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Old Dec 20, 2003, 12:45 PM
ken troxell is offline
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F5J/LMR batteries for 7 cell competition


what is the best new cell on the block for this style of competition? i am currently running a hacker with 4.4:1 gear box and a 14x9.5 prop. cells are cp1700scr at about 35 amps. ken
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Old Dec 20, 2003, 01:46 PM
Protocooler is offline
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Easy,

Sanyo HR 4/5 1950 FAUP actually rule. With those you could allow proping up to 700W (limit for the maxxon gearbox).
That's 39g / cell.

The smaller 1700 AUP cells (34g/cell) could also take it but they'll loose a good share of volts compared to the FAUP at same amps.

Another option is Lipoly (Thunder power or IRate) in 3S2P provided they fit in the fuse...

...Proto
Old Dec 20, 2003, 02:18 PM
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Additional notes: for actual competition, Lipo are out

F5J CLASSES are
Speed 400: brushed, ferrite magnet 400/380 can motors using no more than 8 NiCd or NiMh cells with a maximum 60 second motor run (motor timing adjustment ok)

Seven cell: restricted to 7 NiCd or NiMh cells with a maximum 40 second motor run

Unlimited: no restrictions on motor or number of NiCd or NiMh cells with a maximum 20 second motor run
(for that one you'd need GP3300 I suppose)
Old Dec 20, 2003, 02:35 PM
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Ken,
Since you are in the US, check with the contest director of any competion you are thinking of prepping for. If it is an F5J contest, the above info is fine. If, however, it is an AMA event, the rules are different.

Class B is up to 30 cells but only allows NiCDs and they must weigh less than 2oz each which leaves zapped CP1700SCR's. There probably won't be a Class A event but there might be a NEAC Sport Sailplane event that is essentially an electrified RES event for planes under 100".

Dave
Old Dec 20, 2003, 02:40 PM
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Agree with Proto.

The CP 1700s are fine for what you are doing. The FAUP 1950s will save you an ounce or so and have less resistance, they are the best of the three. The AUP 1700s will save about 3 ounces but have the highest resistance of the three batteries mentioned. I have been using the AUPs 1700s at over 60 amps this past autumn and they are still doing fine, although I get a slightly better climb rate with the heavier CP1700s. It is really a matter of how far you can see with any of these batteries launching a competitive F5J type sailplane.

With a Hacker B40 6, 7or 8L some of us are using 18X10, 17X13 or 18.5X12 props. Climb rates with these props are much better than with the 14X9.5.

For the best performance with the two NIMH batteries mentioned they should be used HOT off the charger (120+ deg f).

Mike
Old Dec 20, 2003, 05:05 PM
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the most powerful battery is the GP3300. Offers the most volts at a given amp level. If you want to get into the 100 amp plus range they are the way to go. In Australian 7 cell comps where each second of motor run counts a negative point, 100 amps are required.
Old Dec 20, 2003, 06:52 PM
ken troxell is offline
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dave...i am not familiar with the NAEC res class. something new? where can i find info? thanks,ken
Old Dec 20, 2003, 08:24 PM
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Sorry, I meant NEAC. It's call 'Sport Sailplane'.

http://www.electricaircraft.org/2003rules.htm

Dave
Old Dec 20, 2003, 11:27 PM
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Ken,

NEAC is the SIG for the AMA in electrics. I'm the Pres and we are responsible for running the Nats and promoting electric competition. Go to www.electricaircraft.org for info. Or go to ezonemag/ AMA/NEAC to post questions. Or just ask me and I'll try to help. We've been around for a while, but have been very silent. I'm trying to revive it so everyone knows who we are.


Ric Vaughn
Old Dec 21, 2003, 01:29 AM
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Re: F5J/LMR batteries for 7 cell competition


Quote:
Originally posted by ken troxell
what is the best new cell on the block for this style of competition? i am currently running a hacker with 4.4:1 gear box and a 14x9.5 prop. cells are cp1700scr at about 35 amps. ken
Ken,

Hacker What motor? And what plane set up? I have a "7 cells" set up on my Graphite, lehner motor and 8:1 gear box, turning a 23x12 prop with 7 x 2400zap, will go to GP3300. The set up pulls about 75 amp. For most of the LMR event, the capacity is not an issue, but bigger cells maintain higher voltage with high current draw. At 35 amps, CP1700 are fine for current level that you are pulling. Actually, the new motor I will be using should pulls about 90-100 amp, hopefully!

Bria, an EAJ


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