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Old Dec 22, 2008, 10:24 PM
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Old Dec 22, 2008, 10:42 PM
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I looked all over and still couldn't find an email address to reach him.

Robert
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Old Dec 22, 2008, 11:01 PM
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Old Dec 23, 2008, 12:08 PM
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Thanks Phil, I sent him an email. I'll let you guys know if/when I hear something back.

Robert
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Old Dec 23, 2008, 05:42 PM
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Hoffman Magnetics has come out with what I CONSIDER a serious contender .I talked to S. Benton for a few minutes & decided to try what they call THE BEAST.Upgraded the ESC & swapped the motor out of a F5 STARMAX. Took it out the same day, the differance was night & day. I'm sold! I now have,on order 2 more Beast for my TWIN 70 Rafale that is on the way.You do not need A Watt meter to SEE the differance. Rafael.H.Vega@maf.nasa.gov
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Old Dec 24, 2008, 06:29 AM
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Quote:
Originally Posted by vegarh
Hoffman Magnetics has come out with what I CONSIDER a serious contender .I talked to S. Benton for a few minutes & decided to try what they call THE BEAST.Upgraded the ESC & swapped the motor out of a F5 STARMAX. Took it out the same day, the differance was night & day. I'm sold! I now have,on order 2 more Beast for my TWIN 70 Rafale that is on the way.You do not need A Watt meter to SEE the differance. Rafael.H.Vega@maf.nasa.gov
Hi Rafael
With your "feeling" on flight .. did you see the difference (without wattmeter) regarding the power, the flight duration or both ?
If the motors have the same Kv, a 1 or 2% difference in efficiency is difficult to perceive along a flight.
Louis
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Old Dec 24, 2008, 10:08 AM
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Quote:
Originally Posted by vegarh
Hoffman Magnetics has come out with what I CONSIDER a serious contender ... You do not need A Watt meter to SEE the differance. Rafael.H.Vega@maf.nasa.gov
A bit off topic don't you think?

Vriendelijke groeten Ron
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Old Dec 24, 2008, 10:15 AM
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Quote:
Originally Posted by rgoble
Does he have an RCG account or do any of you have an email address for him? I don't want to add someone else's data without their permission....
http://www.rcgroups.com/forums/member.php?u=2750

Vriendelijke groeten Ron
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Old Dec 28, 2008, 09:51 AM
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How about contacting Christian Person, the man behind 'Drive Calculator' (together with Helmut Schenk)
http://www.rcgroups.com/forums/showthread.php?t=771184

And Gerd Giese, German motortester
www.elektromodellflug.de - translation

Gelukkig Nieuw Jaar Ron
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Old Dec 28, 2008, 11:21 PM
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Sorry for the lack of updates the lately but I've been busy with the holiday. I have not heard anything back from Bruce yet, but I did finally get in touch with Matttay about his PeakEff website. I think we are going to work out a way for us to automate something to share the data between our sites. However we still need to work out the details.

I will try and get in contact with Christian person and see what he thinks about joining in on it.

Also I'd like to know what every one thinks about putting a restriction on who can add test data to the site? Right now anyone can but Matttay said he disabled it on his site because some people posted inaccurate data (possibly manufactures to make their motors look better then they are).
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Old Dec 31, 2008, 02:07 AM
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Hey, I've got a few observations and maybe some proposals to make:

Would it be wise to specify the full conditions for motor testing in terms of timing advance, dwell, etc? I used to do this kind of thing for three pole brushed 540 motors back in my R/C car racing daze. Modern brushless ESCs all have programmable setups, but I don't know what Low, Medium, or High means in terms of degrees of rotation or the advance curve with RPM. Hmm.

Would it be wise to perhaps start thinking about testing absolute power output of motors using a mass acceleration dynamometer? Once again, this is something we used back in my car racing days. The idea is to have a known mass (a heavy disk on the output shaft) that starts at a dead stop and is accelerated up to terminal speed. By measuring how quickly the motor can accelerate the disk and how much current it draws in doing so you can tell how much oofta the motor can really produce. It isn't dependent on air density, blade size, yada yada yada. I don't know if these brushless ESCs can be used for this test.

Would it be wise to publish an XML/XSL/DTD specification for motor characteristics? It's been a while since I've done any serious XML stuff, but I'd gladly get back into it to support a worthwhile project like this. It's a simple matter to use an import/export filter to get XML data into and out of a relational database, which must be how the raw data is stored on the site, right?

Anyway, you folks have obviously been thinking a lot more about this than me. If I am just stirring the pot without actually contributing I'll be glad to shut the heck up.
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Old Dec 31, 2008, 03:07 AM
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Quote:
Originally Posted by A Useless Geek
Would it be wise to specify the full conditions for motor testing in terms of timing advance, dwell, etc?
I know that exactly which ESC is used during the testing matters because of the resistance it adds to the system. As far as the timing goes I honestly don't know the answer so we will have to wait on the experts to chime in.

Quote:
Originally Posted by A Useless Geek
Would it be wise to publish an XML/XSL/DTD specification for motor characteristics?
You are correct about the raw data on the site being stored in a relational database. I have actually been talking with Matttay, who runs http://www.peakeff.com about creating a way for our sites to share data. What we talked about so far was using XML to pass the data. Here is the first draft of an XSD I created http://www.flybrushless.com/images/DataExchange.xsd

We still have a few things to iron out, but its a start. If/when it gets worked out I would like it to work with DriveCalc and any other programs / sites like it out there. Although so far I have only spoken with Matttay about it.

Thanks,
Robert
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Old Dec 31, 2008, 03:13 AM
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Advance Search - Update

I finally found some time to create a form for the Advance Search. You can access it here http://www.flybrushless.com/search/advance or there is also a link to it from the search page. This should make it a little easier to find exactly what your looking for.

If you have any questions, problems, or ideas for the search please let me know.

Thanks,
Robert
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Old Jan 04, 2009, 07:42 AM
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Estimate of required input power for a chosen static thrust and pitch speed

To a first, very rough, approximation, INPUT POWER is proportional to the product of STATIC THRUST and PITCH SPEED.

INPUT POWER [watts] = 0.14 x STATIC THRUST [oz] x PITCH SPEED [mph]

The constant [0.14] is derived from a number of test points [from the flybrushless lists] which were chosen with the following constraints:
* 3S battery
* moderate power level. [no merit in using trivial-power data]
* test rpm = approx 0.75 x Kv x test voltage [ensures reasonable motor efficiency]
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Old Jan 04, 2009, 08:33 AM
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Hi Peterangus
Do you mean Power In (ESC input) or Power Out (at prop shaft) ?
Ratio of those figures is the efficiency of motor+ESC group
Louis
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