[NSRCA-discussion] Electric props

[Larry]

Hi Stuart,

We need more info. Unfortunately, electrics have more variables than IC 
setups.

What plane is this going into? Specifically what is the all up weight of the 
plane going to be and how much power do you think you need?

What size battery pack are you going to run - ?S?P and what capacity?

Also, what gear ratio?


To start answering your question - every item in an electric power system 
has an effect on power output and amp draw.

Larger diameter/higher pitch props will draw more current and produce more 
power than smaller ones. Assuming all other variables stay the same.

However, you cant just arbitrarily increase/decrease the prop size. The 
total power system has to work together. The batteries need to be able to 
sustain the load and the motor needs to be able to handle the power output.


Larry


----- Original Message ----- 
From: "Stuart Chale" <schale at optonline.net>
To: "'NSRCA Mailing List'" <nsrca-discussion at lists.nsrca.org>
Sent: Thursday, June 22, 2006 9:30 PM
Subject: [NSRCA-discussion] Electric props


> Rather than redo tests that others have done I thought I would question 
> the
> group regarding the different sized electric props available.  It seems 
> like
> there should be a much better consistency and less variability between
> different electric motors compared to different IC setups.
> I am going to run the Hacker C50 14 XL (not comp model) with the 90 amp 
> Acro
> speed controller.  Seems as if most people are running the 22x12 APC E 
> prop.
>
>
> Below is a list of potential props I found on the APC web site.
> If you have tried any of them and found a reproducible difference from the
> 22x12 I, and I am sure others would like your thoughts.  If any of the 
> props
> are too much for the setup please let me know.  (No reason to waste money 
> on
> an unusable prop)
> Hat happens when you run less of a prop say the 20 x 11?  Does the RPM 
> stay
> the same?  Will the current usually go up or down?
> These seem to be the possible choices from APC
>
> 20 x 11
> 20 x 13
> 21 x 14
> 20 x 15
> 22 x 10 ( I would suspect a slower flight speed)?
> 20 x 12 wide
> 21 x 12 wide
> 21 x 13 wide
> 20.5 x 12 wide
>
>
> Thanks
> Stuart Chale
>
> E-Pinnacle should be ready to fly this weekend.
>
>
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