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October 18, 2018, 17:22:33 PM

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Author Topic: I think this outrunner will do?  (Read 225 times)

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Offline cheddar-caveman

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I think this outrunner will do?
« on: October 11, 2018, 16:17:55 PM »
Good day folks.

My new project is a Piper Super Cub park flier, full spec below:
Wing Span: 60-inches
Length: 38.3-inches
Wing Area: 518 Sq. In.
Flying Weight: 24.4 oz.
Wing Loading: 6.77 Oz. / Sq. Ft.

They recommend a Suppo 2217 950 KV Outrunner w/ a 20A ESC, an APC 11-5.5E propeller, and a 2200 mah 2S LiPoly Battery

I already have a 2215 1100Kv motor that came from a dismantled Walrus electric glider which I'm pretty sure will do the trick rather than buy another. Not sure what size prop yet??

Would you agree with my thinking???
« Last Edit: October 11, 2018, 16:19:25 PM by cheddar-caveman »


Offline PDR

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Re: I think this outrunner will do?
« Reply #1 on: October 11, 2018, 16:30:26 PM »
Call me Mr Cynical if you wish, but I seriously doubt you could get anything but the most cartoon-scale of foamy cubs down to 1-1/2lbs for a 60" model. Which kit is it?

If you CAN get it down to that sort of weight then you're looking at ~200watts in a 1-1/2lb model, so it swould probably tow it up, although it will be a large and draggy model for the weight so you should err towards larger, slower-revving props (ie lower Kv rather than higher) to give it enough waft from the wind-shovel (stop me if I'm getting too technical).

PDR
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Offline cheddar-caveman

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Re: I think this outrunner will do?
« Reply #2 on: October 11, 2018, 16:36:05 PM »
Hi PDR, thanks for the reply. This is the build thread for the model - https://www.modelairplanenews.com/piper-pa-18-super-cub-construction-article/#comment-145009

As indicated in the build, I'll be using a 2S 2200 Lipo - not thee 3S 2200 I already have in plenty!

My son part owns/flies the military version of this plane so wanted to build one, and this is the only Super Piper Cub kit I've found. It looks great and with a bit of modification, no flaps and a few more windows it should look the biz!
« Last Edit: October 11, 2018, 16:41:13 PM by cheddar-caveman »


Offline PDR

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Re: I think this outrunner will do?
« Reply #3 on: October 11, 2018, 16:55:07 PM »
It's very lightly built, so if you can build that light I have to assume you could get down to that weight with a lot of care and attention and the result would be very much a "calm evenings only" flyer. Using a 2s battery rather than a 3s one will mean you can turn a larger prop, but you'll have 33% less power, and 130watts for a 1-1/2lb model is sounding very marginal to me.

YMMV,

PDR
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Offline cheddar-caveman

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Re: I think this outrunner will do?
« Reply #4 on: October 11, 2018, 17:14:00 PM »
The build technique is very much how I used to build the old rubber powered planes back in the 50's / 60's! Brings back memories!
Yes it will definitely be a light wind model but it's the looks I'm after rather than the flying!

I'll look at battery weights etc and see what's what but with the 2S, where should I start with a prop please, I have no idea.

Thanks


Offline cheddar-caveman

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Re: I think this outrunner will do?
« Reply #5 on: October 12, 2018, 12:25:25 PM »
Ha! Just found a Turnigy D2836/8 1100Kv which will definitely do the job me thinks!  :)

Battery: 2~4 Cell /7.4~14.8V
RPM: 1100kv
Max current: 18A
No load current: 1A
Max power: 302W
Internal resistance: 0.107 ohm
Weight: 70g (including connectors)
Diameter of shaft: 4mm
Dimensions: 28x36m
Prop size: 7.4V/11x7 14.85V/7x3
Max thrust: 1130g

Just run this up with on a 3S limo and an 11 X 6 prop on it and Im getting ila_rendered on my wattmeter. Motor did get a bit warm but rated at 302W!

I'll be using a 2S in the Piper but I think this should get it gently up into the air!
« Last Edit: October 12, 2018, 14:27:00 PM by cheddar-caveman »

Offline Bad Raven

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Re: I think this outrunner will do?
« Reply #6 on: Yesterday at 21:53:27 »
Just be aware that Suppo and some others usually use rotor dimensions, and Turnigy and others use exterior dimensions, so to the unwary can appear to be more powerful than they are.

My favourite motor (but not for your use) is the Suppo 2212-6, 2300kV, used on many most of my fast wings. Near 400 Watts for around a fiver and yet it lasts well!

Makes a Dr David Halko "Superfly" ballistic................   :ev
The user formerly know as Bravedan........... Well if Prince can do it....................


 

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