Electric F3A
Chad Northeast
chad at f3acanada.org
Thu Sep 22 15:17:34 AKDT 2005
Response to Eric, but meaningful to all, I hope......
> I was told 700 + great flights - So I then ask, at what cost? Was it 20
packs? The cost, unless sponsored, is around $700 a pack (2 sticks). How
deep are your pockets folks?
I have about 400 flights on my setup, x4 Thunder Power 10s4p 5300 packs,
approx 60 cycles. That doesnt add up to 400 flights.....I used some
Apogee's earlier in the season which were not surviving beyond about 30
cycles mainly due to the discharge rating being too low. The new TP
packs though are working very well and I fully expect them to last 100
cycles at least. I roughly calculated that you need around 250 cycles
to equal the cost of pumping 30% into a 160DZ. Ignoring all else,
simply cost of fuel and batteries. The packs are not at that stage yet
IMO, unless you really baby them which wont get you much performance.
> How long did the packs last? Was it months or more like just a few
weeks?
When I say how long I really mean how many cycles. Talking to experienced
electric FAI users I get numbers like 40-60 on the 8000mAh packs, but
better
on the newer ones. Even at the claimed two flights per charge that's still
pretty expensive!
I only get 1 flight per charge on 5.3 Ah packs. I have been flying the
TP's steady since about July 1 of this year.
> Would they be good after a winter of none flying. Could not
get an answer there at all.
No idea, although I may find out this winter! Yes Li-po's do have a
shelf life and degrade over time. I think the reason there is no answer
for this is because the earlier generation packs would not last long
enough to test this out. The newer packs can make it through a whole
season now so we might start seeing some reports on loss of capacity
from sitting around for extended periods.
> Then I got into how many motors have been in Tony/Jerry's plane to
get that
many flights. How many repairs to motors for whatever reason.
I dont run the Hacker, and never will because of the gearbox maintenance
required. The Plettenberg motors that I use required no maintenance
from me, in theory they should last for 1000's of flights provided you
dont overheat and demag them. I put 400 flights on my motor without a
single failure of problem of any kind.
> I then got into how many packs you need to take to the field for a
practice
session or a local contest. That obviously depends upon how many chargers
you have. I used to use three 109's. I saw most using 5 chargers and two,
three or even four, deep cycle batteries
I have 4 packs, 2 Schulze isl6-330d chargers. At the field I use either
a single 28 Ah deep cycle battery, or leave my car running to charge. I
typically only do 5 flights so that means 1 charge. I can get 2 charges
out of the deep cycle before its dead. At contests there is usually a
generator so I run PC converted power supplies (40A) that I got off
Ezone for $18+shipping. It can power both chargers with enough juice to
charge x2 10s packs @4A (my Schulze wont do that, but the bigger ones
and the new TP charger will). Thats enough to keep you going non-stop
at a contest.
I always charge my batteries in series so I charge 2 sets of batteries
at a time. This requires the packs to be within 0.01V of each other
before the charge, which they typically are. With the new TP 210 - 10
cell balancer coming it will make series charging quite safe. Coupled
with their new charger there should be very little chance of an
overcharge on the packs (fire hazard) unless one of the components fail.
> I know that several controllers impersonated in-flight smoke systems.
That
one I knew about and is to be expected when you put a lot of DC electricity
though things, sooner or later, right!
I am running the Schulze 32.55K esc, thats 55A continuous, 73A burst
rating. 400 flights on the same controller not a single problem, and it
runs very cool (less than 100F).
My only complaint with all the equipment I tried were the Apogee packs,
its not that the packs/cells were bad, but that I didnt realize how
often and how long you sometimes run at full throttle with electrics
especially in wind. With this in mind now, I only recommend to people
to run packs that can give them their peak static draw continuously. By
not doing this IMO you are pushing the batteries far too hard and they
will fail on you. The newer 15C packs are all pretty much capable of
providing this kind of power, most of the 10C packs (last years stuff)
were borderline.
The trick to electrics is to cross your t's and dot your i's........move
slowly and understand what is going on. Get a good voltmeter (Fluke
81438 is an excellent buy), IR Thermometer and a wattmeter. Check
things often intially until you are comfortable that everything is
working as planned. Its not like glow where if you prop wrong you land
and change it.....the wrong prop can destroy your motor, controller,
packs! The electric setups need a bit of engineering and planning to
work right, and once you get it they work great!
They are not as cheap as glow and I dont think they ever will be, at
least not in the near future IMO. It wont win you contests, it wont
make you fly better! Its a hell of a lot more work outside of the flying
field keeping packs charged. I did it regardless of cost because I
thought it was super cool and I happen to be an engineer and therefore
tech geek :-)
Chad
Grow Pattern wrote:
> Del,
> It always intrigues me how much people will rationalize once
> they have made a decision to go one way or another. I well remember
> the YS zealots who would tell you how great their engines were. I also
> remember how much they LEFT OUT!
>
> Back then you didn't hear about how many piston, rods, bearings etc.
> that they were going through, especially if they were sponsored or
> psuedo-sponsored.
>
> When, as a reporter, I asked a lot of questions about electrics I
> never go very good answers. I even purchased a bunch of Thunder power
> batteries and Hacker motors and speed controllers. When I wrote on
> this list with even the slightest hint of criticism of electrics my
> e-mail inbox would soon start filling up. I was told I didn't know
> this and I didn't know that etc. well guess what there was a lot i
> didn't know, but also a lot that neither you or I were not getting told.
>
> I had a very hard push back from Jerry Budd about how wrong I was and
> how great the stuff was that he and Tony Frackowiak were running. No
> doubt about their successes and I am absolutely not even trying to
> detract from that at all. BUT when you poke me that hard my instincts
> kick in and go digging.
