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Old Oct 04, 2008, 11:21 AM
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Canada, ON, Brantford
Joined Apr 2007
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Weight Comparison Balsa & Ply vs Fibreglass

Alright then, here we go concerning weights.
Before I get into it, I should begin with a few thoughts.

Concerning the fibreglass fuse.
This layup was only intended to validate the function of the mould and as such I wasn't overly concerned with weight.
I used 7Oz cloth rather than 6Oz - so that will likely save a couple of ounces.
I didn't vacuum bag it - so there will be a slight savings in an improvement of epoxy to cloth ratio there.
I put 5Oz of acrylic paint into the epoxy that wasn't necessary but I wanted some contrast so that I could verify the detail transfer from the mould.
I haven't installed ply for the motor mount, battery tray, or wing mounting blocks, but there's also extra material in the nose of the fibreglass shell yet to be removed in that nose.
All in all I expect these factors to amount to an additional reduction of around 7Oz's in the next layup schedule.

Concerning the plug.
There's alot more filler in the plug than I would've put on a flying model in order to achieve scale outline etc.
There's additional materials in the nose and wing saddle area to facilitate mould construction.

There are no control surfaces on either one at this point.
Alright then...

As it stands now
Plug weight - 49Oz or 3.1lbs
Fibreglass fuse weight - 32Oz or 2lbs even
net reduction - 35%

Considering projected weight reduction of 7Oz's in next layup
Plug weight - 49Oz
Fibreglass fuse weight - 25Oz or 1.56lbs or 1lb 9Oz (this is about what I would expect to see)
net reduction - 49% reduction

I still have a couple of tricks up my sleeve, but I think I'm track anyway.
Just out of curiosity does anybody out there have a fuselage in the works without control surfaces on it yet? I'd like to know what one would come in at without all the filler and extra material on it.
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