[NSRCA-discussion] Main battery redundant lead for receiver

J N Hiller jnhiller at earthlink.net
Wed Jan 25 19:12:54 AKST 2012 

10 lb dry, I'm using a 16 oz tank so it probably brakes ground around 10 lb
12 oz.
'Extraordinary' yah that’s probably excessive based on my personal
preference for simplicity, sorry.
I started to put together an estimate once and found it in my computer.
Doing nothing to lighten the airframe I could make weight but I wouldn't be
happy with it much over 10.5 lb. I like my current airplane weight. I
reduced wing area and I think I got it about right at 920 sq in. which would
be about 27 oz / sq ft with fuel.
You guys are renewing my interest in this new challenge.
Jim

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Peter Vogel
Sent: Wednesday, January 25, 2012 4:54 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

The big difference is just that electrics weigh in with batteries installed
and wet fuel ships weigh in with an empty tank.  What does your #160 weigh
fully loaded with fuel?  In general, the batteries are going to amount to
about 20-25% of the total weight (my 4900mah batteries weigh in at just
under 1200g) but the motor weighs about 350+g LESS than a YS170 (580-620g
for the electric vs. 960g for a YS170) and the total electric power system
(counting ESC) should be under 40% of the all up weight of the aircraft, in
my case it comes to just under 38%.  Glow fuel undoubtedly brings your power
system in to a much lower % of the all up weight, even counting a couple
hundred grams of fuel fully loaded and the muffler/pipe, but airframes seem
to weigh more because they are built to handle a lot more vibration than you
get from an electric.

That said, I don't think we're going to "extraordinary" measures to save
weight, we're just trying to take full advantage of the components we
already have to have (like the main system battery) to serve double duty
without giving up redundant power in the system as a whole.  In my case,
discovering I was 30g overweight I had no trouble shaving the weight:  Swap
a 1350 RX battery for a 450 RX battery (saving 38g), add Chris' main tap as
a redundant power supply to the RX (previously I'd just left the second
power lead to the RX unused and gone without redundancy) at a cost of
probably 3g (no regulator needed, though if I can find a decent one with
minimal weight penalty I'll add it) and now I'm 5g under the limit.  Since I
was on Chris' store and didn't want to get just the power tap, I decided to
give a Falcon V2 carbon prop a try, saving me another 30g.  I could easily
swap out my convenient Secraft wire tensioning system to save another 10-20
grams. I have an irrational dislike of carbon spinners after having one
shatter on me a while back, so I use a 49g Aluminum Tru-turn spinner, if I
were really up against the weight gun I'd swap that out and save another
maybe 20g.  So with no extraordinary measures I reduced my weight by 65g and
added redundant power. Minor tweaks I would prefer not to make would save me
another 20-80g.  Extraordinary measures would replace my beloved Emcotec
arming switch for the main power system with something simple and lighter
like the power unlimited arming plug :-)

And, of course, I never have to worry about my engine dying in flight,
cleanup of glow residue, etc.

Glow->Electric conversions are suboptimal in my humble opinion because you
are essentially bolting a much heavier power system onto a heavy airframe
designed for a bone-shaker of a glow engine, so it's built much heavier than
it needs to be for electric power.

Peter+
On Wed, Jan 25, 2012 at 3:49 PM, J N Hiller < jnhiller at earthlink.net
<mailto:jnhiller at earthlink.net> > wrote:
Hi Mike.
If I could get rid of my greasy stuff I think I'd go all electric but after
reading of the extraordinary measures taken to save a few grams it kind of
depends what I can get an E-Option to weigh. My #2 160 is 10 lb so I could
probably do it. I need to lookup component weights and get an estimated
allowable airframe weight to compare. Maybe next winter; I'll fly what I've
got another season and work on improving piloting skill, if that’s possible
any more. I've never been a switch flipper but I'm thinking I need to start.

Jim

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
<mailto: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 astropuppy
Sent: Wednesday, January 25, 2012 12:47 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

You know you want to go E Jim. As they say in Oregon: "Just do it".

Mike
On Wed, Jan 25, 2012 at 9:47 AM, J N Hiller < jnhiller at earthlink.net
<mailto:jnhiller at earthlink.net> > wrote:
Having judged these sequences I absolutely agree that they have become more
demanding. Do you think you could fly the current schedules with 2006
battery technology?
Not in a hurry to go E-Power but interested.
Jim

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
<mailto: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 Del
Sent: Wednesday, January 25, 2012 6:55 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

Dave.. Love how you win your discussions.. lol .. ;+}

    Del
----- Original Message -----
From:
Dave Lockhart <mailto:DaveL322 at comcast.net>
To: 'General pattern discussion' <mailto:nsrca-discussion at lists.nsrca.org>
Sent: Tuesday, January 24, 2012 7:07 PM
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

2006
9411sa x2 for ailerons
8417sa x1 for elevator
8411sa x1 for rudder

2009
Changed to 3517 x2 for elevator (in the same plane)….no change in mah per
flight

2010
Changed to 8611A on rudder (in the same plane)….no change in mah per flight

Flight times are about 45 seconds shorter now.

