[NSRCA-discussion] E Stuff

Sat Jan 21 13:39:51 AKST 2006

We already have two power tool companies with Li+ ion power packs.  As I
understand it Li+poly are lighter per amount of energy but it seems more
dangerous with respect to charging.  (any battery guru's are welcome to
better explain some of the differences, I would be more than interested).  

I would suspect that saving a few ounces on a battery pack for a hand tool
if not as safe would not be in the toolmakers best interest.  

Anyone know of other industries that would use LI+Poly and require the
discharging abilities that we do?

Also on a quick google search lithium fiber batteries popped up.  Maybe
there is something even more promising on the horizon?

Personally I would like to see the next generation of batteries before
buying several sets.

Stuart

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From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
vicenterc at comcast.net
Sent: Saturday, January 21, 2006 5:12 PM
To: NSRCA Mailing List; NSRCA Mailing List
Cc: Jerry Stebbins
Subject: Re: [NSRCA-discussion] E Stuff

Jerry,

Today we got two e-mails.  One with 30 cycles the other over 170.  At the
Nats. a very well know pilot told me 60 average.  As we can see, it is all
over the map.  I would like to go electric and the advantages of electric
power in pattern are evident.  However, I am not ready until battery
companies give us some minimum expectation in regard battery life.  Clearly
time will tell.  I believe that when we start to see the power tools
manufacturers installing LiPo in their equipment we would be able to expect
a decent life of this packs under high current draw conditions.

Vicente Bortone  

-------------- Original message -------------- 
From: "Jerry Stebbins" <JAStebbins at worldnet.att.net> 

Vicente, I hope that is "tongue in cheek", because any battery manufacturer
to warranty to that, or almost any extent would be killed by his/her
lawyers. They would have so many "exceptions" that they would "never be at
fault". 

If that is anyone's criteria it wll be a long time before they switch.

Jerry

----- Original Message ----- 

From: vicenterc at comcast.net 

To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>  ; NSRCA
Mailing List <mailto:nsrca-discussion at lists.nsrca.org>  

Sent: Saturday, January 21, 2006 2:51 PM

Subject: Re: [NSRCA-discussion] E Stuff

Scott,

I am waiting for my second Abbra.  If Tanic gives me a written warranty that
the battery is going to last around 250 cycles of Master rounds I will make
the switch.  Is that possible?  I will follow charging and break in
instructions.

Thanks 

Vicente Bortone  

-------------- Original message -------------- 
From: "Scott Anderson" <scott at rcfoamy.com> 

Vicente,

You also have to look at replacing bearing, changing batteries in the
support equipment (glow driver/ electric starter) and servos after a time
from vibration, this will increase your glow cost per flight .. Dan Landis
and I are using Tanic packs and he flies FAI and has a set of sticks (
Battery) with over 170 flight and you can't tell the diffrence from that
pack and on with less time on it.. I have just started using Tanic and the
results are very good, Just follow there "breakin" for the packs.

I made the jump to electric in 05 and after the first flight I was hooked
and sold all glow fuel and glow planes.. If you look around you still make
the conversion without  breaking the bank.

Just my 2 cents

Scott Anderson

D3 AVP nsrca 529

Team Tanicpacks.com

Team PMA

----- Original Message ----- 

From: vicenterc at comcast.net 

To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>  ;
Discussion List, NSRCA <mailto:nsrca-discussion at lists.nsrca.org>  

Sent: Saturday, January 21, 2006 1:35 PM

Subject: Re: [NSRCA-discussion] E Stuff

Unfurtunetely, I have to estimate the cost.  I did an estimate how much is
the cost to run my 2c motor per flight.  At $15/gallon using 14 oz of fuel
per fly the cost is $1.75 per flight.  This number is correct since I
usually flight between 200-300 flights per year.  

The question is: what is the life of the batteries?  Base of the feedback I
got at the Nats. the life flying F3A is around 60 flights.  Therefore, if I
am correct the cost per fly is $11.  Assuming that I do 250 flights per year
the cost of electric is $2,750/yr.  The equivalent cost of glow (2C) is
$440/year.  With two kids in college my option is clear.  I am assuming that
the cost of batteries is $640 but not sure now.  

Probably I am wrong in these numbers.  Clearly the cost of the batteries has
to come down or the cycles have to go up to around 400 cycles to get
equivalent cost to glow.  

Any information on this regard is welcome,

Vicente Bortone

-------------- Original message -------------- 
From: "Earl Haury" <ehaury at houston.rr.com> 

The E info on the list has been scant. Probably some are reluctant to hype /
criticize products because of their involvement with suppliers. Some of us
are just blindly exploring options, gathering data / information, and
forming opinions without experience to back up our conclusions. Certainly
information offered by those with experience is very welcome and
appreciated. Those who are qualified experts in the various fields that can
correct / clarify information gained through the school of hard knocks are
not only welcome, but I suspect somewhat obligated to protect the rest of
us. As this entire topic expands there will be conflicting opinions which in
themselves provide info - that's what this list is for and no one should
take offense that some prefer other views.

After teasing the E guys at the Nats I recognized that the E powered
airplanes flew better (I'll admit to being obstinate - but not totally
dumb). There were also differences that seemed related more to E equipment
choices than differences in pilot skills. The info published by Jason,
Frack, Adam, Chad, and others (in RCU forums) provided an insight to the
various equipment choices (and passionate defense of same in some cases).
Interestingly, a lot of the discussions revolve around equipment type rather
than the effect on flight characteristics.

So - I set about trying to determine if E flies better and why. So far the
answer is yes and I'm not sure. While differences in dynamics can be
identified, it's hard to quantify the effects. For example, the lighter /
slower rotating E prop generates a lower gyroscopic precession force during
looping maneuvers than glow - this also suggests the lower rotating mass of
a geared motor might be better. The lighter motor (compared to glow engine)
up front can result in a lower pitch moment of inertia if the tail is light
enough to allow the battery mass to be close to the CG. Airplane smoothness
in rough air is markedly better with E. (I did most of my comparisons with
twin Partners - one glow and one E - at about the same flight weight.)  This
may be an effect of the large diameter prop or lack of vibration effect on
the servos. As others have noted, thrust application is very good with E as
the slower prop is efficient and the mo! ! ! tor is instantly responsive and
very linear. E can be flown slower than or as fast as glow, the airplane is
more stable with E when slow  - again probably the large prop effect.
Overall, it's easier to fly well with E but E won't fix sloppy flying.

As with most things in model aviation - there are learning curves. Some
suppliers are better than others, some equipment is better than others, some
choices will be revisited after experience is gained. The hardest thing to
get used to is the metrification of cost - kilo dollars. Not that E is that
much more expensive than glow - just that very little from glow is useable
with E. That means one must acquire motors, controllers, batteries,
chargers, power supplies, meters, connectors, wire, props, etc. pretty much
from scratch.

If there's interest in this becoming a thread I'll discuss the reasons for
some of my choices of equipment and the data I've generated / will generate
with the full understanding that I might be operating under false
assumptions and some of this stuff will change - I'm still learning.

Earl

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