[NSRCA-discussion] Going Electric - Battery Questions

Sat Dec 8 04:55:53 AKST 2012

I just charge and fly I have about 20 to 25% battery left after I finish the intermediate, my batteries have lots of cycles on them, but they just keep on going and going and going......................

Date: Sat, 8 Dec 2012 08:47:14 -0500
From: chuenkan at comcast.net
To: nsrca-discussion at lists.nsrca.org
Subject: Re: [NSRCA-discussion] Going Electric - Battery Questions

Yeah, it's kinda like what they say around the Indy
race track:  Speed costs money, how fast do you want to go?

Phil Spelt, KCRC President
AMA 1294 Scientific Leader Member
SPA 177 Board Member
(865)435-1476v, (865)604-0541c

On 12/7/2012 11:59 PM, Larry Diamond wrote:

  When
I first started, I thought I heard after a certain point, it was $100
per ounce to shed weight… LOL

  From:
nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Verne
Koester

  Sent: Friday, December 07, 2012 10:52 PM

  To: 'General pattern discussion'

  Subject: Re: [NSRCA-discussion] Going Electric - Battery
Questions

  I’ve
seen guys spend $100 or more to get rid of an ounce on their planes.
I’m just sayin….

  Verne

  From:
  nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]
  On Behalf Of PhilS.

  Sent: Friday, December 07, 2012 9:09 PM

  To: General pattern discussion

  Subject: Re: [NSRCA-discussion] Going Electric - Battery
Questions

  OK, so if my calculations
are correct, a 10% difference in nitro amounts to a 0.14%
difference in weight.  In a 20-oz tank of fuel, I can't think that will
make a noticeable difference in overall aircraft weight or balance. 
So, doing all thehigher math -- actually, since the fuel is going to
fly, we must get into computational fluid dynamics!  ;-{) -- I
calculate that 20 oz of 25% fuel weighs 0.96 oz more than a 20oz tank
of 14% nitro.  If my calcs are correct, that is hardly anything to
write home about!!!

  Phil Spelt, KCRC President
  AMA 1294 Scientific Leader Member
  SPA 177 Board Member
  (865)435-1476v, (865)604-0541c

On 12/7/2012 8:17 PM, Dave Burton wrote: 
  Actually
it does! nitro is approx 9.4 lbs per gal,  methanol is approx 6.7 lbs
per gal.

  From:
  nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]
  On Behalf Of PhilS.

  Sent: Friday, December 07, 2012 7:45 PM

  To: General pattern discussion

  Subject: Re: [NSRCA-discussion] Going Electric - Battery
Questions

  Sorry, Verne, more Nitro
doesn't cost us more weight.  ;-{)

  Phil Spelt, KCRC President
  AMA 1294 Scientific Leader Member
  SPA 177 Board Member
  (865)435-1476v, (865)604-0541c

On 12/7/2012 7:15 PM, Verne Koester wrote: 
  Larry,
20C is 10% nitro, 40C is 40% nitro. Like nitro, more C is more weight
as well in most cases. 

  I
fly Masters with 20C batteries and have my throttle governed back to
make it easier to manage the excess power. I started last season with
25C batteries and had to govern it back even more. Using 40C batteries
would be like sticking a YS 170 on a 110-size plane while probably
putting you over the weight limit.

  Verne

  From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]
  On Behalf Of Larry Diamond

  Sent: Friday, December 07, 2012 6:18 PM

  To: General pattern discussion

  Subject: Re: [NSRCA-discussion] Going Electric - Battery
Questions

  Interesting point... I don't understand how
changing from 20C to 40C pack makes a difference using the same Motor
and ESC combo. If it's battery heat, my electronics background would
tell me the pack is probably being dicharged too deep. Not good for the
life of a battery.

  I suspect the result
of not changing the Motor/ESC and only changing the battery will reult
in a shorter battery life; and, over loading the power plant which will
probably result in damaging the ESC and/or the Motor.

  I could be wrong,
cause I really have no experience with electric power set ups in
planes. I just don't understand the logic going from 20C to 40C and the
result being "too hot for intermediate".

  It wouldn't surprise
me to see Masters or FAI having a higher power set up, like 3,500 to
4,000+ watts. Then depending on the max current draw,  40C may make
sense.

  My set up will
be about 2,700 to 3,000 watts based on specs... It may not be
sufficient for Masters or FAI.

  Perhaps this will
turn out to be a good constructive discussion for a number of people
like me, but I'm curious as to other opinions who have practicle
knowledge.

  Larry Diamond

  From:
Patrick Harris <harris7148 at gmail.com>

  To: General pattern discussion <nsrca-discussion at lists.nsrca.org>

  Sent: Friday, December 7, 2012 2:02 PM

  Subject: Re: [NSRCA-discussion] Going Electric - Battery
Questions

  Larry,

  You have received all good advice. One thing to
keep in mind, is you are not going to be able to fly two full sequences
with pretty much any setup. With the Himax in a Monolog flying
Intermediate, 20C's are going to be perfect. With 20C's and good
throttle management you are going to be able to fly the full
Intermediate and maybe four or five more maneuvers. If you go up to
40C, you will find the Himax way to hot for Intermediate, and you won't
add that much flying time. 

  Another thing about the Himax is it really needs
an aggressive throttle curve on the bottom. If you just fly it out of
the box it will have zip for low end and nuts for high end all at about
mid throttle. On the low end, you will just keep pushing and pushing
and nothing seems to happen until you hit mid throttle and it will go
nuts. The best throttle curve on my Himax looks like a snake. It ramps
up really fast on the low end, tappers off at mid throttle and then
heads back up on the high end, but you need to work it out for your set
up. Trust me, spending a good amount of time getting this right is
going to pay big dividends. If you don't, your uplines are going  to be
way too hot.

  Hey Larry,

As everyone is telling you, the BIG difference between what you're
proposing and what you're accustomed to with Glg to below is that
you'll fly 90% of your sequence at half throttle.  Not figuratively
half throttle... but literally half, or below.  Even a vertical upline
does not need full motor on these setups.   Flying intermediate even
less so.   Also, at full throttle you'll likely only pull about 75amps,
so even 15C batteries would get the job done, but I would stick with 20
and higher.

Mark Atwood

Paragon Consulting, Inc.  |  President

5885 Landerbrook Drive Suite 130, Cleveland Ohio, 44124

Phone: 440.684.3101 x102  |  Fax: 440.684.3102

  mark.atwood at paragon-inc.com<mailto:mark.atwood at paragon-inc.com>  |  http://www.paragon-inc.com/<http://www.paragon-inc.com/>

On Dec 7, 2012, at 1:37 PM, Larry Diamond wrote:

OK, play nice... Never dealt with electrics before... I could be way
off base, but here is a stab at it...

Is my math flawed?

Motor - Himax 6330-210 F3A Motor (210KV)

ESC - Phoenix Ice 80HV - New V2 Version

Battery 10s - 37VDC

Plane - 2M Monolog

Max power range is about ~2,700 to ~3,000 watts with this set up...

Calculated Battery Discharge Rate = 80Amps (ESC rating) divided by
3,500mAh (battery capacity) = 22.9C

Based on this math I suspect that a 30C dicharge rate is good on
paper... additional discharge performane = $$$ and I don't want to
spend money on battery performance I don't need...

Class - Intermediate

What is the recommended battery capacity and discharge rate...?

I understand the many variables associated with the answer like, prop
size, temps, wind, throttle control, yada, yada, yada...

I would like to fly the Intermediate sequence a couple time without
having to refuel electrons...

Larry Diamond

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