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Old Oct 19, 2009, 06:39 AM
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Windsor, Canada, near Detroit
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help needed to enter data on 'flybrushless'

Quote:
Originally Posted by phil alvirez
i have data on the 1811 with 6/3 and 7/3.5. I tried to register but it did not accept me. Besides i have no idea of how to fill the form. I also would like to give details of the equipment i used for this test. Anybody? If you prefer, you can send me a PM to explain me all of it and i will provide all the details on my equipment. Thanks.
so far i can not enter data on flybrushless. Dr Kiwi refered me to Robert (rgoble), and Robert answered to me, saying that he just registered me there, but after trying again, i still am not accepted and don't have a clue how to do it. It keeps telling me that something is wrong with my password and/or name. Robert is having a handful with his new baby girl just born, so i don't want to bother him again. I wonder if anybody else has tried to enter data and has faced the same problems? Perhaps if we could see instructions right there about how to register, more guys can increase the data. I not only have data on the 1811-2000, but on some other motors too, that i would like to share.
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Old Oct 19, 2009, 06:58 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
near Nijmegen, Netherlands
Joined Feb 2001
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A long shot Phil, remove the Flybrushless cookies?

Vriendelijke groeten Ron
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Old Oct 19, 2009, 07:58 AM
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meaning what? please explain

Quote:
Originally Posted by Ron van Sommeren
A long shot Phil, remove the Flybrushless cookies?

Vriendelijke groeten Ron
i need to know exactly what to do to be accepted by flybrushless. can you help me?
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Old Oct 19, 2009, 09:31 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
near Nijmegen, Netherlands
Joined Feb 2001
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I have no idea Phil, have you tried removing the cookies from your system?

Vriendelijke groeten Ron
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Old Oct 20, 2009, 12:58 AM
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cookies? Somebody?

Quote:
Originally Posted by Ron van Sommeren
I have no idea Phil, have you tried removing the cookies from your system?

Vriendelijke groeten Ron
Frankly, dear Ron, I have no idea of what you mean with 'cookies', perhaps because i am new to computers and i have never heard of it in this rcg.
If you were so kind to elaborate i may get it. A technical word for 'cookies'?
Thanks!
Phil
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Old Oct 20, 2009, 02:25 AM
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data on 1811-2000

i am showing data i collected, for 1811-2000 motor.
props are gws Io .45 Rm .74 Kv 1959
using feigao 6a esc-med timing:
prop v a w rpm thrust (gr)
6/3 7.3 3.5 26 9780 165
7/3.5 7.5 3.9 28 8250 170
compared to Bruce Abott's figures:
Bruce: 7/3.5 7 3.9 27 8057 153
using Hi Model FLY12A esc, hard timing:
6/3 7.3 3.5 26 10200 155
7/3.5 7 4.3 30 8700 175
figures from emeter and tahmazo thrust scale
i don't know what esc (and setting) Bruce used on his data; likewise what thrust scale. Mine is a horizontal scale-no 90 degrees arm, and considering the figures of thrust that i get, compared to Bruce's, it is pretty close.
for more details about it: w:http://www.tahmazo.com/products/catalogue/10/137
it is overly expensive, but the mount is quite streamline-not much turbulence.
(i guess Bruce is using an emeter to collect his data)
i also have some figures of other motors in the same class of the 1811 that may be of interest to modelers.

i am presenting this data here for you, the experts, to compare and let me know what do you think.
I have tried to make it available through 'flybrushless', but perhaps due to my lack of experience with computers, i have been unable to break the code to enter it. Regards, Phil
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Last edited by phil alvirez; Oct 20, 2009 at 04:27 PM. Reason: add data
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Old Oct 20, 2009, 02:49 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
near Nijmegen, Netherlands
Joined Feb 2001
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http://en.wikipedia.org/wiki/HTTP_cookie

If you Internet Explorer 8 I can tell you how to remove the cookies. Otherwise you have to google for 'delete cookies'.

