rmh

less than LiPo - but that is the only negative point -
once you fly them and compare how the LiPos MUST stop short of voltage mins -or they DIE and the cost of the lipo and the fragility of them and the fire danger - etc.. You look for how to maximize the a123 good points .
In a Fu-k the cost approach to electric - Li Po rules -but I gave up on that approach--
at the moment my 3.4 lb aerobats perform about as well or better than the Li Po ones I have seen on 4 cell packs
The Czech flyers are seriously using these now in large aerobats - I will look at their results again
OD -is that you?

OhD

It's me. Flying pattern again only because of eletric propulsion. I've got 100 flights on one set of Li-Pos and approaching that on two other sets. If they make it to 200 flights each I figure the cost is less than a high performance glow setup. In the meantine I'm really enjoying it.

Jim Oddino

rmh

great!
The LiPo users I see- tend to abuse the cells and effective cost per flite goes sky high
I am going to do a 6cell A123 setup with a EFlite 60 motor and 16x10 prop - I spent a while this morning speaking with Rojecki about his litle 50 Showtime and a 60 and dual 4200 6 cell lipo packs
He says the plane is fast does all the good stuff for about 7-8 minutes with plenty of reserve
The auw is just under 7 lbs --about like one of my old Tipos done light
so-- if I build for the electric motor I can hit 6 lbs and 700 squares - should work

what are you flying ?

FLYERSG

Dick: Clearly, many RCers are using the A123 cells with excellent results. They certainly appear to be a safer technology and yes, they can be somewhat abused without as much risk as that associated with LiPos. My Partner 2 meter pattern ship, with Thunderpower 5300 cells, weighs 10 lbs 13.5 oz ready to fly. I thought I would compute the weight of my Partner with A123 cells. According to the A123 Systems website, each cell produces a nominal 3.3 volts, weighs 70 grams and is rated at 2.3AH. To put together a pack with sufficient voltage and current capacity to fly a Masters pattern, I would need two strings of 12 cells in parallel or 24 cells. With the resulting 4.6 amps of capacity, I could get through the pattern; however, that pack would weigh 59 ounces (without wiring/connectors) which would add 1 lb 3 ounces to the weight of my ready-to-fly Partner......not an option for me or most other 2 meter pattern ships being used today. Clearly, you are an advocate of the A123 cells.....but I don't see how they can be used in pattern competition due to weight. As a side note, I've been using lithium polymer cells since before most pattern flyers even knew of their existence. I follow the rules for handling, charging, storage, etc. and have had excellent performance without fires or other accidents/incidents. Again, I think the A123 cells clearly have a place in R/C, but I'm not sure, as a result of their weight, they will benefit the pattern community. If I'm missing something, please clarify.

Mike

P.S. I miss your production of outstanding pattern designs....have flown many of them over the years.

EU1a

My Feedback: (1)

Hello All,
I fear to post in the middle of a LiPo vs A123 debate, but this thread is very close to what I've been thinking about lately. I want to get back into pattern after a 20 year absence. I have a mistress and an EU1a both with screaming .61s. A little out of flavor in todays arena. I also have one of Dick's Dalotels. Built back in the 80's, It's never had an engine or radio put in it. Dick, I'm amazed every time I pick it up, how light it is. It's not 2 meter job, as this tread had asked, but I would like to make it electric. Dick, have you ever considered this model for electric or could you point me in the right direction?
Thank you,
Paul

rmh

points always brought up by guys asking about the 123 cells - is the rated power and the weight
first - off they are heavier - no question about it
however the useful charge for a flight exceeds the Lipos
because - you can run em right on down - not to worry- it does not harm em
it will ,however killLiPos

having to double a pack to get same useful power duration - is not true
you can instead, increase voltage and reduce capacity .
I use 4, a123 cells and get very good power for 8-10 min on 3.4 lb pattern model ( a Diamante )
the performance is good at the 40 + amps and a 14x7.
. If it goes flat -(and I have done it - I just land and recharge .
as good as same weight Lipo (11 ozs) yes I think so - I can pound em harder and use em longer than the lipos
I would not consider any of the current pattern designs - (2 meter ) -they are all designed for glow and in my book simply heavier than needed . I have done 2 meter 1280 sq 40 gas powered pattern models which were waaay stronger than required for a electric setup -so yeh -I think I can do it with A123 cells -at least it is worth a shot
The Dalotels were light but heavier than needed for electric.
I had a guy try one years back but the batts n motor killed it then.
I have a new pattern model I am doing -- for the ZDZ40 RE and I have dropped design weight again - I use foam flying surfaces and balsa fuselages so I get best sound damping - -I have looked at the really light all composite ones and -I just don't care for em -beautifully done but FRAGILE and $$SSSpensive.
If you are hung up on the curvy composite pattern look (I am not ) you will have a hard time dropping fuselage weight.
The Dalotel by virtue of its simple angular lines can be done more lightly . The early model can have the wings really lightened and the aft section of the fuselage poked full of holes also I would do a simple fixed position wire gear with doors in place.
Not having to design for IC resonance damping really opens the game.

patternflyr

My Feedback: (17)

For anyone interested in the A123 cells/batteries, Brian at Tanic is selling the packs assembled.
tanicpacks.com

Emory.