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Old Jan 20, 2003, 12:38 PM
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manahawkin, NJ
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mega,jeti,axi to power 118 inch sailplane

I recieved a 118 inch bird of time that I want to convert to e-power and I seem to be banging my head against the wall..

I would prefer direct drive and am leaning towards a mega 30/3 on ten cells swinging a 10x6 folder, or on eight cells swinging a 11x8 folder. I do not want nor need a skyrocket..but do hope to get to thermal hight in reasonable time.

The new AXI 282010 could also do the job with the same battery prop combo's.

Thats my delema..... What should work better in this application?? If the AXI's are durable and as easy as the mega/jeti's to use..it seems a tossup.

Any and all suggestions welcome..

Jarvis
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Old Jan 20, 2003, 01:36 PM
luc
I plant balsa sticks too
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France
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another possibility: the ultra 930/8 for a workhorse brushed.
with 8 cells, it swings an 11*6 at 7500 t/mn for my thermik star 3.
You can see pics and comments (with translator) on my site.
Brushless would be a bit more efficient and more expensive, specifically the controller.
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Old Jan 20, 2003, 04:40 PM
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Czech Republic, Plzeň Region, Město Touškov
Joined Feb 2002
535 Posts
AXi 2820/10, 10cells, 11x6 folder. It will get you to a height quick.
The 930/x is a nice motor, but by the time you buy that and a controller, you may as well spend a few extra bucks and go brushless.
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Old Jan 24, 2003, 05:17 PM
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Sandston Va USA
Joined Mar 2001
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I used a GR1717 speed 600 2.8 gearbox 12x8 folder prop and 10 1700 nicads on mine and it would pull the Bird of Time up pretty fast. Very nice flying plane while it lasted...
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Old Jan 24, 2003, 07:39 PM
RIP Ric
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Marietta, GA
Joined Jun 1999
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11 and 12" props are really small to yank a 118" sailplane up to altitude! In my opinion, you should resign yourself to a geared setup swinging a MUCH bigger prop - the 18/10 would work well, I'd think. Unless there's a motor that will swing that direct-drive..
..a
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Old Jan 25, 2003, 07:20 PM
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manahawkin, NJ
Joined Jan 2000
322 Posts
Andy..I was at the field a few months ago and was admiring a AT-10 large scale model powered by a 4 stroke 120 OS swinging a prop only a few inches larger than the cowling. I don't think it was 3 inches past the cowl.. I remarked about the little prop area beyong the cowl and was advised that the prop is a screw.. making its way foward.. I watched as the pilot took off smartly and proceded to do all sorts of stuff with that model.. Super power..no problem at all..

It really got me thinking... I decided to use the now technology available and bought a megs 45/3e and a 4*40 on 16 2400 nicads swinging an APC 10.5*6.. My o my..

Now that I have this 118 inch Bird-Of-Time I do want to e-power it and from what I have read on this and other sites it is an easy task.

I just cannot seem to decide on a mega 30/3 or AXI 2028/10 on 8 to 10 cells.. they both should do the job admitably..BUT whitch one to purchace has me in a bind. I am trying to to look beyond this model for future applications ..Versatility is a wonderful thing.

Another 45/3e would do the job with 10 to 12 cells..but...

I had hoped someone could shead some light here..others Must have e-powered large sailplanes.. I prefer not to reinvent the wheel ..oh well..

Jarvis
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Last edited by ahab; Jan 25, 2003 at 07:24 PM.
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Old Jan 26, 2003, 05:38 AM
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East Anglia, UK
Joined Sep 2002
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IF you want to go direct drive I don't think there is much to choose from between the AXI and an equivalent mega. I haven't tried either, but I have been following all threads talking about them.

However, for staggering climbrates on sailplanes, a geared large prop combination is the only way to go. And that means a mega, since the axi's are harder to fit to boxes.

Theres a chap at the club with a geared Kontronic setup, and that thing just hauls itself up at 50 degrees, and a 20 second burst seems to get him 500 ft or more.

A hot motor plus a deep ratio gearbox and a BIG prop - well, its unbeatable.
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Old Jan 26, 2003, 10:30 AM
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Bristol, England
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Vintage,

Dar I say that the Model Motors box fits straight on the front of the AXI 2814s and 2820s, but having seen the video of how the 2820/12 on 10 cells turning a 12x8 hauls around Phil Ramsey's Gladiator, there would appear to be little point in bothering with the box.

I have seen a way under propped AXI 2820/10 (11x6 on 8 cells) haul the 2.7m Elegant up convincingly, and correctly propped, it is really going to do things with the Bird of Time.
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Old Jan 26, 2003, 12:25 PM
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Hastings, Hawkes Bay, New Zealand (Aotearoa)
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Ever thought of a Mega 30/4 ? It would turn a 13 x 7 prop on 10 cells for ~ 40A or a bit less. Using CP1700's or 1950 FAUP's would keep the weight down.

My parnter has used this motor in a hotliner running a 12x8 on 12 cells and a sport plane running a 13 x 8 on 10 cells very successfully.


Heather
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Old Jan 27, 2003, 07:49 PM
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manahawkin, NJ
Joined Jan 2000
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Heather..

I have considered the 30/4..and I feel it does nothing the 45/3e can't do, but.........

On ten cells the 45/3e can swing a 13*7 on less amps. I was trying to get a versatile motor other than one I have. The weight difference can be a plus when the breases pick up.. will need no extra balast .

I will re-do the calcs on the 30/4, 30/3, AXI 2820/10 and 2820/12,
one of them should me my-t-fine for this application.

One and all. Thanks for the input...

Jarvis
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Old Jan 28, 2003, 05:28 AM
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East Anglia, UK
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Quote:
Originally posted by John E
Vintage,

Dare I say that the Model Motors box fits straight on the front of the AXI 2814s and 2820s, but having seen the video of how the 2820/12 on 10 cells turning a 12x8 hauls around Phil Ramsey's Gladiator, there would appear to be little point in bothering with the box.

I have seen a way under propped AXI 2820/10 (11x6 on 8 cells) haul the 2.7m Elegant up convincingly, and correctly propped, it is really going to do things with the Bird of Time.
That is interesting John. I wasn't aware of a box for the AXI's.

I wonder if a belt drive would fit. Its a shame to take a quiet motor and slap a whining box on the front
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Old Jan 28, 2003, 05:38 AM
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Bristol, England
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Vintage,

I think most people would agree that the Model Motors box makes hardly any noise at all, but we also stock the Graupner 2.5:1 belt drive that also fits 600 fitting motors with 5mm shaft.
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