrations??? Maybe the mid mount bearing should not be as firmly mounted? Of course that could cause bigger issues than it solves.

At any rate test the crap out of what you have and fly it. At our RC duty cycles it probably will never be a problem.
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Old Jan 12, 2009, 01:12 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
26,747 Posts
Hi Dag...

I had to call Hacker this morning about a problem with and ESC. I talked to Mike, and as I expected, he took care of the problem for me. I also told him I am and avid reader of this thread and I told him how great I think it is that Hacker has been so supportive of your project.

I think that any company that doesn`t support great projects likke this in this day and age of "instant" world-wide communication is foolish...and any company that does, gets the best advertising that can be found... Satisified customers!!! Hacker did it right!!

SteveT
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Old Jan 12, 2009, 02:10 PM
HAL... Open the damn doors!
jfetter's Avatar
Miramar, Florida
Joined Jul 2007
8,471 Posts
Dag,

I know we talked about extending the motor leads, specifically extending the 3 wires between the ESC and motor. Have you talked to Hacker about this? I ask because I've done this before, some 30" and I saw no ill effect but I noticed something in the Spin instructions, they seem to offer a way to extend the leads from the battery to the ESC (preferable I would think);

-----

> Extending the battery cables. As a matter of principle only cables from the battery to the controller can be extended. If the extension is larger than 20 cm it is unavoidable to connect between the cables a low impedance electrolytic capacitor of a capacity 100-300 F. These capacitors must be inserted between every cable section longer than 25-30 cm.

-----

Jack
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Old Jan 12, 2009, 02:25 PM
Registered User
Denmark
Joined Aug 2008
49 Posts
This will give You all the data You'll ever need.
Min Volts, Max Amps, Watts
With censor exact rpm, batt temp, motor temp, ESC temp and so on.
And when it finally gets in the air just add extra censors for altitude, airspeed and if You want GPS.

http://www.eagletreesystems.com/MicroPower/micro.htm
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Old Jan 12, 2009, 04:19 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Wellllll, I think I know what that noise was, I have to be very honest, I really couldn't hear the noise enough to know if it was a problem or just something that comes with this much power, well it was my shafting being to loose on the mid bearing.

Also the bearing it'self was to loose in the rubber mount I had it in.

Funny how things happen. I am learning a lot about shafting.

Thanks all,

DAG
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Old Jan 12, 2009, 04:34 PM
HAL... Open the damn doors!
jfetter's Avatar
Miramar, Florida
Joined Jul 2007
8,471 Posts
Quote:
Originally Posted by dag214
...well it was my shafting being to loose on the mid bearing.

Also the bearing it'self was to loose in the rubber mount I had it in.
Kudo's to Hepdog! I couldn't hear anything but what I expected to hear, good ears!

Jack
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Old Jan 12, 2009, 05:30 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
6,002 Posts
After a bunch of thinking and some true desire to make a great flying plane I may have to just admit that taking on shafting was to to much. Sure I can make it work, but I want to have a plane that has normal duty cycles. Check a nut here tighten a loose screw.

Soooo ,
I have just spent the last 45 minutes running the calcs and with my current datum system if I move the motors back to the rear of the nacelles and keep my Lipo's at the leading edge (which would be a 8" Battery -ESC, and then have 12" from ESC-motor) I can have my CG with in .5" of where I need it, which is still a tad nose heavy, and the plane will weight about 83-88 pounds, that would give my a wing load of about 28-31. One thing that I just found out, the shaft on my Hackers is about 5/8" to short to use my Zingers, but I think the answer to that is to router off .5" from the front of the 3 blades (at the hub) and move the 2 hub halves closer, then the Hacker shaft will work fine.

Thoughts?????

I want a plane to fly, not to work on like the real B-36, in a earlier post someone said that the real B-36 would break just sitting on the runway.

Rock On! all.

DAG
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