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Saturday 7/7/18
2018-07-07, 21:07 by Gary M Jones
I was at the field today between 14:00 & 15:00 all on my own , good flying too. There is a dead sheep along the fence line towards the gate from the pits, I saw the farmer so reported this to her. I hope no one had plans for a BBQ
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Farmer …

Farmer …
Comments: 1
One for the prop nerds
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One for the prop nerds
Ok, quick question..........
I know there is going to be little in it, but which prop would pull more amps......
6x4 or 5.5 x 4.5 Apc?
Ta muchly...........
I know there is going to be little in it, but which prop would pull more amps......
6x4 or 5.5 x 4.5 Apc?
Ta muchly...........
Stubbsy- Posts : 1111
RDMFC Bonus points : 1373
Join date : 2010-08-05
Location : Stubbsy lives in Prestatyn
Re: One for the prop nerds
at some random numbers 5.5x4.5 shows about 10% more
http://www.ecalc.ch/motorcalc_e.htm
or give some more info please - motor KV, and how many cells is a must to know to say anything
http://www.ecalc.ch/motorcalc_e.htm
or give some more info please - motor KV, and how many cells is a must to know to say anything

Robert Piechulski- Posts : 463
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Join date : 2009-06-14
Location : Huddersfield
Re: One for the prop nerds
Sorry Rob- 2800Kv on 3s

Stubbsy- Posts : 1111
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Join date : 2010-08-05
Location : Stubbsy lives in Prestatyn
Re: One for the prop nerds
6x4 - 31.42A <comment Prop may stall -> static thrust may not be reached!>
5.5x4.5 27.44A <comment Prop may stall -> static thrust may not be reached!>
Prop Stall Thrust: If the Pitch is bigger than 66% of its diameter, the airflow will stall resulting in less static thrust and decreasing max. current.
here is manual for the program (link given before)
http://www.ecalc.ch/calcs/help/motorcalchelp.htm
Depending on the model I'd go for 5.5x4.5 if it's a very aerodynamic slick design (or even higher like 4.75x4.75 - 5.25x5.25)
If design has lot of drag - then I'd rather use 6x4
- just play with it
5.5x4.5 27.44A <comment Prop may stall -> static thrust may not be reached!>
Prop Stall Thrust: If the Pitch is bigger than 66% of its diameter, the airflow will stall resulting in less static thrust and decreasing max. current.
here is manual for the program (link given before)
http://www.ecalc.ch/calcs/help/motorcalchelp.htm
Depending on the model I'd go for 5.5x4.5 if it's a very aerodynamic slick design (or even higher like 4.75x4.75 - 5.25x5.25)
If design has lot of drag - then I'd rather use 6x4
- just play with it

Robert Piechulski- Posts : 463
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Join date : 2009-06-14
Location : Huddersfield
Re: One for the prop nerds
Cheers for that Rob...... And thanks for the link too- that's a handy tool!

Stubbsy- Posts : 1111
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Join date : 2010-08-05
Location : Stubbsy lives in Prestatyn
Re: One for the prop nerds
No problem, gave me some time away from water changing in WIFE'S fish tank

Robert Piechulski- Posts : 463
RDMFC Bonus points : 583
Join date : 2009-06-14
Location : Huddersfield
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