Vriendelijke groeten Ron
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Old Oct 20, 2009, 03:58 AM
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cookies indeed

Quote:
Originally Posted by Ron van Sommeren
http://en.wikipedia.org/wiki/HTTP_cookie

If you Internet Explorer 8 I can tell you how to remove the cookies. Otherwise you have to google for 'delete cookies'.

Vriendelijke groeten Ron
Ron: thank you for the info. I just went briefly through the wikipedia as you suggested. I had no idea of all of this. I will study all and see if they can be of some help. So cookies they are!
Phil
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Old Dec 26, 2009, 06:01 PM
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Blackpool, Great Britain (UK)
Joined Dec 2003
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An alternative data presentation

The websites www.flybrushless.com and www.peakeff.com present motor and prop data in a somewhat similar manner.

Both show motor data on a graph derived from motor constants, at selected voltage values.

Both test a limited selection of props by running them on the featured motor, and display the motor and prop data on the same page.
#################################################

This post describes an alternative presentation.

No prop data would be included on the motor page [example,Figure 1, based on a PeakEfficiency graph]. Instead, a prop power constant curve is added to the graph. [The props data is shown on figure 1 because I can't easily erase it].

All the prop data is gathered together on a single [large!] list [see figure 2].

Adding a motor does not involve any props testing. Adding a prop to the list does not involve any motor testing. This makes it easy to update.

This presentation requires very-much-less props testing, since each prop is tested once only. And it would enable a larger choice of props for any particular motor.
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Old Dec 26, 2009, 08:50 PM
Curiouser and curiouser
Kokopeli's Avatar
Rochester, NY, USA
Joined Oct 2005
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Nice idea to take out lots of the work.
I have one question and one concern.
Question: Why does the RPM plot decrease as the current increases?
Concern: Although this format of reporting motor test and prop tests looks interesting, it doesn't appear to be of practical use for me - this assumes that you have a constant voltage source - that is only available on the bench - I need to know how a given motor/prop/battery combination will perform.
Is there an easy way to use a data base like described here to tell me that?
For example:
I pick a motor that I think will power a plane that I intend to build.
Next I pick from my drawer of batteries, all batteries that are not too heavy for this plane.
Now I select a range of props that I believe will work with those two items.
Lastly I set up my power bench and measure thrust, voltage, current and RPM at WOT for the combinations.
I can then look at the results to determine which battery and prop combo will work best with that motor on my desired plane.
I can reduce the setup and work if I have the thrust vs. RPM curves for the props - that allows me to infer thrust from the RPM.
Each time I buy a new motor I run lots of tests to keep my data up to date so that I can dream about all the planes I would like to build without going through the above tests.
I am not sure how the above testing and data recording will help me - seems like the practical link between battery (volts and current) limitations is the real culprit, eh?
Am I overlooking some easy way around making all these measurements?

Walt
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Old Dec 27, 2009, 06:06 AM
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Fourdan's Avatar
Antony (France)
Joined Sep 2003
2,791 Posts
Peterangus
Effectively, Peakeff is a little crowded by propellers
In the same type of presentation you have also
DriveCalc
Scorpion Calc and cousins
see here post #4 http://www.rcgroups.com/forums/showthread.php?t=606703
Louis
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Old Dec 27, 2009, 08:17 AM
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Antony (France)
Joined Sep 2003
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Quote:
Originally Posted by wjbite View Post
Nice idea to take out lots of the work.
I have one question and one concern.
Question: Why does the RPM plot decrease as the current increases?
Concern: Although this format of reporting motor test and prop tests looks interesting, it doesn't appear to be of practical use for me - this assumes that you have a constant voltage source - that is only available on the bench - I need to know how a given motor/prop/battery combination will perform.
Is there an easy way to use a data base like described here to tell me that?
For example:
I pick a motor that I think will power a plane that I intend to build.
Next I pick from my drawer of batteries, all batteries that are not too heavy for this plane.
Now I select a range of props that I believe will work with those two items.
Lastly I set up my power bench and measure thrust, voltage, current and RPM at WOT for the combinations.
I can then look at the results to determine which battery and prop combo will work best with that motor on my desired plane.
I can reduce the setup and work if I have the thrust vs. RPM curves for the props - that allows me to infer thrust from the RPM.
Each time I buy a new motor I run lots of tests to keep my data up to date so that I can dream about all the planes I would like to build without going through the above tests.
I am not sure how the above testing and data recording will help me - seems like the practical link between battery (volts and current) limitations is the real culprit, eh?
Am I overlooking some easy way around making all these measurements?

