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Slow Stick Battery ... Lipo

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Old 12-25-2003, 05:49 PM
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Dart373
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Default Slow Stick Battery ... Lipo

I currently have a stock 280 that came with the plane. Running it on 2 S 1200 Lipo E tec. I am using the stock esc with LVC now.
What I want to do is some AP with an Aiptek Camera. I want to go with the GWS 400 and stay Lipo. What battery would you use. I need to use Etec batteries because a deal i get with them. Thanks for advice.
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Old 12-27-2003, 02:07 AM
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sierra gold
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Default RE: Slow Stick Battery ... Lipo

Most Slow Sticks I have seen come with the GWS EPS 300C motor which is a 370. You seem to be saying yours came with the EPS 100C which is a 280. Are you sure on this?

Anyway, the EPS 300C(370) will fly on an ETec 1200 2S1P pack. However, the GWS EPS 400C (380 motor) really needs 3S (11 volts) LiPos to run strong. I'm not sure that ETec 3S 1200s will like the current of the 380 motor though. The 1200 is a 5-6C cell and that is only 7 amps. You would probably need a 3S2P Etec 1200 pack or a 3S1P TP 2100 pack. I currently fly the EPS 400 on a SS with the TP2100 3S1P and it's a nice combo. The TP2100 is a 6C pack and can safely provide 12 amps.

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Old 12-27-2003, 06:01 PM
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Default RE: Slow Stick Battery ... Lipo

I guess your right. The hobby shop that sold it to me told me it is a 280. But it sure does not look like the 280 pictured. Going by the pictures........ it is the middle engine offered. Thanks. Keith
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Old 01-19-2004, 10:42 AM
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Default RE: Slow Stick Battery ... Lipo

I just switched to a GWS EPS 400C (380 motor) G gear box on my Slow Stick. I tried it with a Kokam LiPo 2s1p 1500mAh with 4 different props. You are right, it is not enough.
I switched to a 3s1p 1500mAh but haven't tried it yet. (Weather)
What gear box and prop are you using?
Doug
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Old 01-19-2004, 01:08 PM
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sierra gold
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Default RE: Slow Stick Battery ... Lipo

My EPS 400 is the 5.28:1 gear box and I spin a 12x8 GWS HD(DD) prop. The EPS 400 prop shaft is larger than the 300 and you either can ream out a GWS SF prop or go with the GWS HD props which are sized for the larger shaft and nut. Looks like the shape of the 12x8 HD doesn't draw any more current than the 12x6 SF prop.

You will like the performance of the 3S Lipos much better.

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Old 01-20-2004, 05:57 PM
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Default RE: Slow Stick Battery ... Lipo

I'm becoming confused again[sm=spinnyeyes.gif].
I tried the 3s1p 1500 mAh High Discharge 8C Kokams today. The gear box is 4.5:1. Close to yours.
With a 1365 prop it cut out at half throttle. I assume the voltage was pulled down to the LVC of 8.4 volts because it will restart after moving the throttle to closed.
With a 1280 it cuts out at just above half throttle.
With a 1180 it cuts out about 3/4 throttle. This is the stock slow stick prop for the 300C motor. When I ran the stock motor with this prop and 2s1p 1500mAh it never cut out and had good power.
With a 1060 it will spin at full throttle but is not much improvement over a stock slow stick in thrust.
I'm using a Castle Creations Pixie20 ESP. Should work?
Is this not enough battery to drive this thing?
These parameters sound close to what your doing.
Regards,
Doug

I think I started asking questions that belong in the "Motors and batteries,..." section. I'm going to copy my questions and repost them over there.
Thanks,
Doug
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Old 01-21-2004, 10:27 AM
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Default RE: Slow Stick Battery ... Lipo

The symptom you describe sounds like the LVC is cutting in.

According to MotoCalc, with the 13x6.5 you are pulling about 12 amps. Should be inline with the 8C of the Kokam 1500, but it is about equal to max. constant current.

My 12x8 HD prop and the 5.28 GB pull about 8.5 amps.

I would speculate that you either don't have a fully charged pack(12.4 volts?), or that the Kokam drops more voltage on a 12 amp draw than does a TP2100.(I have another SS with a brushless that draws about 12 amps successfully on a 2S TP2100)

An AF Super Whattmeter would help you here.

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Old 01-21-2004, 12:25 PM
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Default RE: Slow Stick Battery ... Lipo

Thanks for the help Sierra Gold.
BTW I had a best friend that lived in Meadow Vista Ca, near Auburn.
Doug
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Old 01-21-2004, 12:59 PM
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Default RE: Slow Stick Battery ... Lipo

I think that with 4.5:1 on a 400C you are overdoing it with a 13x6.5, and asking 12A out of Kokam 1500 is too much too! Even though your voltage is dropping to 8.4v because the battery can't handle it, you are probably still pushing ~100W through it (12A x 8.4v). Even though the Slow Stick is quite capable of carrying a bit of weight, and you could change to 3s2p to resolve the problem of voltage drop under load, that motor is going to last long an even shorter time if you run ~130W through it (12A x 11v).

That 400C is really only a 75W-90W motor! If you want more than that, just go brushless. For less than the 114g of a 400C (with prop), you could put on an AXI 2808/20 (110g - motor with prop and adapter) or a Mini AC 1215/20 (94g with gearbox, prop and adapter) - this latter, geared 6.33:1, will give you almost 20oz thrust at only 6.8A with a 12x8HD on it [that would save you having to double your battery weight (from going to 3s2p), and solve both your LVC and motor longevity problems in one hit - and, still using only 3s 1500, give you almost twice the flight time].

Cheers, Phil
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Old 01-21-2004, 03:59 PM
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Default RE: Slow Stick Battery ... Lipo

I looked at the AXI and the Mini AC. Good advice Doc. I am leaning toward the Mini Ac 20 with the 6:1 Planetary Gearbox. Is that the one you were thinking about when you said 6.33:1 gear box? Is it close enough? I still plan to use my 3s1p 1500 Kokams. What speed controller that is compatible with LiPo LVC would you recommend?
Here is where my beginner status really shows up. What prop adapter do I need to use the 12x8HD you recommended
I have found 12x8 Slow Flier props for a 3mm shaft. I have heard of but not found 12x8 direct drive props for 4mm shaft.
One of the reasons I'm doing this hop up is fun = one bad mule slow stick. The other reason is to carry a Aiptek Camera and an extra servo to push the button.
Thanks for your help,
Doug
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Old 01-21-2004, 10:45 PM
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Default RE: Slow Stick Battery ... Lipo

In my opinion, don't go near the expensive 6:1 VMGM planetary gearbox - I have one, but it has always sounded like an egg-beater in gravel! I made up one of David Fordham's ply gearboxes [www.cl-i-max.com] with GWS 400 shaft, spur (12T) and pinion (76T) to get my 6.33:1. [see my post in RC Groups - search for Mini AC (author Dr Kiwi)].

You should get a Phoenix 10P or Phoenix 25P ESC - bigger is usually better, since you can move it into bigger aircraft later!

You need a collet type adapter for 4mm shaft - something like the MP Jet MJ4073 - you'd need to drill out the 12x8HD prop hub (4mm bore) to 6mm to fit the adapter [APC SF props will fit straight on, using one of the spacer rings which come with them].

Cheers, Phil
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