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Old Apr 29, 2012, 09:56 AM
Why kamikaze pilot wear helmet
mikes68charger's Avatar
United States, OH, Columbus
Joined Jul 2010
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Quote:
Originally Posted by mikes68charger View Post
I wish you posted sooner that was a wast of $18
Right. I can't wate

Thrust is real important number for me.

I had a rig set up when I was spending all that $$ on EDF set ups I'm going to use to test these props. It keeps me at a safe distance

I will admit that the ARC 28-58-1 on a 70mm wemo fan would make the most thrust/watts for 110amps/5 pounds EFFLUX around 180ish

But same motor with a prop rocks.
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Old Apr 29, 2012, 03:17 PM
Victim of C.D.O.
murdnunoc's Avatar
United States, TX, Lubbock
Joined Oct 2007
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Mike,
Are you testing the thrust on the bench?

Testing thrust on the oversquare props like 7x10, 7x13 or 8x23 won't give a very good idea of how they'll perform in flight.
These props will give you horrible static thrust results below 100mph airspeed, but start producing big thrust once they're moving forward and the relative angle of attack to the blades starts decreasing.

You could blow a leaf blower on your test rig and THEN measure static thrust!!
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Old Apr 29, 2012, 05:29 PM
"The Judge"
sebbe's Avatar
Sweden
Joined Feb 2006
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how does static Amps general compare with inflight? for these props..

Assuming you fly fast and in a sleek model..

Is static Amps always more ?
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Old Apr 29, 2012, 05:41 PM
Livin it UP when Im goin DOWN
Arcteryxxx's Avatar
Norway, Telemark, Skien
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Quote:
Originally Posted by sebbe View Post
how does static Amps general compare with inflight? for these props..

Assuming you fly fast and in a sleek model..

Is static Amps always more ?
I'd say 15-25% unloading in flight as a rule of thumb with these props. I've tested a bucketfull of props and static A is always more than in-flight.
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Old Apr 29, 2012, 05:44 PM
"The Judge"
sebbe's Avatar
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Originally Posted by Arcteryxxx View Post
I'd say 15-25% unloading in flight as a rule of thumb with these props. I've tested a bucketfull of props and static A is always more than in-flight.
how does unload compare between a "normal" prop like 8x8 to a over squared like 8x17.... can we se any pattern, like the oversquared always unloads more ?
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Old Apr 29, 2012, 06:14 PM
Livin it UP when Im goin DOWN
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A "undersquare" prop seems to unload more than a square as a general statement, but there are many variables to consider, so generalizing is a game of chance. Such variables are eg. the make (design) and pitch, rpm (as a factor of rigidity and airfoil) etc. etc.....
The data from folding prop is very much dependent on rpm and the size of the spinner it's attached to....
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Old Apr 29, 2012, 06:36 PM
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So my 7x13 folders mounted on a 45mm Turbo spinner are a 8x..something?
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Old Apr 29, 2012, 07:07 PM
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Arcteryxxx's Avatar
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You need to measure the width... The prop will draw more amps on a 45mm middle piece than on a 32mm... obviously....
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Old Apr 29, 2012, 07:12 PM
Why kamikaze pilot wear helmet
mikes68charger's Avatar
United States, OH, Columbus
Joined Jul 2010
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Like stated before I can't find any high pich 7in prop. And as I'm trying this motor I don't want to speed the $$ on folding props untill I find out ruffly what prop I need

That's good to know about unloading and low thrust numbers

I know my ARC 28-58-1 with a 6x4 prop is 5.5 pounds. I'm hopeing this big ARC will do an 8x8 with 9 pound. If so I may get 2 of them for my big falcon as in EDF set up I was going to use 12s 5000 mah set up
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Old Apr 29, 2012, 07:22 PM
Livin it UP when Im goin DOWN
Arcteryxxx's Avatar
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Mike: have you contempated a gearbox for your 28-58-1? I have the same motor turning a 15x18 prop on 5S with a Kontronik KPG 5.2:1 gear
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Old Apr 29, 2012, 07:32 PM
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Mike grab an APC Sport (Nitro) prop in either 7x9 or 7x10 and throw that on there and lets see what the numbers show. Those numbers that Murdo posted back on page 2 are Sport or Pylon props. Won't know what you need until you spin her up with something....gotta have a base line.
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Old Apr 29, 2012, 07:35 PM
Livin it UP when Im goin DOWN
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Originally Posted by arcticflyer View Post
Mike grab an APC Sport (Nitro) prop in either 7x9 or 7x10 and throw that on there and lets see what the numbers show. Those numbers that Murdo posted back on page 2 are Sport or Pylon props. Won't know what you need until you spin her up with something....gotta have a base line.
<<<<<<<<<<<<<<<true, so true!
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Old Apr 29, 2012, 08:54 PM
Carbon fiber is our friend
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United States, CA, Lodi
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Originally Posted by jackosmeister View Post
I have one of those 7x7 aeranauts somewhere, I remember working out the max rated rpm was only like 14k! so threw it in the bits box...
Hmm, well I flew a plane 190 mph with one. It worked for me.
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Old Apr 29, 2012, 09:40 PM
Crashing into the sky!
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Auckland NZ
Joined Aug 2007
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I never tried it Steve, just read the 14k rpm rating and thought screw trying that
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Old Apr 30, 2012, 04:38 AM
"The Judge"
sebbe's Avatar
Sweden
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Quote:
Originally Posted by arcticflyer View Post
So my 7x13 folders mounted on a 45mm Turbo spinner are a 8x..something?
Well, Koch:s props are made for 45mm spinners and above,, So I guess its a 7x13 on that spinner..
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