Walt
Hi Walt
The order of steps is better following that
a) Define-start from the plane-model
b) Select the couple prop-rpm (power, static thrust, pitch speed)
c) Then you get the product (Kv x voltage)
if you have the motor-Kv, you choose the voltage and mAh for flight duration
if you have the pack you select the right Kv (motor)

WeboCalc could help you, then Scorpion Calc
Louis
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Old Dec 28, 2009, 03:00 AM
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Joined Dec 2009
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Outrunner Motors for 3.0m long Scale QE2 Ocean Liner

Greetings All and best for the Season and New Year.

You seem to be predominantly Flyboys, however.

I have a question that relates to a 1:100 scale Queen Elizabeth 2 ocean liner.

Twin screw contra rotating 83mm props.

Model is 3.0m and about 60kg ballasted and we seek to upgrade to a 2.4GHz system with a pair of direct drive Outrunner Brushless motors.

Any thoughts as to the source info or ideas from any readers of this e-mail.

How does an FSD 310kV Outrunner Brushless Motor FC6362 sound????? and then which ESC are we looking for.

Successful integration of this technology into the QE2, (15 years old and being renovated) will forge the way for new model of the Queen Mary 2 at about 3.6m requiring 4 motors powering Azimuth Thruster Pods.

Regards and thanks in anticipation.

Gary
Victoria Australia
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Old Dec 28, 2009, 08:08 AM
Curiouser and curiouser
Kokopeli's Avatar
Rochester, NY, USA
Joined Oct 2005
2,061 Posts
Whoa! That sound like you will need LOTS of bench (really tank) testing to find out how it will work.
My first thought is that the props will try to turn WAY too fast. And if you are successful in turning the props you will have to watch the power input closely so you don't burn out the motor. Your props might even cavitate. If so you will need to use a gear box.
Do you know how many watts the old setup used? Do you know what the max RPM was before? Do you have to use those props - maybe because of being a "scale purist"? Smaller props might work better if they don't cavitate.
You are in new territory and will surely need some experimentation.

Walt
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Old Dec 28, 2009, 10:56 AM
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Blackpool, Great Britain (UK)
Joined Dec 2003
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Quote:
Originally Posted by wjbite View Post
Question: Why does the RPM plot decrease as the current increases?
When a motor is turning, it generates an EMF in its windings which opposes the supply voltage. This EMF is proportional to the rpm. It is called the "back EMF"

Let's say the supply is 10V.

When running with no propeller, the motor will reach a speed [the no-load speed, or NLS] such that the back EMF is almost equal to the 10v supply voltage. So, at no-load speed, the voltage across the windings is almost zero.

If a prop is fitted, which reduces the rpm to 80% of the NLS, the back EMF will now be 8V, so the voltage across the windings is now 2V.

If a larger prop is fitted, which reduces the rpm to 60% of NLS, the back EMF will be 6V, so the voltage across the windings is now 4V.

So, as we increase the prop size, the speed reduces, and the EMF across the windings [and hence the current] increases.

[All at wide-open throttle]
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Last edited by peterangus; Dec 28, 2009 at 11:22 AM.
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