I still have the Prestige I flew in 2006, so no change to control surface
size or throw.

I’m pretty sure it is the changes in maneuvers flown and higher average
watts used by the motor in the course of the flight.  :-)

Regards,

Dave



From: nsrca-discussion-bounces at lists.nsrca.org
<mailto: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 Peter Vogel
Sent: Tuesday, January 24, 2012 6:59 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

Digital servos *definitely* draw more power than non-digitals, but they are
much more precise and hold their position better, it's worth the higher draw
for pattern.

Peter+
On Tue, Jan 24, 2012 at 3:46 PM, Doug Cronkhite < seefo at san.rr.com
<mailto:seefo at san.rr.com> > wrote:
I suspect the servos also draw more power than they did years ago.

Doug

Sent from my iPhone

On Jan 24, 2012, at 3:40 PM, "Dave Lockhart" < DaveL322 at comcast.net
<mailto:DaveL322 at comcast.net> > wrote:
When I first started flying electric pattern…..mah per flight was noticeably
lower than now, going from 40-60 per flight to 60-80 per flight…..flying
whatever was the current P/F sequences.  I suspect the increase is due to
higher average flight speeds (much more watts at the motor now) and more
demanding maneuvers (snaps and KE).

Regards,

Dave

From: nsrca-discussion-bounces at lists.nsrca.org
<mailto: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 Keith Hoard
Sent: Tuesday, January 24, 2012 11:02 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

Anthony,

   On a typical flight, I'm guessing the radio only uses around 100-150Mah
of power, while the motor is using 4000Mah, so that's about 4% more draw on
those two cells.  In practice, I haven't been able to see any difference in
the radio cells when I hook them up to my charger at the end of a flight.
Sometimes cells #1 & #2 are the high cells after a flight, so I think the
power draw of the radio is negligible to our motor packs.

The problem with two regulators plugged into the same 10S (or 5S) pack is
that you are creating a dead short between the cells thru the ground wires
(typically a straight wire thru the regulator).

Say you plug Regulator #1 into cells #1&2, and Regulator #2 into cells #6&7.
The regulator's ground wires now have 5 cells of voltage potential (5 X 4.2V
= 21Volts) between them since they are plugged into cells # 1 and #6.  When
those two ground wires are then plugged into your receiver either thru a
switch or direct connection the magic smoke will escape and your retailer
will rejoice.

Also, if you have both of your regulators plugged into your motor pack and
the packs eject like Goose in Top Gun, you've lost both of your redundant
power sources.  However, if you use a tiny 2S LiPo that is physically
separated and secured inside your plane, you have both electrical and
physical redundancy.

Hmmm, just thought of something . . . maybe we should tie down the receiver
so the main regulator can't take the receiver out with it. . . so many
contingencies, so little weight . . .

Keith Hoard
Collierville, TN
khoard at gmail.com <mailto:khoard at gmail.com>
On Tue, Jan 24, 2012 at 8:15 AM, Anthony Romano < anthonyr105 at hotmail.com
<mailto:anthonyr105 at hotmail.com> > wrote:
Seems like a great idea but I have two questions. Do the packs come down out
of balance since two cells are serving extra load? Is there a problem with
parallel operation of two regulators?

Thanks,

Anthony

  _____

From: joddino at socal.rr.com <mailto:joddino at socal.rr.com>
Date: Mon, 23 Jan 2012 15:25:00 -0800
To: nsrca-discussion at lists.nsrca.org
<mailto:nsrca-discussion at lists.nsrca.org>
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

I've been using this setup for sometime and it is working great.  I have my
two cell LiPo charged to 7.5 volts and it is connected to a 6.0 volt
regulator into the receiver.  The cable connected to the balance connector
on the "bottom" 5S is connected to a 6.3 volt regulator so it supplies all
the current to the system and the 2S pack never needs charging.  I'm using
an 800 mAh pack but it could be even smaller.

Jim O


On Jan 23, 2012, at 2:09 PM, Scott McHarg wrote:

Guys,
   Chris Moon just e-mailed me about some leads that were done at the
factory.  These leads run off your balance leads to a voltage regulator and
allow your main battery pack to be utilized as a redundant receiver battery.
It is NOT meant to be a primary but it will save 20+ grams if you're running
2 rx batteries.  You still have to run the 2nd regulator for true redundancy
but you eliminate the 2nd battery.  These leads are factory made and
eliminate the need to make them yourself with the concern about plugging in
to the wrong cell.  I know in my article, I was pretty much against doing
this as a backup but, with Chris having this made at the factory, he has all
but eliminated making a mistake by tying to the wrong cell.  I have the link
that I'll e-mail you off-list or you can just go to his website.  I don't
want to break the NSRCA list rules by advertising for him even though he
advertises with the NSRCA.  The leads are only $3.99 each and are found
under the Connectors/Adapters listing.

Thank,
Scott

--
Scott A. McHarg

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