>
> I was told 700 + great flights - So I then ask, at what cost? Was it
> 20 packs? The cost, unless sponsored, is around $700 a pack (2
> sticks). How deep are your pockets folks?
>
> How long did the packs last? Was it months or more like just a few
> weeks? When I say how long I really mean how many cycles. Talking to
> experienced electric FAI users I get numbers like 40-60 on the 8000mAh
> packs, but better on the newer ones. Even at the claimed two flights
> per charge that's still pretty expensive!
>
> I also found out that the packs were not aging very well. I could not
> find out for sure but I think it was around 3 months before they
> became non-competitive..Would they be good after a winter of none
> flying. Could not get an answer there at all.
>
> Then I got into how many motors have been in Tony/Jerry's plane to
> get that many flights. How many repairs to motors for whatever reason.
> Very hard to get an answer here so I'll will also be vague. Several
> gear boxes and motors/rotors went in and out of that plane. To you and
> I how much that represents not only in dollars, but lost flying time
> while waiting for repairs, is hard to estimate but you can draw your
> own conclusions. You could say that the new electrics are like the old
> YS's. No matter what you say there are definitely a set of "hidden"
> factors that should be put into the equation when comparing electric
> and glow.
>
> I then got into how many packs you need to take to the field for a
> practice session or a local contest. That obviously depends upon how
> many chargers you have. I used to use three 109's. I saw most using 5
> chargers and two, three or even four, deep cycle batteries. I am
> assuming was the case unless there was a 110v supply nearby. Then you
> need to consider maintaining the 12 v batteries as well. i needed six
> packs fro one session. If there was not time between a round to charge
> you needed a fresh pack. Never asked what fresh meant. Maybe I should
> have?
>
> I know that several controllers impersonated in-flight smoke systems.
> That one I knew about and is to be expected when you put a lot of DC
> electricity though things, sooner or later, right!
>
> I don't think that I was lied to, but I do think that when people are
> sponsored or just enamored with the latest purchase that they leave
> out the sort of stuff that we all really need to know. As and aside, I
> have seen a lot more honest reports on electric performance now that
> the world championships are over.
>
> I know that I will get some heat for what I report on this list, but
> if I help a pattern pilot make a better decision it will make the
> asbestos underwear feel more comfortable.
> I am still concerned that regular pattern pilots will spend a lot of
> money, get trapped on the treadmill of "latest" power-pack/motor, and
> then be very disappointed in the longevity of their equipment.
>
> Regards,
>
> Eric.
>
>
>
>
>
>
>
> ----- Original Message ----- From: "Del K. Rykert"
> <drykert2 at rochester.rr.com>
> To: "John Ferrell" <johnferrell at earthlink.net>; "NSRCA Discussion"
> <discussion at nsrca.org>
> Sent: Thursday, September 22, 2005 9:26 AM
> Subject: Re: Electric F3A
>
>
>> For some of us this is why we will never be able to afford to switch
>> even if we felt the desire..
>>
>> Del
>> nsrca - 473
>>
>> ----- Original Message ----- From: "John Ferrell"
>> <johnferrell at earthlink.net>
>> To: "NSRCA Discussion" <discussion at nsrca.org>
>> Sent: Thursday, September 22, 2005 8:07 AM
>> Subject: Re: Electric F3A
>>
>>
>>> Battery prices and their unpredictable life seem to be the major
>>> problem.
>>>
>>> Still, it does not seem to me that one can compute the power needs
>>> for an electric from the experience gained with an IC power plant.
>>>
>>> John Ferrell
>>> http://DixieNC.US
>>>
>>> ----- Original Message ----- From: "John Pavlick" <jpavlick at idseng.com>
>>> To: "NSRCA Discussion" <discussion at nsrca.org>
>>> Sent: Thursday, September 22, 2005 12:21 AM
>>> Subject: RE: Electric F3A
>>>
>>>
>>>> John,
>>>> Don't try to compare Apples and Oranges. I've seen Dan's plane fly
>>>> and yes
>>>> it seems to work very well. Remember though, an electric motor and an
>>>> internal combustion engine have very different torque output /
>>>> power curves.
>>>> While an I.C. engine generally needs to spin faster to generate
>>>> torque, an
>>>> electric motor can generate a lot of torque at very low RPM. Also,
>>>> I don't
>>>> think an electric motor really "unloads" as the plane flies. I've only
>>>> played with the little stuff, so I'm not an expert by any means. It
>>>> will be
>>>> very interesting to see what develops in the near future. If only
>>>> batteries
>>>> were a little more reasonably priced...
>>>>
>>>> John Pavlick
>>>> http://www.idseng.com
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: discussion-request at nsrca.org
>>>> [mailto:discussion-request at nsrca.org]On
>>>> Behalf Of John Ferrell
>>>> Sent: Wednesday, September 21, 2005 11:32 PM
>>>> To: discussion at nsrca.org
>>>> Subject: Re: Electric F3A
>>>>
>>>>
>>>> You are getting through to me...
>>>> Dan Landis was using a Glow prop on his Brio at the Nats. That
>>>> helps me to
>>>> better understand the power requirements.
>>>>
>>>> Other than buy & try, is there a way to determine what kind of
>>>> battery
>>>> requirements might be required to drive an APC 15-12 at about 8200
>>>> rpm? I
>>>> had in mind the same AXI 5330/18 motor that Landis used.
>>>>
>>>> Another way to ask my question is "what does it take to replace a
>>>> YS140?
>>>>
>>>> John Ferrell
>>>> http://DixieNC.US
>>>>
>>>>
>>>> --
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>>>> 9/20/05
>>>>
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>>>
>>>
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