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Global Super Decathlon Conversion

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Old 09-29-2004, 11:36 AM
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Default Global Super Decathlon Conversion

Hello all...

I am planning to covert this ARF to e-power and have a question or two.

The specs are:

WS: 63 inches
WA: 641 sq. in
WL: 20-22 oz/sq ft
Weight: 5.75 to 6.25

This model is designed for a 52-61 TS or 70-91 FS.

I plan to fly it in a "sport" fashion, (as I am certainly no accomplished aerobatic pilot!) and using the "rule of thumb" I guestimate that I will need about 100 watts/lb.

So, 600 watts needed and probably a 40 amp motor (I'm thinking AXI 4120/14) leaves me in need of a 15 volt system.

Am I right so far? I was thinking of a 4S LiPo (600/40=15, 15/3.7=~4S) pack but am unsure about the capacity of the pack I will need.

I was thinking of using four of the new Kokam 2S2100's (20C) packs and rigging a 4S4P system. What do you all think? Or perhaps two of TP's 3S2P 4200's in parallel?

The other question I have has to do with the Kokam series and their parallel connector boards. Will they be able to handle these batteries in the configuration I am thinking? I seem to have read somewhere that 1500 mAh is their max recommended rating but I'm not sure!

Any advice is greatly appreciated!

Thanks!

Curt Hughes
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Old 09-29-2004, 03:49 PM
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Mike Parsons
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Default RE: Global Super Decathlon Conversion

ORIGINAL: curtusua-RCU

I plan to fly it in a "sport" fashion, (as I am certainly no accomplished aerobatic pilot!) and using the "rule of thumb" I guestimate that I will need about 100 watts/lb.

So, 600 watts needed and probably a 40 amp motor (I'm thinking AXI 4120/14) leaves me in need of a 15 volt system.

Am I right so far? I was thinking of a 4S LiPo (600/40=15, 15/3.7=~4S) pack but am unsure about the capacity of the pack I will need.

I was thinking of using four of the new Kokam 2S2100's (20C) packs and rigging a 4S4P system. What do you all think? Or perhaps two of TP's 3S2P 4200's in parallel?

The other question I have has to do with the Kokam series and their parallel connector boards. Will they be able to handle these batteries in the configuration I am thinking? I seem to have read somewhere that 1500 mAh is their max recommended rating but I'm not sure!

Curt Hughes
Curt,
100 watts/lb is a good starting point, but for Sport is more than you will truly need. It is however, my bottom line on any conversion I do, no matter what type of plane it is.
The 4120/14 on a 4S is a good setup and one I have considered myself for this plane.
On batteries:
I have lots of experience with TP's and only experience with the older C kokams. However, from what I have read, they all more or less perform within the specs. So choose one based on price. You are not going to need a 4P for this conversion since the amps will not reach that high. Even on a 10c pack, a 3P is rated at 60 continuous. And since you are looking at ~40 amps, you have some room to play with. I typically will not drop below a 3P for three reasons.... I like the extra flight times given the added mah... It gives me extra headroom in the event I add another plane to my collection which now requires more amp usuage....and it is good to have the extra weight for balancing a model. I would go with a 4S3P TP 6000 or 4S3P Kokam pack. I also recommend that for purposes of obtaining CG, you use two 2S3P's and connect them in Series via the conector board or a simple Series plug that can be soldered together very easily. Just charge them seperately before connecting in series.

-Mike
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Old 09-29-2004, 09:54 PM
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Default RE: Global Super Decathlon Conversion

Mike...

Thanks very much for the input!

I am slightly confused about how to proceed since I already have two of the 2S 2100 packs (Kokam 20C).

I have a TP 4S3P 6000 in my WM Rambler 30 conversion and with the Axi 4120 it flies great. But, I really don't want to switch the battery pack in and out of the two models so I thought I'd try the new Kokams.

I don't see how I can create a 4S3P system using the two packs I already have... I planned to order two more 2100 2S packs soon.

Thanks again!

Curt
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Old 09-30-2004, 10:13 AM
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Default RE: Global Super Decathlon Conversion

ORIGINAL: curtusua-RCU

Mike...

Thanks very much for the input!

I am slightly confused about how to proceed since I already have two of the 2S 2100 packs (Kokam 20C).

I have a TP 4S3P 6000 in my WM Rambler 30 conversion and with the Axi 4120 it flies great. But, I really don't want to switch the battery pack in and out of the two models so I thought I'd try the new Kokams.

I don't see how I can create a 4S3P system using the two packs I already have... I planned to order two more 2100 2S packs soon.

Thanks again!

Curt
Hey Curtis,
Right now, you can only make a 4S or 2S2P if you only have 2- 2S 2100 packs. With 4- 2S packs you can create a 4S2P capable of handling 84 amps @ 20c. You stated earlier in a post of going with a 4S4P which would require a total of 8 2S packs. Unless you need the extra weight of the 4P, it is not necessary. However, my concern would be getting the plane to balance on the 2P. That is why I recommend a 3P and is as far as I will go down in a conversion. I would rather have the extra P to extend flight duration instead of adding dead weight to get the plane to balance.

-Mike
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Old 10-01-2004, 12:00 PM
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Default RE: Global Super Decathlon Conversion

Mike...

Thanks for the suggestions!

I've decided to buyanother TP 4S3P 6000 to keep it simple!

best,
Curt
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Old 10-01-2004, 12:36 PM
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Default RE: Global Super Decathlon Conversion

Glad to help. Good luck and keep us updated.

-Mike
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Old 10-11-2004, 03:27 PM
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Default RE: Global Super Decathlon Conversion

Curt


My friend Jerry K here in Florida wants to convert the same plane. Post pictures here please when you are done if you don't mind.
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