Glow to Electric Conversions Discuss glow/gas conversion to electric here.

Herr Aqua Star seaplane

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Old 12-27-2004, 09:43 PM
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Wazmo
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Default Herr Aqua Star seaplane

I'm considering converting a Herr Aqua Star seaplane to electric. Wingspan is 40 inches, weight is about 19 ounces. I've been told that a Norvel .061 is a good match, but the manufacturer's claim of 0.31 HP (231 watts) seems outrageous for an airframe of this size. I'd like to go with a direct drive outrunner. Any suggestions for target power or specific motor? I'm thinking somewhere around 80 to 100 watts.
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Old 12-28-2004, 11:05 AM
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Matt Kirsch
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Default RE: Herr Aqua Star seaplane

You are wise beyond your post count, my son

Yes, the horsepower claims made by engine manufacturers are usually unrealistic. They're either made using a impractically small propeller, or they're extrapolated (i.e. my engine makes .5 HP at 10000 RPM, therefore it makes 1 HP at 20000 RPM). The horsepower produced by glow engines is also applied to the air VERY inefficiently; instead of slicing through the air, the engine is "Cuisinarting" the air into submission, and getting some thrust back as a side effect...

Take a look at the AXi 2212 series at www.modelmotors.cz.
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Old 12-28-2004, 11:07 PM
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Default RE: Herr Aqua Star seaplane

The airframe (pylon engine) limits prop diameter to 6 inches. I'm having trouble getting more than about 50 watts. The AXI 2212/20 puts out about 45 watts with an APC 6x4, according to MotoCalc. The best I've found so far is a Mega 16-7-12 with the 6x4, at about 55 watts. It's adequate, but I'd like a little more go for short water takeoffs.
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Old 12-29-2004, 06:36 AM
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Henke Torphammar
 
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Default RE: Herr Aqua Star seaplane

make the pylon higher... a 22/12/20 is high reving, pretty much ony useful for this small prop stuff or a heli, so it won´t be good for a parkflyer later on. I would rather pop in a Hacker B20 or so, that you can put on a gearbox later on... much more versitile.

but rise the pylon to take a 7x5-8x6" prop and use a 22/12/26 on 3s 1200 li-po. and throttle up slowly on water so that you won´t flip over
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Old 12-29-2004, 12:42 PM
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Default RE: Herr Aqua Star seaplane

I found that a Hacker B20 26L should give me the power I want with a 6x3 or 6x4 prop. I'll have to bump up the speed controller because it draws a little over 11 amps at full throttle.
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Old 12-29-2004, 01:24 PM
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Default RE: Herr Aqua Star seaplane

Since you're going for "spin the same wood faster" rather than "spin more wood," you've got two choices:

1. "Hotter" motor.
2. Upping the cell count.

Looks like you're opting for #1. If you're maxxed out on cells, then #2 isn't an option anyway.
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Old 12-29-2004, 02:59 PM
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Default RE: Herr Aqua Star seaplane

The Ăśberall Nippy Black 1208/180 brings the current draw under 10 amps (so I can use a CC Phoenix 10) with just a few watts less power, and it appears easier to purchase (and much less expensive) than the Hacker B20 26L. Also pitch speed is closer to predicted flight speeds.

I'm using 3S LiPo, and I'd like to avoid going to 4S as that makes things more complicated. Plus, I can use my existing 3S packs.
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Old 12-29-2004, 03:54 PM
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Default RE: Herr Aqua Star seaplane

the B20 26L is pretty much useless too exept for this :-/ 15 or 18L goes either in a heli, geard for a 20oz 3D plane or direct drive with a 5x5 prop or 6x3.... but at 20 amps not 10...

so I would get some 3s 2100cells and a Jeti advance 18A ESC or maybe CC25.

if you have to limit the power to very little you could as well use a speed 300 7.2v in that case... no need to get a brushless with such a narrow range specially with that low power.

but why not just make the pylon half an inch higher?
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Old 12-29-2004, 06:14 PM
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Default RE: Herr Aqua Star seaplane

Any comments about the possibility of the LiPo battery shorting as a result of water leaking into the hull and causing a fire?
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Old 12-29-2004, 06:59 PM
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Default RE: Herr Aqua Star seaplane

Battery will be fine, though the rx and ESC needs to be well water proofed... / se that no water leaks in + silicone the esc + rx
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Old 01-20-2005, 09:39 AM
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Default RE: Herr Aqua Star seaplane

Don't forget the good old 6v Speed 400 ! Mine has been flying very successfully for 6 yrs with a 6x4 prop and 8 Nimh's . Keep it simple , keep it light and you'll have a nice airplane !

Marc
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Old 01-20-2005, 11:32 AM
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Default RE: Herr Aqua Star seaplane

True, but I should get 20 to 30 minutes flight time with the Nippy/LiPo setup, while the Speed 400/NiMH would probably not get half that.
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Old 01-20-2005, 12:06 PM
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Default RE: Herr Aqua Star seaplane

Not true ! I regularly get 20 minute flights with GP 1100 Nimh's . Don't get me wrong , I love lipo's and outrunners but you're spending a lot more money on something that doesn't need it . There are applications where you NEED Lipo's and brushless motors to get the expected performance. In fact I just got off the phone ordering a Plettenberg Xtra 25-14 for my 78" Funtana Pro.

Marc
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Old 01-22-2005, 08:47 PM
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Default RE: Herr Aqua Star seaplane

I have a couple of Aqua Stars that I want to covert as you did. Do you have any drawings of the expanded power pod? Did you place the batteries in the powerpod or put them down below in the cabin? With a lithium battery up in the power pod would that have a bad impact on the CG for rolls etc.?
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Old 01-25-2005, 08:18 PM
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Default RE: Herr Aqua Star seaplane

Hi,

The power pod is not expanded . It may just look that way because the motor is cowled. I have the battery in the cabin . IMO the pod is not big enough.

Marc
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Old 01-26-2005, 10:50 AM
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Default RE: Herr Aqua Star seaplane

Thanks for the info. Will let you know how I make out
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