[NSRCA-discussion] Going Electric - Battery Questions

PhilS. chuenkan at comcast.net
Fri Dec 7 17:16:12 AKST 2012 

Right, Ed, have handled 25%, not 30%.  However, I don't plan to fly a 
55-gal drum.  lol

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


On 12/7/2012 9:13 PM, Ed Alt wrote:
> Let's stop writing about it then.  Last note however, if you ever 
> handle 55 gal drums of glow fuel, you will definitely notice the large 
> weight difference between 15% and 30% nitro.
> *From:* PhilS. <mailto:chuenkan at comcast.net>
> *Sent:* Friday, December 07, 2012 9:09 PM
> *To:* General pattern discussion 
> <mailto:nsrca-discussion at lists.nsrca.org>
> *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> 
>> [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 
>> <mailto:harris7148 at gmail.com>>
>> *To:* General pattern discussion <nsrca-discussion at lists.nsrca.org 
>> <mailto: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><mailto: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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