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Old Dec 16, 2010, 06:42 PM
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Quote:
Originally Posted by Gohmer View Post
Motor stuff is boring. Can you post a pic of the pies?
I think it would be better if you started a "Pies" thread for that.
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Old Dec 16, 2010, 07:00 PM
Home of A-10 - Farmingdale NY
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United States, NH, Londonderry
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Quote:
Originally Posted by rahtware View Post
Hey guys, the replacement motor/prop arrived and I am in the middle of gathering data. the replacement motor is the one with the smaller, plastic and metal bell. The replacement prop (part # PKZ1017), and the kit prop have the same markings, "9.75X7.5_1".

I plan on making 4 different tests, kit motor/kit prop, kit motor/new prop, new motor/kit prop, new motor/new prop.

Notes, I am:

using my Eagle Tree eLogger V3 to gather the data.

making 1 1/2 minute runs at full throttle to let the motor and Battery stabilize.

using the stock 1300mah battery that came with the BNF kit.

using my Supermate DC6 charger to recharge the battery between tests, and letting the battery rest for an hour after each charge.

All this while I bake two pumpkin pies!

Oh, I can take pics and attach data spreadsheets if anyone is all that interested.
That sounds like a great series of tests...can't wait to see your results.

-mike-
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Old Dec 16, 2010, 07:02 PM
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MMMMMMMMMMMMMMMMMMMM....pie

Id like to see the motor/power results too
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Old Dec 16, 2010, 08:16 PM
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First test delayed while I ran into town (4mi and 52 turns away) to get aluminum foil for the pie shells. After 20 sec the stock motor and prop settled down to (around) 11.83 Amps / 212.9 Watts.

Gohmer, et all, Sorry, suffered a pie delay, more to come....
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Old Dec 16, 2010, 09:02 PM
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Pies in the oven, battery charged and resting.

I had a chance to work with the ET 2D chart and came up with these results for the minute in the middle of the "stable" run time.

V: Min 10.86, Max 11.10, Avg 10.99

A: Min 11.65, Max 12.11, Avg 11.83

W: Min 126.52, Max 133.06 Avg 130.05
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Old Dec 16, 2010, 10:05 PM
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Kit motor / Replacement prop:

V: Min 10.86, Max 10.93, Avg 10.89

A: Min 13.12, Max 13.67, Avg 13.43

W: Min 142.48, Max 149.14, Avg 146.27
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Old Dec 16, 2010, 10:14 PM
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Quote:
Originally Posted by rahtware View Post
After 20 sec the stock motor and prop settled down to (around) 11.83 Amps / 212.9 Watts.
Uhhh, that watt reading has to be wrong. Unless you were running the motor on 18 volts.

112.9 watts right? That would be 9.5 volts.

......Mike
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Old Dec 16, 2010, 10:15 PM
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Pulled the Kit motor, but before I installed the replacement motor I took some pictures.

I didn't have an original Radian so don't know what the motor that came with it looked like.

I'm not too sure about the plastic bell on the replacement motor.
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Old Dec 16, 2010, 11:23 PM
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New motor / Kit prop:

V: Min 10.92, Max 11.15, Avg 11.04

A: Min 12.02, Max 12.47, Avg 12.17

W: Min 131.26, Max 137,42, Avg 134.37

I don't see much of an improvement from the motor that came with the kit...
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Old Dec 17, 2010, 01:47 AM
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Finally!

New motor / new prop

V: Min 10.87, max 10.97, Avg 10.91

A: Min 13.94, Max 14.58, Avg 14.29

W: Min 151.10, Max 158.09, Avg 155.26


Condensed version of data:

Kit motor/kit prop: Average Amps = 11.83; Average Watts = 130.05

kit motor/new prop: Avg Amps = 13.43; Avg Watts = 146.27

new motor/kit prop: Avg Amps = 12.17; Avg Watts = 134.37

new motor/new prop: Avg Amps = 14.29; Avg Watts = 155.26

Seems like the new prop makes up for most of the increase in power... Might just keep the old motor (with the all metal bell), but go with the new prop.

Biggest problem with my data is I don't have a thrust meter. I thought I could feel a difference in "pull", but no way to prove it. And, as Dr Kiwi and others have proved, an increase in power consumed does not always translate to an increase in thrust.

The chart is just a "Print Screen" pic as it is late and I am too tired to figure out how to upload it directly from the Eagle Tree program.

The four separate sections are the different motor/prop combination in the order as listed above in "condensed version..."
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Old Dec 17, 2010, 01:52 AM
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Originally Posted by MS_in_NY View Post
Uhhh, that watt reading has to be wrong. Unless you were running the motor on 18 volts.

112.9 watts right? That would be 9.5 volts.

......Mike
Mike, my bad. I think it was 121.9, but I can hardly focus on the screen now so going to bed and will check it in the morning...zzz
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Old Dec 17, 2010, 01:53 AM
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Oh, almost forgot.
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Old Dec 17, 2010, 02:08 AM
Dixie Normious
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http://www.horizonhobby.com/content/...ast_100710.mp3
Heres a good listen of a little more in dept talk about the Pro.Its starts around 2-3 mins into the Clip
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Old Dec 17, 2010, 02:17 AM
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Originally Posted by rahtware View Post
Mike, my bad. I think it was 121.9, but I can hardly focus on the screen now so going to bed and will check it in the morning...zzz
Don't bother checking that's probably it. That would be 10.3 volts. Not important.

Thanks for doing and posting those tests. There does seem to be 'something' about the props on the Pro that's 'funny'. But the thing that really surprises me is I thought the 'replacement' motor, i.e. the original Radian 480, would pull a lot more amps. I expected 17-18 at least.

.......Mike
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Old Dec 17, 2010, 06:25 AM
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Quote:
Originally Posted by rahtware View Post
Finally!

snip:


Condensed version of data:

Kit motor/kit prop: Average Amps = 11.83; Average Watts = 130.05

kit motor/new prop: Avg Amps = 13.43; Avg Watts = 146.27

new motor/kit prop: Avg Amps = 12.17; Avg Watts = 134.37

new motor/new prop: Avg Amps = 14.29; Avg Watts = 155.26

Seems like the new prop makes up for most of the increase in power... Might just keep the old motor (with the all metal bell), but go with the new prop.

Biggest problem with my data is I don't have a thrust meter. I thought I could feel a difference in "pull", but no way to prove it. And, as Dr Kiwi and others have proved, an increase in power consumed does not always translate to an increase in thrust.

The chart is just a "Print Screen" pic as it is late and I am too tired to figure out how to upload it directly from the Eagle Tree program.

The four separate sections are the different motor/prop combination in the order as listed above in "condensed version..."

Rahtware

That is an EXCELLENT series of tests. And the fact that you took your radings at 20 seconds gives us much truer numbers than an instant or peak test. You have shown that the issue is both the motor and the prop.

We know that not all props of the same specs have the same characteristics. You can have two props that are 9.75X7.75 that have different characteristics based on the airfoil of the blade. (yes, prop have aifroils. They are spinning wings.)

So, it seems they have a motor that is lower performance than the original AND a prop that does not pull as hard as the original. So both need to be changed which yields about a 20% improvement overall. That is significant.


I look forward to hearing your flight reports and a comparison of the climb performance.
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