Great, this gives me something a bit more concrete to go on, a step above
the "TLAR" criteria.
Another side-question on this project: assume a two-piece, 2-meter wing, 550
in^2 area, "type 2" spar, what size wingrod would be needed to match the
spar strength? For a respectable 50 pound winch load and a full-pedal 150
pound winch load?
Again, thanks for your input.
--Bill
>From: Mark Drela <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Subject: Re: [RCSE] Practical application...
>Date: Sun, 08 Jul 2001 23:13:06 -0400
>
> >Two approaches:
> >1. Strengthen the existing [spruce] spar.
> >2. Make a Balsa-Core Carbon spar
> >Question is, how much lighter?
>
>
>Here are some numbers I did some time ago:
>
>The Allegro-Lite spar (#2 type) is stressed for a 150 lb winch load.
>Excluding the joiners, it weighs 3 oz.
>
>An equivalent spruce spar would be a 0.6" x 5" solid cross section
>in the wing center (basically a floor plank). With optimal taper
>towards the tips it would still weigh about 24 oz.
>
>A #1 type spar would be somewhere in between, depending on
>the spruce/carbon mix.
>
>Obviously #2 type is by far the lightest solution. A 2M spar
>which takes a still-respectable 50 lb winch load can weigh only 1 oz!
>
>- Mark
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