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Old Dec 27, 2011, 09:11 PM
Victim of C.D.O.
murdnunoc's Avatar
United States, TX, Lubbock
Joined Oct 2007
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Peter, how thick is that plastic sheet you have over the battery bay?

Does it have similar compression resistance to 2mm Coro?

From what I've seen, when a foam-and-skin structure fails it is usually due to the top surface crumpling.
This is more crucial in the battery bay area, which is an entirely monocoque structure (all load is born by the skin)

Coro does have very good crumple resistance and stiffness for its weight. I'm sure a plastic sheet would, also, if it were at least 1mm thick.

Just my initial thoughts.
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Old Dec 27, 2011, 11:18 PM
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Peter M's Avatar
Newcastle, New South Wales, Australia
Joined Sep 2007
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Murdo,
I agree! The PVC sheet I've used for the bay covers is only about 0.5mm thick and even though it is stiff and will be glassed and taped each flight, it still wouldn't transmit compression forces as good as corflue. Consequently I've just employed a "Beyond the Parkflyer" Stryker technique.

Thank you for speaking up, I appreciate it!

Regards
Peter
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Old Dec 27, 2011, 11:30 PM
never mind the boll⁣⁣⁣ocks
brosius85's Avatar
Australia, NSW
Joined Dec 2010
1,256 Posts


next thing you will have a balsa trailing edge and ply winglets lol

jk
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Old Dec 27, 2011, 11:32 PM
With great pwer comes great 3D
killsdeer4fun's Avatar
Globe, USA, Clemson, SC
Joined Jun 2010
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And boost tabs?
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Old Dec 28, 2011, 01:57 PM
Victim of C.D.O.
murdnunoc's Avatar
United States, TX, Lubbock
Joined Oct 2007
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What's a boost tab?
Do I need one??

I just load 'em up with bigger motors till they give up and go fast!
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Old Dec 28, 2011, 02:28 PM
With great pwer comes great 3D
killsdeer4fun's Avatar
Globe, USA, Clemson, SC
Joined Jun 2010
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Running joke over on Flying Giants.

Here is an explanation though

http://www.rcuniverse.com/forum/m_64.../tm.htm#642275

Its handy in full scale planes where you are the one supplying the work.
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Old Dec 28, 2011, 02:45 PM
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Peter M's Avatar
Newcastle, New South Wales, Australia
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Quote:
Originally Posted by brosius85 View Post


next thing you will have a balsa trailing edge and ply winglets lol

jk
You're not suggesting there is some sort of Darwinian evolution at play?????

PS: I'm sure CK will suggest its actually de-evolution!
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Old Dec 28, 2011, 02:48 PM
Victim of C.D.O.
murdnunoc's Avatar
United States, TX, Lubbock
Joined Oct 2007
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uh...

oh...

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Old Dec 28, 2011, 02:52 PM
Livin it UP when Im goin DOWN
Arcteryxxx's Avatar
Norway, Telemark, Skien
Joined Feb 2010
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Quote:
Originally Posted by Peter M View Post
You're not suggesting there is some sort of Darwinian evolution at play????!
Is this the kind of things the rc pilots in the Northern Territory do?
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Old Dec 28, 2011, 09:02 PM
never mind the boll⁣⁣⁣ocks
brosius85's Avatar
Australia, NSW
Joined Dec 2010
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noooooooooooooo!!! never!!!
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Old Dec 29, 2011, 10:14 PM
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Peter M's Avatar
Newcastle, New South Wales, Australia
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I'm starting think about Gulf Ford GT40 colour schemes.......
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Old Dec 29, 2011, 10:26 PM
Victim of C.D.O.
murdnunoc's Avatar
United States, TX, Lubbock
Joined Oct 2007
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Peter you've done a wonderful job in your layout to get everything farther forward than I've seen it on a Demon with such high power. Bet you won't need nose lead!

Did you use the front spar hole? This has been the limiting factor for how far forward I can get everything, but I've used the rear spar hole in my Demon builds. If you've squeezed everything in and still left the rear hole empty, that'll allow you to run a massive motor without being tail heavy!
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Old Dec 29, 2011, 11:01 PM
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Peter M's Avatar
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Murdo,
Let's hope I haven't gone overboard and it ends up nose heavy!

I've used the front spar hole and have a longer custom made motor plate sitting on top of the spar. This will give me about a 4 to 5mm higher thrustline than standard and the possibility of better motor cooling ala Stryker.

I think it would be possible to leave out the centrally located spar altogether and rely on more geometrically effective surface sparring, but that's for someone else to try like you!

You've probably also noticed that I have the esc "back to front" for the purpose of giving me more space to make connections. Still going to be on the tight side though but should be workable.
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Old Dec 30, 2011, 03:48 AM
Why the dirt on the wings?
moparmyway's Avatar
New York
Joined Jan 2009
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Quote:
Originally Posted by Peter M View Post
Murdo,
Let's hope I haven't gone overboard and it ends up nose heavy!
If you did go overboard, I do have, and MEGA will build a heavier 36mm motor for ya !!

They make 22-80-xx motors that weigh well over 1 pound

That ought to help ya if its nose heavy !!
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Old Dec 30, 2011, 04:09 PM
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Peter M's Avatar
Newcastle, New South Wales, Australia
Joined Sep 2007
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Actually Mopar,
I've just mocked it up to check the CG and a 22-30 or 35 might just be viable.

Let me get it finished so I can see where that pesky CG is actually at before we get too carried away with easily attainable 220 mph pitch speeds. Maybe I am ready for my 3rd Demon build sooner than I thought .......
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Last edited by Peter M; Dec 30, 2011 at 04:16 PM.
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