Re: Calbie Wood Metal Wings
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Thanks Charlie.? That¡¯s ?well-documented quantitative information.? Useful, ¡°good to know¡± stuff folks can work with.? ?
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From: [email protected] <[email protected]> On Behalf Of RV7 builder via groups.io
Sent: Thursday, January 23, 2025 7:58 PM
To: [email protected]
Subject: Re: [TailwindForum] Calbie Wood Metal Wings? Just in case anyone's interested in an apples to oranges to pomegranates comparison, below are my numbers from when I painted my RV7 wings. I failed to weigh the ailerons, flaps and wingtips prior to paint, but there should be minimal weight gain since the entire wing only gained less than 3 lbs. This wing is obviously cantilever, and is rated for 1800 lbs gross in Utility Category (1600 lbs in 6G acro category). Not intended to be a better/worse kind of post; I just always find it interesting to compare design techniques/choices for various missions. I'd love to see numbers for a 'strutted' wood wing rated at the same GW/category/stall speed. Weighed a painted vs unpainted wing ~115" long by ~100" circumference (~79.9 sq feet): unpainted, with only the large pushrod installed and no flaps or aileron:
73.6 pounds Fully painted wing; same conditions:
76.53 lbs So... 46.88 oz over 73.6 sq ft = .6739 oz per sq ft for primer & paint.
Primer was single coat (Summit recommends 1-2 medium wet coats).
Finish was two relatively thin coats (Summit recommends 2-3 medium wet coats)? Wingtips, flaps, & ailerons will add 20-25 sq feet of paint. tip: ~6.5 lbs painted
flap ~5.8 lbs painted
Aileron: ~9.5 lbs painted
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